EFFECTS OF DIFFERENT LEVELS OF DIETARY CENTAURY OIL (Hypericum Perforatum) ON GROWTH PERFORMANCE, SOME ENVIRONMENTAL STRESS PARAMETERS AND ANTIOXIDANT ACTIVITY IN RAINBOW TROUT (Oncorhyncus Mykiss)

This experiment was conducted to evaluate the effect ofdietary centaury oil (Hypericumperforatum) on growth performance, some environmental stress parameters andantioxidant activity in juvenile rainbow trout (Oncorhynchus mykiss). The Experiment, conducted in 500 litrerectangle fiberglass tanks for 90 days, was performed in replicate groups andall tanks were stocked with 35 juveniles (initial mean weight 20g).Experimental feeds were formed as K0 (control group without centaury oilinclusion), KT1 (1 mL/kg), KT2 (2 mL/kg) and KT3 (3 mL/kg) centaury oilsupplements. At the end of the trial parameters were obtained as; weight gain88,86-90,97 (gr), specific growth rate 1,85-1,86 (% day-1), feed conversion rate 1,02-1,07, survival rate97-100%, feed conversion efficiency 98,89-100,05, contidion factor 1,23-1,24,total antioxidant status 1,96-2,07(µmol Trolox equivalents/L), total oxidantstatus 1,10-1,70(µmol H2O2 equivalent/L), oxidative stressindex 56,15-81,44, glucose status 73,00-76,66, cortisol status 0,78-1,13,lysozyme zone diameter 0,90-1,08 (cm). Feed groups showed statisticaldifference in terms of total oxidant status and oxydative stress indexparameters (p<0.05). As result no differences were obtained for growthperformance and stress parameters (p>0.05) but possitive effects uponoxydant status and oxydative stress index were observed.