Acute exposure to microplastics induces metabolic disturbances and gut dysbiosis in adult zebrafish (Danio rerio)

There is limited knowledge of the ecotoxicological impacts of MPs at the environmentally relevant concentration on freshwater animals, even though numerous studies have demonstrated the toxic effects of MPs on living organisms. In this study, zebrafish (Danio rerio) was used as a model organism to investigate the ecotoxicological effects of acute exposure of virgin MPs on changes in metabolome and gut microbiota. High-throughput untargeted metabolomics using liquid chromatography with tandem mass spectrometry (LC-MS/MS) provided comprehensive insights into the metabolic responses of zebrafish exposed to PE (polyethylene) and PES (poly-ester) MPs. Statistical analysis of metabolomics data indicated that 39 and 27 metabolites, such as lysophos-phatidylcholine, phosphocholine, phosphatidylserine, triglyceride, glycosphingolipid, psychosine, 8-amino-7-oxononanoate, cholesterol fatty acid ester, phosphatidylinositol, n-Triacontanol, were significantly altered in PE-and PES-exposed zebrafish, respectively. Furthermore, the enrichment pathway analysis unveiled the syn-thesis of the structural and functional lipids, signaling molecules, fatty alcohol metabolism, and amino acid metabolism, which was considerably perturbated in MPs-exposed zebrafish. In addition, high-throughput DNA sequencing was conducted to examine changes in gut microbiota in the MPs-treated zebrafish. The MPs exposure increased in the relative abundance of Fusobacteria and Proteobacteria, while the relative abundance of Firmicutes declined in MPs-treated zebrafish. Also, microbial diversity and linear discriminant analyses indicated micro -biota dysbiosis, metabolomic dysregulation, and oxidative stress. Taken together, the acute exposure of MPs at environmentally relevant concentrations could disrupt the metabolic interaction via the microbiota-gut-liver-brain relationship, implying gastrointestinal and neurological/immune disorders in zebrafish.

Automated summary

This study investigated the ecotoxicological effects of acute exposure to microplastics (MPs) at environmentally relevant concentrations on the metabolome and gut microbiota of zebrafish. The findings from metabolomics and gut microbiota analysis revealed alterations in metabolites, dysbiosis of gut microbiota, and oxidative stress in zebrafish exposed to MPs. The study suggests that MPs could disrupt the metabolic interaction via the microbiota-gut-liver-brain relationship, leading to gastrointestinal and neurological/immune disorders in zebrafish.