Vet. Res. 36 (2005) 157-166
DOI: 10.1051/vetres:2004060

Administration of Duddingtonia flagrans chlamydospores to goats to control gastro-intestinal nematodes: dose trials

Carine Paraud^a, Hervé Hoste^b, Yves Lefrileux^c, Alain Pommaret^c, Virginie Paolini^b, Isabelle Pors^a and Christophe Chartier<sup>a

a</sup>  AFSSA Site de Niort, Laboratoire d'Études et de Recherches Caprines, 60 rue de Pied de Fond, BP 3081, 79012 Niort Cedex, France
^b  Unité Mixte de Recherches 1225 INRA/DGER, Interactions Hôtes Pathogènes, École Nationale Vétérinaire de Toulouse, 23 chemin des Capelles, 31076 Toulouse, France
^c  Station du Pradel, Ferme Expérimentale Caprine, 07170 Mirabel, France

(Received 3 May 2004; accepted 24 September 2004)

Abstract - The ability of the nematophagous fungus Duddingtonia flagrans to reduce the number of infective nematode larvae in coproculture was investigated in goats using different doses of chlamydospores (0, 1.25 × 10⁵, 2.5 × 10⁵, 5 × 10⁵ chlamydospores/kg BW/day) given by oral administration or by voluntary consumption in feed during natural or experimental infections with nematodes. The kinetics of excretion of D. flagrans chlamydospores in the faeces was also determined using a dose of 5 × 10⁵ chlamydospores/kg BW/day for five days. For all the trials, the faecal nematode egg outputs were determined by a modified McMaster method and standard coprocultures were set up (14 days, 25 °C) to determine the number of larvae emerging from culture in fungus treated and control faeces. When chlamydospores were orally administered, the number of larvae were reduced by 50 to 97% when compared to control cultures. No difference in the level of larval emergence from the culture was seen for experimental or natural infections at the different chlamydospore dose rates. In contrast, when chlamydospores were distributed in the feed, a dose-dependent relationship was observed 10 days after the start of administration, the larval development being 2.0%, 14.0% and 86.9% for 5 × 10⁵, 2.5 × 10⁵ and 0 spores/kg BW/day, respectively. In addition, the kinetic study showed that the larval emergence from coproculture in the fungus group was statistically lower than in the control group from the second day of administration of the chlamydospores and remained lower until the second day after the last administration (p < 0.05). The results indicate that, for goats in farm conditions, a minimum daily dose of 5 × 10⁵ chlamydospores/kg BW must be used to ensure a high treatment efficacy and that daily administration is preferable for maintenance of efficacy over time.

Key words: goat / biological control / Duddingtonia flagrans / nematode parasite / dose trials

Corresponding author: Carine Paraud c.paraud@niort.afssa.fr

© INRA, EDP Sciences 2005