T annins are a complex group of polyphenolic compounds found in many plant species commonly consumed by ruminants.They are conventionally classified into two major groups: Hydrolysable and condensed tannins (Khanbabaee and van Ree, 2001).Even when tannins be toxic when it consumes at high concentrations (reduce voluntary feed intake and nutrient digestibility), at moderate level of intake has been shown benefits on growth performance and/or dietary energy utilization in cattle (Rivera-Méndez et al., 2016) and lambs (Rojas-Román et al., 2017).In this sense, the use of supplemental tannins as a feed additive it has been used in recent years in growing-finishing rations.Recent studies have showed that type of dietary tannins (soluble or condensed) can affect in a different way ruminal microbial metabolism by several mechanism including inhibition of extracellular microbial enzymes, inhibition of oxidative phosphorylation or metal ions deprivations (Huang et al., 2018).This cause changes