A review on the use of coconut oil to mitigate methane emissions in ruminants: mechanisms of action and research progress

Methane (CH4) generated during ruminal fermentation in ruminants is a major contributor to greenhouse gas emissions and represents a substantial loss of dietary energy. Therefore, mitigating enteric CH4 emissions through safe and efficient nutritional strategies is of considerable ecological and economic significance. Coconut oil (CO) has received increasing attention due to its distinctive fatty acid profile. Accumulating evidence indicates that the medium-chain fatty acids (MCFA) abundant in CO exert direct inhibitory effects on rumen protozoa and methanogenic archaea, thereby conferring strong antimethanogenic potential. However, the CH4 mitigation efficacy of CO is often accompanied by trade-offs related to rumen microbial ecology, animal productive performance, and the nutritional quality of animal-derived products, particularly at higher doses where fiber digestibility and dry matter intake (DMI) may decline. Consequently, a clearer definition of safe and effective inclusion levels across different ruminant species and production stages is needed. This review systematically summarizes the physicochemical properties and safety of CO, with particular emphasis on its mechanisms of action within the rumen. Furthermore, current application studies and future research prospects of CO in ruminant production are discussed, providing a scientific reference for its use in nutritional strategy to lower methane in ruminant systems.