White spot syndrome virus (WSSV) infection alters gut histopathology and microbiota composition in crayfish (Procambarus clarkii)

Abstract

Intestinal microbiota influence host health. Numerous pathogens have been reported in crayfish (Procambarus clarkii) breeding systems. White spot disease, which is caused by white spot syndrome virus (WSSV), is the most severe disease observed in crayfish aquaculture systems. The present study investigated changes in intestinal morphology and gut microbiota in crayfish under WSSV infection. WSSV infection caused intestinal villi and hepatopancreas damage. In addition, intestinal microbiota diversity and richness decreased significantly under WSSV infection, and some functions of the intestinal microbiota were altered. Proteobacteria and Firmicutes abundance increased and decreased significantly, respectively, under WSSV infection. At the genus level, the relative abundance of an opportunistic pathogen, Aeromonas, increased significantly, and the abundances of Acinetobacter and Kurthia decreased significantly, in WSSV-infected crayfish. Additionally, according to the results of metagenomics analyses using PICRUSt, the altered microbiota was mainly linked to metabolism, diseases, environmental information processing, organismal systems, and cellular processes. Microbiome phenotype analyses based on BugBase revealed that the potential pathogenicity of intestinal flora in WSSV-infected crayfish was higher than in healthy crayfish. Overall, WSSV infection influenced intestinal and hepatopancreatic morphology, in addition to gut microbiota structure in crayfish.