Proanthocyanidins inhibit methane emissions by interacting with methyl-coenzyme M reductase and reshaping rumen...

Area of Science:

• Agricultural Science
• Environmental Science
• Microbiology

Background:

• Enteric methane (CH4) emissions from ruminants are a significant agricultural greenhouse gas source and represent an energy loss.
• Methyl-coenzyme M reductase (MCR) is the key enzyme in methanogenesis and a target for CH4 mitigation strategies.
• Identifying natural compounds to reduce enteric CH4 is crucial for sustainable livestock production.

Purpose of the Study:

• To identify plant-derived compounds that can mitigate enteric methane emissions.
• To investigate the efficacy of proanthocyanidins (PAC) in reducing CH4 production in ruminants.
• To understand the impact of PAC supplementation on rumen microbial communities and nutrient utilization.

Main Methods:

• Computational screening of 3,900 phytochemicals using molecular docking against the MCR active site.
• In vitro rumen fermentation assays to evaluate CH4 production and dry matter degradability.
• In vivo experiments with lactating dairy cows supplemented with PAC, including microbial community analysis (amplicon sequencing, metagenomics) and metabolomics.

Main Results:

• Proanthocyanidins (PAC) showed strong predicted affinity to the MCR active site.
• In vitro, PAC reduced CH4 production by 22% and increased dry matter degradability.
• In vivo, PAC supplementation (10-20 g/kg DM) reduced CH4 emissions by ~8%, improved nitrogen utilization, and shifted rumen microbial composition, increasing Bacteroidota and decreasing methanogenesis genes.

Conclusions:

• PAC supplementation effectively reduces enteric CH4 emissions in lactating dairy cows.
• PAC induces beneficial shifts in the rumen microbial community and enhances nitrogen utilization.
• PAC represents a promising natural strategy for lowering greenhouse gas emissions and promoting sustainable dairy farming.