Effect of oral cortisol on growth, survival rate, hematocrit and biochemical blood parameters in Common Carp (Cyprinus carpio) fingerling

Cortisol plays an important role in several aspects of fish physiology including ionic and osmotic regulation, growth, stress and immune function. This study conducted to evaluate the long time effect of oral cortisol on the growth performance, survival, biochemical blood parameters in common carp (cyprinus carpio) fingerling. For this purpose, common carp (1.36 ± 0.12 g) was distributed in 4 treatments in 3 replicates and fed with commercial food containing 0 (control), 50, 100 and 200 mg kg-1 food hydrocortisone during 8 weeks. This results showed that no significantly difference in growth performance (growth rate (GR)), specific growth rate (SGR), feed conversion ratio (FCR), Feed intake (FI), survival and hematocrit between treatments (p>0.05). Serum glucose levels in control treatment (73.04±1.40mg/dl) was significantly lower than other treatments by serological investigation (p<0.05) but no significantly difference in serum calcium Ionic factor between treatments (p>0.05). Serum total protein in fish fed cortisol were significantly lower than the control group (p<0.05). The results of this study showed that oral administration of cortisol can increase blood glucose as an energy source for the mechanisms of osmotic in the common carp fingerling.