Effects of dietary supplementation with rosemary and α-Tocopherol acetate on performance and meat quality of chicken meat during refrigerated storage

The effects of rosemary and α-tocopherol, added individually or in combination, on broiler performance, thiobarbituric acid reactive substance (TBARS), total plate count (TPC) and meat color of chicken thigh meat were investigated. Three hundred broiler chicks divided into five groups were fed a basal diet (control) or basal diet supplemented with 5 g rosemary/kg (T1), 10 g rosemary/kg (T2), 200 mg α-tocopherol/kg (T3), or 5 g rosemary/kg + 200 mg α-tocopherol/kg (T4) for 5 weeks. Following slaughter, chicken meat was stored at 4°C for 10 days. All treatments did not influence the performance. Rosemary supplementation delayed lipid oxidation in thigh meat during refrigerated storage. T2 was significantly (p<0.05) more effective in delayed lipid oxidation compared to T1, but was inferior to T3. Samples containing a combination of anti-oxidant had lower TBARS values than those containing the individual antioxidants, indicating a synergistic effect. TPC was significantly increased (p<0.05) in thigh meat of all groups throughout the refrigerated storage. The T3 and control groups showed TPC counts that did not differ from each other during the entire storage period. However, rosemary supplementation was associated with bacterial counts that were significantly lower (p<0.05) than the control and α-tocopherol groups at day 3 of storage and thereafter. For this period, T1 presented TPC counts that were significantly higher than the T2 group (p<0.05). At all storage times, the thigh meat of rosemary-fed chickens was redder than control (higher a^*), while no differences in L^* and b^* values were found. A synergistic effect was obtained from the combination of rosemary with α-toco-pherol, whereas individual use of the antioxidants significantly improved color stability compared to the control.