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

Anti-parasitic properties of tannins have been demonstrated by both in vitro and in vivo studies. Condensed tannins extracted from legume tanniferous forages such as sainfoin (Onobrychis viciifolia), big trefoil (Lotus pedunculatus), birdsfoot trefoil (Lotus corniculatus) and sulla (Hedysarum coronarium) reduced the proportion of Trichostrongylus colubriformis hatched eggs and inhibited egg development of lungworm and gastrointestinal nematodes (mixed species of Ostertagia, Oesophagostomum, Cooperia, Trichostrongylus, and Strongyloides) in a dose-dependent manner (Molan et al., 2000a (Molan et al., , 2000b (Molan et al., , 2002 . Four tropical tanniniferous plant extracts have shown anthelmintic effect on Haemonchus contortus and T. colubriformis, which mainly interfered with the process of larval exsheathment (Alonso-Díaz et al., 2008a , 2008b . Tannins extract from quebracho (Athanasiadou et al., 2001) , chicory (Molan et al., 2003) and green tea (Molan et al., 2004) significantly inhibited the larval migration in a dose dependent manner. These results suggest anti-parasitic effect of tannins occurred throughout different stages of life-cycle of parasite. The anti-parasitic effects of various tannins observed in in vitro studies have also been confirmed in numerous in vivo studies involving in sheep and cattle (Paolini et al., 2003; Heckendorn et al., 2007; Chaweewan et al., 2015; Desrues et al., 2016) .