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Dose response to cinnamaldehyde supplementation in growing beef heifers: Ruminal and intestinal digestion

Dose response to cinnamaldehyde supplementation in growing beef heifers: Ruminal and intestinal... ABSTRACT The objective of this study was to determine if cinnamaldehyde (CIN) could be used to improve feed intake, digestion, and immune status in growing beef heifers fed high-concentrate diets. The experiment was designed as a 4 × 4 Latin square using 4 ruminally and duodenally cannulated beef heifers with 4 treatments: control (no CIN added), 400 mg/d of CIN (low), 800 mg/d of CIN (medium), and 1,600 mg/d of CIN (high), and four 21-d periods. Feed intake, rumen pH and fermentation characteristics, site and extent of digestion, microbial N synthesis, blood metabolites, and acute phase protein response were measured. The diets consisted of 15% barley silage, 80% dry-rolled barley grain, and 5% supplement (DM basis). Intakes (kg/d) of DM, OM, NDF, starch, and N were quadratically (P = 0.04) changed with increasing CIN supplementation. The amount of OM fermented in the rumen quadratically (P = 0.02) decreased with increasing CIN. Digestibilities (% of intake) of OM, NDF, and N in the rumen were not affected by supplementing with low and medium CIN, but they were reduced by 8% (P = 0.10), 31% (P = 0.05), and 17% (P = 0.05), respectively, with high CIN. Similarly, digestibilities of OM and NDF in the total tract also tended to be reduced by 7% (P = 0.10) and 20% (P = 0.10), respectively, with high CIN because supplementation of CIN had minimal effects on intestinal digestibility. Flows (g/d) of microbial N and other nutrients to the duodenum were not affected by CIN supplementation, even though the amount of ruminal fermented OM varied with level of CIN supplementation. Rumen pH, total VFA concentration, and molar proportions of individual VFA were not affected by CIN. Although concentrations of NEFA (P = 0.06) and triglyceride (P = 0.01) were quadratically changed with increasing CIN supplementation, blood concentrations of glucose and urea N, white blood cell counts, serum amyloid A, and lipopolysaccharide in plasma were not affected by CIN. Plasma haptoglobin numerically (P = 0.11) decreased with the medium dose of CIN fed compared with control. The results indicate that supplementation of a high-concentrate diet with a low dose of CIN resulted in small increases in nutrient availability in the rumen due to increased feed intake and greater ruminal digestion of OM. However, feed intake and ruminal digestion of feeds were adversely affected when a high dose of CIN was used. INTRODUCTION Animal scientists are actively seeking alternatives to antibiotic additives and growth promotants because the use of these compounds has become increasingly controversial (Parveen et al., 2006). Plant extracts, such as essential oils (EO), are being promoted as natural feed additives (i.e., antimicrobials) for use in ruminant nutrition. Studies have shown that some EO can favorably alter rumen metabolism (McIntosh et al., 2003; Fraser et al., 2007) and that they possess immuno-stimulating properties (Standen and Myers, 2004). One potential EO of interest is cinnamon oil (Cinnamomum cassia). Cinnamaldehyde (CIN), a phenylpropanoid with antimicrobial activity, is the main active component of cinnamon (C. cassia) oil, accounting for up to 75% of its composition (Calsamiglia et al., 2007). Results from studies conducted in vitro (Cardozo et al., 2005; Busquet et al., 2006) and in vivo (Cardozo et al., 2006; Benchaar et al., 2008; Chaves et al., 2008) to evaluate the effects of cinnamon oil and CIN have been somewhat conflicting, and further research is needed to understand effects on digestion and metabolism in cattle. We reported that dietary supplementation with CIN increased DMI of feedlot cattle in the early weeks of the finishing period, presumably because the cattle were stressed (Yang et al., 2010). It appears from the studies to date that cinnamon oil and CIN can potentially improve ruminal fermentation and digestion, but in beef production systems, the effects may be more relevant when feeding conditions favor low ruminal pH. The objectives of this study were to determine if CIN could be used to improve feed intake, digestion, and immune status in growing beef cattle fed high-concentrate diets. We hypothesized that the dose of CIN would affect the response. To test our hypothesis we fed increasing dose rates of CIN and measured effects on feed intake, ruminal pH, and fermentation, microbial protein synthesis, site and extent of digestion, blood metabolites, and acute phase protein response. MATERIALS AND METHODS The study received approval of the institutional Animal Care Committee of the Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, and was conducted in accordance with the guidelines of the Canadian Council on Animal Care (1993). Experimental Design and Treatments The experiment was designed as a 4 × 4 Latin square balanced for carryover effects using 4 ruminally and duodenally cannulated beef heifers with four 21-d periods. The beef heifers (538 ± 19.5 kg of initial BW; ovariectomized) were randomly assigned to 1 of 4 treatments: 1) control (no CIN added), 2) 400 mg∙heifer−1∙d−1 CIN (low), 3) 800 mg∙heifer−1∙d−1 CIN (medium), and 4) 1,600 mg∙heifer−1∙d−1 CIN (high). Cinnamaldehyde (purity >99%) was provided by Phodé S.A. (Albi, France). Each experimental period lasted 21 d with 14 d of adaptation to experimental treatments and 7 d of sampling and data collection. Diet and Animal Management The diets used consisted of 15% barley silage, 80% dry-rolled barley grain, and 5% supplement (DM basis). The supplement contained a protein source, minerals, and vitamins in excess of the National Research Council (NRC, 1996) nutrient requirements for beef cattle gaining 1.5 kg/d. Diet composition is given in Table 1. The ration was prepared daily using a feed mixer (Data Ranger, American Calan Inc., Northwood, NH). Heifers were adapted to experimental diets by gradually increasing the proportion of concentrate over a period of 2 wk before starting the experiment. Once the animals were on full feed, the experimental diets were offered twice (0830 and 1800 h) daily for ad libitum consumption (10% refusals) with one-half of the daily feed allotment offered at each feeding. The CIN was mixed with rolled barley grain and top dressed onto the ration at each feeding. Quantities of feed offered and refused were recorded daily for each animal for the entire experiment, and samples of the diet and refusals were retained weekly for determination of DM content. Samples of the barley silage and barley grain were also collected weekly and combined for each period. Feeds and refusals were analyzed for analytical DM, OM, N, starch, NDF, ADF, and Yb (digesta flow marker). Table 1. Ingredients and chemical composition of the diet Item  Amount  Ingredient,1 % of DM     Barley silage2  15.0   Barley grain, dry-rolled  80.1   Canola oil  0.14   Canola meal  1.71   Calcium carbonate  1.51   Dicalcium phosphate  0.42   Molasses  0.33   Salt  0.32   Dynamate3  0.38   Beef feedlot premix4  0.05   Vitamin E (500,000 IU/kg)  0.0011   MGA 100 premix (220 mg/kg)  0.024   Flavoring agent5  0.021  Analyzed composition6      DM, %  70.0 ± 2.1   OM, % of DM  92.0 ± 0.5   NDF, % of DM  25.7 ± 2.3   Starch, % of DM  40.6 ± 1.8   CP, % of DM  13.2 ± 0.9   Ca, % of DM  0.62   P, % of DM  0.39  Item  Amount  Ingredient,1 % of DM     Barley silage2  15.0   Barley grain, dry-rolled  80.1   Canola oil  0.14   Canola meal  1.71   Calcium carbonate  1.51   Dicalcium phosphate  0.42   Molasses  0.33   Salt  0.32   Dynamate3  0.38   Beef feedlot premix4  0.05   Vitamin E (500,000 IU/kg)  0.0011   MGA 100 premix (220 mg/kg)  0.024   Flavoring agent5  0.021  Analyzed composition6      DM, %  70.0 ± 2.1   OM, % of DM  92.0 ± 0.5   NDF, % of DM  25.7 ± 2.3   Starch, % of DM  40.6 ± 1.8   CP, % of DM  13.2 ± 0.9   Ca, % of DM  0.62   P, % of DM  0.39  1All ingredients except for rolled grains and forages were provided as part of a mash supplement. 2Composition was 43.0% DM, 11.9% CP, 47.2% NDF, and 32.3% ADF based on 4 samples composited by period. 3Pitman Moore Inc., Mundelein, IL; 18% K, 11% Mg, 22% S, 1,000 mg of Fe/kg. 4Supplied per kilogram of dietary DM: 15 mg of Cu, 65 mg of Zn, 28 mg of Mn, 0.7 mg of I, 0.2 mg of Co, 0.3 mg of Se, 6,000 IU of vitamin A, 600 IU of vitamin D, and 47 IU of vitamin E. 5Anise 420 Power, Canadian Biosystems Inc., Calgary, Alberta, Canada. 6Mean ± SD; n = 4, except for Ca and P, which were for 1 pooled sample. View Large Table 1. Ingredients and chemical composition of the diet Item  Amount  Ingredient,1 % of DM     Barley silage2  15.0   Barley grain, dry-rolled  80.1   Canola oil  0.14   Canola meal  1.71   Calcium carbonate  1.51   Dicalcium phosphate  0.42   Molasses  0.33   Salt  0.32   Dynamate3  0.38   Beef feedlot premix4  0.05   Vitamin E (500,000 IU/kg)  0.0011   MGA 100 premix (220 mg/kg)  0.024   Flavoring agent5  0.021  Analyzed composition6      DM, %  70.0 ± 2.1   OM, % of DM  92.0 ± 0.5   NDF, % of DM  25.7 ± 2.3   Starch, % of DM  40.6 ± 1.8   CP, % of DM  13.2 ± 0.9   Ca, % of DM  0.62   P, % of DM  0.39  Item  Amount  Ingredient,1 % of DM     Barley silage2  15.0   Barley grain, dry-rolled  80.1   Canola oil  0.14   Canola meal  1.71   Calcium carbonate  1.51   Dicalcium phosphate  0.42   Molasses  0.33   Salt  0.32   Dynamate3  0.38   Beef feedlot premix4  0.05   Vitamin E (500,000 IU/kg)  0.0011   MGA 100 premix (220 mg/kg)  0.024   Flavoring agent5  0.021  Analyzed composition6      DM, %  70.0 ± 2.1   OM, % of DM  92.0 ± 0.5   NDF, % of DM  25.7 ± 2.3   Starch, % of DM  40.6 ± 1.8   CP, % of DM  13.2 ± 0.9   Ca, % of DM  0.62   P, % of DM  0.39  1All ingredients except for rolled grains and forages were provided as part of a mash supplement. 2Composition was 43.0% DM, 11.9% CP, 47.2% NDF, and 32.3% ADF based on 4 samples composited by period. 3Pitman Moore Inc., Mundelein, IL; 18% K, 11% Mg, 22% S, 1,000 mg of Fe/kg. 4Supplied per kilogram of dietary DM: 15 mg of Cu, 65 mg of Zn, 28 mg of Mn, 0.7 mg of I, 0.2 mg of Co, 0.3 mg of Se, 6,000 IU of vitamin A, 600 IU of vitamin D, and 47 IU of vitamin E. 5Anise 420 Power, Canadian Biosystems Inc., Calgary, Alberta, Canada. 6Mean ± SD; n = 4, except for Ca and P, which were for 1 pooled sample. View Large Animals were housed in individual tie-stalls on mattresses bedded with wood shavings in the metabolism facility. Water was available freely throughout the experiment. The heifers were released to an outdoor pen for 1 h of exercise daily as the measurement and sampling schedule permitted. Body weight was measured at the beginning of period 1 and at the end of each period at the same time of each weighing (1400 h). Ruminal Fermentation Measurements Ruminal fluid (0.5 L) was collected on d 15 at 1, 3, 5, and 8 h after the morning feeding from multiple sites within the rumen via the rumen cannulas. Samples were immediately squeezed through a 355-µm polyester fabric (PECAP, Sefar Canada, Ville St. Laurent, Quebec, Canada) to obtain the filtrate, and the pH was measured immediately using a pH meter (Accumet model 25, Denver Instrument Company, Arvada, CO). A volume of 5 mL of the filtrate was mixed with 1 mL of 25% HPO3 (wt/vol) or with 1 mL of 1% sulfuric acid for VFA or NH3 analyses, respectively. All samples were stored frozen at −20°C until analysis. Duodenal Flow, Apparent Digestion, and Ruminal Microbial Protein Synthesis Duodenal flows, digestion at sites within the gastrointestinal tract, and apparent total tract digestibility of nutrients were determined using YbCl3 (GFS Chemicals Inc., Powell, OH) as a digesta marker. Ammonia 15N ([15NH4]2SO4, 10.6% atom % 15N; Isotec, Sigma-Aldrich Family, St. Louis, MO) was used as a ruminal microbial marker. The digesta marker (5.5 g of YbCl3∙6H2O, 1.2 g of Yb) and microbial marker (3 g of [15N](NH4)2SO4) were mixed with rolled barley together with CIN and were top-dressed onto the ration of each animal daily starting on d 9 of the period. Daily true consumption of Yb was determined by analysis of Yb in the refusals. During the last 4 d of each period, ruminal samples (~750 g/sample) were collected daily from 4 locations within the rumen, composited, and used to isolate ruminal bacteria. Duodenal samples were collected every 6 h moving ahead 2 h each day for the last 3 d of the period. This schedule provided 12 representative samples of duodenal contents taken at 2-h intervals. Duodenal samples were subdivided using an electric drill fitted with a shaft and propeller (Yang et al., 2007). Each sample was split into 3 fractions that were pooled by heifer within period and retained for chemical analyses as is or after freeze-drying. The sample for cell-free 15N analysis was centrifuged at 27,000 × g for 30 min at 4°C, and the supernatant was stored at −20°C for 15N determination. Fecal samples (~150 g of wet weight) were collected from each heifer from the rectum twice daily (a.m. and p.m.) with the collection time being moved ahead at 2-h intervals over the last 6 d of the sampling period. Fecal samples were immediately subsampled (approximately 50 g), composited across sampling times for each heifer and each period, dried at 55°C for 48 h, ground to pass a 1-mm sieve (standard model 4, Arthur Thomas Co., Philadelphia, PA), and stored for chemical analyses. Before adding the markers, a ruminal and a duodenal sample were taken from each heifer during the first period to determine background concentration of the markers in samples. The ruminal contents were squeezed through polyester monofilament fabric (355-µm mesh opening, PECAP, Sefar Canada) to obtain the filtrate and particles. The filtrate (1 mL) was transferred to a vial containing 5 mL of methyl green-formalin-saline solution for protozoal enumeration. The number of protozoa × 105 per milliliter was counted on a microscope at a magnification of 100 × in a 0.2-mL counting chamber after serial dilution. From each sample, duplicate measurements were conducted and the average was used to determine the number of protozoa present in the initial sample. The particles obtained by squeezing were blended by adding an equal amount of 0.9% NaCl in a Waring blender (Waring Products Division, New Hartford, CT) for 1 min to dislodge particulate-associated bacteria and then squeezed through the polyester fabric. Both filtrates from squeezed and strained homogenate were mixed and centrifuged (800 × g for 15 min at 4°C) to remove protozoa and feed particles, and the supernatant was centrifuged (27,000 × g for 30 min at 4°C) to obtain a mixed ruminal bacteria pellet. Bacterial pellets were accumulated by period and by heifer, freeze-dried, ground using a ball mill, and analyzed for OM, 15N, and total-N. These samples were used as a reference to calculate ruminal microbial protein synthesis. Blood Sampling and Laboratory Analyses Blood samples were obtained from each heifer on d 17 and 21 of each period. At 2 h after morning feeding, blood samples were collected from a jugular vein into two 10-mL vacuum tubes containing Na heparin and one 10-mL vacuum tube without additive (Vacutainer, Becton Dickinson, Franklin Lakes, NJ). Samples were centrifuged (5,000 × g for 20 min at 4°C) within 20 min, and collected plasma and serum were frozen at –20°C until analyzed. A subsample (1 mL) of the plasma was centrifuged at 16,000 × g for 2 min at 4°C (Spectrafuge 16M, National Labnet Co., Woodbridge, NJ) to remove fibrinogen, and the supernatant was used to analyze glucose (slide No. 8130536) and urea N using a dry chemistry analyzer (VetTest analyzer, model 8008, IDEXX Lab, Westbrook, ME). Concentrations of serum NEFA were determined using a commercially available enzymatic colorimetric procedure [NEFA-HR (2); Wako Chemicals, USA Inc., Richmond, VA]. Concentration of plasma triglyceride was determined using a commercially available test kit (#339, Sigma Diagnostics, St. Louis, MO). Concentrations of serum amyloid A (SAA), haptoglobin in the plasma, and lipopolysaccharide binding protein (LBP) in plasma were determined as outlined by Ametaj et al. (2005). The determination of total and differential white blood cells was described in our previous study (Yang et al., 2007). Chemical Analysis All chemical analyses were performed on each sample in duplicate, and where the CV for the replicate analysis was >5%, the analysis was repeated. Analytical DM content of the samples was determined by drying at 135°C for 2 h (AOAC, 1990; method 930.15). Ash content was determined by combustion at 550°C overnight, and OM content was calculated as 100 minus the percentage of ash (AOAC, 1990; method 942.05). The NDF and ADF contents were determined using the methods described by Van Soest et al. (1991) with α-amylase and sodium sulfite used in the NDF procedure. Ruminal VFA were separated and quantified by GLC (Varian 3700, Varian Specialties Ltd., Brockville, Ontario, Canada) using a 15-m (0.53-mm i.d.) fused silica column (DB-FFAP column, J and W Scientific, Folsom, CA), and crotonic acid (trans-2-butenoic acid) was used as the internal standard. Ammonia-N concentration was determined according to the technique of Weatherburn (1967) modified to use a plate reader. Concentrations of Yb in the feed offered, refusals, and duodenal and fecal samples were determined using inductively coupled plasma optical emission spectroscopy according to the AOAC method (AOAC, 1990) modified such that no CaCl2 for Yb determination was used during sample digestion. For the measurement of starch and CP (N × 6.25), samples were ground using a ball mill (Mixer Mill MM2000, Retsch, Haan, Germany) to a fine powder. Starch was determined by enzymatic hydrolysis of α-linked glucose polymers as described by Rode et al. (1999). Total N was determined by flash combustion technique (model 1500, Carlo Erba Instruments, Milan, Italy). The enrichment of 15N in the rumen bacterial and duodenal samples was analyzed by continuous flow measurement of 15N using a combustion analyzer interfaced with a stable isotope ratio mass spectrometer (VG Isotech, Middlewich, UK). Calculations and Statistical Analysis Flows of DM to the duodenum and DM excreted in feces were calculated by dividing Yb actually consumed (daily amount input, grams of Yb per day) by Yb concentration (grams of Yb per kilogram of DM) in the duodenal digesta or feces, respectively. Flows of other nutrients to the duodenum or feces were calculated by multiplying DM flow by their concentration in duodenal or fecal DM. Ruminal microbial protein synthesis for each heifer was estimated by the ratio of 15N flow at the duodenum to 15N concentration of mixed ruminal bacteria. Data were analyzed using the mixed model procedure (SAS Institute Inc., Cary, NC) to account for effects of period, animal, and treatment, where treatments were considered as a fixed effect, whereas period and animal were considered as random effects. The carryover effect was initially included in the model but was removed because it was not significant. Similarly, data for ruminal pH, VFA, NH3-N, and protozoa were analyzed by sampling time using repeated measures techniques. Effect of sampling day (d 17 or 21) and the interaction between treatment and sampling day were included in the model as fixed effects when variables related to blood metabolites and plasma acute phase protein were analyzed. The estimation method was the REML, and the degrees of freedom method was Kenward-Rogers (SAS Institute Inc.). Linear and quadratic orthogonal contrasts were tested using the CONTRAST statement of SAS. Differences between treatments were declared significant at P < 0.05, and means were compared using the Tukey correction for multiple comparisons. Trends were discussed at 0.05 < P < 0.10 unless otherwise stated. RESULTS Intake, Duodenal Flow, and Digestibility Intake of DM ranged from 8.7 to 10.7 kg/d among treatments and was quadratically changed with dose of CIN supplementation due to a slight increase (P < 0.09) for the low dose and a slight decrease for the high dose (Table 2). Although low and high doses differed, they were not different from the control. Intakes of OM, NDF, and starch followed the same general pattern as DMI. Table 2. Effect of cinnamaldehyde (CIN) supplementation on intake, duodenal flow, and site and extent of digestion in growing beef cattle Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  Intake, kg/d                        DM  9.7ab  10.7a  10.1ab  8.7b  0.5  0.04  0.04   OM  8.9ab  9.9a  9.3a  8.0b  0.5  0.04  0.04   NDF  2.51ab  2.77a  2.61a  2.27b  0.17  0.04  0.03   Starch  4.91ab  5.34a  5.09a  4.38b  0.31  0.03  0.03  BW, kg  628ab  632a  625ab  615b  26  0.02  0.21  Duodenal flow, kg/d                        Total OM  4.38  4.47  4.51  4.43  0.39  0.93  0.69   Microbial OM  1.30  1.39  1.44  1.27  0.13  0.73  0.21   NDF  1.48  1.70  1.55  1.59  0.13  0.68  0.32   Starch  0.82  0.77  0.80  0.75  0.11  0.68  0.99  RFOM,1 kg/d  5.81ab  6.78a  6.23a  4.81b  0.54  0.02  0.02  Digestibility, % of intake                        Rumen                         OM (true)2  65.3ab  68.3a  67.1a  60.0b  3.4  0.04  0.06    NDF  40.8a  37.5ab  40.3a  28.3b  6.7  0.05  0.34    Starch  83.0  85.5  84.2  83.3  2.4  0.90  0.54   Intestine                         OM  27.2  25.6  24.7  28.4  2.3  0.63  0.27    NDF  12.1  20.0  11.8  14.2  3.5  0.89  0.66    Starch  13.7  11.3  11.7  12.4  2.2  0.79  0.47   Total                         OM  77.8ab  79.8a  76.1ab  72.7b  3.2  0.05  0.41    NDF  52.9ab  57.4a  52.1ab  42.5b  6.8  0.06  0.23    Starch  96.7  96.8  95.8  95.7  1.3  0.22  0.87  Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  Intake, kg/d                        DM  9.7ab  10.7a  10.1ab  8.7b  0.5  0.04  0.04   OM  8.9ab  9.9a  9.3a  8.0b  0.5  0.04  0.04   NDF  2.51ab  2.77a  2.61a  2.27b  0.17  0.04  0.03   Starch  4.91ab  5.34a  5.09a  4.38b  0.31  0.03  0.03  BW, kg  628ab  632a  625ab  615b  26  0.02  0.21  Duodenal flow, kg/d                        Total OM  4.38  4.47  4.51  4.43  0.39  0.93  0.69   Microbial OM  1.30  1.39  1.44  1.27  0.13  0.73  0.21   NDF  1.48  1.70  1.55  1.59  0.13  0.68  0.32   Starch  0.82  0.77  0.80  0.75  0.11  0.68  0.99  RFOM,1 kg/d  5.81ab  6.78a  6.23a  4.81b  0.54  0.02  0.02  Digestibility, % of intake                        Rumen                         OM (true)2  65.3ab  68.3a  67.1a  60.0b  3.4  0.04  0.06    NDF  40.8a  37.5ab  40.3a  28.3b  6.7  0.05  0.34    Starch  83.0  85.5  84.2  83.3  2.4  0.90  0.54   Intestine                         OM  27.2  25.6  24.7  28.4  2.3  0.63  0.27    NDF  12.1  20.0  11.8  14.2  3.5  0.89  0.66    Starch  13.7  11.3  11.7  12.4  2.2  0.79  0.47   Total                         OM  77.8ab  79.8a  76.1ab  72.7b  3.2  0.05  0.41    NDF  52.9ab  57.4a  52.1ab  42.5b  6.8  0.06  0.23    Starch  96.7  96.8  95.8  95.7  1.3  0.22  0.87  a,bWithin a row, means without a common superscripts letter differ (P < 0.05). 1RFOM = OM that was truly fermented in the rumen calculated by correcting for microbial OM. 2Corrected for microbial portion. View Large Table 2. Effect of cinnamaldehyde (CIN) supplementation on intake, duodenal flow, and site and extent of digestion in growing beef cattle Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  Intake, kg/d                        DM  9.7ab  10.7a  10.1ab  8.7b  0.5  0.04  0.04   OM  8.9ab  9.9a  9.3a  8.0b  0.5  0.04  0.04   NDF  2.51ab  2.77a  2.61a  2.27b  0.17  0.04  0.03   Starch  4.91ab  5.34a  5.09a  4.38b  0.31  0.03  0.03  BW, kg  628ab  632a  625ab  615b  26  0.02  0.21  Duodenal flow, kg/d                        Total OM  4.38  4.47  4.51  4.43  0.39  0.93  0.69   Microbial OM  1.30  1.39  1.44  1.27  0.13  0.73  0.21   NDF  1.48  1.70  1.55  1.59  0.13  0.68  0.32   Starch  0.82  0.77  0.80  0.75  0.11  0.68  0.99  RFOM,1 kg/d  5.81ab  6.78a  6.23a  4.81b  0.54  0.02  0.02  Digestibility, % of intake                        Rumen                         OM (true)2  65.3ab  68.3a  67.1a  60.0b  3.4  0.04  0.06    NDF  40.8a  37.5ab  40.3a  28.3b  6.7  0.05  0.34    Starch  83.0  85.5  84.2  83.3  2.4  0.90  0.54   Intestine                         OM  27.2  25.6  24.7  28.4  2.3  0.63  0.27    NDF  12.1  20.0  11.8  14.2  3.5  0.89  0.66    Starch  13.7  11.3  11.7  12.4  2.2  0.79  0.47   Total                         OM  77.8ab  79.8a  76.1ab  72.7b  3.2  0.05  0.41    NDF  52.9ab  57.4a  52.1ab  42.5b  6.8  0.06  0.23    Starch  96.7  96.8  95.8  95.7  1.3  0.22  0.87  Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  Intake, kg/d                        DM  9.7ab  10.7a  10.1ab  8.7b  0.5  0.04  0.04   OM  8.9ab  9.9a  9.3a  8.0b  0.5  0.04  0.04   NDF  2.51ab  2.77a  2.61a  2.27b  0.17  0.04  0.03   Starch  4.91ab  5.34a  5.09a  4.38b  0.31  0.03  0.03  BW, kg  628ab  632a  625ab  615b  26  0.02  0.21  Duodenal flow, kg/d                        Total OM  4.38  4.47  4.51  4.43  0.39  0.93  0.69   Microbial OM  1.30  1.39  1.44  1.27  0.13  0.73  0.21   NDF  1.48  1.70  1.55  1.59  0.13  0.68  0.32   Starch  0.82  0.77  0.80  0.75  0.11  0.68  0.99  RFOM,1 kg/d  5.81ab  6.78a  6.23a  4.81b  0.54  0.02  0.02  Digestibility, % of intake                        Rumen                         OM (true)2  65.3ab  68.3a  67.1a  60.0b  3.4  0.04  0.06    NDF  40.8a  37.5ab  40.3a  28.3b  6.7  0.05  0.34    Starch  83.0  85.5  84.2  83.3  2.4  0.90  0.54   Intestine                         OM  27.2  25.6  24.7  28.4  2.3  0.63  0.27    NDF  12.1  20.0  11.8  14.2  3.5  0.89  0.66    Starch  13.7  11.3  11.7  12.4  2.2  0.79  0.47   Total                         OM  77.8ab  79.8a  76.1ab  72.7b  3.2  0.05  0.41    NDF  52.9ab  57.4a  52.1ab  42.5b  6.8  0.06  0.23    Starch  96.7  96.8  95.8  95.7  1.3  0.22  0.87  a,bWithin a row, means without a common superscripts letter differ (P < 0.05). 1RFOM = OM that was truly fermented in the rumen calculated by correcting for microbial OM. 2Corrected for microbial portion. View Large Duodenal flows of OM, NDF, and starch were not affected by feeding CIN (Table 2). However, the amount (kg/d) of OM truly fermented in the rumen (RFOM) was quadratically affected by dose of CIN. The RFOM tended to be 17% greater (P = 0.07) for the low dose, but 17% less (P = 0.06) for the high dose compared with the control. Digestibilities (% of intake) of OM and NDF in the rumen were affected by CIN dose, with supplementation with a high CIN dose tending to reduce OM digestibility (P = 0.10) by 8% and reducing NDF digestibility (P = 0.05) by 31% compared with the control (Table 2). No difference was observed for ruminal starch digestibility and intestinal digestibilities (% of intake) of OM, NDF, and starch were not affected by CIN supplementation. Thus, digestibilities of OM and NDF in the total tract reflected differences in ruminal digestibility, with differences between the high and low doses of CIN, although these doses were not different from control. Nitrogen Metabolism and Ruminal Microbial Protein Synthesis Intake of N reflected DMI. It was quadratically changed being greater with 400 mg of CIN than with 1,600 mg of CIN and with the high dose tending (P = 0.10) to be less than control (Table 3). Similarly, duodenal flows of total N and nonammonia N were quadratically changed with dose rate with no differences among the means. However, when expressed as a percentage of N intake, total N and NAN linearly increased with increasing dose of CIN. Duodenal flow of dietary plus endogenous N (g/d) tended (P = 0.10) to linearly increase with increasing CIN supplementation, and its percentage (% of N intake) was greater with high CIN than with control. Ruminal microbial protein synthesis (yield and efficiency) were not affected by treatment. Table 3. Effect of cinnamaldehyde (CIN) supplementation on microbial protein synthesis and protein digestion in growing beef cattle Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  N intake, g/d  205.7ab  227.7a  214.5a  183.8b  14.6  0.04  0.04  Flow to duodenum                        Total                         g/d  183.1  195.6  194.7  188.5  14.4  0.60  0.04    % of intake  89.7  87.9  91.7  102.9  8.2  0.05  0.34   NAN1                         g/d  181.2  193.2  193.0  186.0  14.6  0.67  0.04    % of intake  88.7  86.9  90.9  101.5  8.3  0.05  0.37   Ammonia N, g/d  1.91  2.32  1.71  2.52  0.32  0.16  0.29   Feed + endogenous                         g/d  71.1  77.7  76.3  82.7  10.2  0.10  0.85    % of intake  34.9b  35.5b  35.7b  45.8a  6.1  0.02  0.23   Microbial                         g/d  110.1  115.6  116.7  103.3  9.5  0.37  0.21    % of intake  53.8  51.4  55.2  55.6  4.2  0.56  0.85    g/kg of RFOM2  19.3  17.3  19.1  21.6  1.7  0.19  0.32  N digestibility                        Ruminal (truly), %  65.1a  64.5a  64.3a  54.2b  6.1  0.02  0.24   Postruminal                         % of intake  62.5  62.5  60.3  70.2  5.3  0.13  0.21    % of flow to duodenum  69.0  70.7  66.5  68.1  2.5  0.39  0.66   ADTT,3 % of intake  72.8  74.6  68.7  67.3  4.2  0.10  0.98  Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  N intake, g/d  205.7ab  227.7a  214.5a  183.8b  14.6  0.04  0.04  Flow to duodenum                        Total                         g/d  183.1  195.6  194.7  188.5  14.4  0.60  0.04    % of intake  89.7  87.9  91.7  102.9  8.2  0.05  0.34   NAN1                         g/d  181.2  193.2  193.0  186.0  14.6  0.67  0.04    % of intake  88.7  86.9  90.9  101.5  8.3  0.05  0.37   Ammonia N, g/d  1.91  2.32  1.71  2.52  0.32  0.16  0.29   Feed + endogenous                         g/d  71.1  77.7  76.3  82.7  10.2  0.10  0.85    % of intake  34.9b  35.5b  35.7b  45.8a  6.1  0.02  0.23   Microbial                         g/d  110.1  115.6  116.7  103.3  9.5  0.37  0.21    % of intake  53.8  51.4  55.2  55.6  4.2  0.56  0.85    g/kg of RFOM2  19.3  17.3  19.1  21.6  1.7  0.19  0.32  N digestibility                        Ruminal (truly), %  65.1a  64.5a  64.3a  54.2b  6.1  0.02  0.24   Postruminal                         % of intake  62.5  62.5  60.3  70.2  5.3  0.13  0.21    % of flow to duodenum  69.0  70.7  66.5  68.1  2.5  0.39  0.66   ADTT,3 % of intake  72.8  74.6  68.7  67.3  4.2  0.10  0.98  a,bWithin a row, means without a common superscript letter differ (P < 0.05). 1NAN = nonammonia N. 2RFOM = OM that was truly fermented in the rumen calculated by correcting for microbial OM. 3ADTT = apparent digestibility in the total tract. View Large Table 3. Effect of cinnamaldehyde (CIN) supplementation on microbial protein synthesis and protein digestion in growing beef cattle Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  N intake, g/d  205.7ab  227.7a  214.5a  183.8b  14.6  0.04  0.04  Flow to duodenum                        Total                         g/d  183.1  195.6  194.7  188.5  14.4  0.60  0.04    % of intake  89.7  87.9  91.7  102.9  8.2  0.05  0.34   NAN1                         g/d  181.2  193.2  193.0  186.0  14.6  0.67  0.04    % of intake  88.7  86.9  90.9  101.5  8.3  0.05  0.37   Ammonia N, g/d  1.91  2.32  1.71  2.52  0.32  0.16  0.29   Feed + endogenous                         g/d  71.1  77.7  76.3  82.7  10.2  0.10  0.85    % of intake  34.9b  35.5b  35.7b  45.8a  6.1  0.02  0.23   Microbial                         g/d  110.1  115.6  116.7  103.3  9.5  0.37  0.21    % of intake  53.8  51.4  55.2  55.6  4.2  0.56  0.85    g/kg of RFOM2  19.3  17.3  19.1  21.6  1.7  0.19  0.32  N digestibility                        Ruminal (truly), %  65.1a  64.5a  64.3a  54.2b  6.1  0.02  0.24   Postruminal                         % of intake  62.5  62.5  60.3  70.2  5.3  0.13  0.21    % of flow to duodenum  69.0  70.7  66.5  68.1  2.5  0.39  0.66   ADTT,3 % of intake  72.8  74.6  68.7  67.3  4.2  0.10  0.98  Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  N intake, g/d  205.7ab  227.7a  214.5a  183.8b  14.6  0.04  0.04  Flow to duodenum                        Total                         g/d  183.1  195.6  194.7  188.5  14.4  0.60  0.04    % of intake  89.7  87.9  91.7  102.9  8.2  0.05  0.34   NAN1                         g/d  181.2  193.2  193.0  186.0  14.6  0.67  0.04    % of intake  88.7  86.9  90.9  101.5  8.3  0.05  0.37   Ammonia N, g/d  1.91  2.32  1.71  2.52  0.32  0.16  0.29   Feed + endogenous                         g/d  71.1  77.7  76.3  82.7  10.2  0.10  0.85    % of intake  34.9b  35.5b  35.7b  45.8a  6.1  0.02  0.23   Microbial                         g/d  110.1  115.6  116.7  103.3  9.5  0.37  0.21    % of intake  53.8  51.4  55.2  55.6  4.2  0.56  0.85    g/kg of RFOM2  19.3  17.3  19.1  21.6  1.7  0.19  0.32  N digestibility                        Ruminal (truly), %  65.1a  64.5a  64.3a  54.2b  6.1  0.02  0.24   Postruminal                         % of intake  62.5  62.5  60.3  70.2  5.3  0.13  0.21    % of flow to duodenum  69.0  70.7  66.5  68.1  2.5  0.39  0.66   ADTT,3 % of intake  72.8  74.6  68.7  67.3  4.2  0.10  0.98  a,bWithin a row, means without a common superscript letter differ (P < 0.05). 1NAN = nonammonia N. 2RFOM = OM that was truly fermented in the rumen calculated by correcting for microbial OM. 3ADTT = apparent digestibility in the total tract. View Large Ruminal digestibility of N linearly decreased with increasing CIN supplementation, such that feeding 1,600 mg/d of CIN decreased ruminal digestibility of N by 17% compared with the control (Table 3). In contrast, digestibility of N in the intestine was numerically (P = 0.13) increased by 12% with high CIN. As a result, digestibility of N in the total tract tended (P = 0.10) to linearly decrease with increasing CIN supplementation. Thus, numerically increased intestinal digestibility with high CIN did not compensate for the decreased ruminal digestibility of N. Ruminal pH and Ruminal Fermentation Characteristics Mean daily ruminal pH ranged from 5.83 to 5.99, but was not affected by CIN (Table 4). Concentrations of total VFA and the molar proportions of acetate, propionate, butyrate, and branched-chain VFA, concentration of NH3-N, and the acetate to propionate ratio were not affected by CIN supplementation, except for the proportion of caproic acid, which was quadratically changed, being less with low or medium CIN compared with the control. Total numbers of protozoa and the proportions of Isotrichia, Dasytrichia, and Entodinium were not affected by treatment. Table 4. Effect of cinnamaldehyde (CIN) supplementation on ruminal pH and fermentation characteristics in beef cattle Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  pH  5.99  5.83  5.89  5.91  0.05  0.56  0.11  VFA                        Total, mM  139.9  143.7  142.0  144.2  12.9  0.75  0.91   Acetate (A), mol/100 mol  61.7  56.7  60.8  59.2  1.7  0.68  0.48   Propionate (P), mol/100 mol  19.6  24.1  21.4  23.5  2.3  0.36  0.62   Butyrate, mol/100 mol  13.5  15.1  13.6  12.8  1.1  0.30  0.38   BCFA,1 mol/100 mol  3.4  2.4  2.7  2.7  0.4  0.40  0.16   Valerate, mol/100 mol  1.3  1.5  1.4  1.4  0.1  0.56  0.54   Caproic, mol/100 mol  0.5  0.2  0.2  0.4  0.1  0.71  0.04   A:P  3.39  2.48  3.05  2.71  0.42  0.42  0.53  NH3 N, mM  4.34  4.98  4.71  4.12  1.04  0.50  0.24  Protozoa                        Total, × 105  16.9  16.0  20.8  18.3  4.0  0.47  0.47   % of total                         Isotrichia  1.82  0.99  0.78  0.79  0.60  0.30  0.40    Dasytrichia  6.09  3.68  3.60  2.72  1.46  0.17  0.50    Entodiniumium  91.95  95.23  95.54  96.44  1.99  0.17  0.45  Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  pH  5.99  5.83  5.89  5.91  0.05  0.56  0.11  VFA                        Total, mM  139.9  143.7  142.0  144.2  12.9  0.75  0.91   Acetate (A), mol/100 mol  61.7  56.7  60.8  59.2  1.7  0.68  0.48   Propionate (P), mol/100 mol  19.6  24.1  21.4  23.5  2.3  0.36  0.62   Butyrate, mol/100 mol  13.5  15.1  13.6  12.8  1.1  0.30  0.38   BCFA,1 mol/100 mol  3.4  2.4  2.7  2.7  0.4  0.40  0.16   Valerate, mol/100 mol  1.3  1.5  1.4  1.4  0.1  0.56  0.54   Caproic, mol/100 mol  0.5  0.2  0.2  0.4  0.1  0.71  0.04   A:P  3.39  2.48  3.05  2.71  0.42  0.42  0.53  NH3 N, mM  4.34  4.98  4.71  4.12  1.04  0.50  0.24  Protozoa                        Total, × 105  16.9  16.0  20.8  18.3  4.0  0.47  0.47   % of total                         Isotrichia  1.82  0.99  0.78  0.79  0.60  0.30  0.40    Dasytrichia  6.09  3.68  3.60  2.72  1.46  0.17  0.50    Entodiniumium  91.95  95.23  95.54  96.44  1.99  0.17  0.45  1BCFA = branched-chain fatty acids (isobutyrate + isovalerate). View Large Table 4. Effect of cinnamaldehyde (CIN) supplementation on ruminal pH and fermentation characteristics in beef cattle Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  pH  5.99  5.83  5.89  5.91  0.05  0.56  0.11  VFA                        Total, mM  139.9  143.7  142.0  144.2  12.9  0.75  0.91   Acetate (A), mol/100 mol  61.7  56.7  60.8  59.2  1.7  0.68  0.48   Propionate (P), mol/100 mol  19.6  24.1  21.4  23.5  2.3  0.36  0.62   Butyrate, mol/100 mol  13.5  15.1  13.6  12.8  1.1  0.30  0.38   BCFA,1 mol/100 mol  3.4  2.4  2.7  2.7  0.4  0.40  0.16   Valerate, mol/100 mol  1.3  1.5  1.4  1.4  0.1  0.56  0.54   Caproic, mol/100 mol  0.5  0.2  0.2  0.4  0.1  0.71  0.04   A:P  3.39  2.48  3.05  2.71  0.42  0.42  0.53  NH3 N, mM  4.34  4.98  4.71  4.12  1.04  0.50  0.24  Protozoa                        Total, × 105  16.9  16.0  20.8  18.3  4.0  0.47  0.47   % of total                         Isotrichia  1.82  0.99  0.78  0.79  0.60  0.30  0.40    Dasytrichia  6.09  3.68  3.60  2.72  1.46  0.17  0.50    Entodiniumium  91.95  95.23  95.54  96.44  1.99  0.17  0.45  Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  pH  5.99  5.83  5.89  5.91  0.05  0.56  0.11  VFA                        Total, mM  139.9  143.7  142.0  144.2  12.9  0.75  0.91   Acetate (A), mol/100 mol  61.7  56.7  60.8  59.2  1.7  0.68  0.48   Propionate (P), mol/100 mol  19.6  24.1  21.4  23.5  2.3  0.36  0.62   Butyrate, mol/100 mol  13.5  15.1  13.6  12.8  1.1  0.30  0.38   BCFA,1 mol/100 mol  3.4  2.4  2.7  2.7  0.4  0.40  0.16   Valerate, mol/100 mol  1.3  1.5  1.4  1.4  0.1  0.56  0.54   Caproic, mol/100 mol  0.5  0.2  0.2  0.4  0.1  0.71  0.04   A:P  3.39  2.48  3.05  2.71  0.42  0.42  0.53  NH3 N, mM  4.34  4.98  4.71  4.12  1.04  0.50  0.24  Protozoa                        Total, × 105  16.9  16.0  20.8  18.3  4.0  0.47  0.47   % of total                         Isotrichia  1.82  0.99  0.78  0.79  0.60  0.30  0.40    Dasytrichia  6.09  3.68  3.60  2.72  1.46  0.17  0.50    Entodiniumium  91.95  95.23  95.54  96.44  1.99  0.17  0.45  1BCFA = branched-chain fatty acids (isobutyrate + isovalerate). View Large Blood Chemistry and Immune Status Concentrations of blood glucose and urea N were not affected by CIN supplementation (Table 5). However, increasing CIN supplementation quadratically changed the concentration of blood triglyceride such that it was greater with low and medium CIN doses than with control. Further, CIN tended (P = 0.06) to quadratically change the concentration of serum NEFA, so that it tended to be less (P = 0.10) with low and medium CIN doses than with control. Total white blood cell counts were not affected by treatment, although the proportion of basophils tended (P = 0.08) to linearly decrease with increasing CIN supplementation. Concentration of haptoglobin in the plasma tended (P = 0.10) to quadratically change, being numerically less (P = 0.11) with medium CIN than with control. Concentrations of SAA and LBP were not affected by treatment. Table 5. Effect of cinnamaldehyde (CIN) supplementation on blood variables in beef cattle Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  Blood metabolite                        Glucose, mg/dL  78.5  80.3  81.3  84.0  3.5  0.18  0.96   Triglyceride, mg/dL  8.8  11.8  11.5  9.8  2.0  0.68  0.01   Urea N, mg/dL  21.9  24.5  22.0  20.7  2.6  0.39  0.44   NEFA, µM  71.1  60.3  60.6  66.3  4.3  0.65  0.06  WBC,1 × 103/µL  9.05  9.21  9.69  9.39  0.9  0.49  0.41  Lymphocyte, %  61.8  63.1  67.3  65.0  4.0  0.24  0.22  Neutrophil, %  26.8  23.9  20.3  21.0  4.2  0.14  0.29  Monocyte, %  8.4  7.1  7.4  7.8  1.8  0.45  0.79  Eosinophil, %  3.8  5.0  4.1  6.0  1.3  0.13  0.76  Basophil, %  1.4  0.9  1.0  0.3  0.4  0.08  0.90  Acute phase protein                        Haptoglobin, µg/mL  186  137  116  153  28  0.48  0.10   SAA,2 µg/mL  0.33  0.37  0.33  0.36  0.08  0.56  0.80   LBP,3 µg/mL  1.17  0.93  0.98  1.19  0.16  0.68  0.21  Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  Blood metabolite                        Glucose, mg/dL  78.5  80.3  81.3  84.0  3.5  0.18  0.96   Triglyceride, mg/dL  8.8  11.8  11.5  9.8  2.0  0.68  0.01   Urea N, mg/dL  21.9  24.5  22.0  20.7  2.6  0.39  0.44   NEFA, µM  71.1  60.3  60.6  66.3  4.3  0.65  0.06  WBC,1 × 103/µL  9.05  9.21  9.69  9.39  0.9  0.49  0.41  Lymphocyte, %  61.8  63.1  67.3  65.0  4.0  0.24  0.22  Neutrophil, %  26.8  23.9  20.3  21.0  4.2  0.14  0.29  Monocyte, %  8.4  7.1  7.4  7.8  1.8  0.45  0.79  Eosinophil, %  3.8  5.0  4.1  6.0  1.3  0.13  0.76  Basophil, %  1.4  0.9  1.0  0.3  0.4  0.08  0.90  Acute phase protein                        Haptoglobin, µg/mL  186  137  116  153  28  0.48  0.10   SAA,2 µg/mL  0.33  0.37  0.33  0.36  0.08  0.56  0.80   LBP,3 µg/mL  1.17  0.93  0.98  1.19  0.16  0.68  0.21  1WBC = white blood cells. 2SAA = serum amyloid A. 3LBP = lipopolysaccharide binding protein. View Large Table 5. Effect of cinnamaldehyde (CIN) supplementation on blood variables in beef cattle Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  Blood metabolite                        Glucose, mg/dL  78.5  80.3  81.3  84.0  3.5  0.18  0.96   Triglyceride, mg/dL  8.8  11.8  11.5  9.8  2.0  0.68  0.01   Urea N, mg/dL  21.9  24.5  22.0  20.7  2.6  0.39  0.44   NEFA, µM  71.1  60.3  60.6  66.3  4.3  0.65  0.06  WBC,1 × 103/µL  9.05  9.21  9.69  9.39  0.9  0.49  0.41  Lymphocyte, %  61.8  63.1  67.3  65.0  4.0  0.24  0.22  Neutrophil, %  26.8  23.9  20.3  21.0  4.2  0.14  0.29  Monocyte, %  8.4  7.1  7.4  7.8  1.8  0.45  0.79  Eosinophil, %  3.8  5.0  4.1  6.0  1.3  0.13  0.76  Basophil, %  1.4  0.9  1.0  0.3  0.4  0.08  0.90  Acute phase protein                        Haptoglobin, µg/mL  186  137  116  153  28  0.48  0.10   SAA,2 µg/mL  0.33  0.37  0.33  0.36  0.08  0.56  0.80   LBP,3 µg/mL  1.17  0.93  0.98  1.19  0.16  0.68  0.21  Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  Blood metabolite                        Glucose, mg/dL  78.5  80.3  81.3  84.0  3.5  0.18  0.96   Triglyceride, mg/dL  8.8  11.8  11.5  9.8  2.0  0.68  0.01   Urea N, mg/dL  21.9  24.5  22.0  20.7  2.6  0.39  0.44   NEFA, µM  71.1  60.3  60.6  66.3  4.3  0.65  0.06  WBC,1 × 103/µL  9.05  9.21  9.69  9.39  0.9  0.49  0.41  Lymphocyte, %  61.8  63.1  67.3  65.0  4.0  0.24  0.22  Neutrophil, %  26.8  23.9  20.3  21.0  4.2  0.14  0.29  Monocyte, %  8.4  7.1  7.4  7.8  1.8  0.45  0.79  Eosinophil, %  3.8  5.0  4.1  6.0  1.3  0.13  0.76  Basophil, %  1.4  0.9  1.0  0.3  0.4  0.08  0.90  Acute phase protein                        Haptoglobin, µg/mL  186  137  116  153  28  0.48  0.10   SAA,2 µg/mL  0.33  0.37  0.33  0.36  0.08  0.56  0.80   LBP,3 µg/mL  1.17  0.93  0.98  1.19  0.16  0.68  0.21  1WBC = white blood cells. 2SAA = serum amyloid A. 3LBP = lipopolysaccharide binding protein. View Large DISCUSSION Our study showed that the effects of supplementing feedlot finishing cattle with CIN depended on dose rate of CIN. At a low dose (400 mg/d), there were small, nonsignificant improvements in nutrient intake and digestibility of OM in the rumen and total tract. However, the opposite occurred at a high dose (1,600 mg/d); nutrient intake and ruminal digestibility, especially NDF and feed N digestibility, decreased. Decreased ruminal digestibility of feed N observed with the high dose resulted in greater flow of ruminally undegraded feed protein to the intestine, which could be beneficial for younger cattle with a high requirement for MP. However, the reduced feed consumption and reduced ruminal fiber digestibility observed for the high dose compared with the control would be undesirable for animal performance. Our results indicate that for high-grain diets, the effects of supplemental CIN on DMI depended on dosage. In a companion feedlot study using a similar diet and the same doses of CIN (Yang et al., 2010), we observed that all doses increased DMI in the first 28 d of the feeding period with the greatest increase with the low dose. However, CIN had no effects on DMI after 29 d of the experiment. In contrast, Cardozo et al. (2006) demonstrated a decrease in the concentrate intake in beef heifers fed a high-concentrate diet (90% concentrate + 10% barley straw) supplemented with a mixture of 180 mg/d of CIN and 90 mg/d of eugenol. That dose of CIN was even smaller than the low CIN dose (400 mg of CIN/d) used in our study. Thus, the negative effect of EO supplementation in that study may have been due to the combination of CIN with eugenol as compared with only CIN in our study. The reduction of feed intake by the high CIN dose in our study is supported by Busquet et al. (2003), in which concentrate intake of dairy cattle fed 600 mg of CIN/kg of DM was reduced by 12%. Clearly the dose of CIN used in that study was much greater than that used in our study. It can be concluded that DMI is inhibited with increased doses of CIN supplementation such as 1,600 mg/d or greater, but smaller doses have inconsistent effects on DMI, suggesting that dietary factors (e.g., concentrate level) and type of animal may affect response to dose of CIN. Changes in intake between the low and high dose of CIN did not affect duodenal flows of DM, OM, NDF, or starch because of differences in ruminal digestibility of OM and NDF. It was these differences in ruminal digestibility that compensated for differences in intake because microbial OM flow was not affected by treatment. Because ruminal digestibility (% of intake) of starch did not differ, the amount of starch digested in the rumen would have reflected differences in intake among doses of CIN. Much of the research to date with EO has been conducted in vitro, with only a limited number of animal feeding studies (Cardozo et al., 2006; Chaves et al., 2008). To compare the results from the present study to results from in vitro studies, it is necessary to estimate the concentration of CIN in the rumen fluid of the cattle after steady state was attained (10 d of feeding). Assuming a 60-L rumen volume, a liquid passage rate of 10%/h, and that all the top-dressed CIN was consumed within the first hour of feeding, the 400 mg/d dose would have resulted in a range of 0.6 to 7.2 mg/L over 24 h, the 800 mg/d dose would have resulted in range of 1.1 to 14.5 mg/L, and the 1,600 mg/d dose in a range of 2.3 to 29.0 mg/L. A comparison with in vitro results indicates that the level of CIN required to inhibit rumen fermentation is greater in animals compared with in vitro experimentation. For instance, in the present study low and medium doses of CIN tended to stimulate ruminal fermentation (increased ruminal digestibility); however, the same doses (3 mg/L) inhibited fermentation under continuous flow conditions as reported by Cardozo et al. (2005). Because the effects of EO in animals are dependent on dose rate, in vitro studies are not necessarily indicative of what happens in vivo; the response to a given dose differs in these 2 systems. Results of our study showed that the CIN supplementation had negligible effects on intestinal digestion. Therefore, the linearly decreased digestibilities of OM and NDF in the total tract due to CIN supplementation were mainly attributed to the linear decrease in ruminal digestibility. The data also suggest that the main modulating effects of CIN are in the rumen rather than in the intestine. Even though the total tract digestibilties of OM and NDF linearly decreased with the dose of CIN, the decrease in total digestibilities reached significance only for the high CIN dose as compared with the control or low CIN diets. Therefore, the decrease in total digestibility of OM with the high dose of CIN might be related mainly to the decreased digestion of NDF and protein in the rumen. The greater proportion of dietary N that arrived at the duodenum with high CIN supplementation resulted from the decreased ruminal degradability of feed N. It has been suggested that ruminal deamination is inhibited with CIN supplementation based on the observed reduction of rumen NH3 concentration with added CIN in an in vitro study (Cardozo et al., 2005) and in an animal study (Cardozo et al., 2006). Further evidence for an inhibition of ruminal deamination is the finding of Ferme et al. (2004) that addition of CIN to an in vitro rumen simulation system reduced the population of Prevotella spp., a group of bacteria known to be involved in the deamination process. Although the ruminal degradability of feed N linearly decreased with increasing CIN dose in our study, it is not possible to unequivocally identify the mechanism by which this occurred because we did not measure peptides and AA in the rumen contents or the duodenal flows. Furthermore, the lack of reduction in ruminal NH3 and blood urea N concentration when feeding high CIN was difficult to explain given that intake and ruminal degradability of N were decreased. The lack of effect of CIN on duodenal microbial protein flow in our study is consistent with the report by Busquet et al. (2005) in which there was no change in bacterial N flow in a dual-flow continuous culture supplied with 31.2 or 312 mg/L of CIN. However, in that study, the input and digestibility of DM were not affected by CIN. Supplementation of dairy cow diets with juniper berry oil, another EO, increased the amount of OM digested in the rumen (+13%), but microbial protein synthesis was not different from the control (Yang et al., 2007). It is possible that the inhibition of the deamination process by CIN might have caused an asynchrony between the energy and N availability in the rumen, and thus microbial protein synthesis was not enhanced despite increased energy availability in the rumen. The general lack of treatment effects on ruminal pH and VFA concentration (i.e., total and individual molar proportions) in our study was inconsistent with the changes in DMI and ruminal digestion of nutrients due to CIN supplementation. However, the results agree with those of Cardozo et al. (2006) who reported no differences in ruminal pH, total VFA concentration, or molar proportion of individual VFA despite a reduction in DMI when a mixture of CIN and eugenol was supplemented. In contrast, a consistent change in total VFA concentration and DM disappearance was observed in continuous culture (Busquet et al., 2005). In the rumen, the concentration of VFA reflects the equilibrium between absorption and production of VFA and does not necessarily reflect rumen digestion of OM, whereas VFA concentration in in vitro fermentation is a direct measure of DM digestion. The lack of treatment effect on protozoal numbers in the rumen is consistent with the literature that indicates only very large doses of EO reduce protozoal numbers. Hart et al. (2008) concluded in a review that the effect of EO on rumen protozoa varies with the type of EO tested and that relatively large concentrations of EO are required to decrease protozoal numbers. For example, Benchaar et al. (2008) reported that supplementation of dairy cows diets with 1,000 mg/d of CIN had no effect on the numbers or generic composition of ciliate protozoa. However, feeding 2,000 mg/d of anise extract containing 100 g/kg of anethol to beef heifer decreased counts of holotrichs and entodiniomorphs (Cardozo et al., 2006). Similar blood glucose concentration but less blood NEFA concentration for heifers fed low and medium CIN indicated a more positive energy balance in those groups compared with heifers fed the control diet. The response of blood NEFA to CIN supplementation might be due to the quadratic change in DMI and the amount of OM digested in the rumen, which provided more energy to the animal. Greater concentrations of blood triglycerides with the low and medium CIN also corresponded to greater DMI. The results suggest that the concentrations of some blood metabolites can be altered by addition of CIN through changing of feed intake and digestion processes in the rumen. The release of acute phase proteins is usually attributed to activation of the innate immune system in conditions like inflammation, tissue injury, and infection (Suffredini et al., 1999). The SAA and LBP directly participate in the detoxification and removal of endotoxin during an acute phase response. Emmanuel et al. (2008) reported a 14-fold increase in the concentration of endotoxin in the ruminal fluid with increasing proportions of barley grain in the diet of dairy cows. This was associated with enhanced plasma SAA and LBP. Results of this study showed no differences among the treatment groups regarding plasma SAA and LBP, suggesting a lack of effect of CIN on rumen endotoxin. In conclusion, the results of this study suggest that supplementation of high-grain diets with CIN affected feed intake and ruminal digestion of feeds in a dose-dependent manner. A low dose of CIN tended to increase OM availability in the rumen due to increased feed intake and greater ruminal digested OM. Increased ruminal OM availability did not, however, increase ruminal microbial protein synthesis. In contrast, feed intake and ruminal digestion of feeds was adversely affected when a high dose of CIN was supplemented. Reducing fiber digestion in the rumen would negatively affect feed efficiency, but reducing ruminal CP degradation provides more rumen undegraded protein to the small intestine. The mode of action of CIN appears to be mainly in the rumen, affecting ruminal digestion with minimal effects on intestinal digestion. Further study is warranted to understand the mode of action of CIN in inhibiting CP degradation and fiber digestion in the rumen and modulation of acute protein release by hepatocytes. Finally, caution must be used when interpreting the results from this study because of the small number of animals used; thus, further verification of these findings is warranted. LITERATURE CITED Ametaj B. N. Bradford B. J. Bobe G. Nafikov R. A. Lu Y. Young J. W. Beitz D. C. 2005. Strong relationship between mediators of the acute phase response and fatty liver in dairy cows. Can. J. Anim. Sci.  85: 165– 175. Google Scholar CrossRef Search ADS   AOAC 1990. Official Methods of Analysis.  15th ed. Assoc. Off. Anal. Chem., Arlington, VA. Benchaar C. McAllister T. A. Chouinard P. Y. 2008. Digestion, ruminal fermentation, ciliate protozoal populations, and milk production from dairy cows fed cinnamaldehyde, quebracho condensed tannin, or Yucca schidigera saponin extracts. J. Dairy Sci.  91: 4765– 4777. https://doi.org/19038952 Google Scholar CrossRef Search ADS PubMed  Busquet M. Calsamiglia S. Ferret A. Cardozo P. W. Kamel C. 2005. Effects of cinnamaldehyde and garlic oil on rumen microbial fermentation in a dual flow continuous culture. J. Dairy Sci.  88: 2508– 2516. https://doi.org/15956313 Google Scholar CrossRef Search ADS PubMed  Busquet M. Calsamiglia S. Ferret A. Kamel C. 2006. Plant extracts affect in vitro rumen microbial fermentation. J. Dairy Sci.  89: 761– 771. https://doi.org/16428643 Google Scholar CrossRef Search ADS PubMed  Busquet, M., H. Greathead, S. Calsamiglia, A. Ferret, and C. Kamel 2003. Efecto del extracto de ajo y el cinemaldehido sobre la producción, composición y residuos en leche en vacas de alta producción. ITEA  24 (Vol. Extra): 756– 758. Calsamiglia S. Busquet M. Cardozo W. Castillejos L. Ferret A. 2007. Invited Review: Essential oils as modifiers of rumen microbial fermentation. J. Dairy Sci.  90: 2580– 2595. https://doi.org/17517698 Google Scholar CrossRef Search ADS PubMed  Canadian Council on Animal Care 1993. Guide to the Care and Use of Experimental Animals. Vol. 1.  2nd ed. E. D. Olfert, B. M. Cross, and A. A. McWilliam ed. Can. Counc. Anim. Care, Ottawa, Ontario, Canada. Cardozo P. W. Calsamiglia S. Ferret A. Kamel C. 2005. Screening for the effects of natural plant extracts at different pH on in vitro rumen microbial fermentation of a high-concentrate diet for beef cattle. J. Anim. Sci.  83: 2572– 2579. https://doi.org/16230654 Google Scholar CrossRef Search ADS PubMed  Cardozo P. W. Calsamiglia S. Ferret A. Kamel C. 2006. Effects of alfalfa extracts, anise, capsicum, and a mixture of cinnamaldehyde and eugenol on ruminal fermentation and protein degradation in beef heifers fed a high-concentrate diet. J. Anim. Sci.  84: 2801– 2808. https://doi.org/16971582 Google Scholar CrossRef Search ADS PubMed  Chaves A. V. Stanford K. Gibson L. L. McAllister T. A. Benchaar C. 2008. Effects of carvacrol and cinnamaldehyde on intake, rumen fermentation, growth performance, and carcass characteristics of growing lambs. Anim. Feed Sci. Technol.  145: 396– 408. Google Scholar CrossRef Search ADS   Emmanuel D. G. V. Dunn S. M. Ametaj B. N. 2008. Feeding high proportions of barley grain stimulates an inflammatory response in dairy cows. J. Dairy Sci.  91: 606– 614. https://doi.org/18218747 Google Scholar CrossRef Search ADS PubMed  Ferme D. Banjac M. Calsamiglia S. Busquet M. Kamel C. Avgustin G. 2004. The effects of plant extracts on microbial community structure in a rumen-simulating continuous-culture system as revealed by molecular profiling. Folia Microbiol. (Praha)  49: 151– 155. https://doi.org/15227787 Google Scholar CrossRef Search ADS PubMed  Fraser G. R. Chaves A. V. Wang Y. McAllister T. A. Beauchemin K. A. Benchaar C. 2007. Assessment of the effects of cinnamon leaf oil on rumen microbial fermentation using two continuous culture systems. J. Dairy Sci.  90: 2315– 2328. https://doi.org/17430934 Google Scholar CrossRef Search ADS PubMed  Hart K. J. Yáñez-Ruiz D. R. Duval S. M. McEwan N. R. Newbold C. J. 2008. Plant extracts to manipulate rumen fermentation. Anim. Feed Sci. Technol.  147: 8– 35. Google Scholar CrossRef Search ADS   McIntosh F. M. Williams P. Losa R. Wallace R. J. Beever D. A. Newbold C. J. 2003. Effects of essential oils on ruminal microorganisms and their protein metabolism. Appl. Environ. Microbiol.  69: 5011– 5014. https://doi.org/12902303 Google Scholar CrossRef Search ADS PubMed  NRC 1996. Nutrient Requirements of Beef Cattle.  7th rev. ed. Natl. Acad. Press, Washington, DC. Parveen S. Lukasik J. Scott T. M. Tamplin M. L. Portier K. M. Sheperd S. Braun K. Farrah S. R. 2006. Geographical variation in antibiotic resistance profiles of Escherichia coli isolated from swine, poultry, beef and dairy cattle farm water retention ponds in Florida. J. Appl. Microbiol.  100: 50– 57. https://doi.org/16405684 Google Scholar CrossRef Search ADS PubMed  Rode L. M. Yang W. Z. Beauchemin K. A. 1999. Fibrolytic enzyme supplements for dairy cows in early lactation. J. Dairy Sci.  82: 2121– 2126. https://doi.org/10531597 Google Scholar CrossRef Search ADS PubMed  Standen M. D. Myers S. P. 2004. The roles of essential oils in the modulation of immune function and inflammation: Survey of aromatherapy educators. Int. J. Aromatherapy  14: 150– 161. Google Scholar CrossRef Search ADS   Suffredini A. F. Fantuzzi G. Badolato R. Oppenheim J. J. O'Grady N. 1999. New insights into the biology of the acute phase response. J. Clin. Immunol.  19: 203– 214. https://doi.org/10471974 Google Scholar CrossRef Search ADS PubMed  Van Soest P. J. Robertson J. B. Lewis B. A. 1991. Methods for dietary fiber, neutral detergent fiber and non-starch polysaccharide in relation to animal nutrition. J. Dairy Sci.  74: 3583– 3597. https://doi.org/1660498 Google Scholar CrossRef Search ADS PubMed  Weatherburn M. W. 1967. Phenol-hypochlorite reaction for determination of ammonia. Anal. Chem.  39: 971– 974. Google Scholar CrossRef Search ADS   Yang W. Z. Ametaj B. N. Benchaar C. He M. L. Beauchemin K. A. 2010. Cinnamaldehyde in feedlot cattle diets: Intake, growth performance, carcass characteristics, and blood metabolites. J . Anim. Sci.  https://doi.org/10.2527/jas.2008-1608 Yang W. Z. Benchaar C. Ametaj B. N. Chaves A. V. He M. L. McAllister T. A. 2007. Effects of garlic and juniper berry oils on ruminal fermentation and digestion of lactating dairy cows. J. Dairy Sci.  90: 5671– 5681. https://doi.org/18024759 Google Scholar CrossRef Search ADS PubMed  Footnotes 1 Contribution number 38708053. American Society of Animal Science http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Animal Science Oxford University Press

Dose response to cinnamaldehyde supplementation in growing beef heifers: Ruminal and intestinal digestion

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0021-8812
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1525-3163
DOI
10.2527/jas.2008-1652
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19854990
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Abstract

ABSTRACT The objective of this study was to determine if cinnamaldehyde (CIN) could be used to improve feed intake, digestion, and immune status in growing beef heifers fed high-concentrate diets. The experiment was designed as a 4 × 4 Latin square using 4 ruminally and duodenally cannulated beef heifers with 4 treatments: control (no CIN added), 400 mg/d of CIN (low), 800 mg/d of CIN (medium), and 1,600 mg/d of CIN (high), and four 21-d periods. Feed intake, rumen pH and fermentation characteristics, site and extent of digestion, microbial N synthesis, blood metabolites, and acute phase protein response were measured. The diets consisted of 15% barley silage, 80% dry-rolled barley grain, and 5% supplement (DM basis). Intakes (kg/d) of DM, OM, NDF, starch, and N were quadratically (P = 0.04) changed with increasing CIN supplementation. The amount of OM fermented in the rumen quadratically (P = 0.02) decreased with increasing CIN. Digestibilities (% of intake) of OM, NDF, and N in the rumen were not affected by supplementing with low and medium CIN, but they were reduced by 8% (P = 0.10), 31% (P = 0.05), and 17% (P = 0.05), respectively, with high CIN. Similarly, digestibilities of OM and NDF in the total tract also tended to be reduced by 7% (P = 0.10) and 20% (P = 0.10), respectively, with high CIN because supplementation of CIN had minimal effects on intestinal digestibility. Flows (g/d) of microbial N and other nutrients to the duodenum were not affected by CIN supplementation, even though the amount of ruminal fermented OM varied with level of CIN supplementation. Rumen pH, total VFA concentration, and molar proportions of individual VFA were not affected by CIN. Although concentrations of NEFA (P = 0.06) and triglyceride (P = 0.01) were quadratically changed with increasing CIN supplementation, blood concentrations of glucose and urea N, white blood cell counts, serum amyloid A, and lipopolysaccharide in plasma were not affected by CIN. Plasma haptoglobin numerically (P = 0.11) decreased with the medium dose of CIN fed compared with control. The results indicate that supplementation of a high-concentrate diet with a low dose of CIN resulted in small increases in nutrient availability in the rumen due to increased feed intake and greater ruminal digestion of OM. However, feed intake and ruminal digestion of feeds were adversely affected when a high dose of CIN was used. INTRODUCTION Animal scientists are actively seeking alternatives to antibiotic additives and growth promotants because the use of these compounds has become increasingly controversial (Parveen et al., 2006). Plant extracts, such as essential oils (EO), are being promoted as natural feed additives (i.e., antimicrobials) for use in ruminant nutrition. Studies have shown that some EO can favorably alter rumen metabolism (McIntosh et al., 2003; Fraser et al., 2007) and that they possess immuno-stimulating properties (Standen and Myers, 2004). One potential EO of interest is cinnamon oil (Cinnamomum cassia). Cinnamaldehyde (CIN), a phenylpropanoid with antimicrobial activity, is the main active component of cinnamon (C. cassia) oil, accounting for up to 75% of its composition (Calsamiglia et al., 2007). Results from studies conducted in vitro (Cardozo et al., 2005; Busquet et al., 2006) and in vivo (Cardozo et al., 2006; Benchaar et al., 2008; Chaves et al., 2008) to evaluate the effects of cinnamon oil and CIN have been somewhat conflicting, and further research is needed to understand effects on digestion and metabolism in cattle. We reported that dietary supplementation with CIN increased DMI of feedlot cattle in the early weeks of the finishing period, presumably because the cattle were stressed (Yang et al., 2010). It appears from the studies to date that cinnamon oil and CIN can potentially improve ruminal fermentation and digestion, but in beef production systems, the effects may be more relevant when feeding conditions favor low ruminal pH. The objectives of this study were to determine if CIN could be used to improve feed intake, digestion, and immune status in growing beef cattle fed high-concentrate diets. We hypothesized that the dose of CIN would affect the response. To test our hypothesis we fed increasing dose rates of CIN and measured effects on feed intake, ruminal pH, and fermentation, microbial protein synthesis, site and extent of digestion, blood metabolites, and acute phase protein response. MATERIALS AND METHODS The study received approval of the institutional Animal Care Committee of the Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, and was conducted in accordance with the guidelines of the Canadian Council on Animal Care (1993). Experimental Design and Treatments The experiment was designed as a 4 × 4 Latin square balanced for carryover effects using 4 ruminally and duodenally cannulated beef heifers with four 21-d periods. The beef heifers (538 ± 19.5 kg of initial BW; ovariectomized) were randomly assigned to 1 of 4 treatments: 1) control (no CIN added), 2) 400 mg∙heifer−1∙d−1 CIN (low), 3) 800 mg∙heifer−1∙d−1 CIN (medium), and 4) 1,600 mg∙heifer−1∙d−1 CIN (high). Cinnamaldehyde (purity >99%) was provided by Phodé S.A. (Albi, France). Each experimental period lasted 21 d with 14 d of adaptation to experimental treatments and 7 d of sampling and data collection. Diet and Animal Management The diets used consisted of 15% barley silage, 80% dry-rolled barley grain, and 5% supplement (DM basis). The supplement contained a protein source, minerals, and vitamins in excess of the National Research Council (NRC, 1996) nutrient requirements for beef cattle gaining 1.5 kg/d. Diet composition is given in Table 1. The ration was prepared daily using a feed mixer (Data Ranger, American Calan Inc., Northwood, NH). Heifers were adapted to experimental diets by gradually increasing the proportion of concentrate over a period of 2 wk before starting the experiment. Once the animals were on full feed, the experimental diets were offered twice (0830 and 1800 h) daily for ad libitum consumption (10% refusals) with one-half of the daily feed allotment offered at each feeding. The CIN was mixed with rolled barley grain and top dressed onto the ration at each feeding. Quantities of feed offered and refused were recorded daily for each animal for the entire experiment, and samples of the diet and refusals were retained weekly for determination of DM content. Samples of the barley silage and barley grain were also collected weekly and combined for each period. Feeds and refusals were analyzed for analytical DM, OM, N, starch, NDF, ADF, and Yb (digesta flow marker). Table 1. Ingredients and chemical composition of the diet Item  Amount  Ingredient,1 % of DM     Barley silage2  15.0   Barley grain, dry-rolled  80.1   Canola oil  0.14   Canola meal  1.71   Calcium carbonate  1.51   Dicalcium phosphate  0.42   Molasses  0.33   Salt  0.32   Dynamate3  0.38   Beef feedlot premix4  0.05   Vitamin E (500,000 IU/kg)  0.0011   MGA 100 premix (220 mg/kg)  0.024   Flavoring agent5  0.021  Analyzed composition6      DM, %  70.0 ± 2.1   OM, % of DM  92.0 ± 0.5   NDF, % of DM  25.7 ± 2.3   Starch, % of DM  40.6 ± 1.8   CP, % of DM  13.2 ± 0.9   Ca, % of DM  0.62   P, % of DM  0.39  Item  Amount  Ingredient,1 % of DM     Barley silage2  15.0   Barley grain, dry-rolled  80.1   Canola oil  0.14   Canola meal  1.71   Calcium carbonate  1.51   Dicalcium phosphate  0.42   Molasses  0.33   Salt  0.32   Dynamate3  0.38   Beef feedlot premix4  0.05   Vitamin E (500,000 IU/kg)  0.0011   MGA 100 premix (220 mg/kg)  0.024   Flavoring agent5  0.021  Analyzed composition6      DM, %  70.0 ± 2.1   OM, % of DM  92.0 ± 0.5   NDF, % of DM  25.7 ± 2.3   Starch, % of DM  40.6 ± 1.8   CP, % of DM  13.2 ± 0.9   Ca, % of DM  0.62   P, % of DM  0.39  1All ingredients except for rolled grains and forages were provided as part of a mash supplement. 2Composition was 43.0% DM, 11.9% CP, 47.2% NDF, and 32.3% ADF based on 4 samples composited by period. 3Pitman Moore Inc., Mundelein, IL; 18% K, 11% Mg, 22% S, 1,000 mg of Fe/kg. 4Supplied per kilogram of dietary DM: 15 mg of Cu, 65 mg of Zn, 28 mg of Mn, 0.7 mg of I, 0.2 mg of Co, 0.3 mg of Se, 6,000 IU of vitamin A, 600 IU of vitamin D, and 47 IU of vitamin E. 5Anise 420 Power, Canadian Biosystems Inc., Calgary, Alberta, Canada. 6Mean ± SD; n = 4, except for Ca and P, which were for 1 pooled sample. View Large Table 1. Ingredients and chemical composition of the diet Item  Amount  Ingredient,1 % of DM     Barley silage2  15.0   Barley grain, dry-rolled  80.1   Canola oil  0.14   Canola meal  1.71   Calcium carbonate  1.51   Dicalcium phosphate  0.42   Molasses  0.33   Salt  0.32   Dynamate3  0.38   Beef feedlot premix4  0.05   Vitamin E (500,000 IU/kg)  0.0011   MGA 100 premix (220 mg/kg)  0.024   Flavoring agent5  0.021  Analyzed composition6      DM, %  70.0 ± 2.1   OM, % of DM  92.0 ± 0.5   NDF, % of DM  25.7 ± 2.3   Starch, % of DM  40.6 ± 1.8   CP, % of DM  13.2 ± 0.9   Ca, % of DM  0.62   P, % of DM  0.39  Item  Amount  Ingredient,1 % of DM     Barley silage2  15.0   Barley grain, dry-rolled  80.1   Canola oil  0.14   Canola meal  1.71   Calcium carbonate  1.51   Dicalcium phosphate  0.42   Molasses  0.33   Salt  0.32   Dynamate3  0.38   Beef feedlot premix4  0.05   Vitamin E (500,000 IU/kg)  0.0011   MGA 100 premix (220 mg/kg)  0.024   Flavoring agent5  0.021  Analyzed composition6      DM, %  70.0 ± 2.1   OM, % of DM  92.0 ± 0.5   NDF, % of DM  25.7 ± 2.3   Starch, % of DM  40.6 ± 1.8   CP, % of DM  13.2 ± 0.9   Ca, % of DM  0.62   P, % of DM  0.39  1All ingredients except for rolled grains and forages were provided as part of a mash supplement. 2Composition was 43.0% DM, 11.9% CP, 47.2% NDF, and 32.3% ADF based on 4 samples composited by period. 3Pitman Moore Inc., Mundelein, IL; 18% K, 11% Mg, 22% S, 1,000 mg of Fe/kg. 4Supplied per kilogram of dietary DM: 15 mg of Cu, 65 mg of Zn, 28 mg of Mn, 0.7 mg of I, 0.2 mg of Co, 0.3 mg of Se, 6,000 IU of vitamin A, 600 IU of vitamin D, and 47 IU of vitamin E. 5Anise 420 Power, Canadian Biosystems Inc., Calgary, Alberta, Canada. 6Mean ± SD; n = 4, except for Ca and P, which were for 1 pooled sample. View Large Animals were housed in individual tie-stalls on mattresses bedded with wood shavings in the metabolism facility. Water was available freely throughout the experiment. The heifers were released to an outdoor pen for 1 h of exercise daily as the measurement and sampling schedule permitted. Body weight was measured at the beginning of period 1 and at the end of each period at the same time of each weighing (1400 h). Ruminal Fermentation Measurements Ruminal fluid (0.5 L) was collected on d 15 at 1, 3, 5, and 8 h after the morning feeding from multiple sites within the rumen via the rumen cannulas. Samples were immediately squeezed through a 355-µm polyester fabric (PECAP, Sefar Canada, Ville St. Laurent, Quebec, Canada) to obtain the filtrate, and the pH was measured immediately using a pH meter (Accumet model 25, Denver Instrument Company, Arvada, CO). A volume of 5 mL of the filtrate was mixed with 1 mL of 25% HPO3 (wt/vol) or with 1 mL of 1% sulfuric acid for VFA or NH3 analyses, respectively. All samples were stored frozen at −20°C until analysis. Duodenal Flow, Apparent Digestion, and Ruminal Microbial Protein Synthesis Duodenal flows, digestion at sites within the gastrointestinal tract, and apparent total tract digestibility of nutrients were determined using YbCl3 (GFS Chemicals Inc., Powell, OH) as a digesta marker. Ammonia 15N ([15NH4]2SO4, 10.6% atom % 15N; Isotec, Sigma-Aldrich Family, St. Louis, MO) was used as a ruminal microbial marker. The digesta marker (5.5 g of YbCl3∙6H2O, 1.2 g of Yb) and microbial marker (3 g of [15N](NH4)2SO4) were mixed with rolled barley together with CIN and were top-dressed onto the ration of each animal daily starting on d 9 of the period. Daily true consumption of Yb was determined by analysis of Yb in the refusals. During the last 4 d of each period, ruminal samples (~750 g/sample) were collected daily from 4 locations within the rumen, composited, and used to isolate ruminal bacteria. Duodenal samples were collected every 6 h moving ahead 2 h each day for the last 3 d of the period. This schedule provided 12 representative samples of duodenal contents taken at 2-h intervals. Duodenal samples were subdivided using an electric drill fitted with a shaft and propeller (Yang et al., 2007). Each sample was split into 3 fractions that were pooled by heifer within period and retained for chemical analyses as is or after freeze-drying. The sample for cell-free 15N analysis was centrifuged at 27,000 × g for 30 min at 4°C, and the supernatant was stored at −20°C for 15N determination. Fecal samples (~150 g of wet weight) were collected from each heifer from the rectum twice daily (a.m. and p.m.) with the collection time being moved ahead at 2-h intervals over the last 6 d of the sampling period. Fecal samples were immediately subsampled (approximately 50 g), composited across sampling times for each heifer and each period, dried at 55°C for 48 h, ground to pass a 1-mm sieve (standard model 4, Arthur Thomas Co., Philadelphia, PA), and stored for chemical analyses. Before adding the markers, a ruminal and a duodenal sample were taken from each heifer during the first period to determine background concentration of the markers in samples. The ruminal contents were squeezed through polyester monofilament fabric (355-µm mesh opening, PECAP, Sefar Canada) to obtain the filtrate and particles. The filtrate (1 mL) was transferred to a vial containing 5 mL of methyl green-formalin-saline solution for protozoal enumeration. The number of protozoa × 105 per milliliter was counted on a microscope at a magnification of 100 × in a 0.2-mL counting chamber after serial dilution. From each sample, duplicate measurements were conducted and the average was used to determine the number of protozoa present in the initial sample. The particles obtained by squeezing were blended by adding an equal amount of 0.9% NaCl in a Waring blender (Waring Products Division, New Hartford, CT) for 1 min to dislodge particulate-associated bacteria and then squeezed through the polyester fabric. Both filtrates from squeezed and strained homogenate were mixed and centrifuged (800 × g for 15 min at 4°C) to remove protozoa and feed particles, and the supernatant was centrifuged (27,000 × g for 30 min at 4°C) to obtain a mixed ruminal bacteria pellet. Bacterial pellets were accumulated by period and by heifer, freeze-dried, ground using a ball mill, and analyzed for OM, 15N, and total-N. These samples were used as a reference to calculate ruminal microbial protein synthesis. Blood Sampling and Laboratory Analyses Blood samples were obtained from each heifer on d 17 and 21 of each period. At 2 h after morning feeding, blood samples were collected from a jugular vein into two 10-mL vacuum tubes containing Na heparin and one 10-mL vacuum tube without additive (Vacutainer, Becton Dickinson, Franklin Lakes, NJ). Samples were centrifuged (5,000 × g for 20 min at 4°C) within 20 min, and collected plasma and serum were frozen at –20°C until analyzed. A subsample (1 mL) of the plasma was centrifuged at 16,000 × g for 2 min at 4°C (Spectrafuge 16M, National Labnet Co., Woodbridge, NJ) to remove fibrinogen, and the supernatant was used to analyze glucose (slide No. 8130536) and urea N using a dry chemistry analyzer (VetTest analyzer, model 8008, IDEXX Lab, Westbrook, ME). Concentrations of serum NEFA were determined using a commercially available enzymatic colorimetric procedure [NEFA-HR (2); Wako Chemicals, USA Inc., Richmond, VA]. Concentration of plasma triglyceride was determined using a commercially available test kit (#339, Sigma Diagnostics, St. Louis, MO). Concentrations of serum amyloid A (SAA), haptoglobin in the plasma, and lipopolysaccharide binding protein (LBP) in plasma were determined as outlined by Ametaj et al. (2005). The determination of total and differential white blood cells was described in our previous study (Yang et al., 2007). Chemical Analysis All chemical analyses were performed on each sample in duplicate, and where the CV for the replicate analysis was >5%, the analysis was repeated. Analytical DM content of the samples was determined by drying at 135°C for 2 h (AOAC, 1990; method 930.15). Ash content was determined by combustion at 550°C overnight, and OM content was calculated as 100 minus the percentage of ash (AOAC, 1990; method 942.05). The NDF and ADF contents were determined using the methods described by Van Soest et al. (1991) with α-amylase and sodium sulfite used in the NDF procedure. Ruminal VFA were separated and quantified by GLC (Varian 3700, Varian Specialties Ltd., Brockville, Ontario, Canada) using a 15-m (0.53-mm i.d.) fused silica column (DB-FFAP column, J and W Scientific, Folsom, CA), and crotonic acid (trans-2-butenoic acid) was used as the internal standard. Ammonia-N concentration was determined according to the technique of Weatherburn (1967) modified to use a plate reader. Concentrations of Yb in the feed offered, refusals, and duodenal and fecal samples were determined using inductively coupled plasma optical emission spectroscopy according to the AOAC method (AOAC, 1990) modified such that no CaCl2 for Yb determination was used during sample digestion. For the measurement of starch and CP (N × 6.25), samples were ground using a ball mill (Mixer Mill MM2000, Retsch, Haan, Germany) to a fine powder. Starch was determined by enzymatic hydrolysis of α-linked glucose polymers as described by Rode et al. (1999). Total N was determined by flash combustion technique (model 1500, Carlo Erba Instruments, Milan, Italy). The enrichment of 15N in the rumen bacterial and duodenal samples was analyzed by continuous flow measurement of 15N using a combustion analyzer interfaced with a stable isotope ratio mass spectrometer (VG Isotech, Middlewich, UK). Calculations and Statistical Analysis Flows of DM to the duodenum and DM excreted in feces were calculated by dividing Yb actually consumed (daily amount input, grams of Yb per day) by Yb concentration (grams of Yb per kilogram of DM) in the duodenal digesta or feces, respectively. Flows of other nutrients to the duodenum or feces were calculated by multiplying DM flow by their concentration in duodenal or fecal DM. Ruminal microbial protein synthesis for each heifer was estimated by the ratio of 15N flow at the duodenum to 15N concentration of mixed ruminal bacteria. Data were analyzed using the mixed model procedure (SAS Institute Inc., Cary, NC) to account for effects of period, animal, and treatment, where treatments were considered as a fixed effect, whereas period and animal were considered as random effects. The carryover effect was initially included in the model but was removed because it was not significant. Similarly, data for ruminal pH, VFA, NH3-N, and protozoa were analyzed by sampling time using repeated measures techniques. Effect of sampling day (d 17 or 21) and the interaction between treatment and sampling day were included in the model as fixed effects when variables related to blood metabolites and plasma acute phase protein were analyzed. The estimation method was the REML, and the degrees of freedom method was Kenward-Rogers (SAS Institute Inc.). Linear and quadratic orthogonal contrasts were tested using the CONTRAST statement of SAS. Differences between treatments were declared significant at P < 0.05, and means were compared using the Tukey correction for multiple comparisons. Trends were discussed at 0.05 < P < 0.10 unless otherwise stated. RESULTS Intake, Duodenal Flow, and Digestibility Intake of DM ranged from 8.7 to 10.7 kg/d among treatments and was quadratically changed with dose of CIN supplementation due to a slight increase (P < 0.09) for the low dose and a slight decrease for the high dose (Table 2). Although low and high doses differed, they were not different from the control. Intakes of OM, NDF, and starch followed the same general pattern as DMI. Table 2. Effect of cinnamaldehyde (CIN) supplementation on intake, duodenal flow, and site and extent of digestion in growing beef cattle Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  Intake, kg/d                        DM  9.7ab  10.7a  10.1ab  8.7b  0.5  0.04  0.04   OM  8.9ab  9.9a  9.3a  8.0b  0.5  0.04  0.04   NDF  2.51ab  2.77a  2.61a  2.27b  0.17  0.04  0.03   Starch  4.91ab  5.34a  5.09a  4.38b  0.31  0.03  0.03  BW, kg  628ab  632a  625ab  615b  26  0.02  0.21  Duodenal flow, kg/d                        Total OM  4.38  4.47  4.51  4.43  0.39  0.93  0.69   Microbial OM  1.30  1.39  1.44  1.27  0.13  0.73  0.21   NDF  1.48  1.70  1.55  1.59  0.13  0.68  0.32   Starch  0.82  0.77  0.80  0.75  0.11  0.68  0.99  RFOM,1 kg/d  5.81ab  6.78a  6.23a  4.81b  0.54  0.02  0.02  Digestibility, % of intake                        Rumen                         OM (true)2  65.3ab  68.3a  67.1a  60.0b  3.4  0.04  0.06    NDF  40.8a  37.5ab  40.3a  28.3b  6.7  0.05  0.34    Starch  83.0  85.5  84.2  83.3  2.4  0.90  0.54   Intestine                         OM  27.2  25.6  24.7  28.4  2.3  0.63  0.27    NDF  12.1  20.0  11.8  14.2  3.5  0.89  0.66    Starch  13.7  11.3  11.7  12.4  2.2  0.79  0.47   Total                         OM  77.8ab  79.8a  76.1ab  72.7b  3.2  0.05  0.41    NDF  52.9ab  57.4a  52.1ab  42.5b  6.8  0.06  0.23    Starch  96.7  96.8  95.8  95.7  1.3  0.22  0.87  Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  Intake, kg/d                        DM  9.7ab  10.7a  10.1ab  8.7b  0.5  0.04  0.04   OM  8.9ab  9.9a  9.3a  8.0b  0.5  0.04  0.04   NDF  2.51ab  2.77a  2.61a  2.27b  0.17  0.04  0.03   Starch  4.91ab  5.34a  5.09a  4.38b  0.31  0.03  0.03  BW, kg  628ab  632a  625ab  615b  26  0.02  0.21  Duodenal flow, kg/d                        Total OM  4.38  4.47  4.51  4.43  0.39  0.93  0.69   Microbial OM  1.30  1.39  1.44  1.27  0.13  0.73  0.21   NDF  1.48  1.70  1.55  1.59  0.13  0.68  0.32   Starch  0.82  0.77  0.80  0.75  0.11  0.68  0.99  RFOM,1 kg/d  5.81ab  6.78a  6.23a  4.81b  0.54  0.02  0.02  Digestibility, % of intake                        Rumen                         OM (true)2  65.3ab  68.3a  67.1a  60.0b  3.4  0.04  0.06    NDF  40.8a  37.5ab  40.3a  28.3b  6.7  0.05  0.34    Starch  83.0  85.5  84.2  83.3  2.4  0.90  0.54   Intestine                         OM  27.2  25.6  24.7  28.4  2.3  0.63  0.27    NDF  12.1  20.0  11.8  14.2  3.5  0.89  0.66    Starch  13.7  11.3  11.7  12.4  2.2  0.79  0.47   Total                         OM  77.8ab  79.8a  76.1ab  72.7b  3.2  0.05  0.41    NDF  52.9ab  57.4a  52.1ab  42.5b  6.8  0.06  0.23    Starch  96.7  96.8  95.8  95.7  1.3  0.22  0.87  a,bWithin a row, means without a common superscripts letter differ (P < 0.05). 1RFOM = OM that was truly fermented in the rumen calculated by correcting for microbial OM. 2Corrected for microbial portion. View Large Table 2. Effect of cinnamaldehyde (CIN) supplementation on intake, duodenal flow, and site and extent of digestion in growing beef cattle Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  Intake, kg/d                        DM  9.7ab  10.7a  10.1ab  8.7b  0.5  0.04  0.04   OM  8.9ab  9.9a  9.3a  8.0b  0.5  0.04  0.04   NDF  2.51ab  2.77a  2.61a  2.27b  0.17  0.04  0.03   Starch  4.91ab  5.34a  5.09a  4.38b  0.31  0.03  0.03  BW, kg  628ab  632a  625ab  615b  26  0.02  0.21  Duodenal flow, kg/d                        Total OM  4.38  4.47  4.51  4.43  0.39  0.93  0.69   Microbial OM  1.30  1.39  1.44  1.27  0.13  0.73  0.21   NDF  1.48  1.70  1.55  1.59  0.13  0.68  0.32   Starch  0.82  0.77  0.80  0.75  0.11  0.68  0.99  RFOM,1 kg/d  5.81ab  6.78a  6.23a  4.81b  0.54  0.02  0.02  Digestibility, % of intake                        Rumen                         OM (true)2  65.3ab  68.3a  67.1a  60.0b  3.4  0.04  0.06    NDF  40.8a  37.5ab  40.3a  28.3b  6.7  0.05  0.34    Starch  83.0  85.5  84.2  83.3  2.4  0.90  0.54   Intestine                         OM  27.2  25.6  24.7  28.4  2.3  0.63  0.27    NDF  12.1  20.0  11.8  14.2  3.5  0.89  0.66    Starch  13.7  11.3  11.7  12.4  2.2  0.79  0.47   Total                         OM  77.8ab  79.8a  76.1ab  72.7b  3.2  0.05  0.41    NDF  52.9ab  57.4a  52.1ab  42.5b  6.8  0.06  0.23    Starch  96.7  96.8  95.8  95.7  1.3  0.22  0.87  Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  Intake, kg/d                        DM  9.7ab  10.7a  10.1ab  8.7b  0.5  0.04  0.04   OM  8.9ab  9.9a  9.3a  8.0b  0.5  0.04  0.04   NDF  2.51ab  2.77a  2.61a  2.27b  0.17  0.04  0.03   Starch  4.91ab  5.34a  5.09a  4.38b  0.31  0.03  0.03  BW, kg  628ab  632a  625ab  615b  26  0.02  0.21  Duodenal flow, kg/d                        Total OM  4.38  4.47  4.51  4.43  0.39  0.93  0.69   Microbial OM  1.30  1.39  1.44  1.27  0.13  0.73  0.21   NDF  1.48  1.70  1.55  1.59  0.13  0.68  0.32   Starch  0.82  0.77  0.80  0.75  0.11  0.68  0.99  RFOM,1 kg/d  5.81ab  6.78a  6.23a  4.81b  0.54  0.02  0.02  Digestibility, % of intake                        Rumen                         OM (true)2  65.3ab  68.3a  67.1a  60.0b  3.4  0.04  0.06    NDF  40.8a  37.5ab  40.3a  28.3b  6.7  0.05  0.34    Starch  83.0  85.5  84.2  83.3  2.4  0.90  0.54   Intestine                         OM  27.2  25.6  24.7  28.4  2.3  0.63  0.27    NDF  12.1  20.0  11.8  14.2  3.5  0.89  0.66    Starch  13.7  11.3  11.7  12.4  2.2  0.79  0.47   Total                         OM  77.8ab  79.8a  76.1ab  72.7b  3.2  0.05  0.41    NDF  52.9ab  57.4a  52.1ab  42.5b  6.8  0.06  0.23    Starch  96.7  96.8  95.8  95.7  1.3  0.22  0.87  a,bWithin a row, means without a common superscripts letter differ (P < 0.05). 1RFOM = OM that was truly fermented in the rumen calculated by correcting for microbial OM. 2Corrected for microbial portion. View Large Duodenal flows of OM, NDF, and starch were not affected by feeding CIN (Table 2). However, the amount (kg/d) of OM truly fermented in the rumen (RFOM) was quadratically affected by dose of CIN. The RFOM tended to be 17% greater (P = 0.07) for the low dose, but 17% less (P = 0.06) for the high dose compared with the control. Digestibilities (% of intake) of OM and NDF in the rumen were affected by CIN dose, with supplementation with a high CIN dose tending to reduce OM digestibility (P = 0.10) by 8% and reducing NDF digestibility (P = 0.05) by 31% compared with the control (Table 2). No difference was observed for ruminal starch digestibility and intestinal digestibilities (% of intake) of OM, NDF, and starch were not affected by CIN supplementation. Thus, digestibilities of OM and NDF in the total tract reflected differences in ruminal digestibility, with differences between the high and low doses of CIN, although these doses were not different from control. Nitrogen Metabolism and Ruminal Microbial Protein Synthesis Intake of N reflected DMI. It was quadratically changed being greater with 400 mg of CIN than with 1,600 mg of CIN and with the high dose tending (P = 0.10) to be less than control (Table 3). Similarly, duodenal flows of total N and nonammonia N were quadratically changed with dose rate with no differences among the means. However, when expressed as a percentage of N intake, total N and NAN linearly increased with increasing dose of CIN. Duodenal flow of dietary plus endogenous N (g/d) tended (P = 0.10) to linearly increase with increasing CIN supplementation, and its percentage (% of N intake) was greater with high CIN than with control. Ruminal microbial protein synthesis (yield and efficiency) were not affected by treatment. Table 3. Effect of cinnamaldehyde (CIN) supplementation on microbial protein synthesis and protein digestion in growing beef cattle Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  N intake, g/d  205.7ab  227.7a  214.5a  183.8b  14.6  0.04  0.04  Flow to duodenum                        Total                         g/d  183.1  195.6  194.7  188.5  14.4  0.60  0.04    % of intake  89.7  87.9  91.7  102.9  8.2  0.05  0.34   NAN1                         g/d  181.2  193.2  193.0  186.0  14.6  0.67  0.04    % of intake  88.7  86.9  90.9  101.5  8.3  0.05  0.37   Ammonia N, g/d  1.91  2.32  1.71  2.52  0.32  0.16  0.29   Feed + endogenous                         g/d  71.1  77.7  76.3  82.7  10.2  0.10  0.85    % of intake  34.9b  35.5b  35.7b  45.8a  6.1  0.02  0.23   Microbial                         g/d  110.1  115.6  116.7  103.3  9.5  0.37  0.21    % of intake  53.8  51.4  55.2  55.6  4.2  0.56  0.85    g/kg of RFOM2  19.3  17.3  19.1  21.6  1.7  0.19  0.32  N digestibility                        Ruminal (truly), %  65.1a  64.5a  64.3a  54.2b  6.1  0.02  0.24   Postruminal                         % of intake  62.5  62.5  60.3  70.2  5.3  0.13  0.21    % of flow to duodenum  69.0  70.7  66.5  68.1  2.5  0.39  0.66   ADTT,3 % of intake  72.8  74.6  68.7  67.3  4.2  0.10  0.98  Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  N intake, g/d  205.7ab  227.7a  214.5a  183.8b  14.6  0.04  0.04  Flow to duodenum                        Total                         g/d  183.1  195.6  194.7  188.5  14.4  0.60  0.04    % of intake  89.7  87.9  91.7  102.9  8.2  0.05  0.34   NAN1                         g/d  181.2  193.2  193.0  186.0  14.6  0.67  0.04    % of intake  88.7  86.9  90.9  101.5  8.3  0.05  0.37   Ammonia N, g/d  1.91  2.32  1.71  2.52  0.32  0.16  0.29   Feed + endogenous                         g/d  71.1  77.7  76.3  82.7  10.2  0.10  0.85    % of intake  34.9b  35.5b  35.7b  45.8a  6.1  0.02  0.23   Microbial                         g/d  110.1  115.6  116.7  103.3  9.5  0.37  0.21    % of intake  53.8  51.4  55.2  55.6  4.2  0.56  0.85    g/kg of RFOM2  19.3  17.3  19.1  21.6  1.7  0.19  0.32  N digestibility                        Ruminal (truly), %  65.1a  64.5a  64.3a  54.2b  6.1  0.02  0.24   Postruminal                         % of intake  62.5  62.5  60.3  70.2  5.3  0.13  0.21    % of flow to duodenum  69.0  70.7  66.5  68.1  2.5  0.39  0.66   ADTT,3 % of intake  72.8  74.6  68.7  67.3  4.2  0.10  0.98  a,bWithin a row, means without a common superscript letter differ (P < 0.05). 1NAN = nonammonia N. 2RFOM = OM that was truly fermented in the rumen calculated by correcting for microbial OM. 3ADTT = apparent digestibility in the total tract. View Large Table 3. Effect of cinnamaldehyde (CIN) supplementation on microbial protein synthesis and protein digestion in growing beef cattle Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  N intake, g/d  205.7ab  227.7a  214.5a  183.8b  14.6  0.04  0.04  Flow to duodenum                        Total                         g/d  183.1  195.6  194.7  188.5  14.4  0.60  0.04    % of intake  89.7  87.9  91.7  102.9  8.2  0.05  0.34   NAN1                         g/d  181.2  193.2  193.0  186.0  14.6  0.67  0.04    % of intake  88.7  86.9  90.9  101.5  8.3  0.05  0.37   Ammonia N, g/d  1.91  2.32  1.71  2.52  0.32  0.16  0.29   Feed + endogenous                         g/d  71.1  77.7  76.3  82.7  10.2  0.10  0.85    % of intake  34.9b  35.5b  35.7b  45.8a  6.1  0.02  0.23   Microbial                         g/d  110.1  115.6  116.7  103.3  9.5  0.37  0.21    % of intake  53.8  51.4  55.2  55.6  4.2  0.56  0.85    g/kg of RFOM2  19.3  17.3  19.1  21.6  1.7  0.19  0.32  N digestibility                        Ruminal (truly), %  65.1a  64.5a  64.3a  54.2b  6.1  0.02  0.24   Postruminal                         % of intake  62.5  62.5  60.3  70.2  5.3  0.13  0.21    % of flow to duodenum  69.0  70.7  66.5  68.1  2.5  0.39  0.66   ADTT,3 % of intake  72.8  74.6  68.7  67.3  4.2  0.10  0.98  Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  N intake, g/d  205.7ab  227.7a  214.5a  183.8b  14.6  0.04  0.04  Flow to duodenum                        Total                         g/d  183.1  195.6  194.7  188.5  14.4  0.60  0.04    % of intake  89.7  87.9  91.7  102.9  8.2  0.05  0.34   NAN1                         g/d  181.2  193.2  193.0  186.0  14.6  0.67  0.04    % of intake  88.7  86.9  90.9  101.5  8.3  0.05  0.37   Ammonia N, g/d  1.91  2.32  1.71  2.52  0.32  0.16  0.29   Feed + endogenous                         g/d  71.1  77.7  76.3  82.7  10.2  0.10  0.85    % of intake  34.9b  35.5b  35.7b  45.8a  6.1  0.02  0.23   Microbial                         g/d  110.1  115.6  116.7  103.3  9.5  0.37  0.21    % of intake  53.8  51.4  55.2  55.6  4.2  0.56  0.85    g/kg of RFOM2  19.3  17.3  19.1  21.6  1.7  0.19  0.32  N digestibility                        Ruminal (truly), %  65.1a  64.5a  64.3a  54.2b  6.1  0.02  0.24   Postruminal                         % of intake  62.5  62.5  60.3  70.2  5.3  0.13  0.21    % of flow to duodenum  69.0  70.7  66.5  68.1  2.5  0.39  0.66   ADTT,3 % of intake  72.8  74.6  68.7  67.3  4.2  0.10  0.98  a,bWithin a row, means without a common superscript letter differ (P < 0.05). 1NAN = nonammonia N. 2RFOM = OM that was truly fermented in the rumen calculated by correcting for microbial OM. 3ADTT = apparent digestibility in the total tract. View Large Ruminal digestibility of N linearly decreased with increasing CIN supplementation, such that feeding 1,600 mg/d of CIN decreased ruminal digestibility of N by 17% compared with the control (Table 3). In contrast, digestibility of N in the intestine was numerically (P = 0.13) increased by 12% with high CIN. As a result, digestibility of N in the total tract tended (P = 0.10) to linearly decrease with increasing CIN supplementation. Thus, numerically increased intestinal digestibility with high CIN did not compensate for the decreased ruminal digestibility of N. Ruminal pH and Ruminal Fermentation Characteristics Mean daily ruminal pH ranged from 5.83 to 5.99, but was not affected by CIN (Table 4). Concentrations of total VFA and the molar proportions of acetate, propionate, butyrate, and branched-chain VFA, concentration of NH3-N, and the acetate to propionate ratio were not affected by CIN supplementation, except for the proportion of caproic acid, which was quadratically changed, being less with low or medium CIN compared with the control. Total numbers of protozoa and the proportions of Isotrichia, Dasytrichia, and Entodinium were not affected by treatment. Table 4. Effect of cinnamaldehyde (CIN) supplementation on ruminal pH and fermentation characteristics in beef cattle Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  pH  5.99  5.83  5.89  5.91  0.05  0.56  0.11  VFA                        Total, mM  139.9  143.7  142.0  144.2  12.9  0.75  0.91   Acetate (A), mol/100 mol  61.7  56.7  60.8  59.2  1.7  0.68  0.48   Propionate (P), mol/100 mol  19.6  24.1  21.4  23.5  2.3  0.36  0.62   Butyrate, mol/100 mol  13.5  15.1  13.6  12.8  1.1  0.30  0.38   BCFA,1 mol/100 mol  3.4  2.4  2.7  2.7  0.4  0.40  0.16   Valerate, mol/100 mol  1.3  1.5  1.4  1.4  0.1  0.56  0.54   Caproic, mol/100 mol  0.5  0.2  0.2  0.4  0.1  0.71  0.04   A:P  3.39  2.48  3.05  2.71  0.42  0.42  0.53  NH3 N, mM  4.34  4.98  4.71  4.12  1.04  0.50  0.24  Protozoa                        Total, × 105  16.9  16.0  20.8  18.3  4.0  0.47  0.47   % of total                         Isotrichia  1.82  0.99  0.78  0.79  0.60  0.30  0.40    Dasytrichia  6.09  3.68  3.60  2.72  1.46  0.17  0.50    Entodiniumium  91.95  95.23  95.54  96.44  1.99  0.17  0.45  Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  pH  5.99  5.83  5.89  5.91  0.05  0.56  0.11  VFA                        Total, mM  139.9  143.7  142.0  144.2  12.9  0.75  0.91   Acetate (A), mol/100 mol  61.7  56.7  60.8  59.2  1.7  0.68  0.48   Propionate (P), mol/100 mol  19.6  24.1  21.4  23.5  2.3  0.36  0.62   Butyrate, mol/100 mol  13.5  15.1  13.6  12.8  1.1  0.30  0.38   BCFA,1 mol/100 mol  3.4  2.4  2.7  2.7  0.4  0.40  0.16   Valerate, mol/100 mol  1.3  1.5  1.4  1.4  0.1  0.56  0.54   Caproic, mol/100 mol  0.5  0.2  0.2  0.4  0.1  0.71  0.04   A:P  3.39  2.48  3.05  2.71  0.42  0.42  0.53  NH3 N, mM  4.34  4.98  4.71  4.12  1.04  0.50  0.24  Protozoa                        Total, × 105  16.9  16.0  20.8  18.3  4.0  0.47  0.47   % of total                         Isotrichia  1.82  0.99  0.78  0.79  0.60  0.30  0.40    Dasytrichia  6.09  3.68  3.60  2.72  1.46  0.17  0.50    Entodiniumium  91.95  95.23  95.54  96.44  1.99  0.17  0.45  1BCFA = branched-chain fatty acids (isobutyrate + isovalerate). View Large Table 4. Effect of cinnamaldehyde (CIN) supplementation on ruminal pH and fermentation characteristics in beef cattle Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  pH  5.99  5.83  5.89  5.91  0.05  0.56  0.11  VFA                        Total, mM  139.9  143.7  142.0  144.2  12.9  0.75  0.91   Acetate (A), mol/100 mol  61.7  56.7  60.8  59.2  1.7  0.68  0.48   Propionate (P), mol/100 mol  19.6  24.1  21.4  23.5  2.3  0.36  0.62   Butyrate, mol/100 mol  13.5  15.1  13.6  12.8  1.1  0.30  0.38   BCFA,1 mol/100 mol  3.4  2.4  2.7  2.7  0.4  0.40  0.16   Valerate, mol/100 mol  1.3  1.5  1.4  1.4  0.1  0.56  0.54   Caproic, mol/100 mol  0.5  0.2  0.2  0.4  0.1  0.71  0.04   A:P  3.39  2.48  3.05  2.71  0.42  0.42  0.53  NH3 N, mM  4.34  4.98  4.71  4.12  1.04  0.50  0.24  Protozoa                        Total, × 105  16.9  16.0  20.8  18.3  4.0  0.47  0.47   % of total                         Isotrichia  1.82  0.99  0.78  0.79  0.60  0.30  0.40    Dasytrichia  6.09  3.68  3.60  2.72  1.46  0.17  0.50    Entodiniumium  91.95  95.23  95.54  96.44  1.99  0.17  0.45  Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  pH  5.99  5.83  5.89  5.91  0.05  0.56  0.11  VFA                        Total, mM  139.9  143.7  142.0  144.2  12.9  0.75  0.91   Acetate (A), mol/100 mol  61.7  56.7  60.8  59.2  1.7  0.68  0.48   Propionate (P), mol/100 mol  19.6  24.1  21.4  23.5  2.3  0.36  0.62   Butyrate, mol/100 mol  13.5  15.1  13.6  12.8  1.1  0.30  0.38   BCFA,1 mol/100 mol  3.4  2.4  2.7  2.7  0.4  0.40  0.16   Valerate, mol/100 mol  1.3  1.5  1.4  1.4  0.1  0.56  0.54   Caproic, mol/100 mol  0.5  0.2  0.2  0.4  0.1  0.71  0.04   A:P  3.39  2.48  3.05  2.71  0.42  0.42  0.53  NH3 N, mM  4.34  4.98  4.71  4.12  1.04  0.50  0.24  Protozoa                        Total, × 105  16.9  16.0  20.8  18.3  4.0  0.47  0.47   % of total                         Isotrichia  1.82  0.99  0.78  0.79  0.60  0.30  0.40    Dasytrichia  6.09  3.68  3.60  2.72  1.46  0.17  0.50    Entodiniumium  91.95  95.23  95.54  96.44  1.99  0.17  0.45  1BCFA = branched-chain fatty acids (isobutyrate + isovalerate). View Large Blood Chemistry and Immune Status Concentrations of blood glucose and urea N were not affected by CIN supplementation (Table 5). However, increasing CIN supplementation quadratically changed the concentration of blood triglyceride such that it was greater with low and medium CIN doses than with control. Further, CIN tended (P = 0.06) to quadratically change the concentration of serum NEFA, so that it tended to be less (P = 0.10) with low and medium CIN doses than with control. Total white blood cell counts were not affected by treatment, although the proportion of basophils tended (P = 0.08) to linearly decrease with increasing CIN supplementation. Concentration of haptoglobin in the plasma tended (P = 0.10) to quadratically change, being numerically less (P = 0.11) with medium CIN than with control. Concentrations of SAA and LBP were not affected by treatment. Table 5. Effect of cinnamaldehyde (CIN) supplementation on blood variables in beef cattle Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  Blood metabolite                        Glucose, mg/dL  78.5  80.3  81.3  84.0  3.5  0.18  0.96   Triglyceride, mg/dL  8.8  11.8  11.5  9.8  2.0  0.68  0.01   Urea N, mg/dL  21.9  24.5  22.0  20.7  2.6  0.39  0.44   NEFA, µM  71.1  60.3  60.6  66.3  4.3  0.65  0.06  WBC,1 × 103/µL  9.05  9.21  9.69  9.39  0.9  0.49  0.41  Lymphocyte, %  61.8  63.1  67.3  65.0  4.0  0.24  0.22  Neutrophil, %  26.8  23.9  20.3  21.0  4.2  0.14  0.29  Monocyte, %  8.4  7.1  7.4  7.8  1.8  0.45  0.79  Eosinophil, %  3.8  5.0  4.1  6.0  1.3  0.13  0.76  Basophil, %  1.4  0.9  1.0  0.3  0.4  0.08  0.90  Acute phase protein                        Haptoglobin, µg/mL  186  137  116  153  28  0.48  0.10   SAA,2 µg/mL  0.33  0.37  0.33  0.36  0.08  0.56  0.80   LBP,3 µg/mL  1.17  0.93  0.98  1.19  0.16  0.68  0.21  Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  Blood metabolite                        Glucose, mg/dL  78.5  80.3  81.3  84.0  3.5  0.18  0.96   Triglyceride, mg/dL  8.8  11.8  11.5  9.8  2.0  0.68  0.01   Urea N, mg/dL  21.9  24.5  22.0  20.7  2.6  0.39  0.44   NEFA, µM  71.1  60.3  60.6  66.3  4.3  0.65  0.06  WBC,1 × 103/µL  9.05  9.21  9.69  9.39  0.9  0.49  0.41  Lymphocyte, %  61.8  63.1  67.3  65.0  4.0  0.24  0.22  Neutrophil, %  26.8  23.9  20.3  21.0  4.2  0.14  0.29  Monocyte, %  8.4  7.1  7.4  7.8  1.8  0.45  0.79  Eosinophil, %  3.8  5.0  4.1  6.0  1.3  0.13  0.76  Basophil, %  1.4  0.9  1.0  0.3  0.4  0.08  0.90  Acute phase protein                        Haptoglobin, µg/mL  186  137  116  153  28  0.48  0.10   SAA,2 µg/mL  0.33  0.37  0.33  0.36  0.08  0.56  0.80   LBP,3 µg/mL  1.17  0.93  0.98  1.19  0.16  0.68  0.21  1WBC = white blood cells. 2SAA = serum amyloid A. 3LBP = lipopolysaccharide binding protein. View Large Table 5. Effect of cinnamaldehyde (CIN) supplementation on blood variables in beef cattle Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  Blood metabolite                        Glucose, mg/dL  78.5  80.3  81.3  84.0  3.5  0.18  0.96   Triglyceride, mg/dL  8.8  11.8  11.5  9.8  2.0  0.68  0.01   Urea N, mg/dL  21.9  24.5  22.0  20.7  2.6  0.39  0.44   NEFA, µM  71.1  60.3  60.6  66.3  4.3  0.65  0.06  WBC,1 × 103/µL  9.05  9.21  9.69  9.39  0.9  0.49  0.41  Lymphocyte, %  61.8  63.1  67.3  65.0  4.0  0.24  0.22  Neutrophil, %  26.8  23.9  20.3  21.0  4.2  0.14  0.29  Monocyte, %  8.4  7.1  7.4  7.8  1.8  0.45  0.79  Eosinophil, %  3.8  5.0  4.1  6.0  1.3  0.13  0.76  Basophil, %  1.4  0.9  1.0  0.3  0.4  0.08  0.90  Acute phase protein                        Haptoglobin, µg/mL  186  137  116  153  28  0.48  0.10   SAA,2 µg/mL  0.33  0.37  0.33  0.36  0.08  0.56  0.80   LBP,3 µg/mL  1.17  0.93  0.98  1.19  0.16  0.68  0.21  Item  CIN, mg/animal per d  SE  Contrast, P-value  0  400  800  1,600  Linear  Quadratic  Blood metabolite                        Glucose, mg/dL  78.5  80.3  81.3  84.0  3.5  0.18  0.96   Triglyceride, mg/dL  8.8  11.8  11.5  9.8  2.0  0.68  0.01   Urea N, mg/dL  21.9  24.5  22.0  20.7  2.6  0.39  0.44   NEFA, µM  71.1  60.3  60.6  66.3  4.3  0.65  0.06  WBC,1 × 103/µL  9.05  9.21  9.69  9.39  0.9  0.49  0.41  Lymphocyte, %  61.8  63.1  67.3  65.0  4.0  0.24  0.22  Neutrophil, %  26.8  23.9  20.3  21.0  4.2  0.14  0.29  Monocyte, %  8.4  7.1  7.4  7.8  1.8  0.45  0.79  Eosinophil, %  3.8  5.0  4.1  6.0  1.3  0.13  0.76  Basophil, %  1.4  0.9  1.0  0.3  0.4  0.08  0.90  Acute phase protein                        Haptoglobin, µg/mL  186  137  116  153  28  0.48  0.10   SAA,2 µg/mL  0.33  0.37  0.33  0.36  0.08  0.56  0.80   LBP,3 µg/mL  1.17  0.93  0.98  1.19  0.16  0.68  0.21  1WBC = white blood cells. 2SAA = serum amyloid A. 3LBP = lipopolysaccharide binding protein. View Large DISCUSSION Our study showed that the effects of supplementing feedlot finishing cattle with CIN depended on dose rate of CIN. At a low dose (400 mg/d), there were small, nonsignificant improvements in nutrient intake and digestibility of OM in the rumen and total tract. However, the opposite occurred at a high dose (1,600 mg/d); nutrient intake and ruminal digestibility, especially NDF and feed N digestibility, decreased. Decreased ruminal digestibility of feed N observed with the high dose resulted in greater flow of ruminally undegraded feed protein to the intestine, which could be beneficial for younger cattle with a high requirement for MP. However, the reduced feed consumption and reduced ruminal fiber digestibility observed for the high dose compared with the control would be undesirable for animal performance. Our results indicate that for high-grain diets, the effects of supplemental CIN on DMI depended on dosage. In a companion feedlot study using a similar diet and the same doses of CIN (Yang et al., 2010), we observed that all doses increased DMI in the first 28 d of the feeding period with the greatest increase with the low dose. However, CIN had no effects on DMI after 29 d of the experiment. In contrast, Cardozo et al. (2006) demonstrated a decrease in the concentrate intake in beef heifers fed a high-concentrate diet (90% concentrate + 10% barley straw) supplemented with a mixture of 180 mg/d of CIN and 90 mg/d of eugenol. That dose of CIN was even smaller than the low CIN dose (400 mg of CIN/d) used in our study. Thus, the negative effect of EO supplementation in that study may have been due to the combination of CIN with eugenol as compared with only CIN in our study. The reduction of feed intake by the high CIN dose in our study is supported by Busquet et al. (2003), in which concentrate intake of dairy cattle fed 600 mg of CIN/kg of DM was reduced by 12%. Clearly the dose of CIN used in that study was much greater than that used in our study. It can be concluded that DMI is inhibited with increased doses of CIN supplementation such as 1,600 mg/d or greater, but smaller doses have inconsistent effects on DMI, suggesting that dietary factors (e.g., concentrate level) and type of animal may affect response to dose of CIN. Changes in intake between the low and high dose of CIN did not affect duodenal flows of DM, OM, NDF, or starch because of differences in ruminal digestibility of OM and NDF. It was these differences in ruminal digestibility that compensated for differences in intake because microbial OM flow was not affected by treatment. Because ruminal digestibility (% of intake) of starch did not differ, the amount of starch digested in the rumen would have reflected differences in intake among doses of CIN. Much of the research to date with EO has been conducted in vitro, with only a limited number of animal feeding studies (Cardozo et al., 2006; Chaves et al., 2008). To compare the results from the present study to results from in vitro studies, it is necessary to estimate the concentration of CIN in the rumen fluid of the cattle after steady state was attained (10 d of feeding). Assuming a 60-L rumen volume, a liquid passage rate of 10%/h, and that all the top-dressed CIN was consumed within the first hour of feeding, the 400 mg/d dose would have resulted in a range of 0.6 to 7.2 mg/L over 24 h, the 800 mg/d dose would have resulted in range of 1.1 to 14.5 mg/L, and the 1,600 mg/d dose in a range of 2.3 to 29.0 mg/L. A comparison with in vitro results indicates that the level of CIN required to inhibit rumen fermentation is greater in animals compared with in vitro experimentation. For instance, in the present study low and medium doses of CIN tended to stimulate ruminal fermentation (increased ruminal digestibility); however, the same doses (3 mg/L) inhibited fermentation under continuous flow conditions as reported by Cardozo et al. (2005). Because the effects of EO in animals are dependent on dose rate, in vitro studies are not necessarily indicative of what happens in vivo; the response to a given dose differs in these 2 systems. Results of our study showed that the CIN supplementation had negligible effects on intestinal digestion. Therefore, the linearly decreased digestibilities of OM and NDF in the total tract due to CIN supplementation were mainly attributed to the linear decrease in ruminal digestibility. The data also suggest that the main modulating effects of CIN are in the rumen rather than in the intestine. Even though the total tract digestibilties of OM and NDF linearly decreased with the dose of CIN, the decrease in total digestibilities reached significance only for the high CIN dose as compared with the control or low CIN diets. Therefore, the decrease in total digestibility of OM with the high dose of CIN might be related mainly to the decreased digestion of NDF and protein in the rumen. The greater proportion of dietary N that arrived at the duodenum with high CIN supplementation resulted from the decreased ruminal degradability of feed N. It has been suggested that ruminal deamination is inhibited with CIN supplementation based on the observed reduction of rumen NH3 concentration with added CIN in an in vitro study (Cardozo et al., 2005) and in an animal study (Cardozo et al., 2006). Further evidence for an inhibition of ruminal deamination is the finding of Ferme et al. (2004) that addition of CIN to an in vitro rumen simulation system reduced the population of Prevotella spp., a group of bacteria known to be involved in the deamination process. Although the ruminal degradability of feed N linearly decreased with increasing CIN dose in our study, it is not possible to unequivocally identify the mechanism by which this occurred because we did not measure peptides and AA in the rumen contents or the duodenal flows. Furthermore, the lack of reduction in ruminal NH3 and blood urea N concentration when feeding high CIN was difficult to explain given that intake and ruminal degradability of N were decreased. The lack of effect of CIN on duodenal microbial protein flow in our study is consistent with the report by Busquet et al. (2005) in which there was no change in bacterial N flow in a dual-flow continuous culture supplied with 31.2 or 312 mg/L of CIN. However, in that study, the input and digestibility of DM were not affected by CIN. Supplementation of dairy cow diets with juniper berry oil, another EO, increased the amount of OM digested in the rumen (+13%), but microbial protein synthesis was not different from the control (Yang et al., 2007). It is possible that the inhibition of the deamination process by CIN might have caused an asynchrony between the energy and N availability in the rumen, and thus microbial protein synthesis was not enhanced despite increased energy availability in the rumen. The general lack of treatment effects on ruminal pH and VFA concentration (i.e., total and individual molar proportions) in our study was inconsistent with the changes in DMI and ruminal digestion of nutrients due to CIN supplementation. However, the results agree with those of Cardozo et al. (2006) who reported no differences in ruminal pH, total VFA concentration, or molar proportion of individual VFA despite a reduction in DMI when a mixture of CIN and eugenol was supplemented. In contrast, a consistent change in total VFA concentration and DM disappearance was observed in continuous culture (Busquet et al., 2005). In the rumen, the concentration of VFA reflects the equilibrium between absorption and production of VFA and does not necessarily reflect rumen digestion of OM, whereas VFA concentration in in vitro fermentation is a direct measure of DM digestion. The lack of treatment effect on protozoal numbers in the rumen is consistent with the literature that indicates only very large doses of EO reduce protozoal numbers. Hart et al. (2008) concluded in a review that the effect of EO on rumen protozoa varies with the type of EO tested and that relatively large concentrations of EO are required to decrease protozoal numbers. For example, Benchaar et al. (2008) reported that supplementation of dairy cows diets with 1,000 mg/d of CIN had no effect on the numbers or generic composition of ciliate protozoa. However, feeding 2,000 mg/d of anise extract containing 100 g/kg of anethol to beef heifer decreased counts of holotrichs and entodiniomorphs (Cardozo et al., 2006). Similar blood glucose concentration but less blood NEFA concentration for heifers fed low and medium CIN indicated a more positive energy balance in those groups compared with heifers fed the control diet. The response of blood NEFA to CIN supplementation might be due to the quadratic change in DMI and the amount of OM digested in the rumen, which provided more energy to the animal. Greater concentrations of blood triglycerides with the low and medium CIN also corresponded to greater DMI. The results suggest that the concentrations of some blood metabolites can be altered by addition of CIN through changing of feed intake and digestion processes in the rumen. The release of acute phase proteins is usually attributed to activation of the innate immune system in conditions like inflammation, tissue injury, and infection (Suffredini et al., 1999). The SAA and LBP directly participate in the detoxification and removal of endotoxin during an acute phase response. Emmanuel et al. (2008) reported a 14-fold increase in the concentration of endotoxin in the ruminal fluid with increasing proportions of barley grain in the diet of dairy cows. This was associated with enhanced plasma SAA and LBP. Results of this study showed no differences among the treatment groups regarding plasma SAA and LBP, suggesting a lack of effect of CIN on rumen endotoxin. In conclusion, the results of this study suggest that supplementation of high-grain diets with CIN affected feed intake and ruminal digestion of feeds in a dose-dependent manner. A low dose of CIN tended to increase OM availability in the rumen due to increased feed intake and greater ruminal digested OM. Increased ruminal OM availability did not, however, increase ruminal microbial protein synthesis. In contrast, feed intake and ruminal digestion of feeds was adversely affected when a high dose of CIN was supplemented. Reducing fiber digestion in the rumen would negatively affect feed efficiency, but reducing ruminal CP degradation provides more rumen undegraded protein to the small intestine. The mode of action of CIN appears to be mainly in the rumen, affecting ruminal digestion with minimal effects on intestinal digestion. Further study is warranted to understand the mode of action of CIN in inhibiting CP degradation and fiber digestion in the rumen and modulation of acute protein release by hepatocytes. Finally, caution must be used when interpreting the results from this study because of the small number of animals used; thus, further verification of these findings is warranted. LITERATURE CITED Ametaj B. N. Bradford B. J. Bobe G. Nafikov R. A. Lu Y. Young J. W. Beitz D. C. 2005. Strong relationship between mediators of the acute phase response and fatty liver in dairy cows. Can. J. Anim. Sci.  85: 165– 175. Google Scholar CrossRef Search ADS   AOAC 1990. Official Methods of Analysis.  15th ed. Assoc. Off. Anal. Chem., Arlington, VA. Benchaar C. McAllister T. A. Chouinard P. Y. 2008. Digestion, ruminal fermentation, ciliate protozoal populations, and milk production from dairy cows fed cinnamaldehyde, quebracho condensed tannin, or Yucca schidigera saponin extracts. J. Dairy Sci.  91: 4765– 4777. https://doi.org/19038952 Google Scholar CrossRef Search ADS PubMed  Busquet M. Calsamiglia S. Ferret A. Cardozo P. W. Kamel C. 2005. Effects of cinnamaldehyde and garlic oil on rumen microbial fermentation in a dual flow continuous culture. J. Dairy Sci.  88: 2508– 2516. https://doi.org/15956313 Google Scholar CrossRef Search ADS PubMed  Busquet M. Calsamiglia S. Ferret A. Kamel C. 2006. Plant extracts affect in vitro rumen microbial fermentation. J. Dairy Sci.  89: 761– 771. https://doi.org/16428643 Google Scholar CrossRef Search ADS PubMed  Busquet, M., H. Greathead, S. Calsamiglia, A. Ferret, and C. Kamel 2003. Efecto del extracto de ajo y el cinemaldehido sobre la producción, composición y residuos en leche en vacas de alta producción. ITEA  24 (Vol. Extra): 756– 758. Calsamiglia S. Busquet M. Cardozo W. Castillejos L. Ferret A. 2007. Invited Review: Essential oils as modifiers of rumen microbial fermentation. J. Dairy Sci.  90: 2580– 2595. https://doi.org/17517698 Google Scholar CrossRef Search ADS PubMed  Canadian Council on Animal Care 1993. Guide to the Care and Use of Experimental Animals. Vol. 1.  2nd ed. E. D. Olfert, B. M. Cross, and A. A. McWilliam ed. Can. Counc. Anim. Care, Ottawa, Ontario, Canada. Cardozo P. W. Calsamiglia S. Ferret A. Kamel C. 2005. Screening for the effects of natural plant extracts at different pH on in vitro rumen microbial fermentation of a high-concentrate diet for beef cattle. J. Anim. Sci.  83: 2572– 2579. https://doi.org/16230654 Google Scholar CrossRef Search ADS PubMed  Cardozo P. W. Calsamiglia S. Ferret A. Kamel C. 2006. Effects of alfalfa extracts, anise, capsicum, and a mixture of cinnamaldehyde and eugenol on ruminal fermentation and protein degradation in beef heifers fed a high-concentrate diet. J. Anim. Sci.  84: 2801– 2808. https://doi.org/16971582 Google Scholar CrossRef Search ADS PubMed  Chaves A. V. Stanford K. Gibson L. L. McAllister T. A. Benchaar C. 2008. Effects of carvacrol and cinnamaldehyde on intake, rumen fermentation, growth performance, and carcass characteristics of growing lambs. Anim. Feed Sci. Technol.  145: 396– 408. Google Scholar CrossRef Search ADS   Emmanuel D. G. V. Dunn S. M. Ametaj B. N. 2008. Feeding high proportions of barley grain stimulates an inflammatory response in dairy cows. J. Dairy Sci.  91: 606– 614. https://doi.org/18218747 Google Scholar CrossRef Search ADS PubMed  Ferme D. Banjac M. Calsamiglia S. Busquet M. Kamel C. Avgustin G. 2004. The effects of plant extracts on microbial community structure in a rumen-simulating continuous-culture system as revealed by molecular profiling. Folia Microbiol. (Praha)  49: 151– 155. https://doi.org/15227787 Google Scholar CrossRef Search ADS PubMed  Fraser G. R. Chaves A. V. Wang Y. McAllister T. A. Beauchemin K. A. Benchaar C. 2007. Assessment of the effects of cinnamon leaf oil on rumen microbial fermentation using two continuous culture systems. J. Dairy Sci.  90: 2315– 2328. https://doi.org/17430934 Google Scholar CrossRef Search ADS PubMed  Hart K. J. Yáñez-Ruiz D. R. Duval S. M. McEwan N. R. Newbold C. J. 2008. Plant extracts to manipulate rumen fermentation. Anim. Feed Sci. Technol.  147: 8– 35. Google Scholar CrossRef Search ADS   McIntosh F. M. Williams P. Losa R. Wallace R. J. Beever D. A. Newbold C. J. 2003. Effects of essential oils on ruminal microorganisms and their protein metabolism. Appl. Environ. Microbiol.  69: 5011– 5014. https://doi.org/12902303 Google Scholar CrossRef Search ADS PubMed  NRC 1996. Nutrient Requirements of Beef Cattle.  7th rev. ed. Natl. Acad. Press, Washington, DC. Parveen S. Lukasik J. Scott T. M. Tamplin M. L. Portier K. M. Sheperd S. Braun K. Farrah S. R. 2006. Geographical variation in antibiotic resistance profiles of Escherichia coli isolated from swine, poultry, beef and dairy cattle farm water retention ponds in Florida. J. Appl. Microbiol.  100: 50– 57. https://doi.org/16405684 Google Scholar CrossRef Search ADS PubMed  Rode L. M. Yang W. Z. Beauchemin K. A. 1999. Fibrolytic enzyme supplements for dairy cows in early lactation. J. Dairy Sci.  82: 2121– 2126. https://doi.org/10531597 Google Scholar CrossRef Search ADS PubMed  Standen M. D. Myers S. P. 2004. The roles of essential oils in the modulation of immune function and inflammation: Survey of aromatherapy educators. Int. J. Aromatherapy  14: 150– 161. Google Scholar CrossRef Search ADS   Suffredini A. F. Fantuzzi G. Badolato R. Oppenheim J. J. O'Grady N. 1999. New insights into the biology of the acute phase response. J. Clin. Immunol.  19: 203– 214. https://doi.org/10471974 Google Scholar CrossRef Search ADS PubMed  Van Soest P. J. Robertson J. B. Lewis B. A. 1991. Methods for dietary fiber, neutral detergent fiber and non-starch polysaccharide in relation to animal nutrition. J. Dairy Sci.  74: 3583– 3597. https://doi.org/1660498 Google Scholar CrossRef Search ADS PubMed  Weatherburn M. W. 1967. Phenol-hypochlorite reaction for determination of ammonia. Anal. Chem.  39: 971– 974. Google Scholar CrossRef Search ADS   Yang W. Z. Ametaj B. N. Benchaar C. He M. L. Beauchemin K. A. 2010. Cinnamaldehyde in feedlot cattle diets: Intake, growth performance, carcass characteristics, and blood metabolites. J . Anim. Sci.  https://doi.org/10.2527/jas.2008-1608 Yang W. Z. Benchaar C. Ametaj B. N. Chaves A. V. He M. L. McAllister T. A. 2007. Effects of garlic and juniper berry oils on ruminal fermentation and digestion of lactating dairy cows. J. Dairy Sci.  90: 5671– 5681. https://doi.org/18024759 Google Scholar CrossRef Search ADS PubMed  Footnotes 1 Contribution number 38708053. American Society of Animal Science

Journal

Journal of Animal Science – Oxford University Press

Published: Feb 1, 2013

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