Dietary inulin benefits on growth, digestive ability and intestinal microbiota in yellow catfish exposed to ammonia

Inulin can be selectively utilized by the host intestinal microbiota to promote growth and stress resistance. Although inulin is rarely reported in aquatic animal, it has been widely used in feed production. This study evaluated the effects of dietary inulin on growth, digestive ability, and intestinal microbiota of yellow catfish exposed to ammonia. The results showed that ammonia stress resulted in growth retardation (weight gain and specific growth rate decreased), which may be related to reduced feed utilization (feed intake and feed conversion ratio increased). Dietary inulin supplementation can improve intestinal digestive enzyme activity (lipase and pepsin), blood health and immune response (total protein, 50 % hemolytic complement, immunoglobulin M increased; total cholesterol, glucose, aspartate aminotransferase, and alanine aminotransferase decreased), and liver antioxidant enzyme activity (superoxide dismutase and catalase), but reduce inflammatory response (interleukin-1 and tumor necrosis factor-α) of yellow catfish under ammonia stress. In addition, inulin can increase Turicibacter abundance, and reduced Achromobacter abundance in intestinal microbiota, which was positive correlation with improved growth of yellow catfish exposed to ammonia. This study suggests that inulin can be used as a potential feed additive to help yellow catfish cope with ammonia stress.