Abstract: This study was conducted to investigate the effect of age on nutritional value and antioxidant activity of house-feeding yak meat, and to provide the guidance for the production of high-quality yak meat. The healthy Maiwa male yaks (n = 18) were allocated to three groups (1.5-year-old = ‘AGE1.5’, 2.5-year-old = ‘AGE2.5’ and 4.5-year-old = ‘AGE4.5’) by age, with 6 yaks in each group. Pre-experimental period was 15 days, and the trial period was 180 days. The results showed that: 1) the age had a significant effect on crude protein and crude ash of yak meat (P < 0.05). The content of crude protein in yak meat of AGE4.5 group was 23.50%, and the content of crude ash in yak meat of AGE2.5 group was 1.36%, which was the highest in three groups. 2) The ratio of essential amino acids to total amino acids (EAA/TAA) and essential amino acids to non-essential amino acids (EAA/NEAA) in different age groups were significantly different (P < 0.05), as followed by an order: AGE2.5 > AGE4.5 > AGE1.5. The ratio of flavor amino acids to total amino acids (FAA/TAA) in the AGE2.5 group was 42.88%, which was significantly lower than 43.49% in the AGE1.5 group and 43.43% in the AGE4.5 group (P < 0.05). 3) The effect of age on fatty acids in yak meat was relatively weak. The content of C21:0 in the AGE2.5 group was significantly higher than that of the AGE1.5 and AGE4.5 groups (P < 0.05), while the contents of other fatty acids were not significantly different (P > 0.05). The C22:0 and C20:2 were detected in the AGE1.5 group, but did not detected in the AGE2.5 and AGE4.5 groups. 4) As the extension of age, the content of malondialdehyde (MDA) gradually increased, with increase by 53.80% in the AGE4.5 group when compared with the AGE1.5 group. However, the contents of catalase (CAT), total superoxide dismutase (T-SOD), total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-Px) in yak meat from different age groups were not significant (P > 0.05). In conclusion, age can modify nutritional components of yak meat, but has no significant effect on its antioxidant property.

Key words: age, house-feeding, yak, nutritional value, antioxidation property