The Microbiota as a Performance Enhancer in Athletic Horses

According to a new study, gut bacteria communicate with mitochondria to boost a horse’s athletic performance. Certain microorganisms thus enable more efficient energy production, paving the way for targeted dietary supplementation to improve and maintain the physical condition of athletic horses.   Our digestive tract is home to billions of microorganisms—two to ten times more cells than make up our entire body. Their presence in the gut has been known for over a century, but until recently, methods for studying the details of their interactions were limited. The development of high-throughput sequencing techniques has given new impetus to research and led to significant advances in our understanding of the nature of interactions between the host and its microbiota, among microorganisms themselves, and their impact. In recent years, numerous studies have focused on this topic, and researchers are now seeking to better understand the links between microbiota imbalances and certain conditions, particularly autoimmune and inflammatory diseases. In humans, many of these conditions—such as Parkinson’s disease and Crohn’s disease, which are caused by mitochondrial dysfunction—are believed to be associated with changes in the gut microbiota. In horses, this link between the gut microbiota and mitochondria also appears to exist, according to a new study. French researchers, primarily from INRAE, collected blood and fecal samples from 20 healthy endurance horses of similar age and performance level at the start and finish of the Fontainebleau International Endurance Competition, a race lasting approximately 8 hours. These samples provided information on the composition of the equine microbiota, the metabolites and chemical signals produced by bacteria, and the expression of specific genes. The researchers discovered that certain types of equine gut bacteria are capable of producing chemical signals to communicate with the body’s cells, particularly mitochondria—the cells’ powerhouses that regulate and generate energy—and that this influences their gene expression. The genes thus expressed or activated are thought to help the cells adapt to energy metabolism, for example, during a race. The metabolites produced by gut bacteria are thought to delay hypoglycemia and inflammation in the horse’s body cells, increasing its energy production and prolonging its athletic performance. Mitochondria, which have a bacterial origin, may thus have retained their ability to communicate and interact—or at least to intercept messages from the gut microbiota. According to the researchers, studying horses is a good way to assess the interdependence between gut bacteria and mitochondria, as the level of exercise a horse reaches during an endurance race is similar to that of a human marathon runner. A better understanding of the communication between mitochondrial function and the gut microbiome could also help improve individual horses’ performance. These findings pave the way for new training protocols, including, in particular, a supplemented diet. Supplementation combining probiotics containing beneficial bacteria with prebiotics—which serve as food for these beneficial bacteria—could be an effective way to improve the health and balance of the microbiome in athletic horses, with the goal of enhancing athletic performance. The study’s results also suggest that circulating free fatty acids may act not only as fuel but also trigger mitochondrial inflammatory responses caused by the translocation of intestinal bacterial polysaccharides following exercise. Targeting the gut-mitochondria axis therefore appears to be a winning strategy for improving performance.