Influence of Dietary Berberine on Liver Immune Response and Intestinal Health of Black Sea Bream (Acanthopagrus schlegelii) Fed with Normal and High-Lipid Diets

Abstract

This study designed the normal diet (Con), high-lipid diet (HL), and 50 mg/kg berberine supplemented Con and HL diets (named as ConB and HLB, respectively). Fingerling black sea bream (Acanthopagrus schlegelii) (initial weight $1.47\pm 0.03$  g) were fed these four diets for 8 weeks, and the liver immune response and intestinal health were evaluated. Fish fed the HL diet had the lowest serum glutathione peroxidase and catalase activities, while berberine supplementation significantly improved serum catalase activity ( $P<0.05$ ). The expressions of tumor necrosis factor-alpha (tnfα), nuclear factor-kappa b (nf-κb), and interleukin 1 beta (il-1β) were significantly increased by the HL diet, whereas berberine supplementation significantly downregulated these proinflammation cytokine expressions ( $P<0.05$ ). Berberine supplementation in normal and high-lipid diets significantly promoted hepatic anti-inflammation cytokines interleukin-10 (il-10) and transforming growth factor beta-1 (tgfβ-1) expressions ( $P<0.05$ ). The intestinal expressions of tnfα, nf-κb, and tgfβ-1 were not significantly influenced by different treatments, while Cu/Zn-superoxide dismutase (Cu/Zn-sod) expression was significantly upregulated in the ConB group compared with the Con group. High-lipid diet reduced intestinal villus length. the thickness of muscularis mucosa, mucosal folds, and diversity and richness of intestinal microbiota but increased numbers of goblet cells and width of lamina propria. Berberine supplementation in high-lipid diet alleviated these pathological changes and rebalanced intestinal microbiota composition. At the genus level, fish fed the HL diet had significantly lower abundances of some probiotics such as Lactobacillus and Hydrogenophaga than that of the HLB group ( $P<0.05$ ). In conclusion, berberine supplementation in high-lipid diet reduced liver inflammation, improved the antioxidative status of fish, and alleviated intestinal damage and intestinal microbiota alteration of black sea bream.