2. Body weight at 169 d of age varied from, on average, 1409 g (15 °C, ad libitum) to 943 g (30 °C, 70% schedule) for the white strain and 1947 to 1250 g for the same treatments respectively for the brown strain. Sexual maturity was considerably delayed by the 70% feeding schedule, only slightly by rearing at 30 °C.
3. Rearing at 30 °C tended to depress subsequent egg output. The 70% feeding schedule at least maintained egg output compared with birds fed ad libitum in rearing.
4. There was a highly significant effect of temperature treatment during lay on food intake. The reduction in food intake due to the 21–28 °C cycle, however, appeared small. 相似文献
2. Feeding the diets with increased concentrations of protein apparently does not reduce the growth rate depression of the broiler reared at 26 or 31 °C. 相似文献
2. For males receiving the choice treatments, on average 44.7 and 73.1 % by weight, respectively of the food consumed from 21 d consisted of whole wheat. The corresponding figures for the females were 49.9 and 77.3% respectively.
3. Growth rate from 21 d was significantly lower for the males which received wheat and the cereal‐free higher‐protein food and for the females on either choice treatment. Differences in the treatment means, however, were small. 相似文献
2. Egg output for birds kept at 27 °C from 333 d could not be increased to the maximum rate of output of birds at 21 °C for this period by feeding a diet of equal energy content containing increased proportions of protein‐rich ingredients.
3. The difference in both food intake and egg output between hens maintained at 21 and those maintained at 27 °C appeared to decrease when the higher temperature was introduced at 416 d of age. 相似文献
2. Eighty‐four point six, 69.5 and 31.4% respectively of the food consumed by the birds which received the high‐protein concentrate, protein concentrate or grower diet with wheat consisted of the whole cereal. The corresponding figures for the birds which received barley were 73.9, 41.3 and 10.9% respectively.
3. There were no significant differences in rate of food intake or growth between choice‐fed birds receiving whole wheat and the complete diet‐fed birds with no choice. 相似文献
2. Three hundred and sixty 19‐day‐old female broilers were fed on diets containing supplemental fat/oil (50 g/kg) in the form of beef tallow (BT) (diet T‐T), soyabean oil (SBO) (diet S‐S), rapeseed oil (RSO) (diet R‐R), marine oil (MO) (diet M‐M) or binary mixtures (0.5:0.5 w/w) of these lipids (diets T‐S, T‐R, T‐M, S‐R, S‐M, and R‐M) to 54 d of age. Food intake, live weight, plucked weight and the lipid concentration and fatty acid composition of abdominal fat pad, liver and breast muscle were measured.
3. Food intake, plucked weight and live weight were greatest for diet T‐T and lowest for diet R‐R. Food conversion ratio was poorest for birds fed on diets containing BT. Lipid concentration in abdominal fat pad was significantly higher in birds fed on diets containing SBO. liver lipid concentration was significantly reduced by diets containing RSO.
4. Abdominal fat pad fatty acid profile was most readily altered by dietary fatty acids. There was a strong correlation between dietary fatty acid composition and tissue fatty acid composition for all fatty acids except C14:0, C20:0, C20: 2n‐6 and C20: 4n‐6. The tissue P/S ratio ranged from 0.40 for diet T‐T to 1.40 for diet S‐S. The n‐6/n‐3 ratio was significantly increased by the inclusion of SBO and decreased by the inclusion of MO.
5. Liver fatty acid profile was least modified by dietary fatty acids. There was an inverse relationship between liver and dietary C20:4n‐6 concentration. Tissue C18:2n‐6 and C20:4n‐6 were highly correlated, suggesting significant interconversion by ?‐6 desaturase in this tissue. The n‐6/n‐3 ratio was significantly increased by inclusion of SBO and significantly decreased by the inclusion of MO.
6. In breast muscle MO‐based diets increased the proportion of n‐3 PUFA at the expense of n‐6 PUFA. The tissue concentrations of C18:ln‐9, C18:2n‐6, C20:ln‐9, C20:5n‐3, C22:5n‐3 and C22:6n‐3 were strongly correlated with dietary fatty acid composition. Muscle and diet P/S and n‐6/n‐3 ratios were highly correlated. 相似文献