Improving Ruminant Nutrition and Reducing Methane Emissions by adding Gambir Leaf Extract from Maek

Abstract This study examined gambir ( Uncaria gambir ) leaf extract from the Maek area as a new supplement in ruminant feed rations. Gambir is rich in tannin and catechin compounds. This study aimed to obtain a composition of gambir extract from the Maek area that can optimize nutritional efficiency and reduce methane production because it contains tannin and catechin compounds that can function as effective defaunation and antimetanogenic agents. The research utilized a Randomized Block Design featuring four different treatments, each replicated four times: T0 (standard ration), T1 (ration + 0.5% Maek gambir), T2 (ration + 1% Maek gambir), and T3 (ration + 2% Maek gambir). Crucial metrics were the production of methane gas, digestibility of nitrogen-free extract (NFE), crude fiber, and crude fat. Significant effects (P<0.05) were shown across all parameters by the analysis of variance and the DMRT test. Treatment D yielded the best results: crude fiber digestibility at 66.40%, crude fat digestibility at 67.38%, NFE at 67.98%, and methane production reduced to 7.38 ml/g DM. These findings demonstrate that gambir enhances nutritional performance and reduces methane emissions, promoting sustainability and efficiency in ruminant farming. This study highlights the potential of using local materials in more environmentally friendly livestock feed.