Enantioselective toxic effects of mefentrifluconazole in the early life stage of zebrafish (Danio rerio)

) values (exposed to racemate and enantiomers of MFZ, that is, rac-MFZ/(-)-MFZ/(+)-MFZ) were 1.010, 1.552, and 0.753 mg/L for embryo, and 0.753, 1.187, and 0.553 mg/L for larvae. The rac-MFZ/(-)-MFZ/(+)-MFZ can affect the heart development of zebrafish embryos, accompanied by heart rate inhibition, yolk sac deformities, pericardial deformities, and down-regulation of genes related to cardiotoxicity in larvae in an enantioselective manner. Moreover, the rac-MFZ/(-)-MFZ/(+)-MFZ also can affect the neural development of zebrafish embryos, accompanied by autonomic movement inhibition, swimming speed and swimming distance abnormalities, and down-regulation of genes related to neurotoxicity in larvae in an enantioselective manner. For all toxicity endpoints, the effect of the (+)-MFZ to early-staged zebrafish were significantly greater than that of (-)-MFZ. These results will help distinguishing the difference of MFZ enantiomers to zebrafish, and provide scientific reference for improving the risk assessment of chiral pesticides MFZ.