Transcriptomic and Metabolomic Analysis of White and Yellow Abdominal Fat in Kazakh Horses

The color of fat is an important economic characteristic that influences consumer preferences and market value of meat products. To elucidate the molecular features underlying the color differences in abdominal fat of Kazakh horses, this study employed a multi-omics strategy, combining targeted metabolomics (fatty acid and amino acid analysis), untargeted metabolomics, and transcriptomics to systematically compare white adipose tissue (WAT) and yellow adipose tissue (YAT) samples from the abdominal region of Kazakh horses. Fatty acid composition analysis revealed no significant differences in total saturated and unsaturated fatty acid content between WAT and YAT (<i>p</i> &gt; 0.05). However, the levels of C15:0 and C17:1 were significantly higher in YAT than in WAT (<i>p</i> &lt; 0.05), while C21:0 was extremely significantly higher in YAT (<i>p</i> &lt; 0.01). In contrast, the content of C22:1n9 was significantly lower in YAT (p &lt; 0.05). Amino acid analysis showed that the aspartic acid content in WAT was extremely significantly higher than in YAT (<i>p</i> &lt; 0.01), approximately 3.3 times that of YAT. Further integrated transcriptomic and metabolomic analyses identified key genes such as LPGAT1, AKT2, and ADH5, as well as metabolites like stearic acid and inositol, as potential critical regulators and biomarkers for fat color differentiation. This study provides a theoretical foundation for understanding the molecular basis of color variation in equine adipose tissue and its impact on meat quality.