Effects of dietary Lycium barbarum polysaccharide on the growth, antioxidant, immunity response, and intestinal microbiota in Bulatmai barbel (Luciobarbus capito)

Chinese herbal polysaccharides has the functions of enhancing immunity, anti-oxidation, regulating intestinal flora, which was widely used in animals, but rarely used in fish. This study investigated the influence of dietary Lycium barbarum polysaccharide (LBP) on growth performance, digestive performance, immune performance, gene expression, and intestinal flora in Bulatmai barbel. The control cohort received a basal diet, whereas the treatment cohorts consumed identical basal diets comprising 0.10 %, 0.20 %, and 0.40 % LBP for 8 weeks. The findings indicated that compared with the control cohort, 0.10 % LBP notably enhanced the weight gain rate (WGR) and specific growth rate (SGR), while diminishing the feed coefficient (FCR). Overall, 0.10 % LBP markedly improved digestive performance and elevated trypsin, lipase, and amylase functional levels. Additionally, 0.10 % LBP markedly increased the antioxidant activity in Bulatmai barbel. LBP upregulates the mRNA expression of Heat shock proteins (HSP70), Alkaline phosphatase (AKP), and Superoxide dismutase (SOD). Of note, 0.10 % LBP can increase the diversity and richness of intestinal flora. Furthermore, LBP enhanced the proportional presence of fusobacteria while reducing proteobacteria levels. At the genus level, it elevated the proportional presence of Cetobacterium. Therefore, this study has shown that 0.10 % LBP positively regulated growth performance, digestive performance, immune performance, gene expression, and intestinal flora in Bulatmai barbel. LBP is a feed additive with excellent potential.