Effects of vitamin E on growth performance, tissue α-tocopherol, and lipid peroxidation of starter White Pekin ducks

Effects of vitamin E on growth performance, tissue α-tocopherol, and lipid peroxidation of... ABSTRACT Two experiments were conducted to evaluate the effects of vitamin E on growth performance, tissue α-tocopherol, and lipid peroxidation of White Pekin ducks from hatch to 21 d of age. The 6 supplemental vitamin E levels (0, 5, 10, 20, 40, and 100 mg DL-α-tocopheryl acetate/kg) and 4 supplemental vitamin E levels (0, 10, 20, and 100 mg DL-α-tocopheryl acetate/kg) were utilized in experiments 1 and 2, respectively. All treatments were replicated 8 times using 7 ducklings per pen in experiment 1 and 6 times using 8 birds per pen in experiment 2. All ducks were raised from hatch to 21 d of age. In both experiments, compared with ducks fed vitamin E-supplemented diets, the birds fed basal diets with no supplemental vitamin E had less weight gain and feed intake (P < 0.05) but these two criteria showed no linear or quadratic response to increasing supplemental vitamin E levels (P > 0.05). On the other hand, the plasma or liver α-tocopherol was dependent on supplemental vitamin E levels. The plasma or liver α-tocopherol increased linearly or quadratically as supplemental vitamin E increased gradually in both experiments (P < 0.05). In addition, supplementation of vitamin E in basal diets could reduce liver lipid peroxidation but the further reduction did not take place when supplemental vitamin E level was above 5 mg/kg in experiment 1 or 10 mg/kg in experiment 2 due to no linear or quadratic response to increasing supplemental levels of this vitamin (P > 0.05). Therefore, when including the vitamin E content of basal diets, the dietary total vitamin E should not be less than 10 mg/kg in order to keep optimal growth performance and antioxidant capacity of starter Pekin ducks from hatch to 21 days of age. Plasma or liver α-tocopherol were sensitive indicators for the status of this vitamin. INTRODUCTION Vitamin E is a fat-soluble vitamin that is essential for poultry growth. Jager (1972) observed that vitamin E deficiency could lead to necrocalcinosis in the muscles of the heart, intestine, and gizzard of Pekin ducks and the vitamin E recommendation of NRC (1994) for White Pekin ducks was 10 IU/kg according to this reference. However, after the publication of NRC (1994), new information on the requirement of this vitamin for modern strain ducks was still missing. Furthermore, continued increase in poultry performance dictates the need for continual reevaluation of dietary vitamin specification and the vitamin intake per unit of output was a 0.60% to 0.80% yearly decline per kg body gain for meat poultry due to improving feed efficiency (Leeson, 2007). It is time to update the requirement of this vitamin for ducks. On the other hand, tissue tocopherol and lipid peroxidation were usually used as criteria to evaluate the vitamin E status. In early years, when myopathy of the leg muscles was observed in vitamin E-deficient Pekin ducks, the more severe the myopathy of leg muscles was, the lower the serum tocopherol (Jager, 1972), which showed that serum tocopherol was a sensitive indicator for vitamin E deficiency. Recently, the antioxidant capability of vitamin E was observed in Muscovy ducks in which the lipid oxidation in breast meat was reduced markedly when a high dose of vitamin E was added to diets (Schiavone et al., 2010), but this study was aimed at confirming the effects of vitamin E on lipid stability of duck breast meat and the results were obtained at excessive vitamin E levels (230 vs. 30 mg/kg α-tocopheryl acetate). Therefore, additional duck research on the antioxidant capability of vitamin E at ranges from deficient to adequate levels should be conducted. Herein, considering that the vitamin E requirement of modern strain duck was actually lacking, the objective of the present study was to examine the effects of vitamin E on growth performance, tissue α-tocopherol, and lipid peroxidation of White Pekin ducks and to discuss the requirements of this vitamin for these ducks. MATERIALS AND METHODS All procedures of our experiments were approved by the animal care and use committee of Institute of Animal Sciences of Chinese Academy of Agricultural Sciences. Two dose-response experiments were conducted to evaluate effects of vitamin E on growth performance, tissue α-tocopherol, and lipid peroxidation of starter White Pekin ducks. Experiment 1 was conducted first and was followed by experiment 2. In both experiments, DL-α-tocopheryl acetate was the source of supplemental vitamin E. A dose-response experiment with 6 supplemental vitamin E levels (0, 5, 10, 20, 40, and 100 DL-α-tocopheryl acetate mg/kg) and 4 supplemental vitamin E levels (0, 10, 20, and 100 mg DL-α-tocopheryl acetate/kg) was utilized in experiment 1 and 2, respectively. These two basal diets were formulated to be vitamin E deficient (Table 1) and they contained 7.41 and 1.04 mg/kg α-tocopherol by chemical analysis in experiment 1 and 2, respectively. To produce experimental diets, the basal diet was produced first and then the experimental diets were produced by blending the basal diet and different supplemental levels of DL-α-tocopheryl acetate. In experiment 1, a total of 336 one-d-old male White Pekin ducks were allotted to 6 experimental treatments and each treatment contained 8 replicate pens with 7 ducks per pen. In experiment 2, a total of 192 one-d-old male White Pekin ducks were divided to 4 experimental treatments and each treatment contained 6 replicate pens with 8 ducks per pen. These birds in both experiments were raised from hatch to 21 days. Table 1. Composition of the basal diets in experiment 1 and 2 (% as fed). Ingredient(%) Experiment 1 Experiment 2 Corn starch 26.5 41.7 Soybean 11.5 – Whey dehydrated – 20.0 Peanut meal 22.0 34.5 Wheat 16.0 – Corn 20.2 – Dicalcium phosphate 1.5 1.5 Limestone 1.0 1.0 Premix1 1.0 1.0 Salt (%) 0.3 0.3 Calculated composition Metabolizable energy (kcal/kg)2 2700 2750 Crude protein(%) 19.6 19.0 Methionine(%) 0.45 0.45 Lysine(%) 1.10 1.10 Calcium (%) 1.00 1.10 Nonphytate phosphorus(%) 0.41 0.49 α-tocopherol (mg/kg)3 7.41 1.04 Ingredient(%) Experiment 1 Experiment 2 Corn starch 26.5 41.7 Soybean 11.5 – Whey dehydrated – 20.0 Peanut meal 22.0 34.5 Wheat 16.0 – Corn 20.2 – Dicalcium phosphate 1.5 1.5 Limestone 1.0 1.0 Premix1 1.0 1.0 Salt (%) 0.3 0.3 Calculated composition Metabolizable energy (kcal/kg)2 2700 2750 Crude protein(%) 19.6 19.0 Methionine(%) 0.45 0.45 Lysine(%) 1.10 1.10 Calcium (%) 1.00 1.10 Nonphytate phosphorus(%) 0.41 0.49 α-tocopherol (mg/kg)3 7.41 1.04 1Supplied per kilogram of total diet: Cu (CuSO4•5H2O), 10 mg; Fe (FeSO4•7H2O), 60 mg; Zn (ZnO), 60 mg; Mn (MnSO4•H2O), 80 mg; Se (NaSeO3), 0.2 mg; I (KI), 0.2 mg; choline chloride, 1,000 mg; vitamin A (retinyl acetate), 10,000 IU; vitamin D3 (Cholcalciferol), 3,000 IU; vitamin K3 (menadione sodium bisulfate), 2 mg; thiamin (thiamin mononitrate), 2 mg; riboflavin, 8 mg; pyridoxine hydrochloride, 4 mg; cobalamin, 0.06 mg; calcium-D-pantothenate, 20 mg; nicotinic acid, 50 mg; folic acid, 1 mg; biotin, 0.2 mg. 2The values are calculated according to the AME of chickens (Ministry of Agriculture of China, 2004). 3The data are analyzed values. View Large Table 1. Composition of the basal diets in experiment 1 and 2 (% as fed). Ingredient(%) Experiment 1 Experiment 2 Corn starch 26.5 41.7 Soybean 11.5 – Whey dehydrated – 20.0 Peanut meal 22.0 34.5 Wheat 16.0 – Corn 20.2 – Dicalcium phosphate 1.5 1.5 Limestone 1.0 1.0 Premix1 1.0 1.0 Salt (%) 0.3 0.3 Calculated composition Metabolizable energy (kcal/kg)2 2700 2750 Crude protein(%) 19.6 19.0 Methionine(%) 0.45 0.45 Lysine(%) 1.10 1.10 Calcium (%) 1.00 1.10 Nonphytate phosphorus(%) 0.41 0.49 α-tocopherol (mg/kg)3 7.41 1.04 Ingredient(%) Experiment 1 Experiment 2 Corn starch 26.5 41.7 Soybean 11.5 – Whey dehydrated – 20.0 Peanut meal 22.0 34.5 Wheat 16.0 – Corn 20.2 – Dicalcium phosphate 1.5 1.5 Limestone 1.0 1.0 Premix1 1.0 1.0 Salt (%) 0.3 0.3 Calculated composition Metabolizable energy (kcal/kg)2 2700 2750 Crude protein(%) 19.6 19.0 Methionine(%) 0.45 0.45 Lysine(%) 1.10 1.10 Calcium (%) 1.00 1.10 Nonphytate phosphorus(%) 0.41 0.49 α-tocopherol (mg/kg)3 7.41 1.04 1Supplied per kilogram of total diet: Cu (CuSO4•5H2O), 10 mg; Fe (FeSO4•7H2O), 60 mg; Zn (ZnO), 60 mg; Mn (MnSO4•H2O), 80 mg; Se (NaSeO3), 0.2 mg; I (KI), 0.2 mg; choline chloride, 1,000 mg; vitamin A (retinyl acetate), 10,000 IU; vitamin D3 (Cholcalciferol), 3,000 IU; vitamin K3 (menadione sodium bisulfate), 2 mg; thiamin (thiamin mononitrate), 2 mg; riboflavin, 8 mg; pyridoxine hydrochloride, 4 mg; cobalamin, 0.06 mg; calcium-D-pantothenate, 20 mg; nicotinic acid, 50 mg; folic acid, 1 mg; biotin, 0.2 mg. 2The values are calculated according to the AME of chickens (Ministry of Agriculture of China, 2004). 3The data are analyzed values. View Large In both experiments, during the experimental period, these ducklings were reared in raised wire-floor pens (200 × 100 × 40 cm) and had free access to water and feed. Water was provided by drip-nipple water supply lines and feed was in pellet form. In the duck barns, lighting was continuous and the temperature was kept at 33°C from 1 to 3 d of age and then it was reduced gradually to 25°C until 21 d of age. At the end of both experiments, the body weight gain, feed intake, and feed/gain of ducks from each pen were measured. After fasting for 12 hours, two ducks were selected from each pen according to the average body weight of the corresponding pens and then bled by heart puncture. Blood samples were collected into heparin sodium-anticoagulant tubes and centrifuged at 3,000 rpm for 10 min to obtain plasma. Plasma was kept at −20°C until it was analyzed. Afterwards, these selected birds were killed by CO2 asphyxiation for sampling and livers were collected. The α-tocopherol in plasma, liver, and feed samples were all determined using reversed phase high performance liquid chromatography (2695 Alliance, Waters, Milford, MA) with fluorescence detection according to the method of Jensen et al. (1999). Chromatographic separation was achieved on an Atlantis T3 column (150 × 4.6 mm) (Waters, Milford, MA). The mobile phase was 98% methanol and the fluorescence quantification was performed with an excitation wavelength of 290 nm and emission wavelength of 327 nm. The lipid peroxidation was estimated by spectrophotometric determination of thiobarbituric acid reactive substances (TBARS) with commercial assay kits purchased from Nanjing Jiancheng Institute of Bioengineering (Nanjing, Jiangsu, China) and the TBARS were expressed as nanomoles of malonaldehyde (MDA) per milliliter for plasma and nanomoles of MDA per milligram of protein for liver. Data were analyzed as a completely randomized design using the one-way ANOVA procedure of SAS (SAS Institute, 2003), with pen used as the experimental unit for analysis. When dietary treatment was significant (P < 0.05), means were compared by using Turkey's multiple comparison procedure of SAS (SAS Institute, 2003). The linear and quadratic polynomial contrasts were also performed to determine the effect of supplemental vitamin E on duck performance. The variability in the data was expressed as the standard error of the means (SEM) and a probability level of P < 0.05 was considered to be statistically significant. RESULTS In our study, experiment 1 was conducted first and was followed by experiment 2. The effects of vitamin E on duck response were similar in both experiments and the results of experiment 1 were justified by those of experiment 2. Effects of vitamin E on growth performance of starter Pekin ducks from hatch to 21 days in experiments 1 and 2 are shown in Tables 2 and 3, respectively. In both experiments, except feed/gain, the weight gain and feed intake were both influenced by supplementation of vitamin E (P < 0.05). The ducks fed basal diets with no supplementation of vitamin E had the lowest weight gain and feed intake among all ducks and supplementation of vitamin E in diets could improve weight gain and feed intake significantly (P < 0.05). However, the weight gain and feed intake showed no linear or quadratic response to increasing supplemental vitamin E (P > 0.05). Table 2. Effects of vitamin E on growth performance of Pekin ducks from hatch to 21 days (experiment 1).1 Supplemental vitamin E (mg/kg) Daily feed intake (g/bird/day) Daily weight gain (g/bird/day) Feed/gain (g/g) 0 101.0d 54.3c 1.86 5 109.6a 57.4a 1.91 10 106.6a-c 56.7a,b 1.88 20 102.2c,d 54.7b,c 1.87 40 102.3c,d 55.2a-c 1.85 100 107.7a,b 57.4a 1.88 SEM 3.52 1.39 0.021 Probability Vitamin E 0.003 0.011 0. 210 Vitamin E linear 0.644 0.433 0.856 Vitamin E quadratic 0.704 0.629 0.655 Supplemental vitamin E (mg/kg) Daily feed intake (g/bird/day) Daily weight gain (g/bird/day) Feed/gain (g/g) 0 101.0d 54.3c 1.86 5 109.6a 57.4a 1.91 10 106.6a-c 56.7a,b 1.88 20 102.2c,d 54.7b,c 1.87 40 102.3c,d 55.2a-c 1.85 100 107.7a,b 57.4a 1.88 SEM 3.52 1.39 0.021 Probability Vitamin E 0.003 0.011 0. 210 Vitamin E linear 0.644 0.433 0.856 Vitamin E quadratic 0.704 0.629 0.655 1Results are means with n = 8 per treatment. a–dMeans with different superscripts within the same column differ significantly (P < 0.05). View Large Table 2. Effects of vitamin E on growth performance of Pekin ducks from hatch to 21 days (experiment 1).1 Supplemental vitamin E (mg/kg) Daily feed intake (g/bird/day) Daily weight gain (g/bird/day) Feed/gain (g/g) 0 101.0d 54.3c 1.86 5 109.6a 57.4a 1.91 10 106.6a-c 56.7a,b 1.88 20 102.2c,d 54.7b,c 1.87 40 102.3c,d 55.2a-c 1.85 100 107.7a,b 57.4a 1.88 SEM 3.52 1.39 0.021 Probability Vitamin E 0.003 0.011 0. 210 Vitamin E linear 0.644 0.433 0.856 Vitamin E quadratic 0.704 0.629 0.655 Supplemental vitamin E (mg/kg) Daily feed intake (g/bird/day) Daily weight gain (g/bird/day) Feed/gain (g/g) 0 101.0d 54.3c 1.86 5 109.6a 57.4a 1.91 10 106.6a-c 56.7a,b 1.88 20 102.2c,d 54.7b,c 1.87 40 102.3c,d 55.2a-c 1.85 100 107.7a,b 57.4a 1.88 SEM 3.52 1.39 0.021 Probability Vitamin E 0.003 0.011 0. 210 Vitamin E linear 0.644 0.433 0.856 Vitamin E quadratic 0.704 0.629 0.655 1Results are means with n = 8 per treatment. a–dMeans with different superscripts within the same column differ significantly (P < 0.05). View Large Table 3. Effects of vitamin E on growth performance of Pekin ducks from hatch to 21 days (experiment 2).1 Supplemental vitamin E (mg/kg) Daily feed intake (g/bird/day) Daily weight gain (g/bird/day) Feed/gain (g/g) 0 94.8c 40.7b 2.34 10 103.2a,b 43.6a 2.37 20 101.7b 43.4a 2.35 100 107.0a 43.9a 2.44 SEM 5.10 1.49 0.045 Probability Vitamin E 0.001 0.008 0.376 Vitamin E linear 0.216 0.429 0.038 Vitamin E quadratic 0.432 0.466 0.266 Supplemental vitamin E (mg/kg) Daily feed intake (g/bird/day) Daily weight gain (g/bird/day) Feed/gain (g/g) 0 94.8c 40.7b 2.34 10 103.2a,b 43.6a 2.37 20 101.7b 43.4a 2.35 100 107.0a 43.9a 2.44 SEM 5.10 1.49 0.045 Probability Vitamin E 0.001 0.008 0.376 Vitamin E linear 0.216 0.429 0.038 Vitamin E quadratic 0.432 0.466 0.266 1Results are means with n = 6 per treatment. a–cMeans with different superscripts within the same column differ significantly (P < 0.05). View Large Table 3. Effects of vitamin E on growth performance of Pekin ducks from hatch to 21 days (experiment 2).1 Supplemental vitamin E (mg/kg) Daily feed intake (g/bird/day) Daily weight gain (g/bird/day) Feed/gain (g/g) 0 94.8c 40.7b 2.34 10 103.2a,b 43.6a 2.37 20 101.7b 43.4a 2.35 100 107.0a 43.9a 2.44 SEM 5.10 1.49 0.045 Probability Vitamin E 0.001 0.008 0.376 Vitamin E linear 0.216 0.429 0.038 Vitamin E quadratic 0.432 0.466 0.266 Supplemental vitamin E (mg/kg) Daily feed intake (g/bird/day) Daily weight gain (g/bird/day) Feed/gain (g/g) 0 94.8c 40.7b 2.34 10 103.2a,b 43.6a 2.37 20 101.7b 43.4a 2.35 100 107.0a 43.9a 2.44 SEM 5.10 1.49 0.045 Probability Vitamin E 0.001 0.008 0.376 Vitamin E linear 0.216 0.429 0.038 Vitamin E quadratic 0.432 0.466 0.266 1Results are means with n = 6 per treatment. a–cMeans with different superscripts within the same column differ significantly (P < 0.05). View Large Effects of vitamin E on plasma and liver α-tocopherol and lipid peroxidation of 21-d-old Pekin ducks are shown in Tables 4 and 5, respectively. In both experiments, compared with ducks fed vitamin E-supplemented diets, the ducks fed basal diets with no supplemental vitamin E had lower plasma and liver α-tocopherol (P < 0.05) and plasma and liver α-tocopherol increased linearly or quadratically (P < 0.05) as supplemental vitamin E increased (P < 0.05). On the other hand, in both experiments, supplementation of vitamin E influenced the lipid peroxidation expressed as MDA in the liver (P < 0.05) but not in the plasma (P > 0.05). The ducks fed basal diets with no supplemental vitamin E had the greatest liver MDA among all birds and the supplementation of vitamin E could reduce liver MDA (P < 0.05) as supplemental vitamin E increased. However, the liver MDA showed no linear or quadratic response to this vitamin in both experiments (P > 0.05). Table 4. Effects of vitamin E on plasma and liver α-tocopherol and lipid peroxidation of 21-day-old Pekin ducks (experiment 1).1 Supplemental vitamin E (mg/kg) α-tocopherol Malondialdehyde Plasma (μg/mL) Liver (μg/g) Plasma (nmol/mL) Liver (nmol/mg protein) 0 1.68d 0.54d 5.51 2.88a 5 2.23d 0.91c,d 5.71 2.12a,b 10 3.63c,d 1.32c,d 5.77 1.96a-c 20 5.90c 2.36c 6.07 1.84b,c 40 9.33b 3.96b 5.81 1.51b,c 100 22.76a 9.31a 5.52 1.49b,c SEM 7.942 3.297 0.208 0.512 Probability Vitamin E <0.001 <0.001 0.078 0.002 Vitamin E linear <0.001 <0.001 0.588 0.116 Vitamin E quadratic <0.001 <0.001 0.233 0.069 Supplemental vitamin E (mg/kg) α-tocopherol Malondialdehyde Plasma (μg/mL) Liver (μg/g) Plasma (nmol/mL) Liver (nmol/mg protein) 0 1.68d 0.54d 5.51 2.88a 5 2.23d 0.91c,d 5.71 2.12a,b 10 3.63c,d 1.32c,d 5.77 1.96a-c 20 5.90c 2.36c 6.07 1.84b,c 40 9.33b 3.96b 5.81 1.51b,c 100 22.76a 9.31a 5.52 1.49b,c SEM 7.942 3.297 0.208 0.512 Probability Vitamin E <0.001 <0.001 0.078 0.002 Vitamin E linear <0.001 <0.001 0.588 0.116 Vitamin E quadratic <0.001 <0.001 0.233 0.069 1Results are means with n = 8 per treatment. a–dMeans with different superscripts within the same column differ significantly (P < 0.05). View Large Table 4. Effects of vitamin E on plasma and liver α-tocopherol and lipid peroxidation of 21-day-old Pekin ducks (experiment 1).1 Supplemental vitamin E (mg/kg) α-tocopherol Malondialdehyde Plasma (μg/mL) Liver (μg/g) Plasma (nmol/mL) Liver (nmol/mg protein) 0 1.68d 0.54d 5.51 2.88a 5 2.23d 0.91c,d 5.71 2.12a,b 10 3.63c,d 1.32c,d 5.77 1.96a-c 20 5.90c 2.36c 6.07 1.84b,c 40 9.33b 3.96b 5.81 1.51b,c 100 22.76a 9.31a 5.52 1.49b,c SEM 7.942 3.297 0.208 0.512 Probability Vitamin E <0.001 <0.001 0.078 0.002 Vitamin E linear <0.001 <0.001 0.588 0.116 Vitamin E quadratic <0.001 <0.001 0.233 0.069 Supplemental vitamin E (mg/kg) α-tocopherol Malondialdehyde Plasma (μg/mL) Liver (μg/g) Plasma (nmol/mL) Liver (nmol/mg protein) 0 1.68d 0.54d 5.51 2.88a 5 2.23d 0.91c,d 5.71 2.12a,b 10 3.63c,d 1.32c,d 5.77 1.96a-c 20 5.90c 2.36c 6.07 1.84b,c 40 9.33b 3.96b 5.81 1.51b,c 100 22.76a 9.31a 5.52 1.49b,c SEM 7.942 3.297 0.208 0.512 Probability Vitamin E <0.001 <0.001 0.078 0.002 Vitamin E linear <0.001 <0.001 0.588 0.116 Vitamin E quadratic <0.001 <0.001 0.233 0.069 1Results are means with n = 8 per treatment. a–dMeans with different superscripts within the same column differ significantly (P < 0.05). View Large Table 5. Effects of vitamin E on plasma and liver α-tocopherol and lipid peroxidation of 21-day-old Pekin ducks (experiment 2).1 Supplemental vitamin E (mg/kg) α-tocopherol Malondialdehyde Plasma (μg/mL) Liver (μg/g) Plasma (nmol/mL) Liver (nmol/mg protein) 0 0.57d 0.20d 6.74 1.77a 10 2.40c 1.12c 6.70 1.41b 20 4.18b 1.96b 7.04 1.35b 100 19.15a 9.35a 6.57 1.27c SEM 8.512 4.190 0.199 0.221 Probability Vitamin E <0.001 <0.001 0.692 0.010 Vitamin E linear <0.001 <0.001 0.475 0.327 Vitamin E quadratic 0.002 0.005 0.497 0.276 Supplemental vitamin E (mg/kg) α-tocopherol Malondialdehyde Plasma (μg/mL) Liver (μg/g) Plasma (nmol/mL) Liver (nmol/mg protein) 0 0.57d 0.20d 6.74 1.77a 10 2.40c 1.12c 6.70 1.41b 20 4.18b 1.96b 7.04 1.35b 100 19.15a 9.35a 6.57 1.27c SEM 8.512 4.190 0.199 0.221 Probability Vitamin E <0.001 <0.001 0.692 0.010 Vitamin E linear <0.001 <0.001 0.475 0.327 Vitamin E quadratic 0.002 0.005 0.497 0.276 1Results are means with n = 6 per treatment. a–dMeans with different superscripts within the same column differ significantly (P < 0.05). View Large Table 5. Effects of vitamin E on plasma and liver α-tocopherol and lipid peroxidation of 21-day-old Pekin ducks (experiment 2).1 Supplemental vitamin E (mg/kg) α-tocopherol Malondialdehyde Plasma (μg/mL) Liver (μg/g) Plasma (nmol/mL) Liver (nmol/mg protein) 0 0.57d 0.20d 6.74 1.77a 10 2.40c 1.12c 6.70 1.41b 20 4.18b 1.96b 7.04 1.35b 100 19.15a 9.35a 6.57 1.27c SEM 8.512 4.190 0.199 0.221 Probability Vitamin E <0.001 <0.001 0.692 0.010 Vitamin E linear <0.001 <0.001 0.475 0.327 Vitamin E quadratic 0.002 0.005 0.497 0.276 Supplemental vitamin E (mg/kg) α-tocopherol Malondialdehyde Plasma (μg/mL) Liver (μg/g) Plasma (nmol/mL) Liver (nmol/mg protein) 0 0.57d 0.20d 6.74 1.77a 10 2.40c 1.12c 6.70 1.41b 20 4.18b 1.96b 7.04 1.35b 100 19.15a 9.35a 6.57 1.27c SEM 8.512 4.190 0.199 0.221 Probability Vitamin E <0.001 <0.001 0.692 0.010 Vitamin E linear <0.001 <0.001 0.475 0.327 Vitamin E quadratic 0.002 0.005 0.497 0.276 1Results are means with n = 6 per treatment. a–dMeans with different superscripts within the same column differ significantly (P < 0.05). View Large DISCUSSION In our study, experiment 1 was conducted first and it was followed by experiment 2. In order to justify the results of experiment 1, the total vitamin E content was formulated to 11.04 mg/kg when 10 mg DL-α-tocopheryl acetate was supplemented to the basal diets in experiment 2 and this value was similar to the total vitamin E content (12.41 mg/kg) when 5 DL-α-tocopheryl acetate was supplemented to the basal diets in experiment 1. Therefore, the results of experiment 1 could be justified by those of the following experiment 2 and all results of these two experiments were combined to discuss the effects of vitamin E on duck performance. In our study, the basal diets was deficient in vitamin E and the ducks fed basal diets with no supplementation of vitamin E had the lowest weight gain and feed intake among all ducks. Although supplementation of vitamin E could improve the growth performance of the ducks, the weight gain and feed intake of ducks were not improved further when supplemental vitamin E was above 5 mg/kg in experiment 1 and 10 mg/kg in experiment 2. Our results are supported by Schiavone et al. (2010). In their study, there were no significant differences in growth performance between Muscovy ducks fed diets containing 30 and 230 mg/kg supplemental α-tocopherol acetate. Therefore, the supplemental vitamin E of 5 mg/kg in experiment 1 and 10 mg/kg in experiment 2 may be adequate for duck growth. When the vitamin E contents of the basal diets were included (7.41 mg vitamin E/kg in experiment 1 and 1.04 mg vitamin E/kg in experiment 2), no less than 10 mg/kg total vitamin E was required by starter ducks and this indicates that the NRC (1994) recommendation for this vitamin (10 IU/kg) for Pekin ducks is enough for modern duck strains. Our conclusion is also supported by Guo et al. (2001). In their study, when the basal diet contained 13 mg/kg α-tocopherol, supplementation of vitamin E from 5 to 100 mg/kg in the basal diet had no significant effects on weight gain, feed intake, and feed/gain of broilers from hatch to 3 weeks of age. Unlike growth performance, tissue tocopherol was more sensitive to the change of dietary vitamin E. Whether in experiment 1 or 2, plasma and liver α-tocopherol increased linearly or quadratically as dietary vitamin E increased (Table 4 and 5), which is in agreement with the results of Jager (1972) which showed a similar change in serum tocopherol for ducklings. Furthermore, the status of vitamin E could be indicated by blood tocopherol. In our study, the linear or quadratic dose response increase of plasma α-tocopherol was also accompanied simultaneously with the same change of liver α-tocopherol. Our results are also in agreement with the results in broilers of Jensen et al. (1999). In their study, as supplemental α-tocopherol increased, the increasing concentrations of α-tocopherol in the liver and breast meat was followed by increasing concentrations of α-tocopherol in the plasma. Furthermore, in the study of Jager (1972), the myopathy of leg muscles was a symptom of vitamin E deficiency in ducks and a more severe myopathy of the leg muscles was often accompanied by lower serum tocopherol. Therefore, blood tocopherol could serve as a sensitive indicator for the vitamin E status of ducks when ill ducks are screened for vitamin E deficiency. In our study, the lipid peroxidation expressed as MDA, was measured in the plasma and liver in order to evaluate the antioxidant status of the ducks depending on supplemental vitamin E levels. Supplementation of vitamin E in basal diets could reduce lipid peroxidation in the liver of ducks which is indicated by decreasing MDA at high supplemental vitamin E levels (Tables 4 and 5). Our results are in agreement with the results of Schiavone et al. (2010) in which the lipid oxidation in the breast meat of Muscovy ducks was reduced markedly by addition of 200 mg/kg α-tocopheryl acetate to the diets. However, when supplemental vitamin E was above 5 mg/kg in experiment 1 and 10 mg/kg in experiment 2, the liver lipid peroxidation was not reduced further. Therefore, the antioxidant capacity of vitamin E may be not improved further when dietary total vitamin E is above 10 mg/kg. Our results are supported by Guo et al. (2001) in which supplementation of vitamin E from 5 to 100 mg/kg had no significant effects on TBARS concentrations in hepatic tissues of broiler chicks expressed as MDA with basal diets containing 13 mg/kg α-tocopheryl. In conclusion, in order to maintain optimal growth performance and antioxidant capacity of starter Pekin ducks from hatch to 21 days of age, the dietary total vitamin E level should not be less than 10 mg/kg. The plasma or liver α-tocopherol is dependent on the dietary vitamin E level and both are sensitive indicators for the status of this vitamin. ACKNOWLEDGMENTS This work was sponsored by the earmarked fund for China Agriculture Research System (CARS-42) and the science and technology innovation project of Chinese Academy of Agricultural Sciences (CXGC-IAS-09). REFERENCES Guo Y. , Tang Q. , Yuan J. , Jiang Z. . 2001 . Effects of supplementation with vitamin E on the performance and the tissue peroxidation of broiler chicks and the stability of thigh meat against oxidative deterioration . Anim. Feed. Sci. Technol. 89 : 165 – 173 . Google Scholar CrossRef Search ADS Jager F. C. 1972 . Linoleic acid intake and vitamin E requirement in rats and ducklings . Ann. N.Y. Acad. Sci. 20 : 199 – 211 . Google Scholar CrossRef Search ADS Jensen S. K. , Engberg R. M. , Hedemann M. S. . 1999 . All-rac-tocopherol acetate is a better vitamin E source than all-rac-_-tocop herol succinate for broilers . J. Nutr. 129 : 1355 – 1360 . Google Scholar CrossRef Search ADS PubMed Leeson S. 2007 . Vitamin requirements: is there basis for re-evaluating dietary specifications? World's Poult. Sci. J. , 63 : 255 – 266 . Google Scholar CrossRef Search ADS Ministry of Agriculture of China . 2004 . Feeding standard of chicken . Standards Press of China , Beijing, China . NRC . 1994 . Nutrient Requirements of Poultry . 9th rev. ed . Natl. Acad. Press , Washington, DC . SAS Institute . 2003 . SAS User's Guide: Statistics . Version 9.0 . SAS Institute, Inc. , Cary, NC . Schiavone A. , Marzoni M. , Castillo A. , Nery J. , Romboli I. . 2010 . Dietary lipid sources and vitamin E affect fatty acid composition or lipid stability of breast meat from Muscovy duck . Canadian J. Anim. Sci. 90 : 371 – 378 . Google Scholar CrossRef Search ADS © 2018 Poultry Science Association Inc. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Poultry Science Oxford University Press

Effects of vitamin E on growth performance, tissue α-tocopherol, and lipid peroxidation of starter White Pekin ducks

Poultry Science , Volume Advance Article (6) – Mar 15, 2018

Loading next page...
 
/lp/ou_press/effects-of-vitamin-e-on-growth-performance-tissue-tocopherol-and-lipid-vc1044bizs
Publisher
Oxford University Press
Copyright
© 2018 Poultry Science Association Inc.
ISSN
0032-5791
eISSN
1525-3171
D.O.I.
10.3382/ps/pex443
Publisher site
See Article on Publisher Site

Abstract

ABSTRACT Two experiments were conducted to evaluate the effects of vitamin E on growth performance, tissue α-tocopherol, and lipid peroxidation of White Pekin ducks from hatch to 21 d of age. The 6 supplemental vitamin E levels (0, 5, 10, 20, 40, and 100 mg DL-α-tocopheryl acetate/kg) and 4 supplemental vitamin E levels (0, 10, 20, and 100 mg DL-α-tocopheryl acetate/kg) were utilized in experiments 1 and 2, respectively. All treatments were replicated 8 times using 7 ducklings per pen in experiment 1 and 6 times using 8 birds per pen in experiment 2. All ducks were raised from hatch to 21 d of age. In both experiments, compared with ducks fed vitamin E-supplemented diets, the birds fed basal diets with no supplemental vitamin E had less weight gain and feed intake (P < 0.05) but these two criteria showed no linear or quadratic response to increasing supplemental vitamin E levels (P > 0.05). On the other hand, the plasma or liver α-tocopherol was dependent on supplemental vitamin E levels. The plasma or liver α-tocopherol increased linearly or quadratically as supplemental vitamin E increased gradually in both experiments (P < 0.05). In addition, supplementation of vitamin E in basal diets could reduce liver lipid peroxidation but the further reduction did not take place when supplemental vitamin E level was above 5 mg/kg in experiment 1 or 10 mg/kg in experiment 2 due to no linear or quadratic response to increasing supplemental levels of this vitamin (P > 0.05). Therefore, when including the vitamin E content of basal diets, the dietary total vitamin E should not be less than 10 mg/kg in order to keep optimal growth performance and antioxidant capacity of starter Pekin ducks from hatch to 21 days of age. Plasma or liver α-tocopherol were sensitive indicators for the status of this vitamin. INTRODUCTION Vitamin E is a fat-soluble vitamin that is essential for poultry growth. Jager (1972) observed that vitamin E deficiency could lead to necrocalcinosis in the muscles of the heart, intestine, and gizzard of Pekin ducks and the vitamin E recommendation of NRC (1994) for White Pekin ducks was 10 IU/kg according to this reference. However, after the publication of NRC (1994), new information on the requirement of this vitamin for modern strain ducks was still missing. Furthermore, continued increase in poultry performance dictates the need for continual reevaluation of dietary vitamin specification and the vitamin intake per unit of output was a 0.60% to 0.80% yearly decline per kg body gain for meat poultry due to improving feed efficiency (Leeson, 2007). It is time to update the requirement of this vitamin for ducks. On the other hand, tissue tocopherol and lipid peroxidation were usually used as criteria to evaluate the vitamin E status. In early years, when myopathy of the leg muscles was observed in vitamin E-deficient Pekin ducks, the more severe the myopathy of leg muscles was, the lower the serum tocopherol (Jager, 1972), which showed that serum tocopherol was a sensitive indicator for vitamin E deficiency. Recently, the antioxidant capability of vitamin E was observed in Muscovy ducks in which the lipid oxidation in breast meat was reduced markedly when a high dose of vitamin E was added to diets (Schiavone et al., 2010), but this study was aimed at confirming the effects of vitamin E on lipid stability of duck breast meat and the results were obtained at excessive vitamin E levels (230 vs. 30 mg/kg α-tocopheryl acetate). Therefore, additional duck research on the antioxidant capability of vitamin E at ranges from deficient to adequate levels should be conducted. Herein, considering that the vitamin E requirement of modern strain duck was actually lacking, the objective of the present study was to examine the effects of vitamin E on growth performance, tissue α-tocopherol, and lipid peroxidation of White Pekin ducks and to discuss the requirements of this vitamin for these ducks. MATERIALS AND METHODS All procedures of our experiments were approved by the animal care and use committee of Institute of Animal Sciences of Chinese Academy of Agricultural Sciences. Two dose-response experiments were conducted to evaluate effects of vitamin E on growth performance, tissue α-tocopherol, and lipid peroxidation of starter White Pekin ducks. Experiment 1 was conducted first and was followed by experiment 2. In both experiments, DL-α-tocopheryl acetate was the source of supplemental vitamin E. A dose-response experiment with 6 supplemental vitamin E levels (0, 5, 10, 20, 40, and 100 DL-α-tocopheryl acetate mg/kg) and 4 supplemental vitamin E levels (0, 10, 20, and 100 mg DL-α-tocopheryl acetate/kg) was utilized in experiment 1 and 2, respectively. These two basal diets were formulated to be vitamin E deficient (Table 1) and they contained 7.41 and 1.04 mg/kg α-tocopherol by chemical analysis in experiment 1 and 2, respectively. To produce experimental diets, the basal diet was produced first and then the experimental diets were produced by blending the basal diet and different supplemental levels of DL-α-tocopheryl acetate. In experiment 1, a total of 336 one-d-old male White Pekin ducks were allotted to 6 experimental treatments and each treatment contained 8 replicate pens with 7 ducks per pen. In experiment 2, a total of 192 one-d-old male White Pekin ducks were divided to 4 experimental treatments and each treatment contained 6 replicate pens with 8 ducks per pen. These birds in both experiments were raised from hatch to 21 days. Table 1. Composition of the basal diets in experiment 1 and 2 (% as fed). Ingredient(%) Experiment 1 Experiment 2 Corn starch 26.5 41.7 Soybean 11.5 – Whey dehydrated – 20.0 Peanut meal 22.0 34.5 Wheat 16.0 – Corn 20.2 – Dicalcium phosphate 1.5 1.5 Limestone 1.0 1.0 Premix1 1.0 1.0 Salt (%) 0.3 0.3 Calculated composition Metabolizable energy (kcal/kg)2 2700 2750 Crude protein(%) 19.6 19.0 Methionine(%) 0.45 0.45 Lysine(%) 1.10 1.10 Calcium (%) 1.00 1.10 Nonphytate phosphorus(%) 0.41 0.49 α-tocopherol (mg/kg)3 7.41 1.04 Ingredient(%) Experiment 1 Experiment 2 Corn starch 26.5 41.7 Soybean 11.5 – Whey dehydrated – 20.0 Peanut meal 22.0 34.5 Wheat 16.0 – Corn 20.2 – Dicalcium phosphate 1.5 1.5 Limestone 1.0 1.0 Premix1 1.0 1.0 Salt (%) 0.3 0.3 Calculated composition Metabolizable energy (kcal/kg)2 2700 2750 Crude protein(%) 19.6 19.0 Methionine(%) 0.45 0.45 Lysine(%) 1.10 1.10 Calcium (%) 1.00 1.10 Nonphytate phosphorus(%) 0.41 0.49 α-tocopherol (mg/kg)3 7.41 1.04 1Supplied per kilogram of total diet: Cu (CuSO4•5H2O), 10 mg; Fe (FeSO4•7H2O), 60 mg; Zn (ZnO), 60 mg; Mn (MnSO4•H2O), 80 mg; Se (NaSeO3), 0.2 mg; I (KI), 0.2 mg; choline chloride, 1,000 mg; vitamin A (retinyl acetate), 10,000 IU; vitamin D3 (Cholcalciferol), 3,000 IU; vitamin K3 (menadione sodium bisulfate), 2 mg; thiamin (thiamin mononitrate), 2 mg; riboflavin, 8 mg; pyridoxine hydrochloride, 4 mg; cobalamin, 0.06 mg; calcium-D-pantothenate, 20 mg; nicotinic acid, 50 mg; folic acid, 1 mg; biotin, 0.2 mg. 2The values are calculated according to the AME of chickens (Ministry of Agriculture of China, 2004). 3The data are analyzed values. View Large Table 1. Composition of the basal diets in experiment 1 and 2 (% as fed). Ingredient(%) Experiment 1 Experiment 2 Corn starch 26.5 41.7 Soybean 11.5 – Whey dehydrated – 20.0 Peanut meal 22.0 34.5 Wheat 16.0 – Corn 20.2 – Dicalcium phosphate 1.5 1.5 Limestone 1.0 1.0 Premix1 1.0 1.0 Salt (%) 0.3 0.3 Calculated composition Metabolizable energy (kcal/kg)2 2700 2750 Crude protein(%) 19.6 19.0 Methionine(%) 0.45 0.45 Lysine(%) 1.10 1.10 Calcium (%) 1.00 1.10 Nonphytate phosphorus(%) 0.41 0.49 α-tocopherol (mg/kg)3 7.41 1.04 Ingredient(%) Experiment 1 Experiment 2 Corn starch 26.5 41.7 Soybean 11.5 – Whey dehydrated – 20.0 Peanut meal 22.0 34.5 Wheat 16.0 – Corn 20.2 – Dicalcium phosphate 1.5 1.5 Limestone 1.0 1.0 Premix1 1.0 1.0 Salt (%) 0.3 0.3 Calculated composition Metabolizable energy (kcal/kg)2 2700 2750 Crude protein(%) 19.6 19.0 Methionine(%) 0.45 0.45 Lysine(%) 1.10 1.10 Calcium (%) 1.00 1.10 Nonphytate phosphorus(%) 0.41 0.49 α-tocopherol (mg/kg)3 7.41 1.04 1Supplied per kilogram of total diet: Cu (CuSO4•5H2O), 10 mg; Fe (FeSO4•7H2O), 60 mg; Zn (ZnO), 60 mg; Mn (MnSO4•H2O), 80 mg; Se (NaSeO3), 0.2 mg; I (KI), 0.2 mg; choline chloride, 1,000 mg; vitamin A (retinyl acetate), 10,000 IU; vitamin D3 (Cholcalciferol), 3,000 IU; vitamin K3 (menadione sodium bisulfate), 2 mg; thiamin (thiamin mononitrate), 2 mg; riboflavin, 8 mg; pyridoxine hydrochloride, 4 mg; cobalamin, 0.06 mg; calcium-D-pantothenate, 20 mg; nicotinic acid, 50 mg; folic acid, 1 mg; biotin, 0.2 mg. 2The values are calculated according to the AME of chickens (Ministry of Agriculture of China, 2004). 3The data are analyzed values. View Large In both experiments, during the experimental period, these ducklings were reared in raised wire-floor pens (200 × 100 × 40 cm) and had free access to water and feed. Water was provided by drip-nipple water supply lines and feed was in pellet form. In the duck barns, lighting was continuous and the temperature was kept at 33°C from 1 to 3 d of age and then it was reduced gradually to 25°C until 21 d of age. At the end of both experiments, the body weight gain, feed intake, and feed/gain of ducks from each pen were measured. After fasting for 12 hours, two ducks were selected from each pen according to the average body weight of the corresponding pens and then bled by heart puncture. Blood samples were collected into heparin sodium-anticoagulant tubes and centrifuged at 3,000 rpm for 10 min to obtain plasma. Plasma was kept at −20°C until it was analyzed. Afterwards, these selected birds were killed by CO2 asphyxiation for sampling and livers were collected. The α-tocopherol in plasma, liver, and feed samples were all determined using reversed phase high performance liquid chromatography (2695 Alliance, Waters, Milford, MA) with fluorescence detection according to the method of Jensen et al. (1999). Chromatographic separation was achieved on an Atlantis T3 column (150 × 4.6 mm) (Waters, Milford, MA). The mobile phase was 98% methanol and the fluorescence quantification was performed with an excitation wavelength of 290 nm and emission wavelength of 327 nm. The lipid peroxidation was estimated by spectrophotometric determination of thiobarbituric acid reactive substances (TBARS) with commercial assay kits purchased from Nanjing Jiancheng Institute of Bioengineering (Nanjing, Jiangsu, China) and the TBARS were expressed as nanomoles of malonaldehyde (MDA) per milliliter for plasma and nanomoles of MDA per milligram of protein for liver. Data were analyzed as a completely randomized design using the one-way ANOVA procedure of SAS (SAS Institute, 2003), with pen used as the experimental unit for analysis. When dietary treatment was significant (P < 0.05), means were compared by using Turkey's multiple comparison procedure of SAS (SAS Institute, 2003). The linear and quadratic polynomial contrasts were also performed to determine the effect of supplemental vitamin E on duck performance. The variability in the data was expressed as the standard error of the means (SEM) and a probability level of P < 0.05 was considered to be statistically significant. RESULTS In our study, experiment 1 was conducted first and was followed by experiment 2. The effects of vitamin E on duck response were similar in both experiments and the results of experiment 1 were justified by those of experiment 2. Effects of vitamin E on growth performance of starter Pekin ducks from hatch to 21 days in experiments 1 and 2 are shown in Tables 2 and 3, respectively. In both experiments, except feed/gain, the weight gain and feed intake were both influenced by supplementation of vitamin E (P < 0.05). The ducks fed basal diets with no supplementation of vitamin E had the lowest weight gain and feed intake among all ducks and supplementation of vitamin E in diets could improve weight gain and feed intake significantly (P < 0.05). However, the weight gain and feed intake showed no linear or quadratic response to increasing supplemental vitamin E (P > 0.05). Table 2. Effects of vitamin E on growth performance of Pekin ducks from hatch to 21 days (experiment 1).1 Supplemental vitamin E (mg/kg) Daily feed intake (g/bird/day) Daily weight gain (g/bird/day) Feed/gain (g/g) 0 101.0d 54.3c 1.86 5 109.6a 57.4a 1.91 10 106.6a-c 56.7a,b 1.88 20 102.2c,d 54.7b,c 1.87 40 102.3c,d 55.2a-c 1.85 100 107.7a,b 57.4a 1.88 SEM 3.52 1.39 0.021 Probability Vitamin E 0.003 0.011 0. 210 Vitamin E linear 0.644 0.433 0.856 Vitamin E quadratic 0.704 0.629 0.655 Supplemental vitamin E (mg/kg) Daily feed intake (g/bird/day) Daily weight gain (g/bird/day) Feed/gain (g/g) 0 101.0d 54.3c 1.86 5 109.6a 57.4a 1.91 10 106.6a-c 56.7a,b 1.88 20 102.2c,d 54.7b,c 1.87 40 102.3c,d 55.2a-c 1.85 100 107.7a,b 57.4a 1.88 SEM 3.52 1.39 0.021 Probability Vitamin E 0.003 0.011 0. 210 Vitamin E linear 0.644 0.433 0.856 Vitamin E quadratic 0.704 0.629 0.655 1Results are means with n = 8 per treatment. a–dMeans with different superscripts within the same column differ significantly (P < 0.05). View Large Table 2. Effects of vitamin E on growth performance of Pekin ducks from hatch to 21 days (experiment 1).1 Supplemental vitamin E (mg/kg) Daily feed intake (g/bird/day) Daily weight gain (g/bird/day) Feed/gain (g/g) 0 101.0d 54.3c 1.86 5 109.6a 57.4a 1.91 10 106.6a-c 56.7a,b 1.88 20 102.2c,d 54.7b,c 1.87 40 102.3c,d 55.2a-c 1.85 100 107.7a,b 57.4a 1.88 SEM 3.52 1.39 0.021 Probability Vitamin E 0.003 0.011 0. 210 Vitamin E linear 0.644 0.433 0.856 Vitamin E quadratic 0.704 0.629 0.655 Supplemental vitamin E (mg/kg) Daily feed intake (g/bird/day) Daily weight gain (g/bird/day) Feed/gain (g/g) 0 101.0d 54.3c 1.86 5 109.6a 57.4a 1.91 10 106.6a-c 56.7a,b 1.88 20 102.2c,d 54.7b,c 1.87 40 102.3c,d 55.2a-c 1.85 100 107.7a,b 57.4a 1.88 SEM 3.52 1.39 0.021 Probability Vitamin E 0.003 0.011 0. 210 Vitamin E linear 0.644 0.433 0.856 Vitamin E quadratic 0.704 0.629 0.655 1Results are means with n = 8 per treatment. a–dMeans with different superscripts within the same column differ significantly (P < 0.05). View Large Table 3. Effects of vitamin E on growth performance of Pekin ducks from hatch to 21 days (experiment 2).1 Supplemental vitamin E (mg/kg) Daily feed intake (g/bird/day) Daily weight gain (g/bird/day) Feed/gain (g/g) 0 94.8c 40.7b 2.34 10 103.2a,b 43.6a 2.37 20 101.7b 43.4a 2.35 100 107.0a 43.9a 2.44 SEM 5.10 1.49 0.045 Probability Vitamin E 0.001 0.008 0.376 Vitamin E linear 0.216 0.429 0.038 Vitamin E quadratic 0.432 0.466 0.266 Supplemental vitamin E (mg/kg) Daily feed intake (g/bird/day) Daily weight gain (g/bird/day) Feed/gain (g/g) 0 94.8c 40.7b 2.34 10 103.2a,b 43.6a 2.37 20 101.7b 43.4a 2.35 100 107.0a 43.9a 2.44 SEM 5.10 1.49 0.045 Probability Vitamin E 0.001 0.008 0.376 Vitamin E linear 0.216 0.429 0.038 Vitamin E quadratic 0.432 0.466 0.266 1Results are means with n = 6 per treatment. a–cMeans with different superscripts within the same column differ significantly (P < 0.05). View Large Table 3. Effects of vitamin E on growth performance of Pekin ducks from hatch to 21 days (experiment 2).1 Supplemental vitamin E (mg/kg) Daily feed intake (g/bird/day) Daily weight gain (g/bird/day) Feed/gain (g/g) 0 94.8c 40.7b 2.34 10 103.2a,b 43.6a 2.37 20 101.7b 43.4a 2.35 100 107.0a 43.9a 2.44 SEM 5.10 1.49 0.045 Probability Vitamin E 0.001 0.008 0.376 Vitamin E linear 0.216 0.429 0.038 Vitamin E quadratic 0.432 0.466 0.266 Supplemental vitamin E (mg/kg) Daily feed intake (g/bird/day) Daily weight gain (g/bird/day) Feed/gain (g/g) 0 94.8c 40.7b 2.34 10 103.2a,b 43.6a 2.37 20 101.7b 43.4a 2.35 100 107.0a 43.9a 2.44 SEM 5.10 1.49 0.045 Probability Vitamin E 0.001 0.008 0.376 Vitamin E linear 0.216 0.429 0.038 Vitamin E quadratic 0.432 0.466 0.266 1Results are means with n = 6 per treatment. a–cMeans with different superscripts within the same column differ significantly (P < 0.05). View Large Effects of vitamin E on plasma and liver α-tocopherol and lipid peroxidation of 21-d-old Pekin ducks are shown in Tables 4 and 5, respectively. In both experiments, compared with ducks fed vitamin E-supplemented diets, the ducks fed basal diets with no supplemental vitamin E had lower plasma and liver α-tocopherol (P < 0.05) and plasma and liver α-tocopherol increased linearly or quadratically (P < 0.05) as supplemental vitamin E increased (P < 0.05). On the other hand, in both experiments, supplementation of vitamin E influenced the lipid peroxidation expressed as MDA in the liver (P < 0.05) but not in the plasma (P > 0.05). The ducks fed basal diets with no supplemental vitamin E had the greatest liver MDA among all birds and the supplementation of vitamin E could reduce liver MDA (P < 0.05) as supplemental vitamin E increased. However, the liver MDA showed no linear or quadratic response to this vitamin in both experiments (P > 0.05). Table 4. Effects of vitamin E on plasma and liver α-tocopherol and lipid peroxidation of 21-day-old Pekin ducks (experiment 1).1 Supplemental vitamin E (mg/kg) α-tocopherol Malondialdehyde Plasma (μg/mL) Liver (μg/g) Plasma (nmol/mL) Liver (nmol/mg protein) 0 1.68d 0.54d 5.51 2.88a 5 2.23d 0.91c,d 5.71 2.12a,b 10 3.63c,d 1.32c,d 5.77 1.96a-c 20 5.90c 2.36c 6.07 1.84b,c 40 9.33b 3.96b 5.81 1.51b,c 100 22.76a 9.31a 5.52 1.49b,c SEM 7.942 3.297 0.208 0.512 Probability Vitamin E <0.001 <0.001 0.078 0.002 Vitamin E linear <0.001 <0.001 0.588 0.116 Vitamin E quadratic <0.001 <0.001 0.233 0.069 Supplemental vitamin E (mg/kg) α-tocopherol Malondialdehyde Plasma (μg/mL) Liver (μg/g) Plasma (nmol/mL) Liver (nmol/mg protein) 0 1.68d 0.54d 5.51 2.88a 5 2.23d 0.91c,d 5.71 2.12a,b 10 3.63c,d 1.32c,d 5.77 1.96a-c 20 5.90c 2.36c 6.07 1.84b,c 40 9.33b 3.96b 5.81 1.51b,c 100 22.76a 9.31a 5.52 1.49b,c SEM 7.942 3.297 0.208 0.512 Probability Vitamin E <0.001 <0.001 0.078 0.002 Vitamin E linear <0.001 <0.001 0.588 0.116 Vitamin E quadratic <0.001 <0.001 0.233 0.069 1Results are means with n = 8 per treatment. a–dMeans with different superscripts within the same column differ significantly (P < 0.05). View Large Table 4. Effects of vitamin E on plasma and liver α-tocopherol and lipid peroxidation of 21-day-old Pekin ducks (experiment 1).1 Supplemental vitamin E (mg/kg) α-tocopherol Malondialdehyde Plasma (μg/mL) Liver (μg/g) Plasma (nmol/mL) Liver (nmol/mg protein) 0 1.68d 0.54d 5.51 2.88a 5 2.23d 0.91c,d 5.71 2.12a,b 10 3.63c,d 1.32c,d 5.77 1.96a-c 20 5.90c 2.36c 6.07 1.84b,c 40 9.33b 3.96b 5.81 1.51b,c 100 22.76a 9.31a 5.52 1.49b,c SEM 7.942 3.297 0.208 0.512 Probability Vitamin E <0.001 <0.001 0.078 0.002 Vitamin E linear <0.001 <0.001 0.588 0.116 Vitamin E quadratic <0.001 <0.001 0.233 0.069 Supplemental vitamin E (mg/kg) α-tocopherol Malondialdehyde Plasma (μg/mL) Liver (μg/g) Plasma (nmol/mL) Liver (nmol/mg protein) 0 1.68d 0.54d 5.51 2.88a 5 2.23d 0.91c,d 5.71 2.12a,b 10 3.63c,d 1.32c,d 5.77 1.96a-c 20 5.90c 2.36c 6.07 1.84b,c 40 9.33b 3.96b 5.81 1.51b,c 100 22.76a 9.31a 5.52 1.49b,c SEM 7.942 3.297 0.208 0.512 Probability Vitamin E <0.001 <0.001 0.078 0.002 Vitamin E linear <0.001 <0.001 0.588 0.116 Vitamin E quadratic <0.001 <0.001 0.233 0.069 1Results are means with n = 8 per treatment. a–dMeans with different superscripts within the same column differ significantly (P < 0.05). View Large Table 5. Effects of vitamin E on plasma and liver α-tocopherol and lipid peroxidation of 21-day-old Pekin ducks (experiment 2).1 Supplemental vitamin E (mg/kg) α-tocopherol Malondialdehyde Plasma (μg/mL) Liver (μg/g) Plasma (nmol/mL) Liver (nmol/mg protein) 0 0.57d 0.20d 6.74 1.77a 10 2.40c 1.12c 6.70 1.41b 20 4.18b 1.96b 7.04 1.35b 100 19.15a 9.35a 6.57 1.27c SEM 8.512 4.190 0.199 0.221 Probability Vitamin E <0.001 <0.001 0.692 0.010 Vitamin E linear <0.001 <0.001 0.475 0.327 Vitamin E quadratic 0.002 0.005 0.497 0.276 Supplemental vitamin E (mg/kg) α-tocopherol Malondialdehyde Plasma (μg/mL) Liver (μg/g) Plasma (nmol/mL) Liver (nmol/mg protein) 0 0.57d 0.20d 6.74 1.77a 10 2.40c 1.12c 6.70 1.41b 20 4.18b 1.96b 7.04 1.35b 100 19.15a 9.35a 6.57 1.27c SEM 8.512 4.190 0.199 0.221 Probability Vitamin E <0.001 <0.001 0.692 0.010 Vitamin E linear <0.001 <0.001 0.475 0.327 Vitamin E quadratic 0.002 0.005 0.497 0.276 1Results are means with n = 6 per treatment. a–dMeans with different superscripts within the same column differ significantly (P < 0.05). View Large Table 5. Effects of vitamin E on plasma and liver α-tocopherol and lipid peroxidation of 21-day-old Pekin ducks (experiment 2).1 Supplemental vitamin E (mg/kg) α-tocopherol Malondialdehyde Plasma (μg/mL) Liver (μg/g) Plasma (nmol/mL) Liver (nmol/mg protein) 0 0.57d 0.20d 6.74 1.77a 10 2.40c 1.12c 6.70 1.41b 20 4.18b 1.96b 7.04 1.35b 100 19.15a 9.35a 6.57 1.27c SEM 8.512 4.190 0.199 0.221 Probability Vitamin E <0.001 <0.001 0.692 0.010 Vitamin E linear <0.001 <0.001 0.475 0.327 Vitamin E quadratic 0.002 0.005 0.497 0.276 Supplemental vitamin E (mg/kg) α-tocopherol Malondialdehyde Plasma (μg/mL) Liver (μg/g) Plasma (nmol/mL) Liver (nmol/mg protein) 0 0.57d 0.20d 6.74 1.77a 10 2.40c 1.12c 6.70 1.41b 20 4.18b 1.96b 7.04 1.35b 100 19.15a 9.35a 6.57 1.27c SEM 8.512 4.190 0.199 0.221 Probability Vitamin E <0.001 <0.001 0.692 0.010 Vitamin E linear <0.001 <0.001 0.475 0.327 Vitamin E quadratic 0.002 0.005 0.497 0.276 1Results are means with n = 6 per treatment. a–dMeans with different superscripts within the same column differ significantly (P < 0.05). View Large DISCUSSION In our study, experiment 1 was conducted first and it was followed by experiment 2. In order to justify the results of experiment 1, the total vitamin E content was formulated to 11.04 mg/kg when 10 mg DL-α-tocopheryl acetate was supplemented to the basal diets in experiment 2 and this value was similar to the total vitamin E content (12.41 mg/kg) when 5 DL-α-tocopheryl acetate was supplemented to the basal diets in experiment 1. Therefore, the results of experiment 1 could be justified by those of the following experiment 2 and all results of these two experiments were combined to discuss the effects of vitamin E on duck performance. In our study, the basal diets was deficient in vitamin E and the ducks fed basal diets with no supplementation of vitamin E had the lowest weight gain and feed intake among all ducks. Although supplementation of vitamin E could improve the growth performance of the ducks, the weight gain and feed intake of ducks were not improved further when supplemental vitamin E was above 5 mg/kg in experiment 1 and 10 mg/kg in experiment 2. Our results are supported by Schiavone et al. (2010). In their study, there were no significant differences in growth performance between Muscovy ducks fed diets containing 30 and 230 mg/kg supplemental α-tocopherol acetate. Therefore, the supplemental vitamin E of 5 mg/kg in experiment 1 and 10 mg/kg in experiment 2 may be adequate for duck growth. When the vitamin E contents of the basal diets were included (7.41 mg vitamin E/kg in experiment 1 and 1.04 mg vitamin E/kg in experiment 2), no less than 10 mg/kg total vitamin E was required by starter ducks and this indicates that the NRC (1994) recommendation for this vitamin (10 IU/kg) for Pekin ducks is enough for modern duck strains. Our conclusion is also supported by Guo et al. (2001). In their study, when the basal diet contained 13 mg/kg α-tocopherol, supplementation of vitamin E from 5 to 100 mg/kg in the basal diet had no significant effects on weight gain, feed intake, and feed/gain of broilers from hatch to 3 weeks of age. Unlike growth performance, tissue tocopherol was more sensitive to the change of dietary vitamin E. Whether in experiment 1 or 2, plasma and liver α-tocopherol increased linearly or quadratically as dietary vitamin E increased (Table 4 and 5), which is in agreement with the results of Jager (1972) which showed a similar change in serum tocopherol for ducklings. Furthermore, the status of vitamin E could be indicated by blood tocopherol. In our study, the linear or quadratic dose response increase of plasma α-tocopherol was also accompanied simultaneously with the same change of liver α-tocopherol. Our results are also in agreement with the results in broilers of Jensen et al. (1999). In their study, as supplemental α-tocopherol increased, the increasing concentrations of α-tocopherol in the liver and breast meat was followed by increasing concentrations of α-tocopherol in the plasma. Furthermore, in the study of Jager (1972), the myopathy of leg muscles was a symptom of vitamin E deficiency in ducks and a more severe myopathy of the leg muscles was often accompanied by lower serum tocopherol. Therefore, blood tocopherol could serve as a sensitive indicator for the vitamin E status of ducks when ill ducks are screened for vitamin E deficiency. In our study, the lipid peroxidation expressed as MDA, was measured in the plasma and liver in order to evaluate the antioxidant status of the ducks depending on supplemental vitamin E levels. Supplementation of vitamin E in basal diets could reduce lipid peroxidation in the liver of ducks which is indicated by decreasing MDA at high supplemental vitamin E levels (Tables 4 and 5). Our results are in agreement with the results of Schiavone et al. (2010) in which the lipid oxidation in the breast meat of Muscovy ducks was reduced markedly by addition of 200 mg/kg α-tocopheryl acetate to the diets. However, when supplemental vitamin E was above 5 mg/kg in experiment 1 and 10 mg/kg in experiment 2, the liver lipid peroxidation was not reduced further. Therefore, the antioxidant capacity of vitamin E may be not improved further when dietary total vitamin E is above 10 mg/kg. Our results are supported by Guo et al. (2001) in which supplementation of vitamin E from 5 to 100 mg/kg had no significant effects on TBARS concentrations in hepatic tissues of broiler chicks expressed as MDA with basal diets containing 13 mg/kg α-tocopheryl. In conclusion, in order to maintain optimal growth performance and antioxidant capacity of starter Pekin ducks from hatch to 21 days of age, the dietary total vitamin E level should not be less than 10 mg/kg. The plasma or liver α-tocopherol is dependent on the dietary vitamin E level and both are sensitive indicators for the status of this vitamin. ACKNOWLEDGMENTS This work was sponsored by the earmarked fund for China Agriculture Research System (CARS-42) and the science and technology innovation project of Chinese Academy of Agricultural Sciences (CXGC-IAS-09). REFERENCES Guo Y. , Tang Q. , Yuan J. , Jiang Z. . 2001 . Effects of supplementation with vitamin E on the performance and the tissue peroxidation of broiler chicks and the stability of thigh meat against oxidative deterioration . Anim. Feed. Sci. Technol. 89 : 165 – 173 . Google Scholar CrossRef Search ADS Jager F. C. 1972 . Linoleic acid intake and vitamin E requirement in rats and ducklings . Ann. N.Y. Acad. Sci. 20 : 199 – 211 . Google Scholar CrossRef Search ADS Jensen S. K. , Engberg R. M. , Hedemann M. S. . 1999 . All-rac-tocopherol acetate is a better vitamin E source than all-rac-_-tocop herol succinate for broilers . J. Nutr. 129 : 1355 – 1360 . Google Scholar CrossRef Search ADS PubMed Leeson S. 2007 . Vitamin requirements: is there basis for re-evaluating dietary specifications? World's Poult. Sci. J. , 63 : 255 – 266 . Google Scholar CrossRef Search ADS Ministry of Agriculture of China . 2004 . Feeding standard of chicken . Standards Press of China , Beijing, China . NRC . 1994 . Nutrient Requirements of Poultry . 9th rev. ed . Natl. Acad. Press , Washington, DC . SAS Institute . 2003 . SAS User's Guide: Statistics . Version 9.0 . SAS Institute, Inc. , Cary, NC . Schiavone A. , Marzoni M. , Castillo A. , Nery J. , Romboli I. . 2010 . Dietary lipid sources and vitamin E affect fatty acid composition or lipid stability of breast meat from Muscovy duck . Canadian J. Anim. Sci. 90 : 371 – 378 . Google Scholar CrossRef Search ADS © 2018 Poultry Science Association Inc. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices)

Journal

Poultry ScienceOxford University Press

Published: Mar 15, 2018

There are no references for this article.

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off