The effects of tributyrin and butyrate on equine skeletal muscle

In the equine industry, there is a need for supplements that can improve performance and muscle recovery. Tributyrin and butyrate affect satellite cells and oxidative metabolism in other species. To assess the effects of tributyrin on equine muscle repair, Thoroughbred horses were supplemented tributyrin, and a submaximal exercise test was performed. RNA isolated from the gluteal muscle of horses supplemented with tributyrin had increased myogenin mRNA. Satellite cells isolated from supplemented horses had a higher percentage of proliferating cell nuclear antigen immunopositive cells, indicating tributyrin primed satellite cells to activate. Another experiment was performed to test the effects of tributyrin supplementation on equine muscle metabolism. Horses were fed tributyrin for 30 days while partaking in light exercise training. After the supplementation period, horses performed an exhaustive exercise test. Tributyrin supplementation did not affect performance or measures of oxidative metabolism in the muscle. To measure the effects of butyrate on equine muscle metabolism, Thoroughbred horses were supplemented butyrate for 30 days. At the end of supplementation gluteal muscle from butyrate fed horses had a higher percentage of type IIA fibers. Tributyrin supplementation demonstrated positive effects on satellite cell activation, but failed to increase oxidative metabolism measures. Butyrate did statistically increase the percentage of type IIA fibers, but not oxidative enzyme activity and the modest increase seen would likely not effect performance. Higher doses and longer supplementation of butyrate and tributyrin should be investigated to see if a metabolic shift beneficial to racehorses can be achieved. Furthermore, future research should focus on tributyrin's effects on satellite cells and how supplementation can improve muscle recovery in racehorses.