噻虫嗪对中华绒螯蟹幼蟹的亚急性毒性效应

Subacute Toxic Effects of Thiamethoxam on Chinese Mitten Crab Eriocheir sinensis

在水温(23±2)℃下,采用63 cm×43 cm×20 cm水族箱和半静态毒性实验法,设(0.00μg/L、28.25μg/L、56.5μg/L、113μg/L和226μg/L)5个噻虫嗪(C_(8)H_(10)ClN_(5)O_(3)S)浓度梯度,测定了平均壳长(2.78±0.23)cm中华绒螯蟹(Eriocheir sinensis)幼蟹血淋巴细胞数量、肝胰腺和血淋巴相关免疫酶活性以及肝胰腺和鳃组织免疫和代谢基因表达情况,研究了噻虫嗪对中华绒螯蟹幼蟹的21 d亚急性毒性效应,为噻虫嗪在稻田养殖河蟹的合理用药提供理论依据。结果表明:噻虫嗪对中华绒螯蟹幼蟹的96 h半致死浓度(LC_(50))为452μg/L,安全浓度(SC)为45.2μg/L。噻虫嗪暴露第14 d和21 d,113μg/L和226μg/L噻虫嗪组河蟹的血淋巴细胞数量显著低于对照组(P<0.05);第1 d、4 d、7 d和14 d,28.25μg/L噻虫嗪组河蟹超氧化物歧化酶(SOD)活性显著高于对照组(P<0.05),第7 d、14 d和21 d,226μg/L组SOD活性显著低于对照组(P<0.05);第4 d、7 d、14 d和21 d,56.5μg/L、113μg/L和226μg/L噻虫嗪组河蟹肝胰腺丙二醛含量显著高于对照组(P<0.05);第7 d、14 d和21 d,113μg/L和226μg/L噻虫嗪组河蟹血淋巴谷丙转氨酶和谷草转氨酶活性显著高于对照组(P<0.05);第1 d、4 d和7 d,28.25μg/L噻虫嗪组河蟹血淋巴酚氧化酶(PO)活性显著高于对照组(P<0.05),第7 d、14 d和21 d,226μg/L噻虫嗪组河蟹血淋巴PO活性显著低于对照组(P<0.05);第4 d和第7 d,28.25μg/L和56.5μg/L噻虫嗪组河蟹肝胰腺和鳃组织PO和Na^(+)/K^(+)-ATPase的基因表达水平显著高于对照组(P<0.05),第21 d,226μg/L噻虫嗪组河蟹肝胰腺和鳃组织PO和Na^(+)/K^(+)-ATPase的基因表达水平显著低于对照组、28.25μg/L和56.5μg/L噻虫嗪组(P<0.05)。综上,高浓度的噻虫嗪对于中华绒螯蟹幼蟹的抗氧化酶活性、血淋巴细胞数量和PO及Na^(+)/K^(+)-ATPase的基因表达有较大影响,低浓度的噻虫嗪对中华绒螯蟹幼蟹的抗氧化和代谢系统有刺激作用;在稻田养蟹中,噻虫嗪的使用浓度应不超于45.2μg/L。

The number of lymphocytes,and activities of related immune enzymes in hepatopancreas,and expression levels of immune and metabolic gene in lymphocytes,hepatopancreas and gill tissue were analyzed in Chinese mitten crab Eriocheir sinensis juveniles exposed to thiamethoxam(C_(8)H_(10)ClN_(5)O_(3)S)at concentrations of (0.00μg/L,28.25μg/L,56.5μg/L,113μg/L and 226μg/L)by an semi-static toxic test for 21 days to evaluate the subacute toxiticy of thiamethoxam to the juveniles in order to provide theoretical basis for rational drug use of thiamethoxam in rice-crab co-culture.The results showed that the median lethal concentration(LC_(50))of thiamethoxam for 96 hour exposure was 452μg/L,with safe concentration(SC)of 45.2μg/L.There was significantly lower number of lymphocytes in the crab in 113μg/L and 226μg/L thiamethoxam groups than that that in the control group at the 14 and 21 days(P<0.05).After 1 d,4 d,7 dand 14 d,the activity of superoxide dismutase(SOD)was found to be significantly higher in 28.25μg/L thiamethoxam group than that in the control group(P<0.05),and the activity of SOD in 226μg/L group to be significantly lower than that in control group at the seventh,fourteenth and 21 days(P<0.05).The contents of malondialdehyde in hepatopancreas of the crab were significantly higher in 56.5μg/L,113μg/L and 226μg/L thiamethoxam groups than that in control group at 4 d,7 d,14 d and 21 d(P<0.05).At 7 d,14 d and 21 d,the activities of alanine aminotransferase(GPT)and aspartate aminotransferase(AST)in the hemolymph of crab in 113μg/L and 226μg/L thiamethoxam groups were significantly higher than those in the control group(P<0.05).The activity of phenol oxidase(PO)in the hemolymph of crab was significantly higher in 28.25μg/L thiamethoxam group than that in the control group after 1 d,4 d and 7 d(P<0.05),and the PO activity of hemolymph was significantly lower in 226μg/L thiamethoxam group than that in the control group at 7 d,14 d and 21 d(P<0.05).At 4 d and 7 d,the gene expression levels of PO and Na^(+)/K^(+)-ATPase in hepatopancreas and gills of the crab were significantly higher in 28.25μg/L and 56.5μg/L thiamethoxam groups than those in the control group(P<0.05),and the gene expression levels of PO and Na^(+)/K^(+)-ATPase in hepatopancreas and gills of the crab significantly lower in 226μg/L thiamethoxam group were than those in the control,28.25μg/L and 56.5μg/L thiamethoxam groups after 21 d(P<0.05).In conclusion,high concentration of thiamethoxam leads to a great impact on the antioxidant enzyme activity,the number of lymphocytes and the gene expression of PO and Na^(+)/K^(+)-ATPase of Chinese mitten crab juveniles,and low concentration of thiamethoxam results in promoting the antioxidant and metabolic system of Chinese mitten crab juveniles,with the recommend thiamethoxam concentration of lower than 45.2μg/L in rice crab co-culture.