Attenuation of MEHP-induced hepatotoxicity and gut microbiota dysbiosis by Lactobacillus brevis Lb-0401 in Carassius auratus.

Mono-2-ethylhexyl phthalate (MEHP) is one of the major biologically active metabolites of phthalate plasticizers that pose a health threat to aquatic animals. In this study, we investigated the ecotoxicological effects of MEHP on liver damage and gut microbiota in crucian carp (Carassius carassius) and the mitigating effects of Lactobacillus brevis Lb-0401 as a dietary supplement. The results showed that MEHP induced hepatotoxicity and increased serum AST, ALT and triglyceride levels, while L. brevis Lb-0401 alleviated abnormalities in serum metabolic parameters and increased antioxidant enzymes (T-SOD, CAT, GSH-Px). Further transcriptome and microbiota analysis revealed that MEHP exposure caused hepatic glucose, lipid and purine metabolism disorders, inhibited energy production and disrupted gut microbial homeostasis. Administration of L. brevis Lb-0401 reversed all these changes. In conclusion, this study not only provides new mechanistic insights into the ecotoxicological effects of MEHP, but also suggests a potential strategy using intestinal autochthonous probiotic bacteria to mitigate the harmful effects of phthalate plasticisers on aquatic organisms.