胆汁酸生理功能及其与肠道微生物互作研究进展

Towards the Understanding on the Physiological Functions of Bile Acids and Interactions with Gut Microbiota

胆汁酸(bile acids, BAs)是由胆固醇代谢产生的,在肝脏中胆固醇转化为初级胆汁酸,进入肠道后又经肠道菌群代谢为次级胆汁酸,并通过肠肝循环在体内维持稳态。胆汁酸分子既有亲水端又有亲脂端的结构,可发挥洗涤剂的作用,有助于溶解和吸收膳食中的脂类及脂溶性维生素等,这也使得胆汁酸具有一定的抗菌特性。胆汁酸与肠道菌群的互作不仅体现在其自身的生理功能上,而且肠道细菌的组成及数量也调控着胆汁酸代谢,并通过激活不同的受体信号调节糖脂代谢、能量代谢以及免疫炎症反应等。本文综述了胆汁酸的代谢过程及其如何通过FXR、TGR5等受体信号调控宿主生理功能等,为后续通过科学合理地调控肠道菌群及其代谢物来维护动物健康、促进畜禽生产提供参考。

Bile acids(BAs)are produced from the metabolism of cholesterol.In the liver,cholesterol is converted into primary bile acids,and they are metabolized into secondary bile acids by gut microbiota when they reache the intestinal tract.Their homeostasis are maintained in the body through the enterohepatic circulation.The molecules of bile acids have both hydrophilic and lipophilic ends,which can play the role of detergent and help to dissolve and absorb dietary lipids and lipid-soluble vitamins.This also endows bile acids with certain antibacterial properties.The interaction between bile acids and gut microbiota is not only reflected in their own physiological functions of bile acids,but also in the regulations of the gut microbial composition and abundances in bile acid metabolism.Bile acids regulate glucose,lipid and energy metabolisms,and immune and inflammatory reactions by activating different receptor signal pathways.This article reviews the metabolic process of bile acids,and discusses how it regulates host physiological functions through FXR,TGR5 and other receptor signal pathways.It also provides references for maintaining animal health and promoting livestock and poultry production performance through scientifically and reasonably regulating gut microbiota and its metabolites.