Biological basis for variation in feed intake and nutrient utilization

我们新陈代谢研究计划的总体目标是为加拿大的牛肉和乳制品生产系统做出重大贡献，以满足消费者对可持续和对社会负责的动物农业日益增长的需求。有足够的证据表明，动物和人类的饲料摄入量相对于维持和增重需求以及养分运输和新陈代谢效率的差异存在遗传基础。采食量、维持采食量和增重需求的这些差异，在大小和生长的基础上衡量为低于或高于期望值，现在被报告为剩余饲料采食量。然而，这些反应的生理和代谢基础仍不清楚。我们使用ISC技术对甲烷产生、营养吸收和KM的差异的初步数据表明，这些差异是由胃肠轨迹(GIT)水平上可测量的生理和代谢过程支撑的。该实验室的长期目标是阐明调节相似饲料动物之间饲料摄入量和养分利用效率差异的生理机制。特别是，将研究一组特定的胃肠运动指数(频率、幅度和持续时间)和特定活性(钠+/葡萄糖协同转运体，SGLTS 1、2和3)的营养转运体在调节动物对GIT改变的营养供应的不同反应中的作用。此外，还将研究与关键营养素、葡萄糖和谷氨酰胺代谢有关的代谢过程，以及它们与GIT中不同的营养/饮食诱导反应的关系。对胃肠道的这些生理和代谢过程以及动力和营养转运体所扮演的角色的详细了解，应该为今后饲料/食物评价的改进铺平道路，该评价不仅考虑瘤胃和瘤胃后消化，而且还考虑胃肠道营养物质的命运。

The overall goal of our metabolic research program is to make significant contributions to the beef and dairy production systems in Canada that addresses the increasing consumer demands for a sustainable and socially responsible animal agricultural industry.There is enough evidence to indicate a genetic basis for the variation in feed intake relative to maintenance and gain requirements and the efficiency of nutrient transport and metabolism in animals and humans. These differences in feed intake, maintenance and gain requirements measured as below or above the expected value on the basis of size and growth are now reported as residual feed intake. However, the physiological and metabolic bases for these responses remain unclear. Our preliminary data of differences in methane production, nutrient absorption and Km using ISc technology lead to believe that these differences are underpinned by measurable physiological and metabolic processes at the level of the gastrointestinal track (GIT).The long term goal of this laboratory is to elucidate the physiological mechanisms regulating the variation in feed intake and efficiency of nutrient utilization between animals fed similar diets.  In particular, the roles of a specific group of gastrointestinal motility indices (frequency, amplitude and duration) of contractions and specific active (Sodium+/glucose co-transporter, SGLTs 1, 2 and 3) nutrient transporters in mediating differential animal responses to altered nutrient supply to the GIT will be studied. In addition, the metabolic processes involved in the metabolism of key nutrients, glucose and glutamine and their relationships to differential nutrient/dietary induced responses in the GIT will be studied. A detailed understanding of these physiological and metabolic processes in the GIT and the roles played by motility and nutrient transporters should pave the way for future improvements in feed/food evaluations that considers not only ruminal and post-ruminal digestion but the fates of nutrients in the GIT