Effect of Natural Vitamin E Level and Duration of Supplementation on Growth Performance, Breast Meat Quality and Oxidative Stability of Broilers

摘要

This experiment was conducted to investigate the effects of natural Vitamin E (Nat E Ac) level and duration of supplementation on growth performance, carcass traits, meat quality and α-tocopherol content as well as oxidation stability of plasma and breast meat (refrigerated at 4°C) of broilers. Cobb broilers (n = 315, 21 days old, female) were randomly assigned to 7 treatments (1 control and 6 experiment groups) with 5 replicates and 9 broilers per replicate. Control group was fed with basal diet (Nat E Ac:30 IU kg-1). For the experimental groups, a 2x3 factorial design was used with 2 Nat E Ac levels (Nat E Ac:60 and 120 mg kg-1) and 3 durations (7, 14 and 21 days prior to slaughter at 42 day). The broilers were in the finisher phase (22-42 days) during the treatment. Results showed that broilers fed with higher Nat E Ac levels or fed for a longer duration had significantly (p<0.05) increased percentage of breast and thigh meat, pH24h in breast, glutathione peroxidase in liver and α-tocopherol in plasma, liver and breast meat. Moreover, the broilers also exhibited notably (p<0.05) decreased drip loss and pH in breast meat as well as decreasing content of Malondialdehyde (MDA) in the plasma and breast meat refrigerated at 4°C for 0, 2, 4, 6 and 8 days. There was a significant (p<0.05) interaction between Nat E Ac level and feeding duration that affected the level of MDA in breast meat refrigerated at 4°C for 0, 2, 6 and 8 days. Nat E Ac level, feeding duration and the interaction of these two factors did not markedly (p>0.05) influence growth performance, breast meat color, percentage of eviscerated carcass and abdominal fat, total superoxide dismutase and glutathione peroxidase activities and antioxidation capacity in plasma. Higher Nat E Ac level or prolonged duration of feeding increased the percentages of breast and thigh meat, enhanced the water-holding capacity, the pH24h as well as α-tocopherol retention of breast meat and oxidative stability during refrigerated storage of breast meat thus enhancing the oxidative stability during refrigerated storage and improving breast meat quality.