Plasma Non-targeted Metabolomics Analysis of Yili Horses Raced on Tracks With Different Surface Hardness

In this study, the plasma non-targeted metabolomics of Yili horses were characterized before and after exercise on tracks that differed in surface hardness to better understand exercise-related biochemical changes. Blood samples were obtained from eight trained Yili horses before and immediately after exercise. Samples were used for metabolomic analysis by ultra-performance liquid chromatography-Q-EXACTIVE mass spectrometry. In total, 938 significantly different metabolites involving sugar, lipid, and amino acid metabolism were detected in the plasma, with significant increases in glucose, glucoheptanoic acid, lactic acid, malic acid, and methylmalonic acid and significant decreases in creatinine, D-tryptophan, carnitine, and citric acid after exercise. Among these metabolites, acetylcarnitine, tuliposide, vitamin C, and methylmalonic acid showed regular changes in concentration after exercise on tracks that differed in surface hardness, providing new insights into equine exercise physiology. The findings indicated the potential of vitamin C and methylmalonic acid as novel biomarkers of equine locomotor injury.