棉酚和单宁酸对棉铃虫幼虫生长和消化生理的影响

作者利用昆虫人工饲料测试了棉酚和单宁酸对棉铃虫幼虫生长、营养指标以及中肠主要蛋白酶活力的影响。结果表明,棉酚和单宁酸均能显著地抑制幼虫的生长,但二者之间无交互作用,其中单宁酸的作用较棉酚强。含3％棉酚或单宁酸的人工饲料,饲喂4龄幼虫48h后,可引起幼虫近似消化率减小和食物转化率增大,但食物利用率无显著变化。棉酚在离体条件下对类胰蛋白酶和类胰凝乳蛋白酶活力有不同程度的抑制作用,但在活体条件下,上述酶活力无显著变化,仅有中肠总蛋白酶活力下降。单宁酸在离体条件下对类胰蛋白酶有抑制作用,而对类胰凝乳蛋白酶活力无作用:在活体条件下,仅总蛋白酶活力和弱碱性类胰蛋白酶活力显著下降。由此可知,棉酚和单宁酸对棉铃虫的生长抑制作用与幼虫中肠蛋白酶活力和食物消化率的降低有关。

EFFECTS OF GOSSYPOL AND TANNIC ACID ON THE GROWTH AND DIGESTION PHYSIOLOGY OF COTTON BOLLWORM LARVAE

By using synthetic diet test method,the effects of gossypol and tannic acid on the growth,food utilization and activities of main proteinases in midgut of cotton boll-worm (CBW) Helicoverpa armigera (Hubner) were studied. The results showed that there were significant inhibitions caused non-interactionally by gossypol and tannic acid, in which the inhibition of the latter was stronger than that of the former,on the growth of CBW larvae. As the 4th instar larvae were fed for 48h with synthetic diet contained 3% of gossypol or tannic acid, their approximate digestibility decreased and the conversion efficiency of digested food increased,while the conversion efficiency of ingested food was nearly constant. In vitro, the gossypol inhibited both the activities of trypsin- and chymotrypsin-like enzymes to varying degrees,but the inhibition of tannic acid only acted on trypsin-like enzyme. Whilst in vivo, the gossypol inhibited these enzymes negligibly, and the tannic acid only significantly inhibited those of total proteinase and weak-basic trysin-like enzyme. It was suggested that there should be some factors in CBW larvae interfering with the inhibitions of gossypol and tannic acid on the activities of proteinases.