Seaweed’s Impact on Cow Gut Microbes: A Pathway to Reduced Methane Emissions
A recent study published in Microbiome details how red seaweed (Asparagopsis) impacts the microbial community within a cow’s rumen, offering insights into a potential long-term solution for reducing methane emissions from cattle. researchers from UC Davis and the Innovative Genomics Institute (IGI), comprised of microbiologists, animal and computer scientists, are investigating ways to directly engineer gut microbes to lower methane production, moving beyond reliance on seaweed feed additives.
Previous research demonstrated that Asparagopsis inhibits a key enzyme in methane-producing microbes. This new study reveals that the seaweed doesn’t just block the enzyme, but actively alters gene expression within the rumen microbial community. Specifically,the seaweed caused certain microbial genes to switch on and off,indicating their crucial role in the process of methane reduction. This gene activity resulted in a significant, temporary increase in hydrogen production within the rumen.
Crucially, the research team identified a bacterium from the genus Duodenibacillus capable of utilizing this excess hydrogen. Project leader Matthias Hess, a microbiologist at UC Davis, explained the importance of this finding: “Too much hydrogen can lead to acidosis in the rumen, which can harm the animal. Instead, this organism uses the hydrogen and converts it to succinate, a compound the animal can eventually use to make protein.”
Principal investigator spencer Diamond of the IGI highlighted the potential for leveraging this knowledge. “Hydrogen is a key energy source in the rumen, specifically for methane-producing microbes. This study helps us better understand how other microbes that naturally occur in the rumen can divert this hydrogen away from methanogens and towards bacteria that may make animals more efficient.”
The study involved analyzing rumen fluid from eight cows – four on a standard diet and four supplemented with seaweed for 14 days. Cows receiving the seaweed additive experienced a 60% reduction in methane emissions, a 367% increase in hydrogen production, and improved feed efficiency by up to 74%.
Researchers successfully reconstructed the genome of Duodenibacillus, a bacterium not yet cultivated in a laboratory setting. Analyzing its genetic code provides understanding of its hydrogen consumption mechanisms, its competitive interactions with other microbes, and its overall function within the rumen environment.Current efforts are focused on isolating this Duodenibacillus species for further inquiry.
The research was supported by funding from lyda Hill philanthropies, Acton Family Giving, the valhalla Foundation, Hastings/Quillin Fund, the CH Foundation, laura and Gary Lauder and Family, the Sea Grape Foundation, the Emerson Collective, Mike Schroepfer and Erin Hoffman family Fund, the Anne Wojcicki Foundation through The Audacious Project, the Shurl and Kay Curci Foundation, and the U.S. department of Energy’s office of Science.
