Dynamic remodeling of gut microbiota and untargeted etabolomics in Sebastes schlegelii during Edwardsiella piscicida infection.

Abstract

The intestinal microbiota is a critical mediator of host immune responses and metabolic homeostasis, especially during the pathogenic challenge. This study investigated the dynamic remodeling of the gut microbiota and metabolome in Sebastes schlegelii following infection with the major aquaculture pathogen Edwardsiella piscicida. Using 16S rRNA gene sequencing and untargeted metabolomics, we analyzed the microbial community composition and metabolic profiles of intestinal samples at multiple time points post-infection. Our results revealed significant temporal shifts in bacterial diversity and structure. Notably, the abundances of genera such as Bacteroides, Bacillus, and Lactobacillus increased, while Comamonas and Cutibacterium decreased. Metabolomic analysis identified 1063 metabolites, with lipids and lipid-like molecules being the most abundant. Differential analysis revealed stage-specific metabolic alterations: early infection was marked by the upregulation of pro-inflammatory mediators such as lithocholic acid and palmitoylethanolamide, whereas late infection featured elevated levels of anti-inflammatory metabolites, including cholic acid and agmatine. KEGG pathway analysis indicated an initial enrichment in general metabolic processes, followed by a shift to steroid biosynthesis later in the infection. These findings suggest a coordinated "metabolic switch" mechanism that modulates inflammation and promotes recovery. This study provides novel insights into the microbiota-metabolite-immune network in S. schlegelii and highlights potential biomarkers for monitoring fish health status in aquaculture.