TURKISH JOURNAL OF FISHERIES AND AQUATIC SCIENCES, vol.21, no.8, pp.415-424, 2021 (SCI-Expanded)
Salinity increase in freshwaters affects the physiology and metal uptake in fish, though there is no enough evidence on the influence of salinity on metal-oxide nanoparticle (NPs) toxicity. Therefore, the effects of salinity and NPs (Al2O3, TiO2) were tested in acute (2 days and 10 mg NPs/L) and chronic (20 days and 1 mg NP/L) exposures at different salinities (0 and 10 ppt). Following the exposures, the activities of CAT (catalase), SOD (superoxide dismutase), GPX (glutathione peroxidase), GR (glutathione reductase) and GST (glutathione S-transferase) were determined in the liver of O. niloticus. Data showed that CAT and SOD activities did not change significantly (P>0.05) in acute exposures, though their activities significantly (P<0.05) decreased in chronic exposures at both salinities. Similarly, GPX and GR activities did not respond to acute NP exposures, but their activities decreased significantly in chronic exposures. However, GST showed the opposite response in acute and chronic exposures following NP and salinity exposures. Data showed that chronic exposures were more effective than acute exposures in regard to the response of the enzymes. Data also revealed that salinity did not have a predominant effect on the antioxidant enzymes, and also did not influence NPs toxicity.