Potential and challenges of tannins as an alternative to in-feed antibiotics for farm animal production

Huang, Qianqian; Liu, Xiuli; Zhao, Guoqi; Hu, Tianming; Wang, Yuxi

The anthelmintic mechanisms of plant tannins have been suggested through "direct" action of tannins on parasite cells by 1) reducing establishment of the infective third-stage larvae in the host thereby reducing the host invasion, 2) reducing excretion of nematodes eggs by the adult worms, and 3) reducing development of eggs to third-stage larvae (Athanasiadou et al., 2001 (Athanasiadou et al., , 2005 Brunet et al., 2008; Hoste et al., 2012) and through "indirect" action by improving the host's resistance to nematodes Tzamaloukas et al., 2006; Pathak et al., 2016) . However, similar to their antimicrobial activities, the anthelmintic effects of tannins vary greatly depending on chemical composition and structure of tannins, the parasite species or growth stages and/or the hosts' species (Hoste et al., 2006 (Hoste et al., , 2012 .