Dietary Piper sarmentosum Roxb. Extract Improves Antioxidant Capacity, Lipid Metabolism and Flavor Formation in Male Hainan Black Goat Kids Under Heat Stress

Global warming-induced heat stress causes oxidative imbalance and reduced productivity in livestock. This study investigated the effects of dietary supplementation with Piper sarmentosum Roxb. extract (PSE) on antioxidant capacity, lipid metabolism, and flavor formation in goats under heat stress. Thirty-six healthy 3-month-old male Hainan black goat kids were fed a basal diet supplemented with 0, 200, 400, or 600 mg/kg PSE (dry-matter basis) for 105 days. Specifically, PSE significantly enhanced antioxidant capacity, as indicated by increased total antioxidant capacity and glutathione peroxidase activity, along with reduced malondialdehyde levels (p < 0.05). These changes were accompanied by a decrease in n-6 polyunsaturated free fatty acids and a relative increase in saturated fatty acids (p < 0.05), suggesting a potential improvement in lipid oxidative stability. Further flavoromics analysis revealed a marked shift in meat volatile profiles, characterized by increased esters associated with fruity and waxy notes and decreased aldehydes and alcohols contributing to green and herbal odors. Muscle transcriptomic results further indicated enrichment of redox-related pathways, including oxidoreductase activity and reactive oxygen species metabolism. Overall, PSE, particularly at 600 mg/kg, enhanced antioxidant capacity and regulated redox status and lipid metabolism under heat stress, potentially contributing to improved meat oxidative stability and altered flavor compound formation.