Effects of supplementary and restricted feeding on meat flavor, lipid metabolism and muscle protein metabolism of Hu sheep.

This study investigated dietary regimens on Hu sheep meat quality. Compared to control, supplementary feeding (SF) increased body weight (63.83 %), eye muscle area (89.72 %), and dry matter content (5.99 %) (P < 0.01), while restricted feeding (RF) impaired meat color and reduced intramuscular fat (38.89 %) (P < 0.01). SF elevated concentrations of 67 volatile flavor compounds versus control and 48 compounds versus RF, enhancing sweet- and fatty-flavor associated volatiles. Control and RF exhibited similar flavor profiles. Correlation analysis identified 90 significant associations between fatty acids/amino acids and key volatile compounds. RF upregulated lipolytic enzymes ATGL and CPT1A (P < 0.05), decreased muscle fatty acid content, reduced muscle fiber size (8.85 %), and increased fiber density (113.50 %) (P < 0.01). Conversely, SF activated the AMPK-mTOR-S6K1 pathway, enhancing protein synthesis and amino acid levels. These findings demonstrate that dietary interventions modulate flavor precursors through metabolic pathways, providing scientific support for developing high-quality mutton products.