Geraert P A, MacLeod M G, Larbier M, Leclercq B
Station de Recherches Avicoles, Institut National de la Recherche Agronmique, Monnaie, France.
Poult Sci. 1990 Nov;69(11):1911-21. doi: 10.3382/ps.0691911.
Two experiments were conducted to investigate the effect of dietary protein content (170 to 230 g/kg in Experiment 1 and 131 to 251 g/kg in Experiment 2) and initial growth rate, estimated from live body weight at 4 wk of age, on growth rate from 4 to 7 wk of age, nitrogen retention, energy metabolism, and amino acid catabolism in genetically fat (FL) and lean (LL) lines of chickens. There was no difference between lines in energy utilization either in metabolizability or in expenditure (basal metabolic rate, maintenance, or diet-induced thermogenesis). The only divergence between lines was in the partition of a similar amount of retained energy between lipid and protein deposition. In both experiments, LL chickens showed greater protein retention efficiency than FL birds; moreover, the LL line did not appear more sensitive to low dietary protein contents than the FL line. Selecting birds on their growth rate or live body weight at 4 wk of age resulted in the selection of different rates of fattening. Indeed, the slow-growing FL and LL chickens differed less in their nitrogen metabolism than did fast-growing birds, which were also fatter. The lower protein retention efficiency observed in FL chickens was related to an increase of dietary amino acid degradation as revealed by a greater rate of uric acid excretion in the fed state.
进行了两项试验，以研究日粮蛋白质含量（试验1为170至230克/千克，试验2为131至251克/千克）以及根据4周龄时的体重估算的初始生长速率，对遗传上肥胖（FL）和瘦肉型（LL）品系鸡在4至7周龄期间的生长速率、氮保留、能量代谢和氨基酸分解代谢的影响。在能量利用率方面，无论是代谢能还是能量消耗（基础代谢率、维持需要或日粮诱导产热），品系间均无差异。品系间唯一的差异在于，在相似数量的保留能量中，脂质和蛋白质沉积的分配情况不同。在两项试验中，LL品系鸡的蛋白质保留效率均高于FL品系鸡；此外，LL品系对低蛋白日粮的敏感性似乎并不高于FL品系。根据4周龄时的生长速率或体重选择鸡，会导致选择出不同的育肥速率。实际上，生长缓慢的FL和LL品系鸡在氮代谢方面的差异，小于生长快速且更肥的鸡。FL品系鸡中观察到的较低蛋白质保留效率，与日粮氨基酸降解增加有关，这在采食状态下尿酸排泄速率更高得到了体现。
