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.