Triheptanoin Not the Answer for Horses with PSSM

Triheptanoin, a short-chain fatty acid that is helpful to humans with some metabolic conditions, isn’t effective in the treatment of polysaccharide storage myopathy (PSSM), according to research led by Stephanie Valberg, D.V.M., Ph.D., at Michigan State University.

PSSM is a condition that causes severe muscle cramping, or “tying-up,” and muscle damage during exercise in some horses. These equines have higher than normal levels of glycogen in their muscle fibers and are often managed by using a diet low in starch but high in fat and fermentable fiber. This diet provides plenty of energy for exercise, but minimizes problems caused by abnormal starch metabolism.

Humans with some types of glycogen storage disease have been successfully treated with triheptanoin. However, when this fat was supplemented into the diets of mature Quarter Horses with PSSM, exercise intolerance was found more often in the supplemented horses than in those on the standard PSSM diets.

It is recommended that horses with PSSM should be managed with high-fat, high-fiber, low-starch diets. Vegetable oils and other long-chain fatty acids may be incorporated into diets. Based on the results of this research, triheptanoin should not be used as a treatment.