In vitro efficacy of Duddingtonia flagrans against nematodes of sheep based on in vivo calculations.

Marcelo Beltrão Molento,Clóvis De Paula Santos,Andréia Buzatti,Flávia Biasoli De Araújo

doi:10.1590/s1984-29612017050

Abstract

Duddingtonia flagrans has been tested as an alternative parasite control, but data from in vitro experiments based on in vivo calculations describing nematophagous fungi predation in nematodes are restricted. The objective of this work was to determine the efficacy of D. flagrans against sheep nematode larvae in vitro using in vivo calculations. Fecal samples were introduced to fungi in different concentrations: 0.0/control; 0.05; 0.1; 0.2; 0.4; 0.8; 1.6; 3.2; and 6.4 g corresponding, respectively, to 583.000; 1.166.000; 2.332.000; 4.664.000; 9.328.000; 18.656.000; 37.312.000 and 74.624.000 chlamydospores/kg of body weight. The material was incubated for 14 days, before the larvae recovery (Assay 1). Assay 2 was carried out with the doses of 0.00625; 0.0125; and 0.025 g. The results showed a negative correlation between fungal concentrations and larval numbers for both assays. The fungus demonstrated an efficacy above 89% in both assays. Thus, we consider that the data from in vitro studies based on in vivo calculations may optimize the fungi quantities for field experiments.

Highlights

Endoparasites have become a serious problem to small ruminant farming (TARIQ, 2015)
Duddingtonia flagrans has been tested as an alternative parasite control, but data from in vitro experiments based on in vivo calculations describing nematophagous fungi predation in nematodes are restricted
The objective of this work was to determine the efficacy of D. flagrans against sheep nematode larvae in vitro using in vivo calculations

Summary

Introduction

Endoparasites have become a serious problem to small ruminant farming (TARIQ, 2015). In Brazil, infective larvae of the main nematodes species are available on pasture practically throughout the year, becoming the source of a continuousThe excessive use of anthelmintics to control parasite infections has brought up a sequence of undesirable consequences, such as, the lack of farmer assistance, ecotoxicity and the selection of resistant parasites to different drug classes (MOLENTO, 2004). From the beginning of the 90’s until today, researchers have reported its effectiveness in the control of immature stages of parasites of cattle (LARSEN et al, 1995; SILVA et al, 2013), sheep, and goats (LARSEN et al, 1998; WAGHORN et al, 2003; OJEDA-ROBERTOS et al, 2008; OJEDA-ROBERTOS et al, 2015; FITZ-ARANDA et al, 2015) This fungus is one of the most studied organism for parasite control, data from in vitro experiments based in vivo calculations, describing their nematode predation, are restricted. The objective of this study was to determine the in vitro efficacy of the fungus D. flagrans, using in vivo calculation, at different concentrations against gastrointestinal nematodes of naturally infected sheep

Objectives

Methods

Results