Horse Hindgut Health and Butyrate | BioStarUS

Butyric Acid and Hindgut Health

An estimated 65% of all performance and sport horses experience hindgut ulcers. Stress (including environmental, training, and transport stress), nutrition, and over-use of Omeprazole and NSAIDs are risk factors in the development of colonic ulcers in horses.

Horses are hindgut fermenters. The intestinal contents of food are mixed and fermented in the large colon with the help of microbes, water, electrolytes, and short-chain fatty acids. The short-chain fatty acids are: acetate, propionate, and butyrate.

The walls of the large colon control what’s allowed to cross from the GI tract into the body and bloodstream. When that barrier is damaged or compromised, harmful substances gain access across the intestinal barrier. This can cause systemic health challenges.

What is a hindgut ulcer?

A hindgut ulcer is a thinning of the lining of the colon. That lining is a barrier to keep harmful substances from gaining access to the circulatory system.

The term “hindgut ulcer” can also refer to hindgut inflammation and hindgut stasis. “Hindgut stasis” refers to inefficient fermentation in the large intestine. It can be caused by acidic pH (also known as hindgut acidosis), an unbalanced microbial population, and dehydration.

Equine Gastric System | BioStar US

Short-chain fatty acids: Butyrate

Short-chain fatty acids are the main metabolites produced in the colon by bacterial fermentation of dietary fiber and non-digestible carbohydrates.

The short-chain fatty acids acetate, propionate, and butyrate are essential to this process.

The short-chain fatty acids modulate health through energy metabolism within specific systems including gut barrier function, glucose homeostasis, immunomodulation, and metabolism. The fatty acids also boost the protective mucus layer in the GI tract.

Current research has specifically noted the anti inflammatory and healing abilities of butyrate (also known as butyric acid).

Studies have shown that butyrate can assist the intestinal mucosal immune barrier, reduce the production of pro-inflammatory factors, and reduce the incidence of colonic inflammation in animal and human models.1

Butyric acid molecule | BioStarUS

Butyric Acid Molecule

The effects of diet, stress, NSAIDS, and parasites

  • Hay and forage are critical to the equine GI tract and provide the fiber necessary for the fermentation process of the hindgut and production of butyric acid and the other short-chain fatty acids.
  • Changes in the bacteria colonies in the hindgut affect short-chain fatty acid production. Stress is an important factor, as it can disrupt the colonies of beneficial bacteria in the gut, which then opens the door to inflammation.
  • When too many simple carbohydrates (sugars and simple starches) are undigested in the small intestine, they pass into the colon. This causes a change in the pH of the hindgut, reducing the beneficial colony of bacteria, and reducing mucus production. This in turn can lead to inflammation, and a weakened intestinal barrier.
  • Specific NSAIDs such as phenylbutazone (“bute”) stop the production of beneficial prostaglandins, which are actually important for mucosal protection.
  • Parasite load, particularly tapeworm, can damage the intestinal lining, and consequently lead to hindgut ulcers.

Horse with Healthy Hay | BioStar US


Supportive foods for a horse’s production of butyric acid


alfalfaLegumes such as alfalfa support the body’s production of short-chain fatty acids. Beet fiber (beet pulp) provides non-digestible fiber that provides fermentation benefits.


apple | BioStar USPsyllium, medicinal mushrooms, and apple pectin are fiber-rich carbohydrate foods that are also important for the production of butyric acid. Medicinal mushrooms contain non-starch polysaccharides known as beta-glucans. Beta-glucans have been extensively studied, particularly for their GI tract support, immune support, and in the prevention and treatment of metabolic disease in humans and animals.2

plant chelated | BioStar USMOS (mannan-oligosaccharides) and inulin (prebiotics) are food for the microbes in the hindgut, helping to maintain a healthy colony.


Hindgut pH: the effects of starch and protein


  • Horses eating diets with high levels of non-structural carbohydrates (NSC) are associated with hindgut acidosis, as well as laminitis. High levels of starch entering the hindgut can change the pH of the large intestine. This is also true of the fructans in grass and hay.
  • A healthy hindgut requires a pH of 6.7. A drop in the pH affects the microbial populations, and a drop in pH to 6.0 can indicate subclinical acidosis.
  • This is one good reason to get hay tested and to know how much NSC is in your hay, as well as ESC (ethanol-soluble carbohydrates), which is a subset of WSC (water-soluble carbohydrates), to be sure of the amount of sugars and fructans.

    [Total NSC = WSC (includes ESC) + Starch]

  • Fructans are sugars that can’t be broken down in the foregut. Fructans are resistant to the digestive enzymes in the stomach and small intestine. When fructans pass into the hindgut, they affect the pH and cause an increase in lactic acid. This can lead to an inflammatory response, and even laminitis.


According to a study by the University of Glasgow (2017) “Diets high in crude protein (14-17%) have been seen to increase rumen buffering capacity, indicating that protein in food may act as a buffer against acidity.”3

It’s important to note that alfalfa pellets and cubes provide 15-18% crude protein. Beet pulp, which can also be beneficial to the hindgut, has much lower protein values: 9-10% crude protein.

Assistance from probiotics

Short-chain fatty acids are produced by specific bacteria. Among those bacteria strains is Bifidobacteria.

Research is indicating that an emphasis on stimulation of butyrate with a combination of Bifidobacterium, MOS or inulin, and diet can support a healthy colon and can reduce the consequence of a hindgut disorder.4

Bifidobacterium | BioStar US


Sodium butyrate

Several equine supplement companies have added butyrate in the form of sodium butyrate. Sodium butyrate is produced through hydroformylation from propene and syngas, not from food ingredients. Sodium butyrate is a common industrial chemical; it’s approved as a food additive, fishing bait additive, and a food flavoring.

Biostar does NOT use sodium butyrate. To support the body’s production of short-chain fatty acids including butyrate, maintain pH, and support microbial colonies in the hindgut, we rely on real food ingredients.

Warming and cooling foods

In Ayurvedic medicine, foods and plants are either warming, cooling, or neutral. Warming foods increase digestive fire. Cooling foods cool digestive fire. If your horse has a gastric or hindgut ulcer, you want to reduce the heat.

Yeasts are classified as warming food. But when your horse is dealing with either a hindgut or gastric ulcer, you don’t want to add more heat. You want to cool down the fire.

If your horse has a gastric or hindgut ulcer, look for cooling probiotic supplements that contain Lactobacillus or Bifidobacterium yet do not contain yeast probiotics.

Supplemental support for the hindgut

When evaluating supplements for support of the hindgut, it’s important to pay attention to whether the targeted hindgut ingredients are provided in sufficient amounts. Generally speaking, the more, the merrier. For instance, a probiotic with only 10 million CFU’s of Bifidobacteria is not going to be as effective as a probiotic with 20 billion CFU’s of Bifidobacteria.

To support butyric production and the other short-chain fatty acids, look for probiotic supplements that provide Bifidobacteria, inulin, and MOS in high enough amounts for efficacy. Also look for supplements that provide sufficient amounts of psyllium, medicinal mushrooms, or pectin.

Medicinal mushrooms

Medicinal mushrooms

In Summary

  • Short-chain fatty acids are important in the health and function of the hindgut and the GI tract.
  • Butyric acid (butyrate) enhances the mucosal immune barrier, and provides healthy inflammatory response support in the colon.
  • Hay and feed high in NSC, as well as high fructan content in grasses, can negatively impact the pH of the hindgut, thereby affecting microbial populations, fermentation, and the production of short-chain fatty acids including butyrate.
  • 14-17% crude protein can help maintain the correct pH of the hindgut, which is critical for the fermentation of food by microbes in the hindgut.
  • Specific foods such as alfalfa and beet pulp can support a healthy hindgut. Alfalfa provides more crude protein than beet pulp.
  • Targeted probiotics such as Bifidobacteria with prebiotics such as MOS and inulin are important support for the hindgut.
  • Psyllium, pectin, and medicinal mushrooms support short-chain fatty acid production in the hindgut, particularly butyrate production.
  • Horses with hindgut ulcers benefit from cooling probiotic strains such as Lactobacillus and Bifidobacterium.

Biostar’s targeted formulas for
equine GI tract and hindgut support:

BioFlora EQ Equine Probiotic | BioStar US

BioFlora EQ

BioFlora EQ: Pre and probiotic with Lactobacillus and Bifidobacterium strains, Inulin, and MOS.

Optimum GI EQ | BioStar US

Optimum GI

Optimum GI: Daily wellness formula with additional GI tract support including apple pectin and medicinal mushrooms.

Thera Gard EQ | BioStar US

Thera Gard EQ

Thera Gard EQ: With medicinal mushrooms, apple pectin, and sunflower lecithin; plus marine red algae for bioavailable calcium and fennel seeds.

Tri-Gard EQ

Tri-Gard EQ

Tri-Gard EQ: Fast-acting paste with apple pectin, sunflower lecithin, soil-based probiotics, and chaga mushrooms.






Print Friendly, PDF & Email

You may also like...