Research progress on the application of feed additives in ruminal methane emission reduction: a review

BACKGROUND: Ruminal methane (CH(4)) emissions from ruminants not only pollute the environment and exacerbate the greenhouse effect, but also cause animal energy losses and low production efficiency. Consequently, it is necessary to find ways of reducing methane emissions in ruminants. Studies have reported that feed additives such as nitrogen-containing compounds, probiotics, prebiotics, and plant extracts significantly reduce ruminant methane; however, systematic reviews of such studies are lacking. The present article summarizes research over the past five years on the effects of nitrogen-containing compounds, probiotics, probiotics, and plant extracts on methane emissions in ruminants. The paper could provide theoretical support and guide future research in animal production and global warming mitigation. METHODS: This review uses the Web of Science database to search keywords related to ruminants and methane reduction in the past five years, and uses Sci-Hub, PubMed, etc. as auxiliary searchers. Read, filter, list, and summarize all the retrieved documents, and finally complete this article. RESULTS: Most of the extracts can not only significantly reduce CH(4) greenhouse gas emissions, but they will not cause negative effects on animal and human health either. Therefore, this article reviews the mechanisms of CH(4) production in ruminants and the application and effects of N-containing compounds, probiotics, prebiotics, and plant extracts on CH(4) emission reduction in ruminants based on published studies over the past 5 years. CONCLUSION: Our review provides a theoretical basis for future research and the application of feed additives in ruminant CH(4) emission reduction activities.