Environmental concentration of chlorantraniliprole induces dysbiosis of gut microbiota and metabolism in crayfish (Procambarus clarkii)

The widespread application of chlorantraniliprole (CAP) in rice-crayfish co-culture systems poses a potential threat to the health of the non-target crustacean Procambarus clarkii. However, the sub-chronic effects of environmentally relevant concentrations of CAP on intestinal health remain poorly understood. In this study, we conducted a 14-day exposure experiment at two environmentally realistic CAP doses (0.05 and 0.5 mg/L) to investigate its effects using an integrated approach combining histopathology, biochemical assays, 16S rRNA gene sequencing, and untargeted metabolomics. Our results demonstrated that CAP exposure induced dose-dependent intestinal damage, ranging from villi degeneration to severe enterocyte dissolution and cytoplasmic vacuolation. This structural compromise was accompanied by significant CAP accumulation and oxidative stress, as evidenced by the suppression of antioxidant enzymes (SOD, CAT) and the depletion of GSH, along with increased lipid peroxidation (MDA). Furthermore, CAP exposure caused significant gut microbiota dysbiosis, characterized by an increased Firmicutes/Proteobacteria ratio, reduced alpha diversity, and taxon-specific, dose-dependent shifts in genus abundance. Metabolomic analysis revealed substantial reprogramming of the host-associated metabolome, with the high-dose group exhibiting a distinct profile and a stronger disruption in amino acid metabolism pathways. Crucially, Mantel test analysis revealed a dose-dependent intensification of the microbiota-metabolite correlation, indicating that the dysbiotic gut microbiome actively mediated the host's metabolic dysfunction under high-level CAP exposure. Our findings provide a comprehensive perspective on the intestinal toxicity of CAP in crayfish, highlighting the gut microbiome as a key mediator of pesticide-induced metabolic dysregulation.