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2. The response in shell thickness to ahemeral lighting was more rapid (2.2 d) than for egg weight (4.2 d).
3. Differences between genotypes were evident in both the speed and magnitude of response.
4. Overall, egg weight and shell thickness on the 28‐h cycle were 7% and 8% greater than on 24 h.
5. The allometric increase indicates that the increase in shell weight was on average 14% more than the increase in egg weight. 相似文献
2. Using a geometrical similarity hypothesis, it was found that, although the locomotor apparatus of both strains are similar, the stresses on the pelvic muscles of broad‐breasted turkeys are increased. This is induced by the anterior position of the centres of gravity of their trunks, the result of selected pectoral hypertrophy.
3. The modification to the mechanics of standing may be related to the increase in locomotor disease in strains of giant turkeys. 相似文献
2. Endogenous amino acid flows to the ileum in fasted cockerels were significantly lower than those obtained both by feeding the nitrogen‐free diet, and from regression analysis in either broilers or cockerels. Regression analysis gave the highest flows.
3. The apparent digestibility coefficients of amino acids in a diet containing 200 g/kg crude protein were lower in broilers (0.84) than in cockerels (0.88). When corrected, by regression analysis, for the contribution of endogenous amino acids, the true digestibility coefficients became 0.90 and 0.92 respectively. 相似文献
2. Estimates of the concentration of lysine needed for maximum body weights gain, food consumption and gain:food ratio were calculated using two statistical methods. An average of these estimates was 12.0 g lysine/kg diet to 21 d of age.
3. Chicks given 13.9 or 14.4 g lysine/kg diet were negatively affected by these concentrations. The decreases in average weight gain, food consumption and food efficiency were caused mainly by several chicks that developed severe leg problems and were much smaller than their pen mates. Chicks with no leg problems gained weight as rapidly as chicks receiving optimal amounts of lysine. 相似文献
2. The values for fractional synthesis rate (FSR) estimated in vitro at 20, 30, 45 and 60 min during the embryo culture agreed well, ranging from 35 to 40%/d, suggesting that the method would serve as a useful model for studying the effect of growth promoters in chick embryos.
3. Bovine insulin in the synthetic medium did not affect FSR of protein in chick embryos cultured in vitro. 相似文献
2. Body weight and food utilisation efficiency of White Leghorns at 10 d of age were not affected by diet, whereas the lower concentrations of lysine and methionine depressed these traits in White Rocks.
3. Tryptophan deficiency reduced food intake of White Leghorns, but not White Rocks.
4. With choice feeding of balanced and deficient diets from day 10 to 16, preferences between the diets were minimal for White Leghorns, whereas for White Rocks there was an almost immediate preference for the balanced diet, followed by lack of preference or preference for the deficient diet.
5. Apparently for some genetic stocks there is rapid adjustment to deficiencies in these amino acids with overconsumption, followed by compensation for preference of the balanced diet. The response, however, will vary depending on the deficient amino acid. 相似文献