BPA impairs the intestinal health of Gobiocypris rarus by disrupting gut microbiota, altering fatty acid metabolism, and affecting mucus secretion.

Bisphenol A (BPA) is an endocrine-disrupting chemical that is widely present in aquatic environments. Much research has confirmed that BPA exerts certain toxic effects on the reproduction and development of aquatic organisms. However, current toxicological studies on the changes in gut microbiota and fatty acid metabolism in aquatic organisms exposed to BPA still need to be further elucidated. In this study, Gobiocypris rarus were exposed to BPA at concentrations of 0, 1, 15, and 225 μg/L for 21 days to investigate changes in intestinal microbiota and fatty acid metabolism. Techniques including histological sectioning, fatty acid analysis, 16S rRNA sequencing, and quantitative real-time polymerase chain reaction (qRT-PCR) were employed. The results indicated that BPA exposure induced intestinal tissue damage in rare minnows. Alcian blue-periodic acid Schiff (AB-PAS) staining revealed that BPA exposure significantly promoted mucin secretion and goblet cell maturation. Furthermore, 16S rRNA sequencing indicated that BPA exposure altered gut microbiota composition, with significant increases in the relative abundances of Legionella, Aurantimicrobium, and Rubellimicrobium, while the relative abundance of Cyanobacteriota decreased significantly. Moreover, PICRUSt2 prediction indicated that BPA could disrupt the biosynthesis of secondary metabolites and metabolic pathways. Subsequently, fatty acid analysis showed that BPA exposure induced dysregulation of intestinal fatty acid metabolism, characterized by a significant increase in the relative abundance of butyric acid and saturated fatty acid (SFA), and a significant decrease in the relative abundance of monounsaturated fatty acid (MUFA). qRT-PCR analysis demonstrated that muc-2 and inflammatory factor (il-6, il-10, tnf-α) expression was significantly upregulated after BPA exposure. In summary, this study demonstrates that BPA exposure may impair intestinal health by disrupting gut microbiota and inducing alterations in fatty acid metabolism, particularly changes in butyric acid, which may affect mucus secretion, thereby providing a theoretical basis for assessing BPA's toxic effects on aquatic organisms.