Metabolic Predictors of Equine Performance in Endurance Racing

Abstract

Equine performance in endurance racing depends on the interplay between physiological and metabolic processes. However, there is currently no parameter for estimating the readiness of animals for competition. Our objectives were to provide an in-depth characterization of metabolic consequences of endurance racing and to establish a metabolic performance profile for those animals. We monitored metabolite composition, using a broad non-targeted metabolomics approach, in blood plasma samples from 47 Arabian horses participating in endurance races. The samples were collected before and after the competition and a total of 792 metabolites were measured. We found significant alterations between before and after the race in 417 molecules involved in lipids and amino acid metabolism. Further, even before the race starts, we found metabolic differences between animals who completed the race and those who did not. We identified a set of six metabolite predictors (imidazole propionate, pipecolate, ethylmalonate, 2R-3R-dihydroxybutyrate, β-hydroxy-isovalerate and X-25455) of animal performance in endurance competition; the resulting model had an area under a receiver operating characteristic (AUC) of 0.92 (95% CI: 0.85–0.98). This study provides an in-depth characterization of metabolic alterations driven by endurance races in equines. Furthermore, we showed the feasibility of identifying potential metabolic signatures as predictors of animal performance in endurance competition.

Characterization of exercise-induced hemolysis in endurance horses

“…It provided an in-depth characterization of metabolic alterations induced during the races and we identified potential metabolic predictors of performance. In this study, a significant increase in heme, biliverdin, and bilirubin as well as a correlation between plasma color change, indicative of hemolysis, and average speed was noted ( 38 ).…”

“…Briefly, the samples extracts, obtained from methanol-based solvent extraction with recovery standards, were divided into equal parts and evaporated under nitrogen stream [TurboVap (Zymark)]. The samples were further reconstituted in four different solvents compatible with each analytical methods as previously described ( 38 ). The metabolic measurements were conducted with Waters ACQUITY ultra-performance liquid chromatography (UPLC) and a Thermo Scientific Q-Exactive high resolution/accurate mass spectrometer interfaced with a heated electrospray ionization (HESI-II) source and Orbitrap mass analyzer operated at 35,000 mass resolution ( 44 ).…”

“…The number of eliminated horses in endurance racing oscillate around 50% ( 36 ) and the most common causes of elimination are orthopedic problems and metabolic reasons ( 36 ). The latest include dehydration, electrolytes loses, lactic acid production, and heat generation ( 37 , 38 ). This fact was corroborated by a French study where 12.5% of the competing endurance horses required treatment for metabolic conditions ( 39 ).…”

Baselining physiological parameters in three muscles across three equine breeds. What can we learn from the horse?

“…An example of BCAA that may have an effect on protein turnover in muscle fibers and muscle build-up is pipecolate, which in the present study appeared much higher in Friesian horses in both muscles compared to Warmblood horses ( Sato et al, 2016 ). Pipecolate, is a product of lysine metabolism and its blood levels were found to be lower in Arabian and half-breed Arabian horses after endurance racing ( Halama et al, 2021 ). The amino acid N-(delta)acetylornithine also displays a much higher expression in both muscles of Friesian horses compared to Warmblood horses.…”

Untargeted Metabolomics Profiling Reveals Exercise Intensity-Dependent Alterations in Thoroughbred Racehorses’ Plasma after Routine Conditioning Sessions

“…While recent metabolomics studies have provided valuable insights into the energetic pathways and substrate utilization during exercise, these investigations have predominantly focused on endurance racehorses utilizing a nuclear magnetic resonance spectrometry-based approach − and more recently liquid chromatography coupled to mass spectrometry (LC–MS)-based approach . These investigations have provided valuable insights into previously overlooked metabolites, such as proteins and lipids, during endurance races.…”