Duddingtonia flagrans: Controle biológico de nematodeos de bovinos a campo

Abstract

Biological control is an alternative method to reduce parasite's population by the use of natural antagonist. In the present study, efficacy of nematophagous fungus Duddingtonia flagrans was tested to control gastrointestinal nematodes parasites of cattle livestock in the field. Twenty calves were used, distributed equally in two distinct plots formed by native pasture. Group A was treated with D. flagrans fungus, cultivated in sorghum (1×106 clamidospores kg-1 body weight) mixed with maintenance ration, each day, during eight months. Group B served as a control and did not receive the fungus. Samples for faecal egg count (FEC), were collected each week. There were monthly counts in faecal cultures to identify the species of nematodes larvae, animals weight, blood collection to determine red cell counts and collection of pasture to larvae counting. Temperature and rainfall data were registered daily. The FEC reduced around 56.8% in the last three months of the experiment, with a variation between 40.4 and 67.1% in the treated group (P<0.001). The faecal cultures demonstrated that the main nematodes found in both the groups were Cooperia and Haemonchus. Larvae counting in the pasture showed a reduction percentage around 77.1% in treated group at the end of experiment (P<0.01). It could be concluded with this study, that Duddingtonia flagrans has an important role in the reduction of FEC and significant reduction of larvae in the pasture. Therefore, this nematophagous fungus is efficient as a biological tool to be used in an integrated nematodes control of bovine raised in the field.