Integrated LC-MS-based lipidomics and transcriptomics reveal lipid heterogeneity and flavour variation in different...

Substantial improvements in lamb production have been achieved through genetic selection and advanced husbandry practices; however, whether flavour heterogeneity among different muscle anatomical regions is driven by region-specific metabolic and lipid regulatory patterns remains unclear. We hypothesised that distinct muscle cuts exhibit characteristic flavour profiles associated with differential amino acid composition, lipid molecules, and gene profiles. To verify this hypothesis, the longissimus dorsi muscle (LDM), front leg muscle (FLM), and hind leg muscle (HLM) of Sadumont lamb were systematically compared using integrated omics. Significant differences in amino acid composition were observed among muscles, with glycine and valine showing pronounced variation. The FLM exhibited higher levels of delicious amino acids than LDM and HLM. Volatile profiling revealed distinct aroma signatures, with hexanal predominating in LDM, 1-octen-3-ol and d-limonene characterising FLM, and octanal, nonanal, and benzaldehyde enriched in HLM. Lipidomic analysis showed that LDM was dominated by triacylglycerols, whereas FLM was enriched in phospholipids, particularly phosphatidylcholine and phosphatidylinositol, which are associated with lipid oxidation and flavour precursor generation. The HLM displayed an intermediate lipid profile with slightly elevated C22:6 and C20:5n3. Transcriptomic analysis identified 2595 differentially expressed genes, which were enriched in lipid-related pathways, including fatty acid elongation and metabolism. Notably, divergent expression of PPARA and ACAA2 supported differential regulation of fatty acid oxidation across muscle cuts. These findings support our hypothesis that flavour heterogeneity among muscle cuts is closely linked to cut-specific lipid components and gene expression. Additionally，these molecular markers could be utilised in precision breeding and meat quality optimisation.