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

Abstract

The efficacy of the nematode-trapping fungus Duddingtonia 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 eggs 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 at a dose of 200,000 chlamydopores/kg bw/day, 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 for a month 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 and were then housed for 15 days, after which period they were slaughtered in order to determine the parasite burden present in each animal. Results showed that animals in group T2 harboured significantly less nematodes than their counterpart in group C2. The efficacy of D. flagrans was 92% against the total parasite burden, 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.

In vitro susceptibility of nematophagous fungi to antiparasitic drugs: interactions and implications for biological control

“…Although different fungus MICs were observed, D. flagrans showed the lowest MICs against all drugs tested. As this is one of the most effective predatory fungi against endoparasites (Braga et al, 2011;Sagüés et al, 2011), the results of this study demonstrate the importance of compatibility tests between anthelmintics and nematophagous fungi. On the other hand, the MICs obtained against ivermectin, employed both as an anthelmintic and in ruminant tick control, suggest that the compatibility of this chemical with other biological practices must be known so as to avoid loss of control efficiency.…”

In vitro predatory activity of nematophagous fungi Duddingtonia flagrans on infective larvae of Oesophagostomum spp. after passing through gastrointestinal tract of pigs

“…Prior studies in laboratory, as well as in open field conditions, have shown that nematophagous fungi are capable of controlling infectious forms (L 3 ) of a wide variety of gastrointestinal parasites in domestic animals with success, with special distinction to the species Duddingtonia flagrans (Sagüés et al 2011;Santurio et al 2011). However, for a fungus species to be considered as effective in controlling a range of specified parasites, it is important for it to conserve its predative properties after a complete gastrointestinal transit, besides successfully capturing the aforementioned prey (Waller et al 1994).…”

Soybean protein films. Characterization and potential as novel delivery devices of Duddingtonia flagrans chlamydospores

“…This issue has encouraged the search for novel methods including the 67 biological control by the use of nematophagous fungi against the free living stages of 68 the parasite on pasture (Waller, 1997;Waller et al, 2001a). Biological control offers an 69 effective, renewable and environmentally sound alternative in the reduction of infective 70 larva populations of nematodes in pastures (Larsen, 1999) blocks (Sagüés et al, 2011). The success of all the above mentioned alternatives was 78 found to be dependent on the voluntary and variable intake of the animals which lead to 79 unpredictable results (Waller, 1997;Waller et al, 2001b).…”