Control of infective larvae of gastrointestinal nematodes in heifers using different isolates of nematophagous fungi

Abstract

The effect of different nematophagous fungi [Duddingtonia flagrans (AC001 and CG722) and Monacrosporium thaumasium (NF34)] with regard to controlling infective larvae (L3) of nematodes after gastrointestinal transit in female cattle (3/4 Holstein × Zebu) was evaluated. A total of 24 pubescent female cattle were used, weighing approximately 320 kg each one. There were three treatment groups, each contained six animals that received 150 g of pellets (0.2 g of mycelium), orally in a single dose, in a sodium alginate matrix containing mycelial mass of the fungus D. flagrans (AC001 or CG722) or M. thaumasium (NF34); and one control group (without fungi). Fecal samples were collected from the animals at intervals of 12, 15, 18, 21, 24, 48, and 72 hours. At the end of 17 days, the L3 not subjected to predation were recovered by means of the Baermann method. The fungal isolates tested were capable of destroying the L3 after gastrointestinal transit. It was observed that within 72 hours, the isolates AC001, CG722, and NF34 showed a higher predatory activity (81.2%, 97.3%, and 98.3%, respectively). The results justify the need for studies in the field, and over longer intervals, in order to observe the efficiency of the fungus D. flagrans, or even M. thaumasium, for environmental control over nematodes in naturally infected cattle.

Producción de conidios y clamidosporas de los hongos Duddingtonia flagrans y Monacrosporium thaumasium en diferentes medios sólidos

“…(Tavela et al, 2011) y son eliminadas en las heces, manteniendo la suya capacidad germinativa y de colonización. Ellas ejercen una actividad depredadora y destruyen a los estadios parasitarios de nematodos (Silva et al, 2013) en las heces. Este sistema permite interrumpir el ciclo biológico de los parásitos (Araújo et al, 2004).…”

Predatory activity of nematophagus fungus Duddingtonia flagrans in infective larvae after gastrointestinal transit: biological control in pasture areas and in vitro

“…Previous studies show promising results in the application of biological control in laboratory tests and field conditions (Jobim et al , 2008; Silva et al , 2013). In this way, the fungus contributes to the prophylactic control of nematodes, reducing the number of L3 in pasture and minimizing the risk of reinfection (Knox et al , 2002; Mota et al , 2003).…”

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

“…flagrans is considered the most promising species for biological control of animal endoparasites (SAHOO & KHAN, 2016). 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). Although 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.…”