Jejunal Microbiome and Bile Acids Induced by Diets in Angus Beef Cattle

Abstract

Background: The small intestine, while serving as the main absorption organ, also possesses a unique microbiome environment and holds the critical function of conversion of primary bile acids. Bile acids are, in turn, able to regulate microbiome structure and promote the growth of bacteria that convert primary bile acids to secondary bile acids. However, in beef cattle, few studies have explored the microbiome compositions of the jejunum and its relationships with bile acids. Therefore, the hypothesis is that microbiome compositions in the intestine are influenced by diet style and also related to bile acids.Results: We demonstrated that the influences of diets on the intestinal microbiome could be observed in young beef cattle after weaning. A significantly higher level of microbial diversity was evidenced in feces of grass-fed animals comparing to grain-fed cattle. Top 20 essential genera were obtained with random forest analysis on the fecal microbiome to identify candidate microbial biomarkers. Moreover, the jejunal microbiome of adult Angus beef cattle exhibited significant differences in microbial composition and metabolic potential under different diets. Global balances and microbiome signatures of bile acids were identified. Conclusions: The findings from this study provided deep insights into microbiome compositions in fecal and jejunal and identified relationships between jejunal microbiome and bile acids with diets in Angus beef cattle. Our results should help us better understand grass-fed beef in production practice and potential health benefits.