Reproductive status, antioxidant defences and lipid peroxidation in Octopus tehuelchus (Cephalopoda: Octopodidae) females

Abstract

As in other semelparous cephalopods, Octopus tehuelchus females enter a senescent state after spawning. In several taxa, damage to macromolecules that result from an imbalance between antioxidant defences and the production of reactive oxygen species (i.e. oxidative stress) has been postulated as one of the physiological costs of reproduction and one factor that contributes to ageing. In this work, we evaluate whether enzymatic and non-enzymatic antioxidant defences are conditioned by reproductive status in O. tehuelchus obtained from a wild population. The main antioxidant defences, catalase (CAT), superoxide dismutase (SOD), reduced gluthation (GSH) and lipid peroxidation (TBARS), were assessed in somatic and reproductive tissues from octopus females, at immature, mature and spent stages. Oviducal glands showed an increase in TBARS that coincides with a decrease in GSH when females reach a spent stage. No significant changes were observed in the assayed parameters on the ovary wall, digestive gland, mantle and gills along maturity stages. CAT activity was undetectable in most analysed tissues, SOD activity and GSH were similar to or lower than in other cephalopods, while average TBARS levels in somatic tissues were at least one order of magnitude higher than levels found in other molluscs. Our results show that during sexual maturation and after natural oxidative stress conditions (spawning), only oviducal glands show changes that can be linked with the physiological processes of different reproductive status. The low antioxidant defences and the flat protective reactions after spawning could be associated with the semelparous life history of this species.