B 族维生素作为辅酶，参与碳水化合物、蛋白质和脂肪代谢，在动物生长发育和物质代谢中发挥重要作用。随着草食家畜产业的规模化发展和反刍家畜生产性能的提高，B 族维生素营养研究迎来了新的契机。反刍家畜独特的瘤胃微生物系统既可以生物合成又可以分解代谢B族维生素。遗憾的是，目前关于其代谢机理这一科学问题知之甚少。鉴于维生素B9（叶酸）和B12（钴胺素）功能上相辅相成，且这两种维生素的饲料供给量和瘤胃合成量并不足以满足机体需要量。本项目拟以此两种维生素为切入点，以黑山羊为试验动物，利用微生物学、多组学、生物信息学等技术手段，破译反刍家畜胃肠道细菌维生素B9和B12的合成及分解代谢路径，阐释其代谢过程在瘤胃和后肠道的差异机理，刻画整个胃肠道上细菌代谢维生素B9和B12的图谱，并解析其营养调控机理。旨在为明确反刍家畜B族维生素最适需要量和建立系统科学的维生素营养调控技术方案提供理论基础和技术支撑。

B vitamins act as cofactors for the enzymes involved in the metabolism of carbohydrates, lipids and proteins, and play indispensible roles in the growth and metabolism of animals. With the development of ruminant industry and the improvement of animal production, the researches on B vitamins nutrition ushered in a new development opportunity. In ruminants, ruminal microflora have the capacity to synthesize and degrade B vitamins. However, little studies research on the metabolism mechanism of B vitamins in gastrointestinal bacteria. It has been reported that the supply in folate (vitamin B9) and cobalamin (vitamin B12) in ruminants could be limiting based on estimated ruminal synthesis and dietary supply. Moreover, metabolisms of these two vitamins are closely linked. Therefore, using black goats as experimental animals, this project will use a combination of microbiology, muti-omics and bioinformatics to conduct research on these two vitamins. We will investigate the anabolism and catabolism pathways of vitamins B9 and B12 in gastrointestinal bacteria, explore the discrepancy in metabolism of these two vitamins between ruminal and intestinal bacteria, depict the bacterial metabolic profile of vitamins B9 and B12 in the entire gastrointestinal tract, as well as underline the nutritional manipulation mechanism by diet. The implement of this project will provide foundation for optimal nutritional requirements of B vitamins for ruminants, and establish theoretical basis and technical support for establishing systemic vitamin nutrition manipulation in goats.