Effects of fermented noni juice on growth, antioxidant status, immune response, intestinal microbiota and resistance to Aeromonas hydrophila of juvenile yellow catfish Pelteobagrus fulvidraco fed high‐fat diet

The present study was conducted to evaluate the supplemental effects of fermented noni juice on growth performance, immune response, antioxidant status, intestinal microflora and disease resistance of yellow catfish that fed with high-fat diet. Triplicate groups of yellow catfish (1.00 ± 0.05 g) were fed two levels of lipid (80.00 and 160.00 g/kg dry matter) and two levels of fermented noni juice (0.00 and 20.00 g/kg dry matter) for 56 days. The results showed that high-fat intake could affect growth (weight gain declined) and lead to oxidative stress (superoxide dismutase, catalase and glutathione peroxidase activities declined and malondialdehyde accumulation), immunosuppression (alkaline phosphatase, phagocytic index, respiratory burst, complement C3, C4 and immunoglobulin G declined) and intestinal microflora altered (Proteobacteria and Bacteroides decreased and Firmicutes increased). The dietary fermented noni juice supplementation could mitigate the adverse effect of high-fat intake on yellow catfish growth, oxidative stress, immunosuppression and intestinal microflora homeostasis. After challenge with Aeromonas hydrophila, the cumulative mortality of yellow catfish fed with high-fat diet was higher than that of fish fed high-fat diet supplemented with fermented noni juice.