The aim of this study was to evaluate the effects of Allium mongolicum Regel ethanol extract (AME) on the serum index and meat quality of lambs. A total of 30 male Small-tailed Han sheep (3 months old) with an average weight of 33.60 ± 1.23 kg were divided randomly into one of two groups: the control group (CON) was offered a basal diet, and the AME group was offered a basal diet with supplementation 2.8 g·lamb⁻¹·day⁻¹ AME. The trial lasted for 75 days. AME supplementation significantly decreased the concentration of triglyceride and total cholesterol (p < 0.05), and tended to lower the concentration of non-esterified fatty acids (0.05 < p < 0.1), but significantly increased the concentration of high-density lipoprotein, leptin, and insulin (p < 0.05) in the serum of lambs. AME also decreased cooking losses and shear force and increased the content of intramuscular fat in the longissimus dorsi (LD) muscle of lambs (p < 0.05). In addition, there was no difference in the composition of hydrolyzed protein amino acids in the LD muscle among treatments (p > 0.05). However, AME changed the composition of free amino acids and promoted MUFA and PUFA deposition in the LD muscle of the lambs. These findings indicate that a diet supplemented with AME may improve the lipid metabolic capacity and meat quality of lambs.

Mongolian sheep are characteristically cold-tolerant. However, their cold adaptive processes, such as the physiological feedback adjustments that occur during the cold season, remain unexplored. Therefore, the present study aimed to evaluate the physiological adaptations of Mongolian sheep in cold plateau environments. A comparative analysis of the serum biochemical parameters, immune response, antioxidant capacity, and glucose and lipid metabolism of grazing Mongolian sheep in the cold and warm seasons was conducted. The results showed that in the cold season, the glucose and lipid metabolism and thermogenesis of the grazing Mongolian sheep were notably enhanced. Moreover, the immune responses were stimulated by increased levels of cytokines, such as IL-2, IL-1β, and IL-6, during the cold season. However, the antioxidant defense system was damaged; this damage was mainly characterized by decreased activity of antioxidant enzymes and an increased level of MDA during the cold season. Overall, glucose metabolism, lipid metabolism, thermogenesis, and immune responses were stimulated to meet the requirements of organismal metabolic regulation to enable grazing Mongolian sheep to physiologically adapt to cold climatic conditions.