THE EFFECT OF DIETARY ZATARIA MULTIFLORA BOISS. ESSENTIAL OIL SUPPLEMENTATION ON MICROBIAL GROWTH AND LIPID PEROXIDATION OF BROILER BREAST FILLETS DURING REFRIGERATED STORAGE

Seventy-two 1-day-old broilers were allocated into four groups (basal diet as control, basal diet supplemented with 100, 200, and 400 mg/kg Zataria multiflora essential oil) and fed for 6 weeks. In the term, chicks were slaughtered and their breast fillets were stored at 4C for 12 days. Lipid peroxidation was assessed on the basis of thiobarbituric acid reactive substances formed, whereas microbial growth was assessed on the basis of total viable counts, lactic acid bacteria, Enterobacteriaceae and psychrotrophic bacteria. Results indicated that incorporation of Z. multiflora essential oil in broiler diets caused the delay of lipid peroxidation in raw breast meat (from 296.08 to 472.65 mg/kg malondialdehyde [MDA] equivalents) in comparison with 854.71 mg/kg MDA equivalents of the control sample at the last day of the experiment (P < 0.05). Moreover, breast samples containing higher concentration of Z. multiflora essential oil showed lower bacterial count than the control and 100 ppm essential oil supplemented samples (P < 0.05) during the experiment.