Metagenomic insights into the alterations of gut microbial community in Bufo gargarizans tadpoles following lead exposure

Lead (Pb), a prevalent heavy metal contaminant in aquatic environments, has complex effects on the gut microbiome function of aquatic animals. In this study, metagenomic analysis of Bufo gargarizans tadpoles was carried out following Pb exposure. Moreover, histological analysis was performed on the intestines. The results showed that Pb exposure induced histological damage to the intestinal epithelium. Significant differences in microbial abundance and function were detected in the 200 μg/L Pb group compared to the control group. Specifically, an increase in Bosea and Klebsiella was noted at 200 μg/L Pb, which potentially could induce inflammation in tadpoles. Notably, the decrease in the abundance of glycoside hydrolases subsequent to exposure to 200 μg/L Pb is likely to attenuate carbohydrate metabolism. Furthermore, increased fluoroquinolone-related antibiotic resistance genes (ARGs), phenolic-related ARGs, and iron uptake systems following 200 μg/L Pb exposure might heighten the disease risk for tadpoles. These discoveries augment our comprehension of the influences of Pb on the intestinal well-being of amphibians and offer valuable insights for further assessment of the ecological risks that Pb poses to amphibians.