叶状枝节丛孢大孢变种(Arthrobotrys cladodes var. macroides)对两种毛圆科线虫幼虫杀虫效果的研究

Control efficiency of Arthrobotrys cladodes var. macroides against larvae of two nematode species of Trichostrongylidae

【目的】评估叶状枝节丛孢大孢变种(Arthrobotrys cladodes var.macroides)分离株(F69)的生物学特性及对绵羊胃肠线虫感染性幼虫(L3)的捕食能力.【方法】通过光镜和扫描电镜观察该菌的形态及捕食作用;用2%水琼脂培养基评估该菌对两种混合的毛圆科线虫L3的体外杀虫能力;将该菌的孢子用海藻酸钠制备成包埋颗粒,分析绵羊采食后的杀虫能力.【结果】1)所获得的光镜和电镜结果显示了该菌形态学及其与L3相互作用;2)该菌在体外对L3的杀虫率为73.70%(P<0.05);3)该菌通过绵羊消化道后能够存活,采食后12、24、36、48、72 h粪便中排出真菌孢子,对绵羊粪便中的L3减少率分别为46.74%、60.41%、44.19%、37.36%、21.53%.【结论】本研究为反刍动物寄生线虫生物防治提供了一个有潜力的新候选菌株.

【Objective】To evaluate the biological characteristics of Arthrobotrys cladodes var.macroides isolate(F69)and the predatory ability against the third stage of larvae(L3)of gastrointestinal nematodes in sheep.【Method】The morphology of F69 isolate and the interaction of the fungus with the nematodes were observed by optical microscope and scanning electron microscope;the in vitro predatory capacity of F69 isolates against two mixed trichostrongylide L3 was evaluated on 2% water agar medium(2% WA);the sodium alginate pellets embedding fungus spores were orally fed to sheep,and the control efficacy against L3 were evaluated.【Result】1)The results obtained in light microscope and scanning electron microscope presented the morphological feature of the fungus and the interaction with L3;2)The in vitro experiment showed 73.70% reduction in the number of L3 in fungal treatment group(P<0.05);3)The tested fungus could survive after passing through the digestive tract of sheep,and the spores were excreted in the feces at 12,24,36,48 and 72 hours after feeding the fungus and the predatory rate against L3 in feces of sheep were 46.74% ,60.41% ,44.19% ,37.36% and 21.53% respectively.【Conclusion】The results of this study provide a promising candidate isolate for biological control of parasitic nematodes in ruminants.