Effects of black raspberry extract on gut microbiota, microbial metabolites, and expressions of the genes involved in cholesterol and bile acid metabolisms in rats fed excessive choline with a high-fat diet

Abstract

In our previous study, black raspberry (BR) reduced the serum levels of trimethylamine-N-oxide and cholesterol in rats fed excessive choline with a high-fat diet (HFC). We hypothesized that gut microbiota could play a crucial role in the production of trimethylamine and microbial metabolites, and BR could influence gut microbial composition. This study aimed to elucidate the role of BR on changes in gut microbiota and microbial metabolites in the rats. The phylogenetic diversity of gut microbiota was reduced in the rats fed HFC, while that in the BR-fed group was restored. The BR supplementation enriched Bifidobacterium and reduced Clostridium cluster XIVa. In the BR-fed group, most cecal bile acids and hippuric acid increased, while serum lithocholic acid was reduced. The BR supplementation upregulated Cyp7a1 and downregulated Srebf2. These results suggest that BR extract may change gut bacterial community, modulate bile acids, and regulate gene expression toward reducing cholesterol.