1. Oxidation of meat and membrane from broilers fed on a diet containing 500 mg/kg rosemary and sage extracts was compared to meat and membrane oxidation from broilers receiving a control diet (not enriched with antioxidants) and a diet enriched in alpha-tocopheryl acetate (200 mg/kg). 2. After 9 d of refrigerated storage, thiobarbituric acid reactive substances of white meat from broilers fed on the control and the alpha-tocopheryl acetate-enriched diets were 0.51 and 0.25 mg malonaldehyde/kg meat, respectively. Values for meat from broilers fed on the diets containing the rosemary and sage extracts were in the range 0.30 to 0.35 mg malonaldehyde/kg meat, significantly lower than those from birds fed on the control diet. A similar trend was observed in the dark meat but differences were not significant at 9 d of storage. Similar trends were observed in raw samples stored at -20 degrees C for up to 4 months and in samples cooked at 70 degrees C and kept stored under refrigeration for up to 4 d. 3. The meat from broilers fed on the diet containing spice extracts had smaller concentrations of total cholesterol oxidation products (COPS) than meat from the control group (P < 0.05). Supplemental alpha-tocopheryl acetate reduced the COPS concentrations to a greater extent than did spice extracts (P < 0.05). 4. A similar trend was observed in microsomal fraction isolates, in which the rate of metmyoglobin/hydrogen peroxide-catalysed lipid peroxidation was lower in animals receiving spice extracts than in those fed on the basal diet.

Broilers were fed diets containing oils of varying degrees of unsaturation, namely coconut oil, olive oil, linseed oil and partially hydrogenated soybean oil (HSBO), with and without a-tocopherol supplementation. The different oils significantly (PcO.01) affected the fatty acid composition of the neutral lipids and, to a lesser extent, the fatty acid composition of the phopholipids. Fatty acid composition, in turn, influenced the oxidative stability of the meat during refrigerated and frozen storage. Meat from broilers fed olive oil or coconut oil was consistently more stable than meat from the linseed oil group. Dietary supplementation with a-tocopherol significantly (PcO.01) improved the oxidative stability of the dark and white broiler meat during refrigerated and frozen storage compared to meat from the broilers fed HSBO.

1. Broilers were fed on diets containing oxidised sunflower oil, sunflower oil and sunflower oil supplemented with alpha-tocopherol, butylated hydroxyanisole (BHA) or butylated hydroxytoluene (BHT). 2. Oxidised oil caused a significant reduction in broiler body and carcase weights, whereas alpha-tocopherol and BHA/BHT supplementation improved growth. 3. Meat samples from these broilers were stored at 4 degrees C and -20 degrees C and their oxidative stability evaluated. Feeding oxidised oil to broilers resulted in meat that underwent rapid oxidative changes during refrigerated and frozen storage. 4. On the other hand, dietary alpha-tocopherol and BHA/BHT supplementation increased alpha-tocopherol and BHA/BHT concentrations in meat and significantly (P less than 0.05) improved the oxidative stability of meat during refrigerated and frozen storage.

The effects of different dietary oils and a-tocopherol on the fatty acid composition of mitochondrial and microsomal lipids of broiler muscle and their lability to NADPH-induced peroxidation were investigated. Fatty acid composition of both neutral lipids and phospholipids of mitochondria and microsomes was influenced by dietary oil composition. Supplementation of the diet with u-tocopherol only appeared to increase the a-tocophcrol concentration in the microsomal membranes in the dark meat. The rate of NADPH-induced lipid peroxidation in microsomes and mitochondria was dependent primarily on the fatty acid composition of the membrane lipids, and, to a lesser extent, on the cu-tocopherol content.