Effects of gamma-irradiated ethanolic extract of Iranian propolis on growth performance, immunological and haematological parameters in juvenile common carp (Cyprinus carpio L.)

This study evaluated the oral administration of gamma-irradiated ethanolic extract of Iranian propolis on juvenile common carp. Fish were assigned into five groups and fed on the basal diet (control group) and an enriched diet containing 0.5 g kg-1 of GI-EEP supplements for 45 days. Growth performance, haematological indices, and immunological parameters were measured. The results showed that oral administration of GI-EEP (0, 10, and 30 kGy) significantly improved the growth performance. However, GI-EEP dietary supplements had no significant effects on the survival rate, haematological indices, catalase activity and total mucosal immunoglobulins of fish. A significant increase in lysozyme activities and total immunoglobulins was observed in fish fed on GI-EEP. The results suggested that feeding fish with 50 kGy of GI-EEP decreased certain growth performance indices and immunological parameters. The highest superoxide dismutase activity was observed in the fish fed on 30 kGy of GI-EEP, while the SOD activity significantly decreased in fish fed on 50 kGy of GI-EEP. The overall results of this study showed the use of GI-EEP at 10 and 30 kGy in the diet could improve growth indices and increase the efficiency of the innate immune and cellular antioxidant capacity. In contrast, the biological impact of EEP treated at 50 KGy gamma rays may be significantly reduced due to changes in its quality.