The enantioselective toxicity and oxidative stress of dinotefuran on zebrafish (Danio rerio)

Dinotefuran is a widely used neonicotinoid pesticides in agriculture and it has certain ecological toxicity to aquatic organisms. Studies on the potential toxicological effects of dinotefuran on fish are limited. In the present study, 96 h acute toxicity test indicated that enantiomers of R-(-)-dinotefuran had a greater toxic effect than Rac-dinotefuran on zebrafish, and S-(+)-dinotefuran was the least. In chronic assay, R-(-)-dinotefuran exerted more effects on the development of zebrafish than S-(+)-dinotefuran, and dinotefuran also had enantioselective effect on oxidative stress. Significant changes were observed in the superoxide dismutase (SOD), glutathione Stransferase (GST) and acetylcholinesterase (AChE) activities and malondialdehyde (MDA) contents, which demonstrated dinotefuran induced oxidative stress in zebrafish. Besides, through an ultra-performance liquid chromatography quadrupole-TOF mass spectrometry (UPLC-Q-TOF-MS)-based metabolomics method was used to evaluate the enantioselectivity of dinotefuran enantiomers in zebrafish. The results indicated that R(- )-dinotefuran caused greater disturbances of endogenous metabolites. Phenylalanine metabolic pathways, glycine, serine and threonine metabolic pathways are only involved in zebrafish exposed to R-(-)-dinotefuran; whereas phenylalanine, tyrosine and tryptophan biosynthesis was only involved in zebrafish exposed to S(+)-dinotefuran. This study provides a certain reference value for assessing the environmental risks of dinotefuran enantiomers to aquatic organisms, and has practical significance for guiding the ecologically and environmentally safety use of dinotefuran.

Automated summary

The study demonstrates that R-(-)-dinotefuran has a greater toxic effect on zebrafish, affecting their development, and shows selective effects on oxidative stress. Metabolomics method reveals disturbances of endogenous metabolites caused by R-(-)-dinotefuran. Only phenylalanine metabolic pathways are involved in zebrafish exposed to R-(-)-dinotefuran, while in fish exposed to S(+)-dinotefuran, phenylalanine, tyrosine, and tryptophan biosynthesis are involved.