Researching of antioxidant enzyme activities in rainbow trouts exposed to some of the heavy metals and selenium compounds

ABSTRACTMaster ThesisRESEARCHING OF ANTIOXIDANT ENZYME ACTIVITIES IN RAINBOWTROUTS EXPOSED TO SOME OF THE HEAVY METALS AND SELENIUMCOMPOUNDSAysel ALKANInonu UniversityGraduate School of Natural and Applied SciencesDepartment of Biology55 + ix pages2005Supervisor: Asst. Prof. Dr. İbrahim ÖRÜNIn this study, the effects of cadmium, chromium and selenium on some of thebiochemical markers in the liver and gill tissues of rainbow trout (Oncorhynchus mykissWalbaum, 1792) were investigated to determine antioxidative role of selenium in fish.The activities of Se-dependent Glutathione peroxidase (Se-GSHPx), Superoxidedismutase (SOD), Catalase (CAT) and the changes in levels of malondialdehyde (MDA)were analysed in liver and gill tissues of rainbow trouts exposed to Cd (2 ppm), Cr (2ppm), Se (2 ppm), Cd+Se (2 ppm Cd + 2 ppm Se) and Cr+Se (2 ppm Cr + 2 ppm Se) for aweek.As a result of this study, it was observed that there were statistically significantdecreases in enzyme activities of the groups exposed to Cd, Cr, Cd+Se and Cr+Secompared to control (p<0.05). In addition, it was observed that there were statisticallysignificant increases in MDA levels of the groups exposed to Cd, Cr, Cd+Se and Cr+Secompared to control (p<0.05). The selenium exposure did not cause to changessignificantly in enzyme activities and MDA levels.These results suggest that the negative effects occured on the biochemical markers ofthe groups exposed to heavy metals can be eliminated as a result of seleniumsupplementation.KEY WORDS: Cadmium (Cd), Chromium (Cr), Selenium (Se), Oxidative stress,Antioxidant defence