啶虫脒对家蚕生长发育及中肠抗氧化酶活性的影响

Effects of Acetamiprid on Growth and Development of Bombyx mori and Antioxidant Enzyme Activity of Midgut

杀虫剂啶虫脒被广泛应用于农业害虫防治。采用食下毒叶法测试了啶虫脒对家蚕的急性毒性和慢性毒性。急性毒性测试啶虫脒对家蚕3~5龄幼虫的96 h致死中浓度（LC50）分别为0.361、0.692和1.339 mg/L,表明啶虫脒对家蚕为高风险至极高风险性等级。慢性毒性测试3龄起蚕持续添食低浓度啶虫脒药液后,龄期经过时间延长,眠（熟）蚕体质量以及全茧量、茧层量和茧层率均受到不良影响。另外,当3龄起蚕添食啶虫脒药液的质量浓度≥0.011 mg/L时,5龄6 d幼虫中肠内超氧化物歧化酶（SOD）被激活,酶活力显著上升（P〈0.05）,而过氧化氢酶（CAT）的活性受到显著抑制（P〈0.05）;谷胱甘肽过氧化物酶（GSH-Px）的活性则表现为被低浓度（0.005~0.022 mg/L）啶虫脒药液诱导提升,被高浓度（0.045和0.090 mg/L）啶虫脒药液抑制。试验结果表明,啶虫脒对养蚕业的安全生产存在极高的风险性,在蚕区须规范、合理使用;在高浓度啶虫脒药液处理下,虽然家蚕幼虫中肠的SOD活性上升,但由于CAT及GSH-Px活性均被抑制,家蚕的生长发育和产茧性状受到显著影响。

The insecticide acetamiprid is widely used in controlling agricultural pests. The acute toxicity and chronic tox- icity of acetamiprid to silkworm （Bombyx mori） were tested by using food intake method. Results of acute toxicity bioas- say showed that 96 h median lethal concentration （LCso） of acetamiprid to the 3rd, the 4th and the 5th instar were 0. 361, 0. 692 and 1. 339 mg/L, respectively, indicating that acetamiprid is a high-risk or ultra-high-risk grade poison to silkworm. After treating the 3rd instar newly exuviated silkworm larvae continuously with low concentration of acetamiprid, the duration of each instar was prolonged, and the body weight of moulting or matured larvae, cocoon weight, cocoonshell weight and cocoon shell rate were all adversely affected. In addition, when the 3rd instar newly exuviated larvae were treated with acetamiprid of ≥0. 011 mg/L, the superoxide dismutase （SOD） activity in larval midgut of day 6 of the 5th instar larvae was significantly activated （P〈0.05）, while the catalase （CAT） activity was markedly inhibited （P〈0.05）. The activity of glutathione peroxidase （GSH-Px） was improved by low concentrati- on （0. 005-0. 022 mg/L） of acetamiprid but was inhibited by high concentration （0, 045 and 0. 090 mg/L） of acet- amiprid. The results indicate that acetamiprid has extreme-ly high risk to sericultural production and should be used in sericultural areas with caution. Under high concentration, al- though SOD activity of silkworm larvae was activiated, but CAT and GSH-Px activities of silkworm larvae were both inhibi- ted. This is the reason that acetamiprid can do harm to silkworm growth and development and to cocoon production.