Cagin Cilingir, Ibrahim Diler, Ilter Ilhan, Fatih Gultekin
This experiment was conducted to evaluate the effect of dietary centaury oil (Hypericum perforatum) on growth performance, some environmental stress parameters and antioxidant activity in juvenile rainbow trout (On-corhynchus mykiss). The Experiment, conducted in 500 litre rectangle fi-berglass tanks for 90 days, was performed in replicate groups and all tanks were stocked with 35 juveniles (initial mean weight 20g). Experimental feeds were formed as K0 (control group without centaury oil inclusion), KT1 (1 mL/kg), KT2 (2 mL/kg) and KT3 (3 mL/kg) centaury oil supple-ments. At the end of the trial parameters were obtained as; weight gain 88,86-90,97 (gr), specific growth rate 1,85-1,86 (% day-1), feed conver-sion rate 1,02-1,07, survival rate 97-100%, 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 oxidant status 1,10-1,70(μmol H2O2 equivalent/L), oxidative stress index 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 statistical difference in terms of total oxidant status and oxydative stress index parameters (p<0.05). As result no diffe-rences were obtained for growth performance and stress parameters (p>0.05) but possitive effects upon oxydant status and oxydative stress index were observed.