Performance of chickens and oxidative stability of the produced meat as affected by feed supplementation with oregano, vitamin C, vitamin E and their combinations
An experiment was carried out to investigate the effect of dietary supplementation with oregano, vitamin C, vitamin E and their combination on the performance of broiler chickens and the oxidative stability of breast and thigh muscle tissues. A total of 320 day-old Cobb-500 chicks were randomly allocated into 8 groups with 4 subgroups of 10 birds each. After 42 days of feeding, body weight gain and feed conversion ratio values showed that diet supplementation with oregano exerted a growth-promoting effect compared to control group. To assess the oxidative stability of the produced meat, raw and cooked breast and thigh muscle tissues were submitted to refrigerated-storage-induced lipid oxidation up to 9 days. Results showed that the oxidative stability offered by oregano was superior to that exhibited by vitamin C but inferior to that exhibited by the dietary combination of oregano plus vitamin E that was superior to all other tested dietary treatments. Vitamin C exerted a sparing effect on vitamin E when the latter was present in the diet at 30 mg/kg. When diet supplementation with vitamin E reached 200 mg/kg, the addition of vitamin C could not result in additional increase of the a-tocopherol levels in tissues. The lower MDA values found in tissues after diet supplementation with oregano, are probably the result of various antioxidant constituents that entered the circulatory system, distributed and retained in the tissues, exhibiting antioxiclant activity. Additional research is needed toward identifying and quantifying the main antioxidant constituents of oregano deposited into chicken muscle tissues.