Effects of olive leaf extract (<i>Olea europaea Leecino</i>) on growth, haematological parameters, immune system and carcass composition in common carp (<i>Cyprinus carpio</i>)
Razieh Sokooti, Mojdeh Chelemal Dezfoulnejad, Mehran Javaheri Baboli
Abstract
In this study, the effects of olive leaf extract on growth, haematological parameters, immune system and carcass composition in common carp were examined. In this research, 180 common carp (32.26 ± 1.01 g) were randomly distributed to nine fibreglass tanks. The fish were fed a diet with 200 mg/kg olive leaf extract (group 1), 400 mg/kg olive leaf extract (group 2), and basal food (control group) for 75 days. At the end of the experiment, WG, SGR and PER values were significantly higher in the groups fed the diet containing 200 mg/kg of olive leaf extract compared with the control group. Furthermore, FCR and FER values were improved in the groups fed by diets with various levels of olive leaf extract than the control group. The contents of WBCs, lysozyme and NBT activity were significantly increased in the groups fed diets containing olive leaf extract. Cholesterol content was significantly lower in the group fed diet containing olive leaf extract compared with the control group. Also, serum triglyceride and carcass lipid contents were significantly lower in the group fed diet containing 200 mg/kg of olive leaf extract compared with the control group. Total protein, albumin, globulin and calcium contents were significantly higher in the group fed the diet containing 200 mg/kg of olive leaf extract compared with the control group. Our results demonstrated that diet containing 200 mg/kg olive leaf extract were efficient feed additives and has the potential for use in improving the growth performance and health status for this species.