The Toxicity Of Fungicide Triclopyricarb On Zebrafish (Danio Rerio)

Triclopyricarb(TCP) is a strobilurin fungicide developed by Shenyang Research Institute of Chemical Industry. TCP could be used as a broad-Spectrum fungicide to control the wheat powdery mildew, rice blast and rice false smut and other diseases in many crops. The ecotoxicity of TCP on fish has not been reported. However, other strobilurin fungicides had been reported of presenting high toxicity to fish, so TCP may present the similar toxicity to fish as well.In order to confirm the surmise, the acute toxicity of TCP on zebrafish was studied following the Test Guidelines on Environmental Safety Assessment for Chemical Pesticides and TCP presented high toxicity to zebrafish and the LC50 is 0.169mg/LThe effects of TCP on the fecundity of zebrafish exposed in a short term were researched following the OECD chemical test guideline. The results showed that TCP could affect the spawning of the zebrafish. After the 21 days TCP exposure at the concentration of 2.5×10-2、5×10-2 and 0.100 mg/L, the daily average spawned eggs per female zebrafish in the following 10 days were respectively 58.9,54.9 and 56.0, compared with the blank control of 73.5 and solvent control of 71.5. And the number of daily mean spawned eggs during the 14 days exposure at the concentrations described above (respectively 36.2,36.7,41.5) were also decreased contrast to the control(59.1) and solvent control(56.4). It revealed that TCP could bring negative effects on the fecundity of zebrafish.The developmental toxicity of TCP on zebrafish was observed. The results revealed that TCP had a delay effect on development of zebrafish. It could reduce the hatching rates, survival rates, heart rates of zebrafish embryos. Meanwhile, TCP caused a series of malformations such as yolk sac edema, pericardial edema and body axis curvatures. And the LC50 is 0.169 mg/L.The relative transcript level of immune-related gene such as IFN、IL-8、IL-1β、 CXCL-CIc and CC-Chem was detected by SYBR Green qPCR after the newly fertilized embryos exposed in the TCP at the concentration of 120,24.0 and 4.80 μg/L until hatching. The results showed that TCP had certain interference effect on immune system of zebrafish. Transcript levels of the detected genes were all down-regulated and the CC-Chem was significantly down-regulated (p<0.05) at low concentration of 4.80 μg/L. No significant difference existed compared with the control at medium concentration of TCP exposure and all gene transcript level were up-regulated at high concentration of 120 μg/L, especially the IFN(p<0.05).