| Summary: | 碩士 === 國立嘉義大學 === 食品科學系碩士班 === 91 === Abstract
The purpose of this study was to investigate the effects of dietary vitamin E supplementation on growth and tissue lipid peroxidation of hybrid tilapia.
In Experiment I, the effects of vitamin E supplementation and oxidized oil addition in the diet on the fish growth and tissue lipid peroxidation were studied. Oxidized oil (fish oil：corn oil = 1:1, POV=100meq/kg, AV=1.09mg KOH/g) at the level of 12% was added into the fish diet. In addition, vitamin E was supplemented at the levels of 0, 40，80, 120, 200 and 300 IU vitamin E/kg. After a 14 weeks of feeding period, the calculated maximal growth of hybrid tilapia was found at the level of 66 IU/kg of the vitamin E supplementation with the broken-line regression analysis. Iron-catalyzed ascorbate-dependent lipid peroxidation in muscle and the liver of hybrid tilapia fed diet containing no supplemented vitamin E was significantly higher than that of fish fed diet with vitamin E supplementation (P＜0.05). Liver glutathione (GSH) level increased as the vitamin E content in the diet increased.
In Experiment II, lipid peroxidatiom in muscle and sarcoplasmic reticulum (SR) of hybrid tilapia fed diets containing 0, 100, 200, and 300 IU vitamin E/kg for 8 months was analyzed. Iron-catalyzed NADH- dependent lipid peroxidation in SR of tilapia fed diet without vitamin E supplementation was significantly higher than that of fish fed diets with vitamin E supplementation (P＜0.05). No difference was observed in SR lipid peroxidation between fish fed diet containing 200 and 300 IU vitamin E/kg. Fish muscle was stored at 4℃for 7days or at -40℃for 8 weeks and the thiobarbituric acid reactive substances (TBARS) in fish muscle were analyzed during the storage. The results showed that the TBARS contents decreased as the vitamin E levels in the diets increased. Furthermore, the lag period of oxidation was longer for muscle obtained from fish fed diet containing higher amounts of vitamin E (≧200 IU/kg).
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