Metabolomics analysis and mRNA/miRNA profiling reveal potential cardiac regulatory mechanisms in Yili racehorses under different training regimens.

Yili horses, a versatile breed from Xinjiang, China, are renowned for their racing abilities. However, studies on the links between cardiac morphology, function, and metabolic profiles with performance are limited. This study combined echocardiographic, transcriptomic, and metabolomic analyses to explore these relationships in high-level, average, and untrained Yili horses. Echocardiographic assessments revealed increased left ventricular mass in trained horses, with significant differences in intraventricular septal thickness and left ventricular end-diastolic diameter. RNA sequencing identified 534 differentially expressed genes, 366 differentially expressed miRNAs, highlighting pathways in glycine, serine, and threonine metabolism, oxygen transport (e.g., ALAS2), and ATP generation. Metabolomic analysis revealed variations in acylcarnitine and triglycerides, suggesting training-induced cardiac remodeling regulated by miRNAs. This integrated approach provides new insights into the molecular and metabolic factors influencing performance, offering a foundation for optimized training strategies for Yili horses.