RESUMO
This study examined the effects of dietary alpha-tocopheryl acetate supplementation on antioxidant enzyme activities and fillet quality in commercial-size Sparus macrocephalus. Three hundred fish [main initial weight (350+/-12) g] were divided into three groups (E250, E500 and E1000) and reared in 9 cages. The fish were fed for 8 weeks with three diets containing different levels of dietary alpha-tocopheryl acetate (289, 553, 1 069 mg/kg). Over the experimental period, fish were fed to satiation and reached a final mean weight of (465+/-28) g without significant body weight difference and proximate composition difference. Fillet alpha-tocopherol was significantly (P<0.05) different between groups, reaching levels of 14.2, 22.1, 30.9 microg/mg fillet for groups E250, E500 and E1000, respectively. Total serum superoxide dismutase (SOD) activity increased significantly (P<0.05) in fish fed the diets high in alpha-tocopheryl acetate, but serum glutathione peroxidase (GPX) activity was unaffected. In storage on ice, fillets of fish fed the diets high in alpha-tocopheryl acetate exhibited significantly lower (P<0.05) levels of oxidation. These results suggested that increased dietary alpha-tocopheryl acetate could increase its flesh deposition, increase the activity of SOD and prevent lipid peroxidation of Sparus macrocephalus fillets in retail storage on ice.
Assuntos
Animais , Matadouros , Administração Oral , Suplementos Nutricionais , Ativação Enzimática , Análise de Alimentos , Carne , Classificação , Oxirredutases , Metabolismo , Tocoferóis , alfa-TocoferolRESUMO
The study was conducted to investigate fasting effects on flesh composition and antioxidant defenses of market-size Sparus macrocephalus. Two hundred fish (main initial weight 580 g) were divided into two groups (control and fasted) and reared in 6 cages. After two weeks of adaptation, group I fasted for 28 d; group II was fed normally as a control. In 3, 7, 14, 21 and 28 d, 6 fish per group were sampled for proximate flesh composition, liver antioxidant enzyme activities and malondialdehyde flesh content analyses. In fasted fish, the reduction of lipid content in muscle occurred after day 3, and, compared to controls, the content of protein decreased from day 14, the activities of liver antioxidative enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPX) increased from day 3, and flesh malondialdehyde levels increased from day 21. Flesh fat reduction shows that fasting may be used as a technique to reduce flesh lipid content in Sparus macrocephalus. However, considering flesh protein loss and the subsequent oxidative stress, the fasting technique should be used with precautions.