The antioxidative effect of dietary tea catechins (TC) supplementation at levels of 50, 100, 200 and 300 mg kg(-1) feed on susceptibility of chicken breast and thigh meat to lipid oxidation during frozen (-20 degreesC) storage for 9 months was investigated. Day-old chickens (Cobb 500, n = 200) were randomly divided into six groups. Chickens were fed a basal diet containing 20 mg alpha -tocopheryl acetate kg(-1) feed as control, or a vitamin E supplemented diet (basal diet plus 200 mg alpha -tocopheryl acetate kg(-1) feed), or TC supplemented diets (basal diet plus 50, 100, 200 or 300 mg TC kg(-1) feed) for 6 weeks prior to slaughter. Lipid oxidation (TBARS) was assessed after 0 and 10 days of refrigerated display (4 degreesC) following 1, 3, 6, and 9 months of frozen (-20 degreesC) storage. TC supplementation at all concentrations showed antioxidative effects for both breast and thigh chicken meat during the 9 months of frozen storage compared to the control sample. TC supplementation at levels of 200 and 300 mg kg(-1) feed were more effective (P < 0.05) in delaying lipid oxidation in all meat samples compared to the control. TC supplementation at a level of 200 mg kg(-1) feed showed antioxidant activity equivalent to -tocopheryl acetate fed at the same level up to 3 months of frozen storage. For long-term frozen storage up to 9 months, however, TC supplementation at 300 mg kg(-1) feed was required as a replacement for alpha -tocopheryl acetate at a level of 200 mg kg(-1) feed. The results obtained showed a long-term antioxidative effect exhibited by dietary tea catechins on chicken meat during frozen storage and demonstrated that tea catechins are effective alternatives to vitamin E as natural dietary antioxidants. (C) 2000 Elsevier Science Ltd. All rights reserved.