Time course variations of antioxidant enzyme activities and histopathology of gilthead seabream gills exposed to malathion
M. Rosety1, M. Rosety-Rodríguez2, F.J. Ordonez1 and I. Rosety3
1Human Anatomy and Embryology Department, School of Medicine, University of Cádiz, Spain, 2Medicine Departament, School of Medicine, University of Cádiz, Spain and 3School of Veterinary, University of Córdoba, Spain
Offprint requests to: Dr. F.J. Ordonez, Anatomía y Embriología Humana, Facultad de Medicina, UCA, Pza. Fragela s/n, 11003 Cádiz, Spain. e-mail: franciscojavier.ordonez@uca.es
Summary. In a widely distributed and commercially important fish, gilthead seabream Sparus aurata L., we have studied sublethal effects of malathion in order to identify early warning bioindicators of exposure before irreversible damage occurs.
To achieve this goal, groups of 10 juvenile specimens were exposed for 24, 48, 72 and 96h to a sublethal concentration of malathion (0.4 mg/l). Another group was used as control. The activity of antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) and histopathological features from exposed gills were assessed. It should also be mentioned that no mortality was observed during the whole experience.
The activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) were altered significantly from 24 h onward (p<0.05). It is of interest to note that catalase activity was decreased after exposure instead of increasing as other antioxidant enzymes assessed. On the other hand, histopathological alterations of the gills were observed as early as at 48 h-exposure, but the most severe damage occurred at 96 h exposure.
The evidence presented here, together with other data from the literature, unequivocally established oxidative-stress-inducing effects of malathion in gilthead seabream Sparus aurata. It is also concluded antioxidants employed (SOD, CAT and GPX) changed significantly a long time before histopathological alterations of gills became evident. Consequently, these antioxidant enzymes may be highly recommended as early-warning bioindicators of environmental pollution by malathion in the areas where it is proposed to be used in pest control activities. Histol Histopathol 20, 1017-1020 (2005)
Key words: Antioxidant enzymes, Histopathology, Gills, Sparus aurata, Malathion
DOI: 10.14670/HH-20.1017