Can Yeast Boost a Horse’s Immune System?

Sound nutrition supports your horse’s immune system, allowing him to fend off infections and respond appropriately to vaccines. Some horses, however, have suboptimal immune function or are immunocompromised in some way, leaving them susceptible to disease.

“Supplements designed to provide immune support are popular and may include ingredients such as herbs, prebiotics, and antioxidants like vitamin E,” explained Kathleen Crandell, Ph.D., a nutritionist for Kentucky Equine Research.

Vaccination initiates a coordinated series of events that activate immune responses designed to fight specific infections. This type of immunity involves the production of infection-fighting antibodies by B cells and stimulates cell-mediated immune responses orchestrated by T cells.

Older studies demonstrated that mature horses, often beset with age-related decline in immune function, benefitted from vitamin E supplementation in the face of vaccination.^* Certain vitamin E products have more beneficial effects in horses than others.

According to Crandell, “Nano-E, developed by Kentucky Equine Research, is a natural-source, water-soluble vitamin E that features nanotechnology to deliver its powerful antioxidant. Nano-E is readily absorbed from the digestive tract, providing 250 IU d-alpha-tocopherol per milliliter.”

One team of veterinary researchers recently explored an alternate nutritional supplement called Saccharomyces cerevisiae fermentation product (SCFP) to support immune function in horses. Their study demonstrated beneficial immunomodulatory effects following vaccination, potentially identifying a novel means of boosting immunity through nutrition. ^*

The researchers used a proprietary supplement containing SCFP, which functions as both a prebiotic and probiotic. The supplement was fed to six horses for a total of 56 days. On day 40 of supplementation, horses were vaccinated using an equine influenza vaccine. This vaccine was intended to mimic an influenza vaccine booster, which would increase antibodies against that virus. Five horses served as controls and did not receive the SCFP.

After analyzing various white blood cells involved in immunity and antibodies against the influenza virus, the scientists concluded that SCFP supplementation modulated vaccination-induced responses in supplemented horses.

“The microbiome in the gut is a major part of the body’s immune system. Anything that can improve the health of the intestinal microbiome, such as SCFP with prebiotic and probiotic activity, may fortify the immune system,” Crandell said.

^*Lucassen, A., C. Finkler-Schade, H.-J. Schuberth. 2021. A Saccharomyces cerevisiae fermentation product (Olimond BB) alters the early response after influenza vaccination in racehorses. Animals (Basel) 11(9):2726.

^**Petersson, H.K., D.B. Burr, M. Gomez-Chiarri, et al. 2010. The influence of vitamin E on immune function and response to vaccination in older horses. Journal of Animal Science 88(9):2950-8.