Antioxidant effects of liquorice (Glycyrrhiza uralensis) extract during aging of longissimus thoracis muscle in Tan sheep

•Liquorice extract (LE) was fed to sheep and the antioxidant ability evaluated.•LE increased total flavonoid, vitamin E and glutathione contents in meat.•LE improved free radical scavenging ability of meat.•LE decreased malondialdehyde content and protected the meat against oxidation.

The study was conducted to investigate the potential of liquorice extract (LE) from Glycyrrhiza uralensis as a dietary supplement for sheep to improve antioxidant capacity of meat. Fifty Tan sheep were randomly allocated to five groups with LE supplementation at levels of 0, 1000, 2000, 3000 and 4000 mg/kg feed. After 120 days, the longissimus thoracis muscle was sampled and conditioned for 0, 2, 4, 6 and 8 days at 4 °C. The results revealed that LE scavenged free radical in a dose–response manner in vitro. Supplementation with LE in animal diet increased (P < 0.05) antioxidant content and radical scavenging activity while it decreased (P < 0.05) reactive oxygen species (ROS) and thiobarbituric acid reactive substance (TBARS) levels of meat. Dietary LE supplementation can improve antioxidant capacity of meat, and the optimum dosage range of LE supplementation appeared to be 3000 to 4000 mg/kg feed.