Improving bone health and eggshell quality through maintaining a desired calcium homeostasis in laying hens

产蛋母鸡的骨骼周转与每天的产蛋周期有关。由于快速的骨转换和钙从骨骼中动员形成蛋壳，结构性骨的进行性丢失(骨质疏松症)是蛋鸡行业的一大担忧。骨质疏松症是导致老年蛋鸡骨折的主要原因之一，与疼痛、产蛋量、蛋壳质量和动物福利问题有关。因此，未来的研究需要了解蛋鸡的骨代谢，然后制定遗传、营养和/或管理策略，以维持高效生产，改善动物福利、骨骼健康和蛋壳质量。本研究旨在研究添加适量的家禽钙敏感受体(CaSR)调节剂、钙源和25-羟基胆钙素对蛋鸡钙稳态、蛋壳品质和骨密度的影响。我们将首先研究家禽CaSR在蛋鸡壳腺和骨骼中的表达情况，然后在体外确定家禽CaSR的潜在调节因子。我们还将研究CaSR调节剂和25-羟基胆钙素如何调节成骨细胞和间充质干细胞的分化。最后，我们将在体内研究CaSR调节剂、钙源和25-羟基胆酸二醇对骨骼健康和蛋壳质量的影响。这些结果将有助于我们了解蛋鸡壳腺和骨骼中钙稳态的分子机制，并开发出改善蛋鸡骨骼健康和蛋壳质量的营养途径。该项目有两个行业合作伙伴，包括马尼托巴省鸡蛋农民(MEF)和瓦伦斯坦饲料供应有限公司(WFS)。

Laying hens have a dynamic bone turnover associated with a daily egg laying cycle. Because of rapid bone turnover and calcium mobilization from bones for eggshell formation, progressive loss of structural bone (osteoporosis) is a big concern in the laying hen industry. Osteoporosis is one of the major causes for bone fractures in older laying hens, which are associated with pain, egg production, eggshell quality and animal welfare issues. Therefore, there is a need for future research to understand bone metabolism in laying hens and then develop genetic, nutritional and /or management strategies to maintain efficient production and improve animal welfare, bone health and eggshell quality. This proposal is to investigate the effects of administering an effective amount of poultry calcium sensing receptor (CaSR) modulators, calcium sources, and 25-hydroxycholecalciferol on calcium homeostasis, eggshell quality and bone density in laying hens. We will first investigate the expression of poultry CaSR in shell gland and bone in laying hens and then identify the potential modulators of poultry CaSR in vitro. We will also examine how CaSR modulators and 25-hydroxycholecalciferol regulates the differentiation of osteoblast and mesenchymal stem cells. Finally, we will investigate the effects of CaSR modulators, calcium sources and 25-hydroxycholecaciferol on bone health and eggshell quality in vivo. These results will help us to understand the molecular mechanisms of calcium homeostasis in shell gland and bone, and to develop nutritional approaches to improve bone health and eggshell quality in laying hens. There are two industry partners in this project including Manitoba Egg Farmers (MEF) and Wallenstein Feed & Supply Ltd. (WFS).