Examination of difference in central nervous system between chickens selected for meat and egg production

本研究旨在阐明中枢神经系统在动态平衡、摄食行为、应激反应和渗透调节等方面的差异。蛋鸡在胚胎和孵化早期下丘脑中神经肽Y(NPY)的含量高于肉鸡，这与食欲性外源性NPY不一致。与蛋型鸡相比，下丘脑中高丰度的前阿片黑素皮质素基因，以及脑室注射β-MSH的厌食效应更大，这可能是元型鸡摄取更多饲料的原因。此外，下丘脑中5-羟色胺和多巴胺的周转率也可能与两种鸡不同的取食行为有关。隔离鸡导致的运动活动减少和发声次数减少与褪黑激素生成量…降低有关肉鸡松果体、脑叶、脑干有较多的吸收。肉鸡胚胎期产热量少，脂肪代谢活跃，这可能是肉鸡生长较快的原因之一。名古屋鸡被选为肉鸡和蛋鸡是有用的动物，表明胚胎产热和对应激源的反应是可供选择的项目。高渗盐水注射后下丘脑精氨酸血管生成素基因的表达可能不仅通过下丘脑TONEBP，而且通过TonEBP以外的任何其他途径。对甘丙素和神经肽Y免疫阳性的细胞和纤维在两种类型的鸡中的分布相似。在两种类型的鸡中，下丘脑中的NPY神经元被认为投射到室旁核的小细胞神经元。总的来说，含有调节肽的神经元的结构在两种类型的鸡中几乎没有差异，但在肽基因表达和神经递质代谢方面的一些差异被证明是导致鸡的表型的原因之一。较少

The aim of this project is to clarify the difference in the central nervous system related to homeostasis, feeding behavior, responses to stress and osmotic regulation, between chickens selected for meat and egg production.Neuropeptide Y (NPY) peptide content in the hypothalamus during embryonic and early post-hatched period was larger in the egg-type than in the meat-type chickens, which is inconsistent with orexigenic exogenous NPY. Compared to egg-type chickens, higher abundance proopiomelanocortin mRNA in the hypothalamus and larger anorexigenic effect of intracerebroventricularly injected beta-MSH in the meta-type chickens are likely to be responsible for their ability to eat more feed. In addition to this, the turnover rate of serotonin and dopamine in the hypothalamus might be also associated with the different feeding behavior between both types of chickens.Less locomotion activity and vocalization number induced by isolation of chickens was involved in the lower melatonin prod … More uction in the pineal, lobe, brain stem in the meat-type chickens. Heat production during embryonic period was less and lipid metabolism in the meat-type chickens was more active than those in the egg-type chickens, which may be one of factors to make the former grow faster. Nagoya chickens being selected for meat- and egg-types were useful animals to show that the embryonic heat production and responses to stressor are items for selection.Arginine vasotocin gene expression in the hypothalamus responding to hypertonic saline injection was likely to be mediated through hypothalamic not only TonEBP but any other pathway than TonEBP.Distribution of cells and fibers immunoreactive to galanin and NPY in the hypothalamus was similar between both the types of chickens. NPY neuron in the hypothalamus was suggested to project to the parvocellular neuron of the paraventriclular nucleus in both types of chickens.Collectively, there is little differences in the structure of the neuron containing regulatory peptide between the two types of chickens, but some differences in the expression of peptide genes and in neurotransmitters metabolism have been shown to contribute to the phenotype of chickens. Less