Regulation of Gastrointestinal Growth and Function

加拿大有1500多万只反刍动物生产牛奶和肉类，为加拿大经济贡献了400多亿美元。在加拿大大约50,000个农场中饲养的反刍动物遵循动物福利的最高标准，然而，幼畜和成熟家畜的胃肠疾病和紊乱仍然严重威胁着动物福利和农业的盈利能力。在出生后的第一周，反刍动物的瘤胃是功能性的，在引入和食用谷物和牧草等饲料之前，瘤胃一直处于非功能性状态。对反刍动物养殖者来说，从新生儿依赖牛奶提供的营养向谷物和牧草提供的营养过渡的过程具有重要的经济和动物福利意义，因为改善反刍动物早期的营养状况可以降低死亡率和疾病易感性，并增加体重和产奶量。***本研究的总体假设是，刺激反刍动物功能适应的胃肠道信号通路受到饮食和微生物群之间特定相互作用的调节。本研究的长期目标是提高我们对胃肠道生长和功能的理解，并开发新的有效策略来改善反刍动物的胃肠道健康。第一个实验的目的是确定断奶如何通过IGF-1信号通路影响幼年反刍动物的胃肠道生长。第二个实验通过IGF-1信号传导研究了接种成熟反刍动物微生物群对未成熟反刍动物胃肠道发育的影响。最后的实验将确定肠内GLP-2和IGF-1信号通路如何与瘤胃沟通，从而影响瘤胃的生长和功能。****这项研究将全面了解胃肠道对从饮食、微生物群及其代谢物最终产物接收的感觉信息的综合反应。拟议中的研究还将深入了解饮食和微生物因素如何影响许多物种的胃肠道生长和功能。由此产生的知识和创新与利用营养物质和微生物群改善牲畜胃肠道健康有关，最终将有助于设计无抗生素的动物生产系统

There are over 15 million ruminants in Canada producing milk and meat, which contributes over 40 billion dollars to Canada's economy. The ruminants raised on approximately 50,000 farms throughout Canada follow the highest standards of animal welfare, however gastrointestinal diseases and disorders in young and mature stock are still a serious threat to animal welfare and the profitability of agriculture. During the first week of life, ruminants are born as functional mongastrics, and the rumen remains non-functional until the introduction and consumption of feedstuffs such as grains and forages. The process of transition from their neonatal reliance on nutrients supplied from milk to nutrients supplied from grain and forages is of important economic and animal welfare significance to ruminant producers, as improvements to ruminant nutritional regimes in early life can decrease mortality and disease susceptibility, as well as increase weight gain and milk production. *** The overall hypothesis for this research is that gastrointestinal signaling pathways that stimulate functional adaptations in the ruminant are regulated by specific interactions among diet and microbiota. The longterm goal of this research is to improve our understanding of gastrointestinal growth and function and to develop novel and effective strategies to enhance ruminant gastrointestinal health. The aim of the first experiment is to determine how weaning can impact gastrointestinal growth of the young ruminant via IGF-1 signaling pathways. The second experiment examines the impact of microbiota inoculation from mature ruminants on the gastrointestinal development via IGF-1 signaling in immature ruminants. The final experiment will determine how GLP-2 and IGF-1 signaling pathways in the intestine communicate with the rumen to impact its growth and function.**** This research will provide a comprehensive understanding of the integrated responses of the gastrointestinal tract to the sensory information it receives from the diet, microbiota and their metabolite end-products. The proposed research will also provide insight into how dietary and microbial factors can impact gastrointestinal growth and function across many species. The resulting knowledge and innovations related to improving gastrointestinal health in livestock using nutrients and microbiota will ultimately aid in the design of antibiotic-free animal production systems.***