Table_5_The Relationship Between Gut Microbiome and Bile Acids in Primates With Diverse Diets.xlsx

Primates have evolved a variety of feeding habits and intestinal physiological structure. Gut microbiome act as metabolic organs in many biological processes and play a vital role in adaptation to dietary niches. Gut microbiome also convert primary bile acids (BAs) to secondary. BAs profile and gut microbiome are together influenced by diets and play a significant role in nutrient absorption. The regulation between gut microbiome and BAs metabolism is bidirectional although the relationship in primates consuming diverse diets is still unclear. Here, we investigated gut microbiome structures, fecal BAs profile, and their relationship in primates preferring three distinct diets. We found that gut microbiome communities are well differentiated among dietary groups. Folivorous primates had higher Firmicutes abundance and lower Prevotella to Bacaeroides ratios, possibly related to fiber consumption. Frugivorous primates are colonized predominantly by Prevotella and Bacteroides, pointing to an increased adaptation to high-sugar and simple carbohydrate diets. Likewise, BA profiles differ according to diet in a manner predictable from the known effects of BAs on metabolism. Folivorous primates have high conjugated bile acid levels and low unconjugated to conjugated BA ratios, consistent with their fiber-rich leaf-eating diet. Much of the differentiation in secondary and unconjugated BAs is associated with microbiome composition shifts and individual bile acid concentrations are correlated with the abundance of distinct bacterial taxonomic groups. Omnivores have higher concentrations of secondary BAs, mainly lithocholic acid (LCA). These levels are significantly positively correlated with the presence of Clostrida species, showing that the digestion requirements of omnivores are different from plant-eating primates. In conclusion, gut microbiome and BAs can respond to changes in diet and are associated with nutrient component consumption in each diet primate group. Our study is the first to demonstrate BA profile differentiation among primates preferring diverse diets. BAs thus appear to work with gut microbiome to help primates adapt to their diet.

灵长类动物演化出了多样的摄食习性与肠道生理结构。肠道微生物组（gut microbiome）作为代谢器官参与诸多生物学过程，在动物适应不同饮食生态位的过程中发挥关键作用。肠道微生物组还可将初级胆汁酸（primary bile acids, BAs）转化为次级胆汁酸。胆汁酸谱与肠道微生物组共同受饮食调控，并在营养吸收中扮演重要角色。尽管不同饮食类型的灵长类之间的互作关系仍不明确，但肠道微生物组与胆汁酸代谢之间的调控是双向的。
本研究针对偏好三种截然不同饮食类型的灵长类，探究了其肠道微生物组结构、粪便胆汁酸谱及其二者间的关联。研究发现，不同饮食类群的肠道微生物组群落结构存在显著分化。叶食性灵长类的厚壁菌门（Firmicutes）丰度更高，普雷沃氏菌属（Prevotella）与拟杆菌属（Bacteroides）的比值更低，这可能与其摄入大量膳食纤维相关。果食性灵长类的肠道菌群以普雷沃氏菌属与拟杆菌属为主，表明其更适应高糖与简单碳水化合物的饮食。
同样，胆汁酸谱也随饮食类型呈现差异，且这种差异可依据已知的胆汁酸代谢效应进行预测。叶食性灵长类的结合型胆汁酸水平较高，游离型胆汁酸与结合型胆汁酸的比值较低，这与其富含纤维的叶食性饮食特征相符。次级胆汁酸与游离胆汁酸的分化大多与微生物组组成的变化相关，且不同胆汁酸的浓度与特定细菌分类群的丰度存在关联。杂食性灵长类的次级胆汁酸（主要为石胆酸，lithocholic acid, LCA）浓度更高，该水平与梭菌属（Clostrida）物种的丰度呈显著正相关，表明杂食性灵长类的消化需求与植食性灵长类存在差异。
综上，肠道微生物组与胆汁酸可响应饮食变化，并与各饮食类群灵长类的营养组分摄入相关联。本研究首次证实了偏好不同饮食的灵长类之间存在胆汁酸谱分化。由此可见，胆汁酸或可与肠道微生物组协同帮助灵长类适应其饮食类型。