Study of the impact of hypothalamic factors on reproduction in poultry

在大多数鸟类物种中，光周期的变化是成功繁殖所必需的。在家禽中，光刺激导致下丘脑-垂体-性腺轴激活，促性腺激素释放激素（GnRH）、促黄体生成激素（LH）和促卵泡激素（FSH）分泌增加。在达到产蛋高峰后，母鸡逐渐停止产蛋，进入光不应期或表达孵化行为。除了这种已建立的涉及GnRH的刺激途径外，还提出了一种涉及促性腺激素抑制激素（GnIH）的潜在抑制途径。我们最近发现，GnRH和GnIH受体的基因表达在生殖周期中波动，它们的mRNA水平在鸡中呈负相关。然而，参与这些神经内分泌通路控制的确切分子机制仍有待确定。这一点至关重要，因为雌性的产卵期和雄性的生育力是家禽业成功的两个基石。因此，该项目旨在优化现有程序，并为未来的生殖技术开发新工具。通过研究GnRH和GnIH在体内和体外的作用机制，将获得新的知识，并通过研究各种光刺激范式对遗传盲鸡繁殖轴的影响，将实现现有管理程序的优化。我们最近在圭尔夫大学建立了。因此，拟议的研究将有助于加强家禽业在区域（安大略）和国家（加拿大）一级。此外，研究生将进行研究，从而有助于培养高素质的人才。

In most avian species, changes in photoperiod are required for successful reproduction. In poultry, photostimulation results in the activation of the hypothalamo-pituitary-gonadal axis with an increase in gonadotropin releasing hormone (GnRH), luteinizing hormone (LH) and follicle stimulating hormone (FSH) secretion. After reaching a peak in egg production, hens progressively cease laying and enter either a photorefractory stage or express incubation behaviour. In addition to this established stimulatory pathway involving GnRH, a potential inhibitory pathway involving a gonadotropin inhibiting hormone (GnIH) has also been proposed. We have recently shown that the gene expression of both GnRH and GnIH receptors fluctuate during a reproductive cycle, and that their mRNA levels are inversely correlated in chickens. However, the exact molecular mechanisms involved in the control of these neuroendocrine pathways still remain to be determined. This is of critical importance since the duration of an egg-laying period in females, and fertility in males are two corner stones of a successful poultry industry. Thus, this project aims at optimizing existing procedures and developing new tools for reproductive technologies of the future. New knowledge will be acquired by studying the mechanisms of action of both GnRH and GnIH in vivo as well as in vitro, and optimization of existing management procedures will be achieved by studying the effects of various photostimulation paradigms on the reproductive axis in a strain of genetically blind chickens we recently established at the University of Guelph. As a result, the proposed research will help strengthen the poultry industry at both a regional (Ontario) and national (Canada) level. Furthermore, research will be performed by graduate students, thus contributing to the training of highly qualified personel.