Researchers tested whether a natural seaweed extract called Ascophyllum nodosum could reduce methane gas produced by cows’ digestive systems. Using lab simulations of cow stomachs, they found that adding the seaweed extract to cow feed reduced methane production by up to 34%. This matters because methane from livestock contributes to climate change, and finding natural ways to reduce it could help make farming more environmentally friendly. The seaweed extract appears to work by changing how food breaks down in the cow’s stomach, redirecting hydrogen away from methane production.
The Quick Take
- What they studied: Whether adding seaweed extract to cow feed could reduce the amount of methane gas cows produce during digestion
- Who participated: This wasn’t a study with live animals. Instead, researchers used lab equipment that simulates how a cow’s stomach works to test different amounts of seaweed extract mixed with cow feed
- Key finding: Adding 0.3% seaweed extract to grass-based feed reduced methane production by 34%, and adding 0.5% to silage-based feed reduced it by 23-26%. All tested amounts reduced total gas production by 20-24%
- What it means for you: If these lab results hold up in real farms, seaweed extract could become an affordable, natural way to make livestock farming more environmentally friendly. However, this is early-stage research, and more testing with actual animals is needed before farmers can use it widely
The Research Details
Scientists conducted two separate experiments using a special lab machine called RUSITEC that mimics how a real cow’s stomach digests food. In the first experiment, they added different amounts of seaweed extract (0.1%, 0.2%, and 0.3%) to grass-based feed and measured what happened. In the second experiment, they tested higher amounts (0.3%, 0.4%, and 0.5%) with silage-based feed (fermented grass). Both experiments included a control group with no seaweed extract to compare results.
The researchers measured several things: how much of the feed was broken down, how much methane gas was produced, how much total gas was created, and what chemical changes happened in the simulated stomach. They also tracked hydrogen levels, which is important because hydrogen is used to make methane, so less hydrogen in methane means it’s being used for something else.
This approach is valuable because it lets scientists test many different amounts quickly and safely in controlled conditions before trying anything with real animals. The RUSITEC machine is considered a reliable way to predict how things will work in actual cow stomachs.
Using a lab simulation is important because it allows researchers to test multiple doses safely and quickly without needing to work with live animals first. This controlled approach helps identify the best dosage before moving to expensive and time-consuming farm trials. The results can help guide future research with real cows
This study was published in PLoS ONE, a well-respected scientific journal. The researchers tested two different types of feed (grass and silage) and multiple dosage levels, which strengthens their findings. However, this is lab-based research, not real-world testing, so results may differ when used with actual animals. The study doesn’t specify exact sample sizes for the lab simulations, which is a minor limitation
What the Results Show
In the first experiment with grass-based feed, the highest dose of seaweed extract (0.3%) produced the most dramatic results: methane production dropped by 34%, total gas dropped by 20%, and methane per unit of digestible food dropped by 30%. This happened mainly because the seaweed extract slowed down how quickly food was broken down in the simulated stomach.
In the second experiment with silage-based feed, all three doses of seaweed extract (0.3%, 0.4%, and 0.5%) reduced methane by 23-26% and total gas by 20-24%. Interestingly, these reductions happened even though the seaweed extract didn’t significantly change how much of the food was digested. This suggests the seaweed works through a different mechanism—possibly by redirecting hydrogen away from methane production.
Across both experiments, the seaweed extract consistently reduced the amount of hydrogen that was converted into methane. In the second experiment, hydrogen recovery decreased by 22% across all seaweed treatments, suggesting the seaweed is redirecting this hydrogen toward other chemical processes instead of methane production.
In the second experiment, the seaweed extract reduced how much of the dry matter (total solid food) and organic matter was broken down compared to the control group. However, it didn’t affect the breakdown of protein or fiber, which are important nutrients for cows. The overall fermentation process in the simulated stomach remained relatively normal, suggesting the seaweed extract doesn’t disrupt the cow’s digestive health while reducing methane
This research builds on previous studies showing that seaweed and seaweed extracts can reduce methane in ruminant animals. What’s new here is the systematic testing of different doses and the finding that seaweed works through multiple mechanisms—sometimes by slowing digestion and sometimes by redirecting hydrogen. This suggests seaweed extract is a robust solution that works in different feeding situations
The biggest limitation is that this research was done in a lab machine, not with real cows. Real animals have more complex digestive systems and behaviors that could affect results. The study also doesn’t tell us how long the effects would last if seaweed extract were used continuously on a farm, or whether cows would accept the taste of seaweed-supplemented feed. Additionally, the study doesn’t provide cost-benefit analysis, so we don’t know if seaweed extract would be affordable for farmers to use at scale
The Bottom Line
Based on this lab research, seaweed extract shows promise as a natural methane-reducing feed additive (moderate confidence level). The most effective dose appears to be 0.3-0.5% of the feed’s dry weight. However, these are preliminary findings from controlled lab conditions. Before farmers should consider using this, more research is needed with actual animals on real farms to confirm the results work in practice and to determine the best way to deliver it (confidence level: moderate)
This research is most relevant to livestock farmers, agricultural scientists, and environmental advocates interested in sustainable farming. It may eventually interest feed manufacturers and agricultural companies. General consumers who care about reducing livestock’s environmental impact should also pay attention to this research as it develops. This doesn’t apply to people who don’t work with or own livestock
If seaweed extract were used on farms today, methane reduction would likely happen immediately since it works during digestion. However, it will take 2-5 years of additional farm-based research before this could become a standard farming practice, and another 1-2 years after that for regulatory approval and commercial availability
Want to Apply This Research?
- If you manage livestock, track weekly methane reduction metrics (if you have measurement tools) or monitor feed costs and animal health markers when introducing seaweed extract supplementation at 0.3-0.5% of daily feed intake
- For farmers: Source food-grade seaweed extract and gradually introduce it to your livestock feed at recommended doses while monitoring animal acceptance and health. For consumers: Look for dairy and beef products from farms using sustainable feed additives like seaweed extract when available
- Track animal health indicators (weight gain, milk production if applicable, digestion quality) monthly for 3-6 months when introducing seaweed extract. Monitor feed costs and calculate return on investment. Document any changes in animal behavior or feed acceptance
This research is based on laboratory simulations of cow digestion, not studies with live animals or real-world farm conditions. Results may differ significantly when applied to actual livestock. Before using seaweed extract as a feed additive, consult with a veterinarian or animal nutritionist, as individual animals may respond differently. This information is not a substitute for professional agricultural or veterinary advice. Always follow local regulations regarding feed additives for livestock. The long-term safety and efficacy in commercial farming settings have not yet been established through peer-reviewed farm trials
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.