The potential for mitigation of methane emissions in ruminants through the application of metagenomics, metabolomics, and other -OMICS technologies

Ruminant supply chains contribute 5.7 gigatons of CO(2-eq) per annum, which represents approximately 80% of the livestock sector emissions. One of the largest sources of emission in the ruminant sector is methane (CH(4)), accounting for approximately 40% of the sectors total emissions. With climate change being a growing concern, emphasis is being put on reducing greenhouse gas emissions, including those from ruminant production. Various genetic and environmental factors influence cattle CH(4) production, such as breed, genetic makeup, diet, management practices, and physiological status of the host. The influence of genetic variability on CH(4) yield in ruminants indicates that genomic selection for reduced CH(4) emissions is possible. Although the microbiology of CH(4) production has been studied, further research is needed to identify key differences in the host and microbiome genomes and how they interact with one another. The advancement of “-omics” technologies, such as metabolomics and metagenomics, may provide valuable information in this regard. Improved understanding of genetic mechanisms associated with CH(4) production and the interaction between the microbiome profile and host genetics will increase the rate of genetic progress for reduced CH(4) emissions. Through a systems biology approach, various “-omics” technologies can be combined to unravel genomic regions and genetic markers associated with CH(4) production, which can then be used in selective breeding programs. This comprehensive review discusses current challenges in applying genomic selection for reduced CH(4) emissions, and the potential for “-omics” technologies, especially metabolomics and metagenomics, to minimize such challenges. The integration and evaluation of different levels of biological information using a systems biology approach is also discussed, which can assist in understanding the underlying genetic mechanisms and biology of CH(4) production traits in ruminants and aid in reducing agriculture’s overall environmental footprint.