Fresenius Environmental Bulletin, cilt.20, sa.1, ss.3-11, 2011 (SCI-Expanded)
Seasonal fluctuations in antioxidant (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPx; glutathione reductase, GR; glucose-6-phosphate dehydrogenase, G6PD) and biotransformation enzyme activities (glutathione 5-transferase, GST) and lipid peroxidation (LPO) levels of livers and gills in European catfish (Silurus glanis) and Bulatmai barbel (Barbus capito capito) were determined. Superoxide dismutase, CAT, GPx, GR, G6PD and GST activities were higher in the liver compared to gills for both species. The exception was being in B. capito capito where GR was higher in the gills compared to the than liver during autumn and winter. However, LPO levels were higher in the gills compared to the liver. At the end of present study, it was concluded that antioxidant defense system for both species were affected by many endogenous and exogenous factors. However, it is difficult to determine what is the most critical factor affecting ADS in these species because of complex effects of these factors on the antioxidant defense system. © by psp.