Efficacy of different concentrations of Duddingtonia flagrans chlamydospores against different levels of faecal egg counts of cattle gastrointestinal nematodes

ZEGBI, SARA; SAGÜÉS, MARÍA FEDERICA; SAUMELL, CARLOS; IGLESIAS, LUCÍA; GUERRERO, INÉS; FERNÁNDEZ, SILVINA

Conferencia; 27th Conference of the World Association for the Advancement of Veterinary Parasitology; 2019

WAAVP

The nematophagous fungus Duddingtonia flagrans is a biocontrol agent that reduces the number of infective larvae of gastrointestinal nematodes in animal faeces, thus, lowering pasture infectivity. However, the minimum amount of fungal chlamydospores in faeces required for this effect is largely unknown. The following in vitro study aimed to determine the fungal efficacy of four different chlamydospores concentrations against three different levels of cattle faecal egg counts. The chlamydospores concentrations tested were 11000, 6250, 3000 and 1000 chl/g faeces. Faeces from naturally-infected calves were used to obtain faecal egg counts of 100, 480 and 840 epg. Ten faecal cultures of 10 g faeces each were set up for each chlamydospores concentration/faecal egg count combination, plus one control group for each faecal egg count level without chlamydospores. All cultures were kept at room temperature (20-26ºC) for two weeks and then L3 were recovered from each individual culture by overnight baermannisation, counted and identified. The larval reductions by D. flagrans, in decreasing order of chlamydospores concentrations, were: 100% (P