Scientists tested whether giving sheep special mixtures of helpful bacteria could improve how their stomachs work and reduce methane gas—a major contributor to climate change. Using lab tests that mimic sheep’s digestive systems, researchers found that four-strain probiotic blends significantly improved how well sheep broke down food, produced less methane and ammonia, and created more beneficial fatty acids. The results suggest that carefully designed probiotic supplements could be a practical way to make livestock farming more environmentally friendly while potentially improving animal nutrition.

The Quick Take

  • What they studied: Whether special blends of four different helpful bacteria could improve how sheep’s stomachs work and reduce the amount of methane gas they produce
  • Who participated: This was a laboratory study using simulated sheep stomach fluid rather than live animals. Researchers tested five different conditions: a control group with no bacteria added, and four treatment groups with different probiotic blends at two different doses each
  • Key finding: Sheep that received the probiotic blends digested their food better, produced significantly less methane and ammonia, and had more beneficial fatty acids in their digestive systems compared to the control group
  • What it means for you: If these lab results hold up in real sheep, farmers could potentially use these probiotic blends to reduce environmental pollution from livestock while improving animal nutrition—though more testing in actual animals is needed before widespread use

The Research Details

This was an in vitro study, which means the researchers didn’t work with live sheep. Instead, they used a laboratory technique called gas production testing that simulates what happens inside a sheep’s stomach. They created five different test conditions: one control group with regular feed and no probiotics, and four treatment groups receiving two different probiotic blends at two different doses each. The probiotic blends contained four types of helpful bacteria mixed together in equal amounts. Researchers measured how well the food was broken down, how much methane and ammonia were produced, and how many beneficial fatty acids were created.

The study followed a completely randomized design, which means the different treatments were assigned randomly to reduce bias. All measurements were taken under controlled laboratory conditions to ensure fair comparisons between groups. The researchers used established scientific methods to measure digestibility, gas production, and microbial populations.

This research approach is important because it allows scientists to quickly test multiple probiotic combinations and doses before spending time and money testing them in live animals. The gas production technique accurately mimics what happens in a real sheep’s stomach, making the results relevant to actual farming. By testing four-strain blends instead of single bacteria, researchers could see if combining different bacteria works better than using just one type—which is a practical question for farmers.

This study has some important strengths: it tested multiple probiotic combinations at different doses, used established laboratory methods, and measured multiple important outcomes. However, readers should know that this is a laboratory study, not a test in live animals, so results may differ in real farming conditions. The study doesn’t specify the exact number of repetitions or statistical details, which would help assess reliability. The findings are promising but represent an early-stage investigation that needs follow-up studies in actual sheep before farmers should change their practices.

What the Results Show

The probiotic blends significantly improved how well sheep could digest dry matter (the solid parts of food) and fiber, with the ABLB blend showing the best results. This means the sheep’s stomachs were working more efficiently to break down and absorb nutrients from their feed.

Methane production dropped noticeably in all probiotic-treated groups compared to the control. Since methane is a major greenhouse gas produced by livestock, this reduction could have real environmental benefits if confirmed in live animals. The blends also reduced ammonia-nitrogen levels, which is important because excess ammonia can harm animal health and the environment.

Total volatile fatty acids—beneficial compounds produced during digestion—increased significantly in treated groups. These fatty acids are important for sheep health and energy production. The probiotic treatments also reduced the number of protozoa (tiny organisms in the sheep’s stomach), which appears to be one way the probiotics help reduce methane production.

The study found improvements in predicted energy values, meaning the feed would provide more usable energy to the sheep. Organic matter digestibility also improved, indicating that more of the food was being broken down and used by the animal. These secondary findings suggest that probiotics don’t just reduce methane—they may actually improve overall nutrition and animal performance.

Previous research has tested single bacteria or two-strain combinations, but this appears to be one of the first studies examining four-strain probiotic blends. The results build on earlier findings showing that probiotics can help reduce methane, but suggest that combining multiple bacteria types may work better than using just one or two. The improvements in digestibility and nutrient absorption align with what scientists have seen in other probiotic studies, but the methane reduction appears more substantial than some previous single-strain research.

The biggest limitation is that this was a laboratory study using simulated stomach fluid, not actual live sheep. Results in real animals may differ due to factors like individual variation, diet complexity, and the animal’s overall health. The study doesn’t specify how many times each test was repeated, making it harder to judge how reliable the results are. The research also doesn’t test long-term effects or whether the benefits would continue over weeks or months of feeding. Finally, the study doesn’t include information about cost-effectiveness or practical implementation on farms.

The Bottom Line

Based on this research, the four-strain probiotic blends appear promising for reducing methane from sheep and improving digestion. However, these are early-stage laboratory findings. The recommendation level is ‘promising but needs confirmation’—farmers should wait for follow-up studies in live animals before making major changes. If future research confirms these results, the ABLB blend at the higher dose (4 × 10⁹ CFU/g) appears most effective based on this study.

Sheep farmers and livestock producers should pay attention to these findings, as should environmental scientists and policymakers concerned about livestock emissions. Feed manufacturers might be interested in developing these probiotic products. However, individual consumers shouldn’t change their behavior based on this single lab study. Veterinarians should monitor this research area for practical applications. People concerned about climate change and agriculture should find this research relevant but remember it’s still in early stages.

If these results hold up in live animals, benefits would likely appear within days to weeks of starting the probiotic supplementation, since the digestive system responds relatively quickly to dietary changes. However, environmental benefits from reduced methane would only become significant if many farms adopted the practice. Long-term studies would be needed to confirm that benefits continue over months or years.

Want to Apply This Research?

  • If you raise sheep or manage livestock, track daily methane-related metrics: record feed intake amounts, monitor animal weight gain or milk production weekly, and note any changes in digestion (manure consistency). If probiotics are added, compare these metrics before and after supplementation to see if real-world results match laboratory predictions.
  • For farmers: Consider requesting that your feed supplier develop or source the four-strain probiotic blends tested in this study. Start with a small trial group of animals before committing to herd-wide supplementation. For consumers: Look for products from farms using methane-reducing strategies, as this may become a marketing point as the technology develops.
  • Establish a baseline of current performance metrics (feed efficiency, animal growth, milk production if applicable) before any probiotic supplementation. After introducing probiotics, measure the same metrics monthly for at least 3-6 months to determine if laboratory benefits translate to real-world improvements. Track costs carefully to ensure the probiotic supplement doesn’t exceed the value of improved performance.

This research is a laboratory study and has not been tested in live animals. Results may differ significantly in real-world farming conditions. Before making any changes to livestock feeding practices or purchasing probiotic supplements, consult with a veterinarian or animal nutritionist familiar with your specific operation. This study should not be considered definitive evidence for commercial use until confirmed by additional research in live animals. Always follow local regulations regarding animal feed supplements and consult with your feed supplier about product safety and efficacy claims.