Saponins are natural detergents found in many plants. There have been increased interests in saponin-containing plants as possible means of suppressing or eliminating protozoa in the rumen. A decrease in protozoa numbers has been reported in the rumen of sheep infused with saponins or fed on saponin-containing plants. Decreased numbers of ruminal ciliate protozoa may enhance the flow of microbial protein from the rumen, increase efficiency of feed utilization and decrease methanogenesis. Saponins are also known to influence both ruminal bacterial species’
composition and number through specific inhibition, or selective enhancement, of growth of individual species. Saponins have been shown to possess strong defaunating properties both in vitro and in vivo which could reduce CH4 emissions
(Rowlinson et al., 2008).