The positive effects of single or conjoint administration of lactic acid bacteria on Channa argus: Digestive enzyme activity, antioxidant capacity, intestinal microbiota and morphology

Abstract

In the present study, we aimed to evaluate the single or conjoint effects of Lactococcus lactis (L. lactis) L19 and Enterococcus faecalis (E. faecalis) W24 isolated from the intestine of Channa argus (C. argus) on digestive enzyme activity, antioxidant capacity, intestinal microbiota and morphology of C. argus (initial weight, 9.50 ± 0.03 g). The fish were fed for 56 days with a basal diet (CK) or diets supplemented with 1.0 × 108 CFU/g of L. lactis (L19), E. faecalis (W24), L. lactis + E. faecalis (L + W). Results indicated that these three lactic acid bacteria (LAB) supplementary diets especially the L19 produced significant improvement in the digestive enzyme activity (protease, amylase and lipase) in liver, stomach and intestine compared with control (P < .05). LAB supplementations were enhanced the liver and intestine antioxidant status (SOD, CAT, GSH-Px, T-AOC and MDA) in comparison to the control (P < .05). Serum biochemical parameters (ALT and AST) of fish fed with LAB supplemented diets showed significantly decreased compared with control (P < .05). The intestinal morphology showed protection in fish fed both L19 or/and W24. High-throughput sequencing revealed L19 supplementation can effectively increase the generation of probiotic bacteria and decrease the abundance of aquatic pathogens. Therefore, supplementation of L. lactis L19 showed more effective protection than E. faecalis W24 or the mixture of the two for promoting digestive enzyme activity, antioxidant capacity, intestinal microbiota and morphology of C. argus.