St. Stoyanova*, I. Sirakov, K. Velichkova, Y. Staykov
Department of Biology and Aquaculture, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria (Manuscript received 15 October 2015; accepted for publication 19 February 2016)
Abstract. Water pollution from industrial production and developing agriculture is a serious problem in aquaculture. The aim of this study was to determine the content of heavy metals Zn (zink), Pb(lead), Ni (nickel) and Cd (cadmium) in the muscles of common carp (Cyprinus carpio L.) and rainbow trout (Oncorhynchus mykiss W.), grown under different technologies. In the current study were investigated common carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss), cultivated in net cages, earthen ponds and raceways. The concentration of heavy metals in the muscles of fish was determined by the methods of AAS in the Scientific laboratory of the Faculty of Agriculture. The influence of different production technologies on the bioaccumulation of Zn, Pb, Ni and Cd (in the flesh of common carp and rainbow trout) was found. The Ni content in muscles was 31.25% higher in common carp, cultured at earthen ponds, compared with its content in the flesh of the fish raised in net cages. The concentration of Pd and Ni in rainbow trout, raised in raceways was higher than that determinated for rainbow trout cultivated in net cages, by 25.0% and 7.14%, respectively. The concentration of Cd and Zn of these species, grown in raceways were lower by 33.33% and 2.14%, respectively, compared with their concentration in rainbow trout, cultivated in net cages.