Heck A, Metayer S, Onagbesan O M, Williams J
Station de Recherches avicoles, INRA, Centre de Tours, 37380, Nouzilly, France.
Domest Anim Endocrinol. 2003 Oct;25(3):287-94. doi: 10.1016/s0739-7240(03)00064-x.
An evaluation of the insulin-like growth factors (IGF) system in the ovaries of heavy breeder hens during the growing phase was performed to measure the effect of feed restriction. The transcripts of IGF-I, IGF-II, IGF receptor (IGF-R), two IGF binding proteins (IGFBP-2 and IGFBP-5), GH receptor (GH-R) and insulin receptor (I-R) were measured by RT-PCR at 4, 8, 12 and 16 weeks of age in the ovaries of ad libitum fed and feed restricted hens. The transcripts of all genes screened were detected in all feed regime groups and at all ages sampled. However, no significant overall effects of feed restriction on these transcripts were found despite the marked difference in body growth (200% at 16 weeks of age). Similarly there were no significant age effects except for the expression of GH-R-that showed a decrease after 8 weeks of age (P<0.01). Although feed restriction seems to have a relatively limited effect on the expression of these components of the ovarian IGF system in juveniles, a more detailed determination is necessary to determine possible changes nearer to sexual maturity (16 weeks of age onwards). It is concluded that components of the IGF system, GH or insulin may not be involved in the mechanisms that, through restricted feeding, alter ovarian development and function during growth to enable better reproductive performance during lay.
为了测定限饲的影响，对育成期重型蛋种鸡卵巢中的胰岛素样生长因子（IGF）系统进行了评估。通过RT-PCR测定了自由采食和限饲母鸡卵巢在4、8、12和16周龄时IGF-I、IGF-II、IGF受体（IGF-R）、两种IGF结合蛋白（IGFBP-2和IGFBP-5）、生长激素受体（GH-R）和胰岛素受体（I-R）的转录本。在所有采食方式组和所有采样年龄中均检测到了所有筛选基因的转录本。然而，尽管体重增长存在显著差异（16周龄时相差200%），但未发现限饲对这些转录本有显著的总体影响。同样，除了GH-R的表达在8周龄后下降（P<0.01）外，未发现显著的年龄效应。尽管限饲似乎对幼年鸡卵巢IGF系统这些成分的表达影响相对有限，但需要更详细的测定来确定接近性成熟（16周龄及以后）时可能的变化。得出的结论是，IGF系统、生长激素或胰岛素的成分可能不参与通过限饲改变生长过程中卵巢发育和功能以在产蛋期实现更好繁殖性能的机制。
