Exploring Condensed Tannin to Control Gastro-Intestinal Parasitism in Small Ruminants

Gastrointestinal nematode (GIN) infections are one of the common causes of morbidity and/or mortality in small ruminants, especially in tropical and subtropical countries practicing pastoral grazing systems. At present, since most of the GIN is known to be resistant to one or more anthelmintic drugs, the research impetus for alternative strategies to sustainably control internal parasites (helminths) has emerged. In this context, use of many phytochemicals, mainly condensed tannin (CT) has become increasingly popular and efficacious as that of conventional antiparasitic drugs. It seems that consumption of plants containing CT may affect GIN in a number of ways that involve a direct effect on the parasite and an indirect effect through improved protein nutrition and immune status of the host. Furthermore, CT could complex with nutrients and directly inhibit nutrient supply for larval growth of nematodes or indirectly decrease their metabolism through inhibition of oxidative phosphorylation, ultimately causing larval death. In this way, the host animal will be benefitted from improved nutrient utilisation, productive performance and immunological (both humoral- and cell-mediated) responses in small ruminants. Therefore, CT supplementation in diets of small ruminants—as a natural feed additive—may act as a natural deworming agent without possibly having any residual effect on animal products. The present chapter briefs the role of CT in controlling GIN along with the current updates on the research progress made in this area of veterinary science.