高效氯氰菊酯对非洲爪蟾蝌蚪生存和变态发育影响

Effects of the beta-cypermethrin on the survival and metamorphosis of Xenopus laevis tadpoles

目的研究高效氯氰菊酯原药对非洲爪蟾蝌蚪的生存和变态发育的影响。方法采用水生生物急、慢性实验方法,随机挑选发育到第51期的正常非洲爪蟾蝌蚪进行急、慢性毒性实验。急性毒性实验随机分为对照组和7个剂量组,高效氯氰菊酯染毒质量浓度分别为0.00和0.80、0.96、1.15、1.38、1.66、1.99、2.40μg/L,每组30只非洲爪蟾蝌蚪。观察染毒24、48、72和96 h时非洲爪蟾蝌蚪存活情况,计算上述4个时间点的半数致死浓度(LC50)。慢性毒性实验随机分为对照组和4个剂量组,高效氯氰菊酯染毒质量浓度分别为0.00和0.05、0.10、0.20、0.40μg/L,每组90只非洲爪蟾蝌蚪。观察变态高峰前期(第58期)和变态高峰期(第66期)非洲爪蟾蝌蚪的存活情况、体质量、体长和完成变态反应所需时间。结果急性毒性实验中,对照组和0.80μg/L剂量组非洲爪蟾蝌蚪在24、48、72和96 h 4个时间点均无出现死亡现象;2.40μg/L剂量组非洲爪蟾蝌蚪在24 h时全部死亡。8组非洲爪蟾蝌蚪在上述4个时间点存活率均随染毒剂量的增加而降低(P<0.01)。上述4个时间点LC50分别为1.71、1.66、1.55和1.49μg/L,安全浓度为0.15μg/L。慢性毒性实验中,变态高峰前期5组非洲爪蟾蝌蚪的存活率比较,差异无统计学意义(P>0.05);在变态高峰期,5组非洲爪蟾蝌蚪存活率随染毒剂量的增加而降低(P<0.01),其中,0.20和0.40μg/L剂量组非洲爪蟾蝌蚪存活率均低于对照组(71.1%vs 88.9%,65.6%vs 88.9%,P<0.006)。在变态高峰期时,各组非洲爪蟾蝌蚪的体质量和体长分别比较,差异均无统计学意义(P>0.05);0.20和0.40μg/L剂量组非洲爪蟾蝌蚪从第51期到完成变态反应所需时间长于对照组[(92.21±2.81)vs(89.43±2.41)d,(95.55±5.54)vs(89.43±2.41)d,P<0.01]。结论高效氯氰菊酯对非洲爪蟾蝌蚪的急性毒性为剧毒,且其可干扰非洲爪蟾蝌蚪的变态发育。

Objective To investigate the effects of beta-cypermethrin on the survival and metamorphosis of Xenopus laevis tadpoles. Methods Xenopus laevis tadpoles at stage 51 were randomly selected and tested by acute and chronic toxicity experiments. In acute toxicity test,240 tadpoles were randomly divided into 8 groups according to the exposure dose of beta-cypermethrin,including 0. 00μg/L dose group（ control group）and 0. 80,0. 96,1. 15,1. 38,1. 66,1. 99 and 2. 40μg/L dose groups,with 30 tadpoles in each group. Then the survival situation of Xenopus laevis tadpoles in 24,48,72 and 96 hours were observed,as well as the lethal concentrations of 50%（ LC50 ）in the above four time points. In chronic toxi-city test,450 tadpoles were randomly divided into 5 groups according to the exposure dose of beta-cypermethrin,including 0. 00 μg/L dose group（ control group）and 0. 05,0. 10,0. 20 and 0. 40 μg/L dose groups. The survival situation,body weight,body length and the time of completed the allergy in the early stage of the abnormal peak（ stage 58）and abnormal peak（stage 66）were all observed. Results In the acute toxicity test,there was no tadpoles died in the above four time＆amp;nbsp;points in the control group and 0. 80μg/L dose group,but all of the tadpoles were dead in the 24 hours of 2. 40μg/L dose group. The survival rate was decreased with the increasing of the infected doses（P〈0. 01）. The LC50 was 1. 71,1. 66, 1. 55 and 1. 49 μg/L at 24,48,72 and 96 hours time point respectively,while the safe concentration was 0. 15μg/L. In the chronic toxicity test,the survival rates in 5 groups showed no significant differences in stage 58（ P＆gt;0. 05 ）. But in stage 66,the survival rate was decreased with the increasing of the infected doses（ P〈0. 01）,while the survival rates in 0. 20 and 0. 40 μg/L dose groups were lower than that of the control group respectively（ 71. 1% vs 88. 9%,65. 6% vs 88. 9%,P〈0. 006 ）. In stage 66,the body weight and body length in 5 groups showed no significant differences （P〉0. 05）,while the time of completing the allergy in 0. 20 and 0. 40 μg/L dose groups was longer than that of the con-trol group respectively[（92. 21 ± 2. 81）vs（89. 43 ± 2. 41）,（95. 55 ± 5. 54）vs（89. 43 ± 2. 41）,P〈0. 01]. Conclu-sion Beta-cypermethrin was hypertoxic to Xenopus laevis tadpoles in acute toxicity test. Xenopus laevis tadpoles metamor-phosis was highly affected by beta-cypermethrin.