Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Kobe, Japan.
Comp Biochem Physiol A Mol Integr Physiol. 2011 Aug;159(4):422-6. doi: 10.1016/j.cbpa.2011.04.008. Epub 2011 Apr 29.
Broiler chicks eat more food than layer chicks. In this study, we examined the involvement of orexigenic peptide neuropeptide Y (NPY) in the difference in food intake between broiler and layer chicks (Gallus gallus). First, we compared the hypothalamic mRNA levels of NPY and its receptors (Y1 and Y5 receptors) between these strains at 1, 2, 4, and 8 days of age. Daily food intake was significantly higher in broiler chicks than layer chicks after 2 days of age. However, the hypothalamic NPY mRNA level was significantly lower in broiler chicks than layer chicks except at 8 days of age. In addition, the mRNA levels of NPY receptors were also significantly lower in broiler chicks than layer chicks at 2 and 4 days of age (Y1 receptor) or 2 days of age (Y5 receptor). These results suggest that the differences in the expressions of hypothalamic NPY and its receptors do not cause the increase in food intake in broiler chicks. To compare the orexigenic effect of NPY between broiler and layer chicks, we next examined the effects of central administration of NPY on food intake in these strains. In both strains, central administration of NPY significantly increased food intake at 2, 4 and 8 days of age. All our findings demonstrated that the increase in food intake in broiler chicks is not accompanied with the over-expression of NPY or its receptor.
肉鸡雏鸡比蛋鸡雏鸡吃更多的食物。在这项研究中，我们研究了食欲肽神经肽 Y（NPY）在肉鸡和蛋鸡之间食物摄入差异中的作用（Gallus gallus）。首先，我们比较了这两个品种在 1、2、4 和 8 日龄时下丘脑 NPY 和其受体（Y1 和 Y5 受体）的 mRNA 水平。2 日龄后，肉鸡雏鸡的日采食量明显高于蛋鸡雏鸡。然而，除 8 日龄外，肉鸡雏鸡的下丘脑 NPY mRNA 水平明显低于蛋鸡雏鸡。此外，2 日龄和 4 日龄（Y1 受体）或 2 日龄（Y5 受体）时，肉鸡雏鸡的 NPY 受体 mRNA 水平也明显低于蛋鸡雏鸡。这些结果表明，下丘脑 NPY 及其受体表达的差异不会导致肉鸡雏鸡采食量增加。为了比较 NPY 在肉鸡和蛋鸡之间的食欲作用，我们接下来研究了 NPY 对这些品系的中枢给药对食物摄入的影响。在这两个品系中，NPY 的中枢给药在 2、4 和 8 日龄时均显著增加了食物摄入量。我们所有的发现表明，肉鸡雏鸡采食量的增加并没有伴随着 NPY 或其受体的过度表达。
