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2. There were some differences between the two ages; these could largely be reconciled by considering the likely differences in the proportion of feather protein.
3. The results were compared with similar values for the chicken and goose; overall there is a striking similarity, both in absolute concentrations and relative proportions of amino acids. 相似文献
2. Addition of 10 g ascorbic acid/kg to the control diet (without excess tyrosine) produced no beneficial effects on performance. Excess dietary tyrosine caused depressions in all measures of performance.
3. Adding 0.1, 1, 10 or 20 g ascorbic acid/kg to the diet containing excess tyrosine tended to improve performance.
4. Subcutaneous injection of 50 mg ascorbic acid/bird d to chicks receiving excess tyrosine brought about a significant improvement in body‐weight gain.
5. The elevation of plasma free tyrosine caused by excess dietary tyrosine decreased as dietary ascorbic acid increased.
6. Ascorbic acid can alleviate, though not completely counteract, the adverse effect of excess dietary tyrosine. 相似文献
2. In the early stage of growth the feather shaft is held in place by cell indentations, whereas later, bridges are seen which probably hold the feather more firmly. 相似文献
First European Symposium on Poultry Welfare. Edited by L. Yding S0RENSEN. Published by the Danish Branch of World's Poultry Science Association. 1981. 238pp. D.Kr.90. ISBN 87–88162–00–1. 相似文献
2. Phenotypic correlations between total plasma triglyceride concentration and fat content were + 0.50, + 0.37 and + 0.39 for the three groups of male broilers and +0.33 for the group of females. Triglyceride content of plasma very low density lipoprotein (VLDL) plus low density lipoprotein (LDL) showed similar correlations with fat content.
3. Selection of birds from a flock of 550 male broilers on the basis of high or low plasma VLDL plus LDL triglyceride concentrations produced groups with significant differences in body fat content but little difference in body weight.
4. The results suggest that measurements of plasma triglyceride concentration could be used as an indirect means of selecting for decreased body fat content in broiler breeding programmes. 相似文献
2. Age at first egg, body‐weight gain and egg production were affected by energy allowance. Birds on the lower energy allowances came into lay later than birds on the higher energy allowances and at a lower body weight.
3. Body‐weight gain decreased with decreasing energy allowance. The decrease in egg output in response to decreasing energy allowance resulted from more birds ceasing to lay and fewer birds laying on more than 3 d per week. Similar changes in the distribution of rates of lay were observed on each treatment as the flock aged.
4. The relationship between body‐weight gain and egg number on each treatment was negative from 21 to 36 weeks, but became less consistent with age.
5. Protein intake had little effect on body weight. At the lowest energy allowance, egg number and egg weight decreased with increasing protein allowance. This effect was not observed on the higher energy allowances. 相似文献
2. Injecting the growing embryo with amino acids equivalent to the amount of protein used resulted in higher weight of chicks at all stages up to 56 d. 相似文献