奶牛饲料利用效率差异的微生物学与代谢机制研究

Feed efficiency in dairy production is generally lower in China than in the developed countries, which not only results in the general waste of existing resources, but also cause environmental pollution. Our previous study showed that there existed large variation of individual cows in feed efficiency. Besides genetics aspect, little information is available on the factors influencing feed efficiency by individual cows′ physiological and nutritional metabolism. In this proposed study, we intend to compare the microbial communities and function in the rumen of lactating cows that exist large difference in feed efficiency, indicated by residual feed intake. Meanwhile, the metabolomics approach based on GC-TOF/MS will be employed to analyze the metabolite profile of the biofluids (rumen fluid, milk, serum and urine, etc.) collected from these cows. We will screen significantly different metabolites and key metabolism pathway, which can provide deep insight and better understanding of cows′ metabolic physiology. Combining the ruminal microbiomes and biofluid metabolites related with different feed efficiency to determine the association between key metabolites and milk production traits, the final goal of this proposal is to understand the microbial and metabolism basis for varying feed efficiency in lactating dairy cows, which will further enhance our ability to efficiently utilize feed resources by lactating dairy cows.

我国奶牛养殖业的饲料效率普遍低于发达国家，不仅造成现有资源的普遍浪费，而且引起对环境的污染。前期研究发现，饲料利用效率存在很大的个体差异，除了遗传因素，奶牛个体的生理与营养代谢对饲料利用效率的影响有待深入探究。本研究旨在从表观、消化、代谢三个层面入手，利用宏基因组学等手段研究饲料利用效率（用剩余采食量表示）存在差异的奶牛其瘤胃微生物的菌群区系变化与功能；并采用代谢组学研究方法，分析奶牛的生物体液，寻找差异代谢产物，进而解析关键代谢通路；结合微生物学机制、关键差异代谢通路、代谢组与产奶性状的关联等，基本阐明影响泌乳奶牛饲料利用效率的微生物学与代谢机制，研究结果将为提升奶牛生产效率提供基础知识和科学指导。

我国奶牛养殖业的饲料效率普遍低于发达国家，不仅造成现有资源的普遍浪费，而且引起对环境的污染，因此本项目围绕影响饲料效率的瘤胃微生物学及其奶牛代谢机制开展系统研究。利用宏基因组学、代谢组学等多组学技术，研究饲料效率差异奶牛瘤胃微生物的菌群组成与功能；采用代谢组学研究方法，对奶牛的生物体液进行分析，寻找差异代谢产物，进而解析关键代谢通路；结合微生物学机制、关键差异代谢通路、代谢组与产奶性状的关联等，以图阐明影响泌乳奶牛饲料利用效率的微生物学与代谢机制。本研究在荷斯坦奶牛群体中发现了奶牛饲料效率与泌乳性能上较大的个体差异，基于全身体液代谢组学揭示了不同饲料效率奶牛的差异乳蛋白前体物合成、氮代谢、乳腺氨基酸代谢作用机制。对差异饲料效率奶牛开展瘤胃宏组学测定与分析，系统解析了影响奶牛饲料效率的瘤胃微生物互作与代谢机制，鉴定了基石微生物及其下游代谢通路，确定了一些可预测饲料效率表型的关键瘤胃代谢物。探究了日粮中添加蛋氨酸对提高奶牛饲料效率的影响，发现奶牛对蛋氨酸响应的个体差异及其背后的生理与微生物机制。上述研究结果将为提升奶牛生产效率提供基础知识和科学指导。