Zubair A K, Leeson S
Department of Animal and Poultry Science, University of Guelph, Ontario, Canada.
Poult Sci. 1996 Jun;75(6):719-28. doi: 10.3382/ps.0750719.
Three experiments were conducted to determine growth performance, body composition changes, and adipocyte characteristics of male broilers subjected to early-life feed restriction. The purpose of Experiment 1 was to determine 42-d growth performance and body composition changes. Treatments used were full-fed control and 50% physical feed restriction during the period 6 to 12 d of age. Experiment 2 was conducted to determine the adipocyte characteristics during and after feed restriction to 42 d of age. An additional treatment involved gradual refeeding following the feed restriction period. Experiment 3 was designed to test the effect of feeding different types of dietary fat during realimentation on the abdominal fat pad (AFP) size, and lasted until 18 d of age. Three types of fats were tested, namely animal-vegetable (A-V) blend, flax oil, and animal tallow, each represented by full-fed and feed-restricted treatments. Complete compensatory growth by feed-restricted birds relative to controls was not achieved by 42 d in either Experiments 1 or 2. Early feed restriction resulted in lower body fat percentage at 12 d (P < 0.05), although by 42 d a higher rate of fat deposition mainly by hypertrophy of adipocytes resulted in no difference in fatness. Gradual reintroduction into ad libitum feeding did not alter such adipocyte hypertrophy nor improve compensatory growth response during refeeding. There was consistent improvement in feed efficiency associated with early-life feed restriction (P < 0.05). The use of different types of dietary fat did not effect the AFP when expressed as percentage body weight. Birds that were fed A-V blend during the refeeding period had bigger AFP (grams per bird), a situation that is attributable to differences in body weight. Attainment of growth compensation by the feed-restricted broilers apparently requires a more prolonged growth period or a less severe feed restriction program than that used here. Saturation of dietary fat has no effect on realimentation characteristics of the broiler.
进行了三项试验以确定早期限饲的雄性肉鸡的生长性能、体成分变化和脂肪细胞特征。试验1的目的是确定42日龄时的生长性能和体成分变化。所用处理为全喂量对照和在6至12日龄期间进行50%的物理限饲。试验2旨在确定限饲至42日龄期间及之后的脂肪细胞特征。另一种处理是在限饲期后逐渐恢复饲喂。试验3旨在测试恢复饲喂期间饲喂不同类型日粮脂肪对腹脂垫（AFP）大小的影响，试验持续至18日龄。测试了三种类型的脂肪，即动植物混合油、亚麻油和动物脂，每种脂肪都有全喂量和限饲处理。在试验1和试验2中，限饲鸡在42日龄时均未实现相对于对照的完全补偿生长。早期限饲导致12日龄时体脂百分比降低（P<0.05），尽管到42日龄时，主要通过脂肪细胞肥大导致的较高脂肪沉积速率使肥度没有差异。逐渐恢复至自由采食并未改变这种脂肪细胞肥大，也未改善恢复饲喂期间的补偿生长反应。早期限饲与饲料效率的持续提高相关（P<0.05）。以体重百分比表示时，使用不同类型的日粮脂肪对AFP没有影响。在恢复饲喂期饲喂动植物混合油的鸡的AFP更大（克/只），这种情况可归因于体重差异。限饲肉鸡实现生长补偿显然需要比此处使用的更长的生长周期或更宽松的限饲方案。日粮脂肪的饱和度对肉鸡的恢复饲喂特征没有影响。
