Search

Metals are ubiquitous in the environment and accumulate in aquatic organisms and are known for their ability to enhance the production of reactive oxygen species (ROS). In aquatic species, oxidative stress mechanisms have been studied by measuring antioxidant enzyme activities and oxidative damages in tissues. The aim of this study was to apply and validate a set of oxidative stress biomarkers and correlate responses with metal contents in tissues of common octopus (Octopus vulgaris). Antioxidant enzyme activity (catalase--CAT, superoxide dismutase--SOD and glutathione S-transferases--GST), oxidative damages (lipid peroxidation--LPO and protein carbonyl content--PCO) and metal content (Cu, Zn, Pb, Cd and As) in the digestive gland and arm of octopus, collected in the NW Portuguese coast in different periods, were assessed after capture and after 14 days in captivity. CAT and SOD activities were highly responsive to fluctuations in metal concentrations and able to reduce oxidative damage, LPO and PCO in the digestive gland. CAT activity was also positively correlated with SOD and GST activities, which emphasizes that the three enzymes respond in a coordinated way to metal induced oxidative stress. Our results validate the use of oxidative stress biomarkers to assess metal pollution effects in this ecological and commercial relevant species. Moreover, octopus seems to have the ability to control oxidative damage by triggering an antioxidant enzyme coordinated response in the digestive gland., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Metals are environmentally ubiquitous and can be found at high concentrations in seawater and subsequently in marine organisms. Metals with high redox potential can trigger oxidative stress mechanisms with damaging effects in biological tissues. In aquatic species, oxidative stress has been evaluated by assessing antioxidant enzymes activities and oxidative damages in tissues. The purpose of this study was to evaluate oxidative stress biomarkers and metal residues in white seabream (Diplodus sargus), a species entering aquaculture production in Portugal. Metal residues (Cu, Cd, As and Pb), in liver and muscle, as well as oxidative stress biomarkers were assessed at different stages in the life cycle of white seabream under culture conditions and in wild specimens, of a marketable size. Metal concentrations in tissues were low, and below the established limits. However, wild white seabream showed higher accumulation than cultured ones. Antioxidant enzymes, namely catalase (CAT) and superoxide dismutase (SOD), were correlated with metal accumulation. Oxidative damages to tissues were low, with wild white seabream showing lower levels than cultured fish. This study showed that white seabream has a good antioxidant defense system, capable of reducing oxidative damages in tissues resulting from the presence of metals.

This study aimed to investigate the relationships between levels of organochlorine compounds (PCBs and DDTs), polycyclic aromatic hydrocarbons (PAHs), metals and biomarkers of exposure (EROD and GST) and oxidative stress biomarkers, in wild and cultured European seabass (Dicentrarchus labrax). Additionally, the fatty acid profile was determined in muscle to assess differences between cultivated and wild specimens of marketable size. Although results pointed to relatively low concentration of contaminants, wild specimens presented enhanced accumulation of metals and cultivated specimens higher levels of organic compounds. Biomarkers were correlated with contaminants in tissues, showing that higher levels can cause effects at the biochemical level. Wild specimens have presented higher content on omega-3 fatty acids in muscle. Besides the useful application of biomarkers in wild species, this study has shown that they can also be applied to monitor biological effects in the fish farming process. [Copyright &y& Elsevier]