Effects of dietary berberine hydrochloride inclusion on growth, antioxidant capacity, glucose metabolism and intestinal microbiome of largemouth bass (Micropterus salmoides)

The present study was conducted to investigate the influence of berberine inclusion on growth, antioxidant capacity, glucose metabolism and intestinal microbiome of largemouth bass. Three experimental diets were formulated with 0, 100, and 400 mg/kg berberine hydrochloride, which were fed to triplicate groups of juvenile largemouth bass twice daily for 11 weeks. The results of feeding trial revealed that dietary berberine inclusion produced no significant influence on growth performance of largemouth bass. However, the inclusion of dietary berberine significantly reduced serum glucose content, and alleviated hepatic glycogen accumulation. Gene expression analysis indicated that dietary berberine inclusion significantly elevated the expression of insulin pathway related genes, such as insulin receptor a (IRa), phosphatidylinositol-3-kinase p85 alpha (PI3KR1) and serine/threonine kinase 1 (AKT1), which was partly associated with the repressed expression of glycolysis related genes, glucokinase (GK) and phosphofructokinase liver type (PFKL). Additionally, the inclusion of dietary berberine significantly decreased the content of lipid peroxidation products, MDA. Meanwhile, the antioxidant capacity was significantly elevated at both transcriptional level and enzymatic level, which was suggested to be mediated by Nrf2/Keap1. The analysis of bacterial 16S rRNA V3–4 region indicated that the intestinal microbiota profile was significantly altered at both phylum and genus level, with elevated relative abundance of Fusobacteria, and Cetobacterium, and deceased enrichment for potential pathogenic bacteria genera Plesiomonas with the inclusion of dietary berberine. In summary, the inclusion of dietary berberine improved glucose metabolism, antioxidant capacity and intestinal microbiome of largemouth bass.