British Poultry Science

Jordan, F. T.

doi: 10.1080/00071668508416781pmid: 3882197

Abstract 1. Man in managing poultry for human benefit has found that his methods may precipitate or exacerbate certain diseases: among which are the mycoplasmoses of fowls and turkeys. 2. Control measures for these conditions have therefore been sought and to make them effective it has been necessary to study the epidemiology, diagnosis and pathogenesis of these conditions. Much is now known about their epidemiology although certain aspects still require investigation. 3. More sensitive and specific methods of diagnosis are also required and although it is possible to control these conditions by eradication the mycoplasmoses are still an economic problem. Under existing management systems, therefore, development and use of effective vaccines and additional drugs are essential. 4. It is noteworthy that the pathogenesis of at least one of the avian mycoplasmoses is similar to human immune‐complex disease. In further elucidation of this complex the fowl may be a useful experimental animal. 5. Thus the association of people, poultry and pathogenic mycoplasmas not only involves attempts to control the pathogens in order to attain maximum production by poultry but also could include the utilisation of poultry and the pathogen in an attempt to elucidate some of the diseases of people.

Chadwick, A.; Rapson, E. B.; Carlos, G. M.; Lee, D. L.

doi: 10.1080/00071668508416782pmid: 3971193

Abstract 1. 50 000 oocysts of Eimeria tenella were inoculated into three‐week‐old cockerels and the effect of the infection (coccidiosis) on circulating concentrations of glucose, prolactin, sodium, potassium and haematocrit was determined. 2. At day 5 of infection haematocrit was reduced and glucose was increased. From day 7 onwards prolactin concentration was elevated in infected birds compared with control and pair‐fed birds. Plasma electrolytes were unchanged. 3. It appears likely that loss of water resulting in osmotic changes during infection is the major reason for the observed changes in prolactin concentration in infected cockerels.

Williams, J. B.; Etches, R. J.; Rzasa, J.

doi: 10.1080/00071668508416783pmid: 3971194

Abstract 1. A pause in laying was induced in hens by infusing 30 μg corticosterone/h, feeding diets deficient in calcium or sodium and by food and water withdrawal. 2. In hens infused with corticosterone, food consumption remained high and body weight was unchanged, although liver weight doubled. The other treatments were associated with a decline in food consumption and a loss of body weight but liver weight was unchanged. 3. The weight of the ovary was reduced most severely in hens infused with 30 μg corticosterone/h, but the number of follicles weighing more than 12 mg was not altered by any of the treatments. A decrease in the number of large, yolk‐filled follicles was matched by an increase in the numbers of small follicles. All treatments resulted in an increase in the number of atretic follicles. 4. All treatments produced an elevation of plasma corticosterone concentrations within the normal physiological range, and a decrease in plasma LH concentrations. These features may constitute part of the physiological mechanism causing regression of the ovary and the cessation of egg‐laying, but they do not prevent recruitment of small follicles to the stage which precedes entry into the hierarchy of large, yolky follicles.

Newcombe, M.; Summers, J. D.

doi: 10.1080/00071668508416784pmid: N/A

Abstract 1. Two‐week‐old broiler and Leghorn cockerels were fed on diets containing 0, 100, 200, 300, 400, 500 or 600 g cellulose/kg in either crumble or mash form for 4 weeks. 2. Intake of the mash form of the cellulose‐diluted diets and associated body weights were less than those associated with the equivalent crumble diets which may have been due to decreased palatability of the former. 3. Broilers were unable to compensate for dietary dilution with cellulose by increasing food intake sufficiently to maintain nutrient intake with either mash or crumbled diets at any dilution. 4. At 100 g cellulose/kg for the mash diets and 100 and 200 g/kg for crumbled diets, Leghorns increased volume ingested by as much as 40% and maintained body‐weight gain and nutrient intake. 5. The results could be of value in designing feeding programmes for egg‐and meat‐type pullets.

Campbell, R. G.; Karunajeewa, H.; Bagot, I.

doi: 10.1080/00071668508416785pmid: N/A

Abstract 1. The effects of food intake on growth and carcase composition of male and female meat‐type Pekin ducks were investigated between 14 and 56 d of age and between 0.416 kg (14 d) and 2.5 kg live body weight. 2. Males grew faster between 14 and 56 d of age and contained less fat and more protein and water in the eviscerated carcase at 56 d than females. 3. For both sexes, food : gain ratio deteriorated as food intake increased from 0.49 ad libitum intake to ad libitum intake. Growth rate, carcase weight and carcase fat content increased linearly with increase in food intake. Carcase fat content at 56 d was more sensitive to change in the amount of food consumed than either growth rate or carcase weight. 4. Between 0.42 kg (14 d) and 2.50 kg live body weight, growth rate and food :gain ratio improved as food intake was increased from 0.61 ad libitum to ad libitum. Males grew faster and produced leaner carcases than females. 5. Carcase fat content at 2.50 kg live body weight (1.60 kg carcase) increased in a curvilinear fashion with increase in food intake, and the magnitude of the response was lower for females than for males. A similar interaction existed between the effects of sex and the amount of food consumed for the proportions of protein and water in the eviscerated carcase at 2.50 kg live body weight.

Griffin, H. D.; Whitehead, C. C.

doi: 10.1080/00071668508416786pmid: N/A

Abstract 1. Plasma very low density lipoprotein (VLDL) concentrations were measured in two groups of male turkeys at 18 or 20 weeks of age and one group of female turkeys at 16 weeks of age. Values were similar to those of broilers at 7 weeks of age. 2. Carcase analysis was performed on the birds in each group with mean plasma VLDL concentrations in the upper and lower 10 percentiles. In each group the birds with the lowest plasma VLDL concentrations had significantly less abdominal and/or total fat than those with the highest concentrations. 3. The results indicate that plasma VLDL concentration can be used as an indirect method of estimating fatness in male and female turkeys.

Ockleford, Elizabeth M.; Vince, Margaret A.

doi: 10.1080/00071668508416787pmid: N/A

Abstract 1. Hatching of the eggs of the bobwhite and Japanese quail and of the domestic fowl is known to be accelerated by stimulation with artificial clicks. 2. Clicks were given to eggs of the three species at a rate known to accelerate hatching. The clicks were of two types: consisting mainly of sound (using a piezoelectric stimulator) and consisting mainly of movement (using a vibration generator). 3. The amplitude of clicks was varied, in order to identify that range of amplitudes which was effective for accelerating hatching without reducing hatchability. 4. A point near the centre of this range was found to correspond with the amplitude of natural clicks given by the embryos of both species of quail. Domestic fowl clicks were of lower amplitude than was required for artificial clicks to be effective.

Chen, C.; Pearson, A. M.; Coleman, T. H.; Gray, J. I.; Wolzak, A. M.

doi: 10.1080/00071668508416788pmid: 3918770

Abstract 1. Broiler chickens were fed a diet containing 2057 and 1323 μg/kg feed of aflatoxins B1 and B2, respectively, for 35 d. Effects of aflatoxins on growth, food consumption, efficiency of food utilisation and manifestations of aflatoxicosis were compared with control birds at the end of the feeding trial and at 1, 2,4,8 and 16 d after replacing the contaminated feed. 2. No difference in food consumption was observed between the controls and the aflatoxin‐fed chickens, but efficiency of food utilisation was decreased from 2.2 for the controls to 2.4 g food/g gain for the group fed aflatoxins. 3. Aflatoxins caused depressed growth and enlargement of the kidney, liver, heart and gall bladder. Haemorrhagic spots were present on the surface of the muscles and some of the livers. Most livers from aflatoxin‐fed birds were pale and infiltrated with lipid. 4. After withdrawal of the food containing aflatoxins, all apparent gross lesions of aflatoxicosis disappeared, with no evidence of any lesions 8 d after removal of the contaminated diet.

Whitehead, C. C; Pearson, R. Anne; Herron, Kathleen M.

doi: 10.1080/00071668508416789pmid: 3971195

Abstract 1. Production of eggs or normal chicks was depressed when practical diets containing 168 g or 137 g of crude protein (CP)/kg were not supplemented with synthetic biotin. 2. Overall egg production and hatchability of fertile eggs was signficantly (P < 0.05) higher with the diets containing 137 g CP/kg. 3. Biotin requirement was higher with the diet containing 168 g CP/kg and was estimated to be about 100 μg of available biotin/kg, equivalent to a daily intake of 16 μg for food‐restricted hens. 4. Biotin concentrations in egg yolk and chick plasma were related to maternal intake and increased with maternal age. The minimum yolk biotin concentration indicative of adequate maternal status was about 550 μg/g. 5. Chicks from young hens fed insufficient biotin had the poorest biotin status at hatching and their growth potential and viability were reduced.

Wilson, S. C.; Jennings, R. C.; Cunningham, F. J.

doi: 10.1080/00071668508416790pmid: 3971196

Abstract 1. Hens maintained on 16 h light :8 h darkness were subjected to an abrupt advance of darkness by between 4 and 13 h. 2. When darkness was advanced so that it occurred less than 6 to 8 h after ovulation, the next expected preovulatory release of luteinising hormone (LH) and ovulation was usually delayed or blocked. This was associated with a reduction in the ability of injected ovine LH to stimulate the secretion of progesterone. 3. When the advance meant that darkness occurred at more than 6 to 8 h after ovulation subsequent ovulations were advanced by as much as 5 h within a 3 d period. 4. The hastening effect of an advance of darkness on follicular maturation was associated with an increased secretion of LH in response to injected progesterone. 5. An advance of darkness by 4 or 7 h was associated with an earlier onset of the circadian increase in the secretion of corticosterone and changes in the tonic secretion of LH, notably a tendency for plasma concentrations of LH to increase during the first 4 to 5 h of advanced darkness, followed by a steep decline.