以生长猪为研究对象，以微生物菌群数量最多、代谢最旺盛的大肠为研究器官，结合微生物组学和代谢组学技术，研究大肠微生物及其代谢对肠腔中不同组合碳氮尤其是不同结构的非消化多糖或寡糖等营养素的响应，研究微生物代谢变化对肠腔中营养素及代谢物组成的影响，通过肠上皮细胞培养，研究肠上皮营养素感应受体对不同碳氮组合下的肠道微生物差异代谢物的响应，揭示肠腔内微生物与营养代谢互作机制；结合肠瘘管和血插管技术，研究肠道微生物差异代谢物（单一和混合的）对主要营养素入门脉供应和机体整体代谢的影响；通过回盲肠瘘管灌注抗生素和外源菌或抑制剂等干预大肠微生物代谢，研究微生物差异代谢对机体整体代谢网络的调节，揭示肠道微生物---宿主共代谢互作机制，探析肠道微生物对机体整体水平上的营养代谢调节作用，为定向调节营养代谢进而提高生产效率提供新思路。

The proposed project will integrate fields of animal nutrition, biochemistry and gut microbial ecology, and apply techniques including microbial functional genomics and metabolic profiling to investigate the interplay of microbiota and nutrient/ metabolite in the intestine and its impact on the systemic nutritional metabolism of the growing pig. With the most abundant microbiota and highest degree of microbial activity in the pig body, the large intestine will be used as a focus in this study. In vivo and in vitro fermentation experiments will be conducted to assess the response of microbiota and its metabolism to different form and combinations of C and N in the lumen and in turn the influence of microbial activity on the composition and levels of nutrients or metabolites in the lumen will be investigated. To further understand the interaction between microbiota and nutrients, cell culture of pig intestine epithelium will be applied to assess the responsiveness of the nutrient sensing receptors to microbial metabolites. Pigs with intestinal cannula and portal catheters will also be adopted to further investigate the effects of individual or combined metabolites derived from intestinal microbiota on nutrient fluxes, nutrient sensing and whole body metabolism of carbohydrate, nitrogen and fat. The impact of gut microbiota intervention in the pig on the whole body metabolism will be further assessed. Metabolite correlations between intestinal microbe, blood and urine will be deciphered to uncover the metabolic axis between the gut microbiota and the whole body of the pig. Through these, we anticipate to assess the potential of the gut microbiota in directionally manipulating whole body nutritional metabolism of the growing pig, which may provide new frame work guidelines for strategies towards swine production efficiency.