Effects of tannins in goats infected with gastrointestinal nematodes

Abstract

SummaryInfections of the gastrointestinal tract with nematodes remains one of the main pathological constraints associated with outdoor breeding of goats both in temperate and tropical areas. The usual mode of control of these parasitic infections is based on the repeated use of chemical anthelmintics, but the prevalence and diffusion of anthelmintic resistances in nematode populations is particularly high in goats, and the sustainability of the system is now questioned. Therefore, there is a deep interest to seek and explore alternative solutions to chemotherapy. Among those, tannins and tanniferous plants represent one of the most promising options. However, information on the effects of these polyphenolic compounds on nematode infection in goats is far less abundant than in sheep. This review presents data obtained from both outdoor and indoor studies aiming at examining the relationship between the consumption of tannins or tanniferous plants, particularly those composing the vegetation of rangeland and the resistance and resilience of goats to trichostrongyle infections. Results from in vitro studies with extracts from different plants which are grazed or browsed by goats are also discussed in relation with the possible mechanisms of action of tannin in goats. These results are compared to those acquired in sheep and are discussed in relation with the physiological adaptation of goats to tannin consumption. Further research perspectives and possible applications for the control of nematode infections in goats are also briefly evoked.