Effects of polystyrene microplastics on the composition of the microbiome and metabolism in larval zebrafish.

Microplastics are major pollutants in marine environment and may have health effects on aquatic organisms. In this study, we used two sizes (5 and 50 μm diameter) of fluorescent and virgin polystyrene microplastics to analyze the adverse effects on larval zebrafish. In our study, we evaluated the effects on larval zebrafish after exposure to 100 and 1000 μg/L of two sizes of polystyrene microplastics for 7 days. Our results show that polystyrene microplastics could cause alterations in the microbiome at the phylum and genus levels in larval zebrafish, including changes in abundance and diversity of the microbiome. In addition, metabolomic analysis suggested that exposure to polystyrene microplastics induced alterations of metabolic profiles in larval zebrafish, and differential metabolites were involved in energy metabolism, glycolipid metabolism, inflammatory response, neurotoxic response, nucleic acid metabolism, oxidative stress. Polystyrene microplastics also significantly decreased the activities of catalase and the content of glutathione. In addition, the results of gene transcription analysis showed that exposure to polystyrene microplastics induced changes in glycolysis-related genes and lipid metabolism-related genes, confirming that polystyrene microplastics disturbed glycolipid and energy metabolism. Taken together, the results obtained in the present study indicated that the potential effects of environmental microplastics on aquatic organisms should not be ignored.