The effect of condensed tannins from seven herbages on Trichostrongylus colubriformis larval migration in vitro

Abstract

Abstract. The effects of condensed tannins (CT) extracted from seven forages on the motility of the economically important nematode, Trichostrongylus colubriformis (Giles, 1892), were evaluated by using a larval migration inhibition (LMI) assay. The assay involved incubation of third stage (L3) exsheathed T. colubriformis larvae with CT extracted from Lotus pedunculatus, Lotus corniculatus, sulla (Hedysarum coronarium), sainfoin (Onobrychis viciifolia), Dorycnium rectum, Dorycnium pentaphyllum and dock (Rumex obtusifolius) and measurement of larval migration through nylon mesh with a 20µm pore size. At 100 µg ml -1 , CT from L. pedunculatus, L. corniculatus, sulla, sainfoin, D. rectum, D. pentaphyllum and dock inhibited 20%, 10%, 15%, 25%, 28%, 32% and 27% of the larvae, respectively from passing through the sieves compared to controls (no CT added). At 1000 µg CT ml -1 , CT purified from D. pentaphyllum had the highest inhibitory activity (63%) against 1-month old larvae followed by sainfoin (59%), L. pedunculatus (57%), D. rectum (53%), dock (50%), sulla (40%) and L. corniculatus (37%). Seven-month old larvae were more sensitive to the action of CT than 1-month old larvae (P < 0.001). Addition of 2 µg polyethylene glycol ([PEG] per µg CT; to remove the effect of CT) eliminated 81-93% of the CT activity (P < 0.001) compared to incubations without PEG. The impact of CT on larval migration suggests a possible role for these plants in ruminant diets as a means to reduce dependence upon proprietary anthelmintics.

Effects of the repeated distribution of sainfoin hay on the resistance and the resilience of goats naturally infected with gastrointestinal nematodes

“…The objective was to avoid any bias in interpretation of results in relation to nutrition, since it has been repeatedly shown that any difference in host diets, and particularly in regard to protein components, might greatly influence the host response to nematode infections (Van Houtert and Sykes, 1996;Coop and Kyriazakis, 2001). In most studies on bioactive forages, it has been postulated that some plant secondary metabolites, and particularly condensed tannins, might present antiparasitic properties and this hypothesis has been substantiated by several in vivo (Athanasiadou et al, 2000a(Athanasiadou et al, ,b, 2001 or in vitro results (Molan et al, 2000a(Molan et al, , 2003a. On the other hand, it is important to note that during the week when hay was provided to goats, the consumption of sainfoin hay was significantly higher than for the rye grass one.…”

“…Several examples obtained from controlled indoor in vivo assays or from in vitro studies have been accumulated supporting the hypothesis for a role of plant secondary metabolites, and particularly condensed tannins, in these antiparasitic effects (Athanasiadou et al, 2003;Kahn and Diaz-Hernandez, 2000;Molan et al, 2000aMolan et al, ,b, 2003a. In sheep, several studies have shown that the consumption of some bioactive, legume forages like sulla (Hedysarium coronarium), maku (Lotus pedunculatus) or birdsfoot trefoil (Lotus corniculatus) were associated with some positive effects on the host resilience and/or host resistance to parasite infection (Niezen et al, 1995(Niezen et al, , 1998aMarley et al, 2003).…”

In VitroAnthelmintic Effects of Medicinal Plants Used in Czech Republic

“…The total effect was observed for all concentrations on the level of 22-87% and for a concentration of 1000 µg/mL, ranging from 27% to 63%. We can compare the result with the LMI test performed with seven plant extracts against the larvae of T. colubriformis, where at the same concentration (1000 µg/mL), the range was from 37% to 63% (Molan et al, 2000).…”

Use of ‘natural’ products as alternatives to antibiotic feed additives in ruminant production

“…At the rumen level, the optimal concentration of CTs to reduce proteolysis in vitro has been set at about 400 mg CTs per ml and above (Aerts et al, 1999). The same concentration reduced the growth of several bacterial strains from the rumen (Molan et al, 2000).…”