Effects of various plant-based condensed tannin on rumen microbiome population: A meta-analysis

Abstract Tannins are bioactive compounds found in plants and are very prospective for use in reducing methane gas production by ruminants. The effect of extracts of tannin compounds on methane gas parameters effectively reduces methane production. However, the population dynamics of the rumen microbiome showed varying results depending on tannin levels, types of tannins, and sources of tannins used. This study analyzed the effect of extracts of condensed tannin (CT) compounds from various plants on rumen microbiome populations using a meta-analysis approach. A total of 9 articles comprising 27 studies (comparisons) were selected for meta-analysis. The results showed that condensed tannins effectively reduced the rumen’s protozoa and methanogenic archaea population (p0.05). Sub-group analysis based on various plants showed that Leucaena had the best effect (p<0.01) on reducing archaea methane populations. The research conclusion proves that CT is effective in reducing the population of methane-forming precursor bacteria, such as archaea and protozoa, without affecting the total bacterial population in the rumen.