Antioxidant Effect of Dietary Zataria multiflora boiss Extract Supplementationon and Susceptibility of Chicken Meat to Lipid Oxidation during Frozen Storage

The antioxidant effect of dietary Zataria multiflora boiss (ZMBE) extract supplementation on the suscepti-bility of chicken thigh muscle to lipid oxidation during frozen storage at -20 °C for 6 months was examined in this experiment. Three hundred thirty six day-old chicks were allocated to 7 dietary treatments with 4 replicates (12 birds each) in a completely randomized design. The dietary treatments in this study were: T1) basal diet [control group, without Zataria multiflora boiss extract (ZMBE)], T2) and T3) [basal diet plus 0.5% and 1% of ZMBE for 42 days], T4) and T5) [basal diet plus 0.5% and 1% ZMBE in the last two weeks of rearing period] and T6) and T7) [basal diet plus 0.5% and 1% ZMBE in the last week of rearing period], respectively. The susceptibility of meat to lipid oxidation was determined by measuring the pH and thiobarbituric acid reactive substances (TBARS) level of thigh muscle after 2, 4 and 6 months of storage, respectively. Results clearly demonstrated a major impact on the oxidative stability of broiler meat by ZMBE treatments when compared to control group (P 0.05). However, TBARS values of meat increased pH and moisture content decreased with increasing storage time (P 0.05).