Bioaccumulation of waterborne cadmium and its effect on carcass quality of Sterlet (Acipenser ruthenus)

    The sublethal effects of water - born cadmium (Cd) on carcass quality (moisture, protein, fat and ash contents) and its accumulation in different tissues including gill, kidney, liver and muscle were analyzed. For this purpose, 60 juvenile Sterlet, Acipenser ruthenus, (39.98 ± 0.45 g weight and 22.45 ± 0.65 cm length) were randomly distributed in 4 experimental groups, each containing 3 replicates, with five fish per replicate. The fish were exposed to different concentrations of Cd for 21 days under semi-static experimental condition as follows: 0, 16, 32 and 64 µg/L Cd. At the end of the experiment, the carcass quality (without head and inside body cavity) and Cd accumulation using wet method were determined in different tissues including gills, liver, muscle and kidney in 3 fish from each replicate. The results showed that  moisture, protein, fat and ash contents were in the range of 78-81, 12.6-14, 3.5-4.5 and 12.6-14% respectively without any significant differences among groups (P>0.05). By increasing in Cd concentration of the water, the accumulation in all tested tissues (muscle as an exception) was elevated significantly (P<0.05). In all treated groups, the highest accumulation was measured in the kidney, followed by the gills. However, there were no significant differences in Cd accumulation in gills, kidney and liver in any treated group (P>0.05). The only elevation was observed in Cd accumulation in the gill in comparison between the control and fish exposed to 16 µg/l Cd (P<0.05). Based on the results, it could be concluded that although sublethal Cd exposure for 21 day did not affect the carcass quality in juvenile Sterlet, it couldbe accumulated in different tissues (muscle as an exception) in a dose response manner.