Gastrointestinal modification based on probiotic feed additive enviro-alleviators to reduce enteric methane production in ruminant and non-ruminant livestock

Abatement of livestock enteric-produced methane (CH 4 ) has become an avenue of interest to improve global economical and environmental burdens. Among these approaches, probiotic feed additives (PFAs) are increasingly pointed out in literature to potentially facilitate effective gastrointestinal tract (GIT) microbiome manipulation. These modulations aim to improve enteric fermentation without harming livestock health or productivity, while also reducing CH 4 emissions to help ease food supply chain pressures. Agricultural by-product wastes have increased over the previous three decades, and notably, PFAs are also proposed as livestock feedstuff nutrient availability enhancers. While numerous studies have examined the effects of PFAs on fermentation parameters, direct comparative investigations into their specific impact on GIT CH 4 profiles across both ruminant and non-ruminant species remain limited in literature. Herein, we characterize and summarize the CH 4 status reported by previous studies based on dictating GIT fermentative parameters of ruminants and non-ruminants supplemented with PFAs, along with their corresponding comparable CH 4 -reducing mechanism pathway. Simultaneously, we also evaluate PFA species for their potential to reduce enteric-produced CH 4 in livestock, alongside their intricate optimizing implications and delivery efficacy within farming systems. Justifiably, livestock productivity remains vital, as farming remains an essential practice for humans to derive dietary commodities. This review provides connected insights into existing gaps and prospective opportunities to better understand host-microbiome interactions in reducing agricultural CH 4 emissions, aiding farmers to better grasp the application potential of PFAs as a possible sustainable practice for future livestock-derived food security. Through literature retrieval of previous studies as described in the introduction section, we provide review work revolving around the comparable administering of PFA for reduced CH 4 emissions from ruminant and non-ruminant livestock farming practices. Herein, we summarize these previous studies, providing optimization insights that may drive the sustainability of food commodities derived from livestock and environmental protection when their diets are subjected to PFA. • Global PFA market will rise by USD 3.1 billion by 2026 and reviewed PFAs show roles in CH 4 ​reduction studies. • PFA administration modulates livestock GIT by improving feed nutrient availability to achieve CH 4 ​reduction. • Ruminant and non-ruminant livestock show similar fermentation mechanisms yielding lower CH 4 ​after PFA use. • Linking sustainable livestock CH 4 ​reduction and food security using PFA faces present optimization limitations. • Molecular and omics-based feed biotechnology directs PFAs to modulate GIT for better livestock health and performance.