早期限饲对肉鸡肌肉生长及生产性能的长期影响

Long-term effect of early feed restriction on muscle growth and production performance of broilers

本研究旨在比较不同生长阶段隔日限饲（早期限饲：1—14日龄限饲，后期限饲：50—63日龄限饲）对肉鸡肌肉生长及相关激素水平的影响，并探讨早期限饲对肉鸡肌肉生长的程序化作用。试验结果：1）早期限饲组整个试验阶段体重均极显著低于对照组，后期限饲组限饲一周后体重显著低于对照组并于63日龄实现完全补偿生长；2）早期限饲组14日龄和63日龄胸肌、腓肠肌重均显著低于对照组；后期限饲组63日龄胸肌、腓肠肌重均显著低于对照组，且二者与早期限饲组均差异不显著；3）早期限饲显著降低了14日龄肉鸡肌肉中DNA、RNA和蛋白含量，63日龄恢复至正常水平，且核酸、蛋白水平在胸肌和腓肠肌内的趋势表现不一致；4）早期限饲组14日龄血清中1、3、T4水平均显著低于对照组，63日龄血清1、3水平仍显著低于对照组；后期限饲组63日龄血清1、3水平显著低于对照组，T4水平与对照组差异不显著。结果表明：1）限饲可显著阻碍肉鸡肌肉的生长；2）不同部位的肌肉对限饲的敏感度不同；3）早期营养因子对肉鸡肌肉的生长具有“程序化”作用，甲状腺激素可能参与这衅过程的调节。

The present experiment was carried out to investigate the effect of intermittent feed restriction on muscle growth and hormone levels in different stages （ERG： early feed restriction group; LRG： later feed restriction group） of broilers, and to examine the long effect of early feed restriction on muscle growth. The results showed： 1 ） body weight of ERG was significantly lower throughout the whole experimental period, and body weight of LRG was significantly lower after feed restricting for 1 week whereas no difference on 63 d compare with the control group; 2 ） in ERG group the lateral gastrocnemius muscle weight and pectoral muscle weight were significantly lower on 14 d and 63 d, and the pectoral and lateral gastrocnemius muscle weight were significantly lower on 63d in the LRG; 3 ） the DNA, RNA and protein contents in ERG decreased significantly on 14 d whereas no difference on 63 d, and no consistent trend was observed on nucleic acid and protein contents in pectoral and lateral gastrocnemius muscle ; 4 ） the T3, T4 levels was significantly lower on 14 d while only T3 level was still lower on 63 d, and in the LRG, T3 level, not T4, was also significantly lower on 63 d. These results implied： 1 ） feed restriction could markedly delay the muscle growth of broiler, and the effect has long lasting; 2 ） different response to early feed restriction was observed between pectoral and lateral gastrocnemius muscle; 3 ） thyoxine hormones might be included in this process.