Equine gastric ulcer syndrome (EGUS) refers to any ulceration of the inside of a horse’s stomach and often causes severe physical pain, leading to clinical signs such as behavior changes, weight loss, and loss of appetite.
The mainstay treatment for EGUS is initially omeprazole, said Frank Andrews, DVM, MS, Dipl. ACVIM, LVMA equine committee professor of equine medicine and director of equine health and sports performance (EHSP) at Louisiana State University’s School of Veterinary Medicine, in Baton Rouge, during his presentation at the 2024 American Association of Equine Practitioners Convention, held Dec. 7-11, in Orlando, Florida. However, omeprazole might not be suited for long-term use; therefore, Andrews and his team of researchers set out to study a beta-glucan and hyaluronan product (relyneGI), which might be effective when used long-term or in conjunction with omeprazole.
Studying Beta-Glucan and Hyaluronan for EGUS
Hyaluronan is a high-molecular-weight glycosaminoglycan found in joint, intestinal, and gastric tissues. “It functions to maintain gastric and intestinal homeostasis, innate immunity, and modulates inflammation,” said Andrews. “In rats—which have a similar stomach to a horse with a squamous and glandular region—hyaluronan has been proven to protect the gastric lining and improve gastric mucosa integrity.” Beta-glucan is an integral part of cell walls and activates maturation, differentiation, and proliferation of immune cells, he added. It also has probiotic properties and has been proven safe for use in horses.
Beta-glucans have various sources (e.g., cereal grains, yeast, mushrooms) that affect their molecular structure and branching patterns. These structural variations influence their solubility, viscosity, and, ultimately, their biological effects on the body. Schizophyllan, a type of fungal beta-glucan, stimulates the immune system by activating immune cells and promoting the production of cytokines, which can enhance the body’s defense mechanisms and accelerate wound healing.
Andrews and his team studied the efficacy of a new gastric support supplement with beta-glucan and hyaluronan for reducing the incidence of gastric ulcers in 12 stall-confined Thoroughbred and Thoroughbred-cross horses with naturally occurring gastric ulcers. They divided the horses evenly into treatment and control groups and performed a gastroscopy on and weighed each horse at the beginning of the study after a two-day acclimatization period.
Over the 35-day treatment period, the team of researchers administered 1 ounce of the supplement mixed in the grain three times daily (known as the high-stress dose) to the treatment group of horses and a 1-ounce dose of a placebo mixed in the grain three times daily to the control group. The researchers were masked to the treatment to avoid bias in ulcer scores and repeated gastroscopies and weights on Days 14, 28, and 35.
Beta-Glucan and Hyaluronan Effects on Equine Gastric Ulcer Scores
Andrews and his team saw a significant increase in all study horses’ weight over the course of the study period, but the treatment did not affect body weight. The mean nonglandular EGUS and severity scores were significantly lower in the treatment group on Days 28 and 35. “The nonglandular ulcers were healed, except for mild hyperkeratosis, on these dates as well,” Andrews said. “The mean glandular (gastric ulcer) and severity scores were significantly lower after 14 days in the treatment group. The ulcers did heal, but some reoccurred in both groups of horses by Day 28, which is not uncommon in these types of ulcers.” The mean gastric fluid pH remained low and variable throughout the course of the study in both groups of horses.
Take-Home Message
Based on his team’s research, Andrews said he believes the beta-glucan and hyaluronan supplement might have uses for managing horses with EGUS long-term and/or in conjunction with appropriate pharmaceutical treatment. They observed a clear improvement in nonglandular and glandular gastric ulcer scores in the treatment group and did not observe any adverse effects from the supplement. Horses readily consumed it, he added. Andrews said the limitations of the study included a small number and limited breed of horses, short treatment period, and the horses were individually stalled and not exercised or in training. Andrews and his team hope to address these limitations in future research by determining if the beta-glucan and hyaluronan product tested in this study will act synergistically with omeprazole or other medications to improve stomach health in horses as well as prevent recurrence of stomach ulcers. Supplements should not be used to treat disease but should be used to improve stomach health after discontinuation of pharmacologic agents, he added.
