Seasonal and ontogenetic changes modulate oxygen consumption and antioxidant defenses in the cutlassfish Trichiurus...

Several oxidative stress markers and liver oxygen consumption were measured in different tissues of the marine fish Trichiurus lepturus in late summer and late winter, as well as in juveniles and adult females. Oxygen consumption in liver, superoxide dismutase (SOD) and catalase (CAT) activity in liver, red cells, lens and roe, vitamin E, ubiquinol₁₀, β-carotene in liver, red cells, and roe, as well as contents of reduced glutathione (GSH) and lipoperoxidation (TBARS) in red cells were evaluated. Regarding ontogeny, compared to adult fish, juveniles showed significant higher SOD activity in liver and lens, as well as higher liver contents of vitamin E. In contrast, adult females showed higher contents of vitamin E in roe, ubiquinol₁₀ in liver and roe, and higher GSH levels in red cells, while the other markers remained unchanged. Regarding seasonal changes, no differences were detected in adult females for liver CAT and ubiquinol₁₀, CAT in roe, vitamin E in roe and in red cells, liver and red cell ubiquinol₁₀, and in GSH in red cells. However, and coinciding with the spawning period of late summer, liver oxygen consumption, SOD and CAT activity and ubiquinol₁₀ contents in roe and SOD activity in red cells, and red cell TBARS contents were higher compared to late winter. These temporal antioxidant adjustments of Trichiurus lepturus seem to be parallel to the higher oxygen consumption typical of juvenile forms and also to the intense spawning and foraging activities of adult females in late summer.