Introduction: Common carp is one of the economically important species of the carp family, and densely breeding this species in breeding ponds is associated with a challenge called stress, which can lead to the occurrence of various viral, bacterial, fungal, and parasitic diseases. One of the parasites that spread in dense culture conditions with stress and changes in water hydrochemistry is the protozoan Ichthyophthirius multifiliis. This parasite attaches to the skin, fins, and gills of carp fish, causing irritation and anxiety, and causing lesions along with secondary infections, leading to fish mortality. Oleuropein, which is the most abundant phenolic compound in olive leaf extract, has good antimicrobial effects against bacteria, viruses, and parasites, in addition to its antimicrobial and antioxidant properties, olive leaf extract has anti-inflammatory properties that are useful in healing damage caused by microorganisms. The aim of this study was to investigate the various properties and effects of this extract and its effect on the parasites Ichthyophthirius multifiliis in laboratory conditions on carp (Cyprinus carpio) so that we can use this drug, if it is effective, in the control, prevention, and treatment of this parasite in fish farms.
Materials & Methods: Fifty carp infected with the external parasite Ichthyophthirius multifiliis weighing 45-60 g were placed in two control and treated aquariums with a volume of 1×1×2 cubic meters of water with temperature conditions of 25-28°C and pH 7.2, equally with appropriate aeration and nutritional conditions. The treated fish were anesthetized using clove extract and their level of infection was checked before the experiment.
Results: The experiment showed that with increasing concentration of olive leaf essential oil and time, the rate of trophont mortality increased, and this difference was significant (P<0.5). The experiment also showed that concentrations of 0.5, 1, and 1.5 ml of olive leaf essential oil had good effects on the mortality rate of parasite larvae. When parasite larvae were exposed to a concentration of 0.5 ml for 60 minutes, almost 100% of them were killed, and the difference was significant (P<0.5).
Conclusion: The results of this study showed that olive leaf essential oil has very favorable and good effects in eliminating parasites on the external surfaces of the carp body. |
