Environmentally-Relevant Concentrations of Atrazine Had Minor Impacts on Gut Microbiota and Liver Metabolite in Juvenile Turtles

Toxic effects of herbicide atrazine (ATR) have been evaluated in various aquatic organisms, but our understanding of its potential impacts in reptile species remains limited. In this study, the functional performances, and gut microbiota and liver metabolite alterations of ATR-exposed Mauremys sinensis juveniles were measured to evaluate its potential toxic effects in turtles. ATR exposure had no impact on the growth rate, but would allow turtles to right themselves more quickly. Despite having no difference in gut microbial diversity, the microbial composition was slightly changed after ATR exposure. For example, a few bacterial genera were shown to increase in exposed turtles (e.g., Turicibacter), or only observed in higher-concentration groups (e.g., Dialister, Alistipes, Delftia). Similarly, only a few identified liver metabolites were found to change significantly (e.g., decreased levels of arginine and N-acetylneuraminate; increased levels of glutathione and isomaltose in low-concentration exposure group) after ATR exposure. Overall, minor alterations in gut microbial composition and liver metabolite indicated that ATR exposure at environmentally-relevant concentrations only produced limited impacts in turtle species, although these alterations might have potentially adverse consequences on the long-term health of exposed turtles.