Nutritional composition and antioxidant activity of vobla roach (Rutilus rutilus caspicus) muscle tissue exposed to heavy metals

The present study was carried out to study the toxic effects of different sublethal concentrations of cadmium chloride and lead salts [CdCl2 and Pb(NO3)2] on lipid, carbohydrate, protein contents and antioxidant enzymes of vobla-roach (Rutilus rutilus caspicus), a common Caspian fish species, in laboratory bioassays. R. rutilus caspicus was exposed to various sublethal concentrations of CdCl2 and Pb(NO3)2, i.e. 0.75, 1.5 and 2.25 mg L-1 for 24, 48, 72 and 96 hr. Then, the fishes were sacrificed and muscle was collected for the determination of carbohydrates, lipids, proteins, lipid peroxidation (LPO), catalase (CAT) and superoxide dismutase (SOD) activities. The results showed that the maximum decrease in lipid, carbohydrate and protein contents were observed 96 hr after treatment with 2.25 mg L-1 of Pb(NO3)2 (55.76%, 46.25% and 48.81%, respectively). Furthermore, antioxidant enzyme activities increased when fishes were exposed to cadmium and lead. The maximum increase in the lipid peroxidation and superoxide dismutase was recorded at 96 hr after treatment with 2.25 mg L-1 of Pb(NO3)2 (184.47 % and 110.52 %, respectively). According to the results, catalase activity decreased with increasing concentration of heavy metals and exposure duration. The maximum decrease in catalase activity was observed 96 hr after treatment with 2.25 mg L-1 of Pb(NO3)2 (81.21 %). In general, both heavy metals were highly toxic in muscle of R. rutilus caspicus, with lead showing higher toxicity then cadmium in terms of nutritional parameters and antioxidant enzyme activity.