Predatory effects of the fungus Arthrobotrys cladodes on sheep gastrointestinal nematodes

Abstract

ABSTRACT The biological control of gastrointestinal nematodes of animals using nematophagous fungi is considered a promising approach. The objective of this study was to evaluate the effectiveness of Arthrobotrys cladodes (CG 719) isolates in vitro and after passage through the gastrointestinal tract of sheep. In experiment 1, the in vitro predatory capacity of A. cladodes against gastrointestinal nematodes in sheep was evaluated. Petri dishes containing fungi cultured on water agar medium were inoculated with 2,000 infective larvae of sheep gastrointestinal nematodes. Experiment 2 involved treatment and control groups comprising six sheep each. The animals in the treatment group received single 10 g doses of pellets containing fungal formulations, and fecal samples were collected after 12, 24, 36, 48, 60, and 72 h. In experiment 1, a larval reduction of 72.3% was observed at 7 days after the larval inoculation. In both assays of experiment 2, larval reductions were significant (p < 0.01). In assay A, this fungus was able to pass throught the gastrointestinal tract of sheep, with a larval reduction of 83.5%. In assay B, proportion of larvae recovered from coprocultures was reduced by 72.4%. Thus, we concluded that pelleted formulations of A. cladodes were effective against gastrointestinal nematodes in vitro and after passage through the gastrointestinal tract of sheep.