多菌灵亚致死剂量对意大利蜜蜂幼虫生长发育和解毒酶系活性的影响

Effects of sublethal doses of carbendazim on the growth and detoxifying enzyme activities of honeybee(Apis mellifera ligustica) larvae

【目的】本研究旨在探讨亚致死浓度水平的多菌灵农药对意大利蜜蜂Apis mellifera ligustica幼虫生长发育和解毒酶系活性的影响。【方法】以饲喂添加不同浓度(0.25和0.75 mg/g a.i.,校准死亡率<5%)多菌灵的饲料作为处理组,以基础饲料作为对照。实验室内人工饲养意大利蜜蜂1日龄幼虫直至羽化出房,记录和测定幼虫生长发育指标(蛹重、化蛹率和羽化率),并测定1日龄蛹的保幼激素和蜕皮激素滴度、总蛋白浓度以及总超氧化物歧化酶和主要解毒酶系活性。【结果】对照组与各处理组之间的意大利蜜蜂蛹体重、化蛹率、羽化率无显著差异(P>0.05);0.75 mg/g a.i.多菌灵处理组中总蛋白浓度显著降低(P<0.05);0.25和0.75 mg/g a.i.多菌灵处理组中总超氧化物歧化酶(T-SOD)活性显著增加(P<0.05),分别是对照组的135%和128%;0.25和0.75 mg/g a.i.多菌灵处理组中保幼激素(JH)滴度显著高于对照组(P<0.05),分别为对照组的1.57和1.75倍;其拮抗激素蜕皮激素(Ecd)滴度则低于对照组,分别只有对照组的62%和65%,差异极显著(P<0.01)。处理组幼虫化蛹时间延长;对解毒酶系酶活性测定发现,细胞色素P450(CYP450)和羧酸酯酶(Car E)活性出现相同的变化趋势,具体表现为在0.25 mg/g a.i.多菌灵处理组中被激活升高(P<0.05),在0.75 mg/g a.i.多菌灵处理组中激活效应消失,酶活性下降,但并未出现抑制现象(P>0.05)。谷胱甘肽-S-转移酶(GST)活性在对照组和处理组间略有不同,但无显著差异(P>0.05)。【结论】选取的亚致死剂量多菌灵农药不会导致蜜蜂急性死亡,但会对幼虫生长发育具有抑制作用,对解毒酶系也产生不同程度的影响,这可能对蜜蜂的健康发育和日后蜂群的稳定具有潜在的危害。

【Aim】 This study aims to explore the sublethal effects of carbendazim on the growth and development and detoxifying enzyme activities of the larvae of the Italian honeybee, Apis mellifera ligustica. 【Methods】 Larvae in two treatment groups were fed with diets containing 0.25 and 0.75 mg/g a.i. carbendazim （relative mortality rate〈5%）, respectively, while those in the control group with the normal diets. All larvae were reared with different diets until eclosion, and their growth indexes （pupal weight, pupation rate and eclosion rate）, total protein concentration, and T-SOD and detoxifying enzyme activities were assayed. 【Results】 There were no significant differences in the pupal weight, pupation rate and eclosion rate of A. m. ligustica among all groups （P〉0.05）. The total protein concentration in pupae decreased in the treatment group fed with diets containing 0.75 mg/g a.i. carbendazim （P〈0.05）. The total superoxide dismutase activities in the treatment groups fed with diets containing 0.25 and 0.75 mg/g a.i. carbendazim tended to be significantly higher than that in the control group, being 1.35- and 1.28.fold as high as the control group, respectively. The juvenile hormone titer in the treatment groups fed with diets containing 0.25 and 0.75 mg/g a.i. carbendazim were significantly higher than that in the control group, being 1.57- and 1.75-fold as high as the control group, respectively. Ecdysone titers in the treatment groups fed with diets containing 0.25 and 0.75 mg/g a.i. carbendazim were only 62% and 65% of the control group, respectively （P〈0.05）. The cytochrome P450 （CYP450） and carboxylesterase （CarE） activities were increased in the low-dose （0.25 mg/g a.i.） treatment group （P〈0.05）, and then returned to the normal level in the high-dose （0.75 mg/g a.i.） treatment group, but no inhibitory effect on the activities of the two enzymes was found （P〉0.05）. There was no significant difference in glutathione-S-transferase （GST） activity between treatment groups and the control group （P〉0.05）. 【Conclusion】 These results demonstrate that sublethal doses of carbendazim restrain the growth and development of A. m. ligustica larvae, but do not cause their acute death, and may cause potential harm to the stability and development of the colony.