The growth-promoting and lipid-lowering effects of berberine are associated with the regulation of intestinal bacteria and bile acid profiles in yellow catfish (Pelteobagrus fulvidraco)

Berberine has growth-promoting and lipid-lowering effects potentially through the regulation of intestinal microbiota and bile acid profiles. This experiment aimed to investigate the effect of dietary berberine on the intestinal microbiota-bile acid-farnesoid X receptor (FXR) axis in yellow catfish (Pelteobagrus fulvidraco). Fish (initial weight: 1.32 +/- 0.26 g) were fed a control diet or a diet supplemented with 100 mg/kg (BBR100) or 400 mg/kg berberine (BBR400) for 60 days. The BBR400 group showed significant improvements in growth performance, hepatic antioxidant enzyme activities, intestinal lysozyme activity, cholic acid, ethylchenodeoxycholic acid, and hydroguinone carboxylic acid contents, along with significantly lower intestinal immunoglobulin M, complement 3, complement 4, serum total cholesterol (TCH), and triglyceride (TG) contents, compared to the control group (P < 0.05). In addition, both levels of berberine resulted in significant reductions in viscerosomatic index, hepatosomatic index, condition factor, hepatic TCH, TG, and malondialdehyde contents, as well as serum alanine aminotransferase activity and low-density lipoprotein cholesterol content. Berberine supplementation also significantly upregulated the expression of intestinal fxr and fibroblast growth factor 19, as well as hepatic fxr, short heterodimeric partners, and lipolysis genes, while inhibiting the expression of lipogenesis genes. Furthermore, berberine treatment improved intestinal histological parameters and increased the abundance of probiotic bacteria such as Ruegeria and Bifidobacterium, while reducing potential pathogenic bacteria such as Pseudomonas, Psychrobacter, Vibrio, and Pseudonocardia. Overall, this study suggests that berberine's growthpromoting and lipid-lowering effects might be attributed to its modulation of intestinal microbiota, bile acid profile, and hepatic and intestinal FXR signaling.