# Integrated Gut Microbiome and Metabolome Analysis in Largemouth Bass (Micropterus salmoides) Following Viral Infection

## TL;DR

This study explores how a virus affects the gut bacteria and metabolism in largemouth bass, revealing disruptions that could worsen intestinal health.

## Contribution

The study provides an integrated analysis of gut microbiome and metabolome changes in largemouth bass following viral infection.

## Key findings

- Viral infection caused microbial dysbiosis with reduced diversity and shifts in dominant taxa.
- Metabolomic changes were observed in amino acid and carbohydrate metabolism pathways.
- Opportunistic bacteria correlated with harmful metabolites, suggesting immune dysfunction.

## Abstract

This study investigates changes in the gut microbiome and metabolome of largemouth bass following infection with largemouth bass virus. We integrated microbiome analysis via 16S rRNA sequencing and metabolomics using ultra-performance liquid chromatography–tandem mass spectrometry to examine how viral infection affects microbial composition and metabolic pathways in largemouth bass gut. The results showed that viral infection caused significant microbial dysbiosis, including reduced microbial diversity and shifts in dominant taxa. Additionally, metabolomic profiling revealed changes in metabolic pathways, particularly those related to metabolism. These changes suggest that the virus disrupts both microbial and host metabolism, potentially exacerbating intestinal damage.

Largemouth bass (Micropterus salmoides) is an important aquaculture species increasingly threatened by viral diseases, particularly largemouth bass virus (LMBV), which can cause significant mortality. However, integrative analyses linking LMBV-induced gut microbiota dysbiosis to metabolomic dysfunction are limited. In this study, we profiled the intestinal microbiome and metabolome alterations in largemouth bass following LMBV infection and conducted an integrated analysis. Infected fish showed reduced alpha diversity and significant shifts in community structure, including increased relative abundances of Bacteroidota and Fusobacteriota and a decrease in Proteobacteria. Opportunistic taxa, such as Pseudomonas and Mycobacterium, were enriched after infection. Metabolomic profiling revealed differential metabolites primarily involved in amino acid and carbohydrate metabolism. Integrative correlation analyses further identified significant associations between opportunistic bacteria and putative harmful metabolites, suggesting that LMBV-induced dysbiosis disrupts host metabolic homeostasis and contributes to immune dysfunction. These findings may clarify the microbiota–metabolite landscape during LMBV infection.