ABSTRACT
Objective: Biological control of gastrointestinal nematodes of ruminants
Design: Case-control study
Samples: A total of 50 sheep feces naturally infected by Haemonchus contortus ova
Procedure: Arthrobotrys oligospora [111.37 and 251.83], Daddingtonia flagrans [583.91] and Haptocillium sphaerosporum [381.84] were obtained and the nematophagous activity of these isolates was studied after addition of 8000, 20000 and 100000 conidia to 1 gram of fecal samples containing 70 ova of Haemonchus contortus per each petridish. All of the samples were incubated at 25-27°C for 8 days and then, the nematophagous effect of fungal isolates were determined after calculation of third staged larval reduction using Berman method
Statistical analysis: One-way ANOVA and complementary method of Tukey were used
Results: Study of nematophagous effects of 8000 conidia of all above-mentioned fungi and 20000 conidia of A. oligospora [251.82] on the third stage larvae of H. contortus showed that there was not any significant difference as compared with the control groups. But for 20000 conidia of A. oligospora [111.37] and D. flagrans [583.91] and also 100000 conidia for all above-mentioned fungi, significant reduction in larvae of H. contortus was observed as compared with the control groups. In H. sphaerosporum, the percentage of larvae reduction for 8000 and 20000 conidia was determined as 21.46% and 48.99%, respectively. But, the increasion of conidia to 100.000 caused only 42.28% reduction in infective larvae so above-mentioned fungus can not function as an effective agent in biological control of H. contortus
Clinical implications: The present study showed that we can control gastrointestinal nematodes by use of nematode-trapping fungi, in suitable conditions along with chemical treatment.