Stabilized fermentation product of Cetobacterium somerae improves gut and liver health and antiviral immunity of zebrafish.

Abstract Probiotics are widely used in aquafeeds and exhibited beneficial effects on fish by improving host health and resisting pathogens. However, probiotics applied to aquaculture are mainly from terrestrial sources instead of the host animal. The purpose of the work was to evaluate the effects of stabilized fermentation product of commensal Cetobacterium somerae XMX-1 on gut, liver health and antiviral immunity of zebrafish. A total of 240 zebrafish were assigned to the control (fed a basal diet) and XMX-1 group (fed a basal diet with 10 g XMX-1/kg diet). After four weeks feeding, growth performance, feed utilization, hepatic steatosis score, TAG, lipid metabolism related genes and serum ALT were evaluated. Furthermore, serum LPS, the expression of Hif-1α, intestinal inflammation score, antioxidant capability and gut microbiota were tested. The survival rate and the expression of antiviral genes were analyzed after challenge by spring viremia of carp virus (SVCV). Results showed that dietary XMX-1 did not affect growth of zebrafish. However, dietary XMX-1 significantly decreased the level of serum LPS, intestinal inflammation score and intestinal MDA, as well as increased T-AOC and the expression of Hif-1α in zebrafish intestine (p