噻虫嗪对鲫鱼的急性毒性和抗氧化酶及乙酰胆碱酯酶活性的影响

Acute Toxicity of Thiamethoxam and Activities of Antioxidant Enzymes and Acetylcholinesterase in Juvenile Crucian Carp Carassius auratus

在水温(24±1)℃、pH 7.0±0.5、溶解氧(5±1)mg/L条件下,采用半静态毒性试验方法,用丙酮将噻虫嗪稀释成质量浓度为24.35、28.73、33.90、40.00、47.20 mg/L的溶液,以丙酮作为对照,研究噻虫嗪对体质量(19.81±2.40)g鲫鱼幼鱼的急性毒性,以及1 mg/L和10 mg/L噻虫嗪对鱼体肝脏和鳃中超氧化物歧化酶、过氧化氢酶和脑中乙酰胆碱酯酶活性的影响。试验结果显示,噻虫嗪对鲫鱼幼鱼的24、48、72、96 h半致死质量浓度分别为39.22、35.84、30.71、28.95 mg/L。1 mg/L和10 mg/L噻虫嗪处理后,鲫鱼幼鱼肝脏和鳃组织中超氧化物歧化酶、过氧化氢酶活性在12~96 h内均呈先升后降的趋势;脑组织中乙酰胆碱酯酶的活性在不同处理时间各不相同,但总体趋势表现为先诱导后抑制。试验结果表明,噻虫嗪胁迫可引起鲫鱼幼鱼抗氧化防御系统和神经系统的功能紊乱,从而影响鱼类的正常生长发育。

Acute toxicity of thiamethoxam to juvenile crucian carp Carassius auratus with body weight of(19.81±2.40)g was investigated at water temperature of(24±1)℃,pH 7.0±0.5,dissolved oxygen level of(5±1)mg/L,and thiamethoxam dilution to 24.35,28.73,33.90,40.00 and 47.20 mg/L with acetone as the control by a semi-static toxicity method,and the effects of different concentrations(1 and 10 mg/L)of thiamethoxam on the activities of superoxide dismutase(SOD),catalase(CAT)and acetylcholinesterase(AChE)in different tissues of crucian carp was determined to understand the effect of thiamethoxam on the biochemical indices of crucian carp juveniles.It was found that the median lethal concentration of thiamethoxam to the juvenile was 39.22 mg/L in 24 h,35.84 mg/L in 48 h,30.71 mg/L in 72 h,and 28.95 mg/L in 96 h.There was increase in activities of SOD and CAT in the liver and gills first,and decrease then in the crucian carp juveniles exposed to 1 and 10 mg/L of thiamethoxam.The activity of AChE in the brain was varied with treatment period,wholly induced first and then inhibited.The findings indicated that thiamethoxam caused the dysfunction of fish antioxidant defense and neural system,thereby affecting the normal growth performance of fish.