Why Soil-Based Organisms (Bacillus Bacteria) Are Important for GI Tract Health
Soil-based organisms (SBOs) are probiotic bacteria found in healthy soils that are classified as Bacillus strains. They have the unique ability to survive harsh environments – like the journey through the stomachs of horses, dogs, and humans — and provide many benefits for gastrointestinal (GI) tract health.
The relationship of Bacillus with plants and mammals
Bacillus have a symbiotic relationship (two species living on/near and interacting with one another for survival purposes) with the soil food web. These strains of bacteria drive nutrient cycling and decompose organic matter, improving soil health and, in turn, boosting plant health.
So, when animals put their muzzles in the soil and/or eat the plants around them, they consume Bacillus. When the predators inevitably hunt the grazers, they too benefit from the bacteria the prey had traveling through its GI tract.
Our ancestors were in contact with soil/dirt every day and ate plants that carried residual Bacillus on their stems, roots, and leaves.
Benefits of Bacillus bacteria
They are spore-forming, allowing them to survive the stomach acids of mammals and colonize the lower GI tract. Common probiotic strains, such as Lactobacillus and Bifidum (non-spore-forming), cannot survive the stomach without the protective measures of microencapsulation or enteric coatings.
They can block pathogenic bacteria in the intestines. In particular, B. subtilis and B. coagulans form a protective barrier that leaves less space and fewer resources for pathogenic organisms to colonize.
They can act as immune modulators, capable of enhancing innate and adaptive immune systems.
They (specifically B. subtilis) produce beneficial digestive enzymes, including:
Proteases (for protein digestion)
Lipases (for lipid digestion)
Amylases (for carbohydrate digestion)
They can improve the body’s ability to resist specific pathogens. B. subtilis helps to defend against E. coli, and surfactin (a lipopeptide biosurfactant produced by Bacillus and promising bioactive compound) has shown inhibitory effects on bacterial and viral pathogens.1,2
They can provide respiratory protection, as recent studies in mice, pigs, and children have shown. Bacillus subtilis may also be beneficial in preventing the production of allergic lung disease.3,4
They can strengthen the intestinal barrier by increasing tight junction proteins. The effects of this ability can help reduce the inflammatory response in the GI tract and can stimulate mucin production, which reduces the chances of leaky gut syndrome.5
How do I know if my horse needs SBOs like Bacillus?
Your horse may benefit from the support of a probiotic that includes Bacillus if he/she…
Does not have access to healthy pastures for six or more hours a day.
Has recently completed a round of antibiotics.
Needs digestive enzyme support.
Is dealing with leaky gut syndrome.
Has a weak or compromised immune system.
Is stressed.
The impact of stress on the microbiome of the gut
Stress can induce dysbiosis (loss of beneficial bacteria in the gut and the overpopulation of harmful bacteria), which can cause bloating, constipation, and diarrhea. Because Bacillus is so successful in crowding out harmful bacteria in the GI tract, it can be very beneficial for horses under stress.
How do I know if my dog needs SBOs like Bacillus?
Generally, dogs that live a rural lifestyle on farms and ranches shouldn’t need Bacillus supplementation daily; their noses and lips are in contact with SBOs on a regular basis, anyways. This is also true of dogs that often spend time in a backyard with healthy soil.
Your dog may benefit from the support of a probiotic that includes Bacillus if he/she…
Spends time in dog parks and/or walking neighborhood streets, as the probability of being in contact with pathogenic (harmful) bacteria increases in these environments.
Has recently completed a round of antibiotics.
Needs digestive enzyme support.
Is dealing with leaky gut syndrome.
Has a weak or compromised immune system.
Is stressed.
Has constipation or diarrhea issues.
BioStar products formulated with Bacillus bacteria for GI tract health
For horses:
Sym-Biota EQ™ provides multiple Bacillus strains in liquid form, plus medicinal mushrooms (with fulvic and humic acids) that replicate the soil web components found in healthy pastures. 50 billion CFUs per 4 mL.
Click to learn more about Sym-Biota EQ!
Hedgerow GI™ provides the patented Bacillus strain DE-111® alongside five strains of microencapsulated Lactobacillus and Bifidus probiotic bacteria. For digestion and gut support, the powder also includes fulvic and humic acids and a selection of plants commonly found in old English hedgerows. 150 billion CFUs per 15g.
Click to learn more about Hedgerow GI™!
Hedgerow Restore™ includes the same ingredients as Hedgerow GI™, with the added benefits of eggshell membrane collagen and the Ayurvedic support of Triphala, lion’s mane mushrooms, and holy basil. 150 billion CFUs per 13.2g.
Click to learn more about Hedgerow Restore™!
For dogs:
Sym-Biota K9™ is a liquid blend of multiple Bacillus strains and medicinal mushrooms, with the addition of fulvic and humic acids to replicate the web components of healthy soil. 25 billion CFUs per 2mL.
Click to learn more about Sym-Biota K9™!
Hedgerow K9 Boulardii™ is formulated to support and maintain a healthy GI tract with the yeast probiotic strain Saccharomyces boulardii, inulin, and Bacillus subtilis (DE-111®). Chamomile flowers, pumpkin, and nettle offer added stress support. 12.4 billion CFUs per 3.02g.
Click to learn more about Hedgerow K9 Boulardii™!
Breakthroughs with Bacillus: Scout, Cape, & Basil
References
1 High-dose multi-strain Bacillus probiotics enhance treatment and reduce antibiotic usage in children with persistent diarrhea through immune and microbiota modulation | Scientific Reports: https://www.nature.com/articles/s41598-025-15199-y
2 Surfactin from Bacillus subtilis enhances immune response and contributes to the maintenance of intestinal microbial homeostasis | Microbiology Spectrum: https://journals.asm.org/doi/10.1128/spectrum.00918-24
3 Bacillus subtilis Provides Long-Term Protection in a Murine Model of Allergic Lung Disease by Influencing Bacterial Composition | Semantic Scholar: https://pdfs.semanticscholar.org/64a6/659491bfa62d34f3e375b34fa8cf43a8af4e.pdf
4 Oral administration of Bacillus subtilis promotes homing of CD3+ T cells and IgA-secreting cells to the respiratory tract in piglets | ScienceDirect: https://www.sciencedirect.com/science/article/abs/pii/S0034528821000746
5 Effect of Bacillus subtilis Strains on Intestinal Barrier Function and Inflammatory Response | Frontiers in Immunology: https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2019.00564/full
About the Author: With over 30 years experience in the equine and human supplement industry, Tigger Montague knows nutrition from the synthetic side as well as the whole food side. She started BioStar US in 2006 with formulas she created in her kitchen. Before she started the company, she was an avid rider and competitor with eventing and show jumping, until she got hooked on dressage in the late 1980’s. She has competed on horses she’s owned and trained all the way from training level to Grand Prix.
