Tannins with Anthelmintic Properties

Condensed tannins (CT) are a part of the polyphenols present in plants and are found at greatest concentration in dicotyledons such as leguminous plants. Consumption of plants containing CT may affect resistance and resilience of ruminant livestock to parasitic gastrointestinal (GI) nematodes in either indirect or direct ways. Condensed tannins of various temperate herbaceous species have the potential to increase the supply and absorption of digestible protein which will indirectly improve host resistance and resilience to GI nematodes Condensed tannin-containing forages and CT extracts may also directly assist in reducing infections of GI nematodes. For example, consumption of the CT-containing perennial Mediterranean legume 'Hedysarum coronarium' is associated with reduced abomasal and intestinal nematode numbers and this association does not appear to be mediated through digestible protein supply. In addition, CT extracted from a number of woody plants has been shown to reduce in vitro nematode viability. Condensed tannins have the potential to offer a viable alternative to the use of chemotherapy to control infections of parasitic GI nematodes but further research is required.