Changes in tissue α-tocopherol status and degree of lipid peroxidation with varying α-tocopheryl acetate inclusion in diets for the African catfish |
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| Authors: | RTM BAKER SJ DAVIES |
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| Institution: | Fish Nutrition Unit, Department of Biological Sciences, University of Plymouth, Plymouth, United Kingdom |
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| Abstract: | Juvenile African catfish, Clarias gariepinus (Burchell), were fed low-tocopherol, practical test-diets containing graded levels of α-tocopheryl acetate (0, 80, 200 and 500 mg kg?1 dry feed) at proportionately 0.02 body weight per day for 70 days. After the feeding period, selected fish tissues were assayed for α-tocopherol and thiobarbituric acid reactive substances (TBARS) concentrations, before and after iron-ascorbate stimulated peroxidation. Results show that tissue accretion of α-tocopherol in muscle, liver and blood plasma increased linearly (R2= 0.83, 0.82 and 0.93, respectively) in response to elevated dietary supplementation of α-tocopheryl acetate within the range of doses under study. In muscle and liver this resulted in a significant decrease (P < 0.05) in basal TBARS and TBARS after stimulated peroxidation, indicating a greater stability against oxidation. Growth indices were not significantly affected (P > 0.05) by dietary α-tocopheryl acetate inclusion. Clarias fed the highest α-tocopheryl acetate dose (500 mg kg?1 dry feed) were observed to have significantly lower (P < 0.05) haematocrit (% packed cell volume) than fish fed the basal diet (0 mg kg?1 dry feed). It was concluded that supplemental α-tocopheryl acetate in practical diets, for Clarias gariepinus, was effective in reducing the degree of tissue-lipid peroxidation under conditions of increased oxidative stress. Thus, the post mortem resistance to oxidation achieved would improve the stability of catfish products destined for human consumption. |
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| Keywords: | α-tocopherol catfish Clarias gariepinus lipid peroxidation TBARS vitamin E |
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