肠道微生物通过胆汁酸调控草鱼脂肪代谢的研究

鱼类的脂肪代谢一直是研究的热点。通常认为胆汁酸参与了脂肪代谢，但最近的研究发现肠道微生物也能够参与脂肪代谢，然而其作用途径尚不清楚。已发表的文献资料显示，肠道微生物可以调控胆汁酸代谢。因此，我们推测，肠道微生物可能是通过胆汁酸调控了脂肪代谢。本项目拟通过对草鱼胆汁酸与肠道微生物之间关系的研究，试图鉴定具有显著相关关系的微生物类群和胆汁酸种类。然后，分离培养与胆汁酸显著相关的关键微生物类群，进一步将关键微生物添加到草鱼饲料中开展养殖实验，通过对草鱼胆汁酸代谢和脂肪代谢相关指标的解析，弄清关键微生物对胆汁酸代谢与脂肪代谢的影响；同时，将与关键微生物显著相关的胆汁酸添加到饲料中开展养殖实验，通过对脂肪代谢相关指标的研究，揭示胆汁酸在脂肪代谢中的作用，从而弄清肠道微生物调控脂肪代谢的途径。本项目的完成将进一步丰富脂肪代谢基础理论，同时为鱼类营养性疾病的预防与治疗提供重要依据。

Fat is one of the most important nutrients animals need. Fat metabolism has always been a hot spot of research. It is generally believed that bile acids are involved in fat metabolism. However, recent studies have indicated that intestinal microbes can affect host lipid metabolism, the mechanism is still unclear. Studies on intestinal microbes have found that they regulate the metabolism of bile acids. Therefore, we speculate that intestinal microbes may regulate fat metabolism through bile acids. To test this hypothesis, we have established a method for the determination of bile acid in grass carp, and systematically determined intestinal microbiota of the fish. In the present study, we intend to (1) disclose the relationships between bile acids and intestinal microbes, and determine their significant correlations through comprehensive analysis of grass carp bile acids and intestinal microbiota; (2) reveal the relationships between intestinal microbes and metabolisms of bile acids and fat via bacterial feeding experiments of grass carp and the comparative studies on the relative indexes of bile acid and fat metabolism; and (3) untie the relationships between bile acid and fat metabolism via bile acid feeding experiments of grass carp and the comparative studies on the relative indexes of bile acid metabolism. The purpose of the present study is to uncover the mechanisms that intestinal microbiota regulates fat metabolisms. This project will further fulfill and enrich the theory of fat metabolism, and offer new ideas on prevention and treatment of nutrition-related diseases on fish.