Effects of antimicrobial peptides on non-specific immunity responses and gut microbes of tsinling lenok trout (Brachymystax lenok tsinlingensis)

Abstract

Abstract Antimicrobial peptides (AMPs) are an important component of non-specific immunity and play a key role in cellular host defense against pathogens and tissue damage infections. We investigated the effects of AMP supplementation on the antioxidant capacity, non-specific immunity and intestinal microbiota of tsinling lenok trout. Different diets (CT, A120, A240 and A480) containing graded levels of AMP peptides (0, 120 mg kg− 1, 240 mg kg− 1, 480 mg kg− 1) were feed to 240 fish for 8-weeks. Our study findings showed that the activity of total antioxidant capacity (T-SOD) and glutathione peroxidase (GSH-Px), lysozyme (LZM), catalase (CAT) and acid phosphatase (ACP) in the A240 and A480 group were higher than that in the CT group (P < 0.05). Malondialdehyde (MDA) content in AMP group was significantly lower than that in CT group (P < 0.05). Furthermore, we harvested the midgut and applied next-generation sequencing of 16S rDNA. The results showed that the abundance of Halomonas in AMP group was significantly lower than that in CT group. Functional analysis showed that the abundance of chloroalkane and chloroalkene degradation pathway increased significantly in AMP group. In conclusion, AMP enhanced the antioxidant capacity, non-specific immunity, and intestinal health of tsinling lenok trout.