Effects of difenoconazole on hepatotoxicity, lipid metabolism and gut microbiota in zebrafish (Danio rerio)

In current study, larvae and adult zebrafish were exposed to difenoconazole to assess its effect on hepatotoxicity, lipid metabolism and gut microbiota. Results demonstrated that difenoconazole could induce hepatotoxicity in zebrafish larvae and adult, 0.400, 1.00, 2.00 mg/L difenoconazole caused yolk retention, yolk sac edema or liver degeneration after embryos exposure for 120 h, hepatocyte vacuolization and neoplasm necrosis were observed in adult liver after 0.400 mg/L difenoconazole exposure for 21 d. RNA sequencing showed that the 41 and 567 differentially expressed genes in zebrafish larvae and liver induced by 0.400 mg/L difenoconazole, were concentrated in pathways related to protein digestion and absorption, pancreatic secretion, steroid biosynthesis, and different metabolic pathways including galactose or sugar metabolism. Difenoconazole exposure caused lipid accumulation in larval yolk sac, and the elevated triglyceride (TG), malondialdehyde (MDA) and reactive oxygen species (ROS) levels in larvae and liver, which further confirmed the lipid metabolism disorders induced by difenoconazole. The results further showed that difenoconazole increased the abundance of gut microbiota such as Firmicutes, Aeromonas, Enterobacteriaceae and Bacteroides, further suggested that gut microbiota might participate in lipid metabolism and hepatotoxicity during zebrafish development. These findings advanced the field of the difenoconazole-induced developmental toxicity in larvae and adult zebrafish, and the imbalance of gut microbiota provided the plausible mode of action for the liver damage and disordered lipid metabolism in zebrafish.