OPTIMIZING THE USE OF DUDDINGTONIA FLAGRANS CHLAMYDOSPORES AGAINST HAEMONCHUS CONTORTUS IN FECES OF SHEEP

Abstract

The aim of this study was to identify the proportion of D. flagrans chlamydospores that led to the highest trapping efficacy in the presence of eggs or L3 larvae of H. contortus. Firstly, five groups of 15 coprocultures each were prepared, with proportions of eggs:chlamydospores (E:C) in Groups I throught V of 1:0 (Control group),  1:1, 1:10,  1:100, and 1:1.000, respectively. A second batch of fifty coprocultures was then prepared, with five groups of 10 coprocultures each and larvae:chlamydospore (L:C) ratios equal to those used to evaluate different E:C ratios (Groups VI, VII, VIII, IX and X). Larval reduction percentages were calculated to estimate trapping efficacy. Numbers of larvae harvested from cultures seeded with eggs and chlamydospores at E:C ratios of less than 1:1 were lower than those from the control (P<0.05).  Similarly, when L3 larvae were used as bait, the reduction percentage initially increased with increases in chlamydospore density, but efficacy did not continue to increase at L:C proportions beyond 1:10 (P>0.05). This study demonstrates the importance of adjusting the dose of D. flagrans chlamydospores to achieve 10 chlamydospores for each egg or larvae in the faeces, in order to reach the optimal use.