Effect of variety differences on the meat quality traits and flavour of donkey meat based on transcriptomic and metabolomic analysis

Abstract

To investigate whether variations in donkey meat quality stem from breed-specific regulation of muscle metabolism, we employed headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), together with metabolomic and transcriptomic analyses to compare the longissimus dorsi muscles of Guangling donkeys and Jinnan donkeys. The results indicated that the longissimus dorsi muscle of the Guangling donkeys group was more tender. Heptanal and nonenal make important contribution to the flavour of Guangling donkey meat, and the odor activity value (OAV) of heptanal was significantly higher than that in Jinnan donkey meat. Aldehydes were found to have the greatest influence on the flavour of donkey meat. The 932 differentially expressed genes (DEGs) identified through transcriptome analysis were primarily related to alanine, aspartate, glutamate, starch and sucrose metabolism, cGMP-PKG, MAPK, and estrogen signaling pathways. Metabolomics analysis revealed 76 differential metabolites that were significantly enriched in lipid-related pathways, including glucagon, AMPK, cAMP signaling, and cysteine and methionine metabolism. Collectively, these findings support our original hypothesis that coordinated gene–metabolite interactions underlie breed-specific differences in donkey meat quality. The preliminary identification of DEGs and metabolites affected by breed differences, together with the screening of major flavour compounds, provides an important theoretical basis for subsequent molecular validation and for the improvement of meat quality in donkey breeding programmes.