Abstract:
Studies in field of toxic effects of nanoparticles on fish are not yet sufficient and seem to be very limited in comparison with more conventional pollutants such as heavy metals and pesticides. Hence, following exposures of 1.0 and 5.0 mg/L titanium dioxide nanoparticles (TiO2-NPs) for 4 and 14 days antioxidant enzymes responses in gill chosen as the target tissue of Oreochromis niloticus were investigated. TiO2-NPs did not induce mortality in fish during exposure period. However, the present investigation provides important evidence on induced responses in O. niloticus after TiO2-NPs exposures. Generally acute exposure of TiO2-NPs caused decreases in activities of superoxide dismutase (27%), catalase (60%), and glutathione peroxidase (37%), while its exposure for 14 days increased the catalase (61%), glutathione peroxidase (32%), glutathione-S-transferase (54%), and glutathione reductase (93%) activities. The findings of this investigation allow us to conclude that the gill of fish can be used as a good target tissue to reflect the toxic effects of TiO2-NPs and these particles can potentially cause oxidative stress which that may lead to disturbance in the antioxidant enzymes systems by either stimulating or inhibiting their activities. Also our work indicated that the antioxidant enzymes of the fish can be used as biomarkers for monitoring nanoparticle toxicity.
