Oxidative defenses in the sea bass, Dicentrarchus labrax.

A study on the oxidative defenses during larval growth and under stress conditions was carried out in the bred sea bass, Dicentrarchus labrax. A high-pressure liquid chromatography (HPLC) method was used for the quantitative determination of vitamins C and E; glutathione peroxidase activity was measured by an enzymatic assay. Vitamin E was measured in the seminal fluid, eggs, embryos and larvae. Vitamins C and E, and glutathione peroxidase activity were measured in adults of Dicentrarchus labrax under normal conditions and subjected to hypoxia. Vitamin E content was high in seminal fluid, eggs, and embryos and at the early stage of larval development. It decreased slowly, but steadily, throughout the larval growth. In adults exposed to hypoxia, vitamins C and E levels were significantly lower with respect to the control group. Glutathione peroxidase levels showed a decrease in the hypoxia-subjected group, although the values were not significant.