Regulation of nitrogen salvage in non-ruminants

非反刍动物氮回收的调控

• 批准号: RGPIN-2017-05275
• 负责人: Columbus, Daniel
• 金额: $ 1.89万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=681646
• 关键词: Regulation; nitrogen; salvage; non; ruminants

Pigs and other non-ruminant animals are capable of salvaging nitrogen through the process of urea recycling and subsequent microbial amino acid production in the gastrointestinal tract. However, the regulatory mechanisms for urea recycling into the gut and the factors (e.g., dietary, physiological) influencing the extent of urea recycling and subsequent nitrogen utilization are not well understood. In the ruminant, it has been shown that urea transport into the rumen is due, in part, to facilitative urea transporters (UT-B and aquaporins) in addition to non-specific paracellular movement. Dietary factors, such as fibre and protein intake, may influence nitrogen salvage through altering the gut environment and changes in nutrient supply to the animal and resident microbes. The hypothesis is that urea recycling and nitrogen salvage is a regulated process that can be manipulated through changes in dietary protein and fibre intake. The objectives are to determine (i) the effect of diet composition (e.g., protein and fibre content) on extent of urea recycling and fate of recycled urea, (ii) the mechanism and regulation of urea transport across the gut wall, (iii) effect of diet composition on nitrogen utilization in the non-ruminant, and (iv) the effect of oscillating dietary protein on nitrogen utilization and retention. To address these objectives, a PhD student, 4 MSc students, and a BSc Honours thesis student will be recruited to complete a series of animal experiments in pigs, an agricultural important animal species. A combination of isotope infusion, growth performance, nitrogen-balance, and in vitro (e.g., Ussing chamber) techniques will be used. The proposed research program will provide novel information on the mechanisms regulating urea recycling and nitrogen salvage in the non-ruminant animal which will lead to the development of novel feeding programs to improve nitrogen retention and sustainability of pork production. The objectives of this research program will benefit my long-term research objective to characterize the interaction of feed components and animal physiology in order to better understand the impact of these factors on nutrient utilization for animal growth and health.

猪和其他非反刍动物能够通过尿素回收过程以及随后胃肠道中微生物氨基酸的产生来回收氮。 然而，尿素循环进入肠道的调节机制以及影响尿素循环程度和随后的氮利用的因素（例如饮食、生理）尚不清楚。 在反刍动物中，研究表明，除了非特异性的旁细胞运动外，尿素转运到瘤胃的部分原因还在于促进尿素转运蛋白（UT-B 和水通道蛋白）。 膳食因素，例如纤维和蛋白质摄入量，可能会通过改变肠道环境以及动物和常驻微生物的营养供应变化来影响氮回收。假设尿素回收和氮回收是一个受调节的过程，可以通过改变膳食蛋白质和纤维摄入量来控制。 目的是确定（i）日粮成分（例如蛋白质和纤维含量）对尿素回收程度和回收尿素的命运的影响，（ii）尿素跨肠壁运输的机制和调节，（iii）日粮成分对非反刍动物氮利用的影响，以及（iv）振荡日粮蛋白质对氮利用和 保留。 为了实现这些目标，将招募一名博士生、四名硕士生和一名荣誉学士学位论文学生来完成一系列猪（一种重要的农业动物物种）的动物实验。 将使用同位素输注、生长性能、氮平衡和体外（例如尤斯室）技术的组合。 拟议的研究计划将提供有关非反刍动物尿素回收和氮回收调节机制的新信息，这将导致开发新的饲养计划，以提高猪肉生产的氮保留和可持续性。 该研究计划的目标将有利于我的长期研究目标，即表征饲料成分和动物生理学的相互作用，以便更好地了解这些因素对动物生长和健康的营养利用的影响。