"Efficacy of an energy block containing Duddingtonia flagrans in the control of gastrointestinal nematodes of sheep"

SAGÜÉS MARÍA F.; FUSÉ LUIS A.; FERNÁNDEZ ALICIA S.; IGLESIAS LUCÍA E.; MORENO FABIANA C.; SAUMELL CARLOS A.

Buenos Aires

Conferencia; 23rd. International Conference of the World Association for the Advancement of Veterinary Parasitology; 2011

Asociación Argentina de Parasitología Veterinaria (AAPAVET)

New alternatives for the control of gastrointestinal nematodes affecting livestock production worldwide have been studied for some time. Amongst them, biological control is one of the most promising strategies due to its ecological sustainability characteristic. Of all natural antagonists studied to this day, the one with the best possibilities to control gastrointestinal nematodes in livestock is the nematode-trapping fungus Duddingtonia flagrans. The efficacy of the nematode-trapping fungus D. flagrans incorporated into an energy block was evaluated for the control of gastrointestinal nematodes in sheep. Four naturally parasitised sheep with average nematode egg counts of 2,470 egg per gram grazed by pairs on two similar parasite-free paddocks for 30 days. During that period, one pair of sheep (treated animals, T1) received an energy block containing chlamydospores of D. flagrans, while the second pair (control animals, C1) received a fungus-free energy block. The animals in both groups were taken off the paddocks after contaminating the pastures with either nematode eggs plus fungal chlamydospores (T1) or nematode eggs alone (C1). Twelve parasite-free sheep were divided into two groups of six animals each. The treated group (T2) was placed on the paddock previously contaminated with parasites and fungus, while the control group (C2) was placed on the parasite-only paddock. These two groups grazed on their respective paddocks during 30 days, after were slaughtered in order to determine the parasite burden present in each animal. Results showed that animals in T2 harboured significantly less nematodes than their counterpart in group C2. The efficacy of D. flagrans was 100% against Haemonchus contortus and Teladorsagia circumcincta, 89.9% against Trichostrongylus colubriformis, 87.5% against Cooperia onchopora, and 90% against Trichostrongylus axei. No efficacy was detected against Nematodirus spathiger, Trichuris ovis and T. skrjabini.The energy block performed effectively as a vehicle for the administration D. flagrans, which lowered the number of infective larvae on pasture, thus decreasing the adult worm burden in sheep.