Management of Enteric Methane Emissions in Ruminants Using Feed Additives: A Review

Abstract

In ruminants’ metabolism, a surplus of hydrogen is removed from the reduction reaction of NAD+ (nicotinamide adenine dinucleotide) by the formation of methane by methanogenic bacteria and archaea methanogens. The balance of calculations between VFA (volatile fatty acids), CO2, and CH4 indicates that acetate and butyrate play a role in methane production, while the formation of propionate maintains hydrogen and therefore reduces methane production. CH4 formation in ruminant livestock is not desired because it reduces feed efficiency and contributes to global warming. Therefore, numerous strategies have been investigated to mitigate methane production in ruminants. This review focuses on feed additives which have the capability of reducing methane emissions in ruminants. Due to the environmental importance of methane emissions, such studies are needed to make milk and meat production more sustainable. Additionally, the additives which have no adverse effects on rumen microbial population and where the reduction effects are a result of their hydrogen sink property, are the best reduction methods. Methane inhibitors have shown such a property in most cases. More work is needed to bring methane-reducing agents in ruminant diets to full market maturity, so that farmers can reap feed cost savings and simultaneously achieve environmental benefits.

Enhancing Digestibility of Chlorella vulgaris Biomass in Monogastric Diets: Strategies and Insights

“…Therefore, the reasons for choosing microalgae as an ingredient or supplement for animal feed are, for instance, their high nutritional value, if cultured under optimal conditions and fed to adapted animals [ 6 ], and their ability to act as feed additives. Particularly, extracted algal bioactive compounds can improve animal production by exerting antimicrobial and immunomodulatory activities [ 7 ] or inhibit methanogenesis in ruminants with positive effects on reducing methane emissions [ 8 , 9 ]. These factors have driven the exploitation of microalgae for human nutrition, animal feed, biofuels, and bioremediation in recent years [ 10 ].…”

Methane reduction by quercetin, tannic and salicylic acids: influence of molecular structures on methane formation and fermentation in vitro

“…Both in vitro simulation of rumen fermentation and in vivo studies with cows, goats, and sheeps, have been performed with feed incubated in sacco in the rumen or with feeding of biomass from plants rich in PSMs and extracts of varied origins as reviewed in different works 11 , 21 – 23 . For example, a large in vitro screening study with 450 plant species showed methane-reducing properties of 35 plant species.…”

The role of veterinary research in human health promotion in South Asia

“…Apart from this problem, another matter of concern is the livestock methane emissions that have serious implications in the context of global warming and climate change (Johnson and Johnson 1995). Researchers are carrying out studies to understand the methane emissions from livestock and are trying to explore the mitigation strategies that range from management aspects to nutritional interventions (Kumari et al 2020;Palangi and Lackner 2022).…”