热应激奶牛瘤胃异常代谢产物的生成及其对乳蛋白前体物重分配的调节机理

Heat stress is one of the most important factors that affects the economics of the dairy industry. Heat stress not only reduces milk production, but also reduces milk protein content. The production and utilization of milk protein precursors (e.g. glucose and amino acids) plays an important role in the efficiency of milk protein synthesis. Based on our previous research, abnormal metabolites like lipopolysaccharides in the rumen increase, and milk protein precursors are repartitioned when cows under heat stress; however, the exact mechanism is not yet clear. In this proposal we hypothesized that heat stress affects rumen fermentation in dairy cows, produces abnormal rumen metabolites, damages the function of the rumen epithelial barrier, and alters milk protein precursor repartitioning. To confirm this hypothesis, this proposal will use systems biology thinking, combining the microbial metabolism of the rumen, tissue distribution, utilization and partitioning of milk protein precursors by the mammary gland, integrating the study of mechanisms affecting milk protein synthesis in heat-stress dairy cows. The results will enrich and improve our understanding of the direct mechanisms of heat stress affecting milk protein synthesis, and further provide a theoretical and methodological basis for alleviating heat stress, improving the efficiency of milk protein synthesis, and improving the health of dairy cows under heat stress.

热应激是影响奶牛养殖业经济效益的最主要因素之一，热应激不仅降低奶牛产奶量，也降低乳蛋白的含量。乳蛋白前体物的生成与利用是影响乳蛋白合成效率的重要因素，本课题组前期的研究表明，奶牛处于热应激时瘤胃异常代谢产物脂多糖的含量升高，乳蛋白前体物发生重分配，但具体机制尚不明确。为此，本项目提出假设：热应激影响奶牛瘤胃发酵，产生异常代谢产物，损伤瘤胃上皮屏障作用进而参与调节乳蛋白前体物的重分配。为证实这一科学假设，本项目应用系统生物学思维，从瘤胃代谢、组织分配和乳腺利用切入，整合研究热应激奶牛瘤胃微生物代谢与乳蛋白前体物分配影响乳蛋白合成的微观机理，揭示热应激奶牛瘤胃关键异常代谢产物生成与乳蛋白前体物重分配之间的调节关系，阐明热应激影响奶牛乳蛋白前体物重分配的调节机理，研究结果可丰富和完善热应激影响乳蛋白合成的直接机制，为缓解奶牛热应激、提高奶牛合成乳蛋白的效率和奶牛健康提供理论与方法依据。

热应激是影响奶牛养殖业经济效益的最主要因素之一，热应激不仅降低奶牛产奶量，也降低乳蛋白的含量。乳蛋白前体物的生成与利用是影响乳蛋白合成效率的重要因素，本课题组前期的研究表明，奶牛处于热应激时瘤胃异常代谢产物脂多糖的含量升高，乳蛋白前体物发生重分配，但具体机制尚不明确。为此，本项目提出假设：热应激影响奶牛瘤胃发酵，产生异常代谢产物，损伤瘤胃上皮屏障作用进而参与调节乳蛋白前体物的重分配。为证实这一科学假设，本项目应用系统生物学思维，从瘤胃代谢、组织分配和乳腺利用切入，整合研究热应激奶牛瘤胃微生物代谢与乳蛋白前体物分配影响乳蛋白合成的微观机理，揭示热应激奶牛瘤胃关键异常代谢产物生成与乳蛋白前体物重分配之间的调节关系，阐明热应激影响奶牛乳蛋白前体物重分配的调节机理，研究结果可丰富和完善热应激影响乳蛋白合成的直接机制，为缓解奶牛热应激、提高奶牛合成乳蛋白的效率和奶牛健康提供理论与方法依据。