Investigation of antioxidant enzyme activities in rainbow trout (Oncorhynchus mykiss) juveniles fed diets supplemented with dandelion (Taraxacum officinalis) and lichen (Usnea barbata)

In this study, antioxidant effects of dandelion (Taraxacum officinalis) and lichen (Usnea barbata) in rainbow trout were investigated. With this aim, four different concentration of aqueous methanolic extract of plants (0 % (Control), % 0.1, %0.5 and % 1) were prepared and added to the feed. Fish were fed with the diet for 75 days. The tissue samples (liver and white muscle) were taken from each experimental groups at every 15th, 45th and 75th day of the study. From all samples, to determine antioxidant activity, SOD, CAT, GPX, G6PDH and lipid peroxidation were investigated. At the end of the study, growth performance was also determined. In the study, SOD activity was increased in group % 0.1 K on 15 and 45th day of the study compared to control. However, all lichen groups SOD activity were decreased compared to control in all sampling time except 15th day fo the study in % 0.1 U group. CAT showed no activity compared to control (P>0.05) in all experimental group's except % 0.1 K on 75th day. GPX activity showed no differences on 15th day of the study compared to control. There was an increasing activity in group % 1 K and % 1 U, and decreasing activity in group %0.1 U and % 0.5 U compared to control (P<0.05). G6PDH was increased in all dandelion groups and lichen groups compared to control on 15th day of the study. All the other sampling time, G6PDH was significantly decreased compared to control except 75th day of the study in % 0.5 K group. Lipid peroxidation was significantly decreased in all dandelion groups compared to control. However, in lichen groups it was found that a significant increasing. No significant differences were determined amongs groups in terms of growth performance. According to the study results, dandelion showed an antioxidant character even though lichen showed no antioxidative activity