Felix Hidalgo

Sea urchins are invertebrates that play a crucial role in marine ecosystems by controlling benthic algal communities and whose natural populations are being affected by different biotic and abiotic factors. Triggering physiological processes promotes the activation of certain metabolic pathways, so oxidative status markers could be a suitable tool to asses maturation stage in which natural populations are. Antioxidant status of three species of Mediterranean Sea urchins, A. lixula, P. lividus and S. granularis, was evaluated in gonadal and digestive tissue. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione s-transferase (GST), glucose 6-phosphate dehydrogenase (G6PDH), NAD(P)H: quinone oxidoreductase (NQO1) and lipid peroxidation were assayed. Significant differences were found among species, displaying in general higher antioxidant activity in A. lixula and S. granularis compared to P. lividus. A significant effect of sex was observed with females exhibiting a higher gonadosomatic index and higher levels of lipid peroxidation mainly in A. lixula. These results seem to be related to metabolic fluctuations associated with the gonadal maturation stage. Changes in digestive tissue were less evident, but some differences among species could be related to triggered digestive processes for replenishment of energy reserves in gonads. Oxidative status can be a useful complementary tool to evaluate gonadal condition in species of sea urchin from the same habitat. Integrative physiological and biochemical studies will contribute to the knowledge of invertebrate physiology.