| Abstrakt: |
AbstractThe purpose of the present study was to evaluate and assess the capability of Zataria multiflora, Geranium herbarium, and Eucalyptus camaldolensisessential oils in treating Saprolegnia parasitica–infected rainbow (Oncorhynchus mykiss) trout eggs. A total of 150 infected eggs were collected and plated on glucose-pepton agar at 24°C for 2 weeks. The antifungal assay of essential oils against S. parasiticawas determined by a macrodilution broth technique. The eggs were treated with essential oils at concentrations of 1, 5, 10, 25, 50, and 100 ppm daily with three repetitions until the eyed eggs stage. Of 150 eggs examined, S. parasitica(54.3%), Saprolegniaspp. (45%), and Fusarium solani(0.7%) were isolated. The minimum inhibitory concentrations of Z. multiflora, E. camaldolensis, and G. herbariumessential oils against S. parasiticawere 0.9, 2.3, and 4.8 ppm, respectively. Zataria multifloraand E. camaldolensisat concentrations of 25, 50, and 100 ppm, and G. herbariumat concentration of 100 ppm had significant differences in comparison with negative control (p<0.05). The results revealed that malachite green, followed by Z. multiflora, E. camaldolensis, and G. herbariumtreated eggs had remained the most number of final eyed eggs after treatment. The highest final larvae rates belonged to malachite green, E. camaldolensis, Z. multiflora,and G. herbarium, respectively. The most hatching rates were recorded with malachite green (22%), and then Z. multiflora(11%), E. camaldolensis(7%), G. herbarium(3%), and negative control (1%). Zataria multifloraand E. camaldolensiswere more effective than G. herbariumfor the treatment of S. parasitica-infected rainbow trout eggs in aquaculture environment. |
