The effects of dietary carotenoid on oxidative damage in the gonads of sea urchin Loxechinus albus

MALANGA G F, PÉREZ A F, CALVO J, PUNTARULO S

Montevideo, Uruguay

Conferencia; Free Radicals, V Meeting of SFRBM, V International Conference on Peroxynitrite and RNS; 2007

Changes in the production of reactive oxygen species on aquatic organisms had been related to environmental or physiological variations. Carotenoids are often found among sea invertebrates protecting their lipid constituents against oxidation.and influencing on their coloration. Loxechinus albus, is a edible sea urchin inhabiting the Beagle Channel. In this study, dietary carotenoids were fed to L. albus as prepared diets to test their effects on the sea urchin´s gonads oxidative metabolism. The animals were fed with one of the following diets: (A) enriched with all-trans â-carotene 0.02%; (B) enriched with all-trans â-carotene 0.045%, or (C) control diet (macroalgae) for 16 weeks. The artificial diets had the same basic content of protein, lipid, carbohydrate, ash and energy. Total carotenoid concentration in the gonad were measured spectrophotometrically. The content of lipid antioxidant (a-tocopherol and b-carotene) was quantified by reverse-phase HPLC. At the end of the tested period (16 weeks) the gonads did not showed any differences in either total carotenoid concentration or b-carotene content from animals feed with diet A, B or C. However, both parameters showed two fold increase in the gonads isolated from animals feed with diet B as compared to either animals control or animals feed diet A, after the initial 8 weeks of treatment. Over the feeding period (16 weeks) the a-tocopherol content increased in gonads from an value of 0.22±0.05 nmol/mgFW in animals control to 0.95±0.33 and 1.1±0.5 nmol/mgFW for diet A and B, respectively. The content of TBARS, as an index of lipid peroxidation, showed an initial value of 19±2 nmol/mgFW, and was decreased after 16 weeks of treatment to 7.6±0.9, 15 ±4 and 17±2 nmol/mgFW for the animals feed with diet A, B and C, respectively). Overall, the results presented here suggest that the exogenous supplementation with all-trans â-carotene 0.045% over an 8 weeks period afforded the maximum level of protection against lipid peroxidation since endogenous cellular protection mechanisms could be triggered under those conditions, and further increases in either antioxidant content or time of supplementation did not lead to increase in protection