Acute toxicity of fenoxycarb to zebrafish(Brachydanio rerio) at different development stages and chronic toxicity to embryo and sac-fry stage

In order to provide information for the safety and rational use of fenoxycarb, the acute toxicity of fenoxycarb to different development stages of zebrafish(Brachydanio rerio) was investigated by semi-static method. Results showed that the 96 h LC50 values of fenoxycarb were 2.35,0.98,1.87 and 1.67 mg/L for embryo, 12 h-old larva, 72 h-old larva and adult of zebrafish, respectively. There were also some sublethal and teratogenic effects observed. Fenoxycarb could affect the spontaneous movements, heart rate,hatching rate of embryo and the body length of hatched larvae, as well as cause pericardial edema, axial malformation and unnormal develpoment of melanocytes in the embryo of zebrafish. The chronic toxicity of fenoxycarb to zebrafish embryo and sac-fry stage was further studied. According to different endpoints tested, the lowest observed effect concentration(LOEC)values of fenoxycarb to 24 h spontaneous movements, 48 h heart rate,72 h teratogenic rate and the body length of 11 d hatched larvae of embryo and sac-fry stage were 0.60, 0.20, 0.60, 0.80 mg/L, respectively, and the no observed effect concentration(NOEC)values were 0.40, 0.10, 0.40, 0.60 mg/L, respectively; Inhibition on the hatching of zebrafish embryos by fenoxycarb was observed. The results suggested that the heart rate of zebrafish embryo was the most sensitive endpoint for chronic toxicity test of fenoxycarb.