Effects of weaning American glass eels () with the formula diet on intestinal microbiota and inflammatory cytokines genes expression.

This study aimed to investigate the effects of weaning American glass eels () with the formula diet on intestinal microbiota and the expression of inflammatory cytokines genes. During the feeding trial, the control group (termed IF group) was fed with initial feed for 34 days, and the experimental group (termed FF group) was fed with initial feed for 30 days, and then weaned with the formula diet for 4 days. After feeding trial, intestines were subjected to microbiota analysis using 16S rDNA high-throughput sequencing, and expression of three inflammatory cytokines genes in gut were examined by qPCR. The results indicated that the species richness and diversity of intestinal microbiota exhibited significantly higher in FF group than that in IF group  < 0.05). At the phylum level, the core intestinal microflora was the same for two groups. The most abundant phylum was Firmicutes in IF group, while it was Proteobacteria in FF group. Five genera were significantly higher in the IF group compared with the FF group, and was the most major enriched biomarker at genus level. Nine genera were significantly higher in the FF group compared with the IF group, and was the most major enriched biomarker. Weaning from initial feeding diet to formula feeding diet enhanced the expression levels of and , and there was no significant change in expression between the two groups. These findings would be very useful to improve the diet formulation for weaning stage of American glass eels.