Dynamics and regulation of endogenous amino acid synthesis in pigs

猪内源氨基酸合成的动态和调控

• 批准号: RGPIN-2016-04496
• 负责人: deLange, Cornelis
• 金额: $ 3.42万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=630814
• 关键词: Dynamics; regulation; endogenous; amino; acid

With the rapidly increasing demand for high quality food protein for human consumption, competition between humans and animals for alternative dietary protein sources has increased. It is thus important to accurately characterize protein (i.e., amino acids, AA; nitrogen, N) bioavailability in dietary protein sources and dietary AA requirements. The latter requires an understanding and quantification of the biological processes that contribute to dietary AA requirements, including dynamics of using different N sources for endogenous synthesis of AA. The long term aim of this research is to improve N utilization efficiency in non-ruminant animals and humans through improved understanding of the dynamics of using various N sources (essential and non-essential AA, non-protein N) for the endogenous synthesis of conditionally limiting and non-essential AA that are needed for protein synthesis and other metabolic functions. The research objectives are to explore in the growing pig: (1) dynamics and relative efficiency of using ammonia-N absorbed from either the upper or lower gut for body protein synthesis; (2) dynamics and regulation of ammonia-N capturing, as well as urea and net AA synthesis in visceral organs; (3) relative use of threonine and ammonia-N for the endogenous synthesis of glycine under defined conditions, and (4) more accurately define dietary requirements for total N and N-sources to satisfy needs for endogenous AA synthesis for optimizing N utilization in growing pigs fed diets deficient in non-essential AA N. A series of visceral organ mass balance and isotope tracer studies will be conducted to quantify endogenous AA synthesis in (surgically modified) growing pigs, and explore its regulation. These studies will be complemented with enzyme kinetics and gene expression assays, digestibility and N-balance observations, as well as statistical and mathematical (modelling) analyses. The proposed research will yield much needed quantitative information about endogenous AA synthesis when pigs are fed diets that are marginally deficient in non-essential AA N and improve our understanding of basic aspects of AA metabolism in non-ruminant animals and humans. Ultimately this research will lead to improved utilization of dietary N in both non-ruminant animals and humans, reducing losses of harmful N into the environment, as well as increased flexibility in the use of alternative protein sources for feed and food. The proposed research will also contribute to training of highly qualified personnel.

随着人类对优质食品蛋白质的需求迅速增加，人类和动物之间对替代膳食蛋白质来源的竞争也日益激烈。因此，准确表征膳食蛋白质来源中蛋白质（即氨基酸，AA；氮，N）的生物利用度和膳食 AA 需求非常重要。后者需要了解和量化有助于膳食 AA 需求的生物过程，包括使用不同氮源进行 AA 内源合成的动态。这项研究的长期目标是通过更好地了解使用各种氮源（必需和非必需 AA、非蛋白质 N）来内源合成蛋白质合成和其他代谢功能所需的条件限制和非必需 AA 的动态，从而提高非反刍动物和人类的氮利用效率。研究目标是在生长猪中探索：（1）利用从上消化道或下消化道吸收的氨氮进行体内蛋白质合成的动态和相对效率； (2) 内脏器官中氨氮捕获、尿素和净AA合成的动态和调控； (3) 在规定条件下相对使用苏氨酸和氨氮来合成甘氨酸的内源性，以及 (4) 更准确地确定总氮和氮源的日粮需求，以满足内源性 AA 合成的需要，从而优化饲喂缺乏非必需 AA N 日粮的生长猪的氮利用率。将进行一系列内脏器官质量平衡和同位素示踪研究，以量化内源性 （经过手术改造的）生长猪的 AA 合成，并探索其调控。这些研究将得到酶动力学和基因表达测定、消化率和氮平衡观察以及统计和数学（建模）分析的补充。当猪饲喂略微缺乏非必需 AA 的日粮时，这项研究将产生急需的关于内源 AA 合成的定量信息，并提高我们对非反刍动物和人类 AA 代谢基本方面的理解。最终，这项研究将提高非反刍动物和人类对膳食氮的利用，减少有害氮进入环境的损失，并提高饲料和食品中替代蛋白质来源的使用灵活性。拟议的研究还将有助于培养高素质人才。