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Abstract

2Lipid peroxidation, specifically polyunsaturated fatty acid (PUFA) oxidation is highly deleterious, resulting in damage to cellular biomembranes, and may be a principal cause of several diseases in fish including jaundice and nutritional muscular dystrophy. Tissue lipid PUFA content and composition are critical factors in lipid peroxidation, as is the level of endogenous antioxidant molecules such as vitamin E. The primary objective of the present study was the characterization of antioxidant systems in a cultured juvenile marine fish, gilthead sea bream (Sparus aurata) with the underlying aim to understand how to avoid oxidation problems that may cause pathologies and disease and so to enhance growth and quality of early ongrowing stages. Juvenile sea bream were fed diets having either high or low levels of fish oil and supplemented or basal levels of vitamin E with PUFA/vitamin E ratios ranging from 117 ± 12 in the diet with low PUFA supplemented with vitamin E to 745 ± 48 in the diet with high PUFA with no additional vitamin E. None of the diets had serious deliterious effects on growth or survival of the fish, but the different dietary regimes were effective in significantly altering the PUFA/vitamin E ratios in the fish livers with values ranging from 5.7 ± 0.4 in fish fed the diet with low PUFA supplemented with vitamin E to 91.1 ± 13.2 in fish fed the diet with high PUFA with no additional vitamin E. This had effects on the peroxidation status of the fish as indicated by the significantly altered levels of in vivo lipid peroxidation products measured in liver, with fish fed the diet rich in PUFA and low in vitamin E showing significantly higher values of thiobarbituric acid reactive substances (TBARS) and isoprostanes. The isoprostane levels generally followed the same pattern as the TBARS levels supporting its value as an indicator of in vivo oxidative stress in fish, as it is in mammals.However, few significant effects on antioxidant enzyme activities were observed suggesting that more severe conditions may be required to affect these activities such as increasing the PUFA/vitamin E ratio or by increasing peroxidative stress through the feeding of oxidized oils.

Efectos de la administración de melatonina en el daño oxidativo y los patrones diarios de actividad motora del carpín

“…In muscle, melatonin significantly lowered values, coinciding with the effect observed in other antioxidants in fish like vitamin E (16). In contrast, in liver (Fig.…”

Effects of dietary vitamin E on growth performance, antioxidant capacity and lipid metabolism of juvenile golden pompano Trachinotus ovatus

“…However, no significant differences were observed between the raw and cooked muscle, when VE levels increased from 61.16 to 144.88 mg/kg. The results might be attributed to that VE could protect biological membranes containing PUFA against free radicals formation and effectively minimize lipid peroxidation, thus increasing PUFA content and stability in fish (Mourente et al, 2000;Tocher et al, 2003). In general, dietary supplementation of more…”

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“…Vitamin E (α-Tocopherol) is an important micronutrient that affects the reproduction performance of farmed fishes. Increasing vitamin E in the diet increases spawning and fertilization success, egg diameter, egg survival hatchability and larval survival (Mourente et al, 2000;Gammanpila et al, 2007).…”