Evaluating the effectiveness of a Mexican strain ofDuddingtonia flagransas a biological control agent against gastrointestinal nematodes in goat faeces

Abstract

AbstractThe use ofDuddingtonia flagransin the control of goat nematodes was investigated. Initially, the time of passage of chlamydospores through the digestive tract of goats was evaluated. Two groups of seven parasite-free kids were formed. Group A received a single dose of 3.5×106D. flagranschlamydospores (FTHO-8 strain) per kg of live weight. Group B did not receive any chlamydospores. Faeces were obtained from each kid daily from day 4 prior to inoculation until day 5 post-inoculation (PI) and were placed in Petri dishes containing water agar. Gastrointestinal nematode infective larvae were added to each Petri dish and incubated at 25°C for 7 days. Petri dishes were examined to detect the fungus and trapped nematodes. A second trial evaluated the effect ofD. flagranson the number of gastrointestinal nematode larvae harvested from goat faecal cultures in naturally infected goats. Two groups of seven goats were formed. The treated group received a single dose of 3.5×106D. flagranschlamydospores per kg of liveweight. The control group did not receive any chlamydospores. Faeces were obtained twice daily from each kid. Two faecal cultures were made for each kid. One was incubated for 7 days and the other for 14 days. Gastrointestinal nematode larvae were recovered from each culture and counted. Percentage of larval development reduction was determined using a ratio of larvae/eggs deposited in the control and treated groups.Duddingtonia flagranssurvived the digestive process of goats, and maintained its predatory activity, being observed from 21 to 81 h PI (3 to 4 days). A reduction in the infective larvae population in the treated group compared to the non-treated group was observed in both incubation periods (7 days: 5.3–36.0%; 14 days: 0–52.8%,P>0.05). Although a single inoculation ofD. flagranscan induce a reduction of infective larvae collected from faeces, a different scheme of dosing may be needed to enhance the efficacy ofD. flagransin goats.