Investigation of anesthetic efficiency of yarrow (Achillea millefolium) and melisa (Melissa officinalis) essential oils on rainbow trout (Oncorhynchus mykiss)

In the present study anesthetic effect of Yarrow (Achillea millefolium L.) and Melisa (Melissa officinalis L.) essential oils was investigated in rainbow trout (Oncorhynchus mykiss). Fish with a mean weight of 50 g were used in the experiment. Both essential oils were prepared at different concentrations to determine the anesthetic effect. Anesthesia induction and recovery times were evaluated for each fish. Then, the histopathological effects on fish tissues of essential oils at anesthetically effective concentrations were examined. As a result of this study, major components were found as trans-caryophyllene, citral and germacrene for melisa oil and pinene, sabinene, trans-caryophyllene and eucalyptol (1,8-cineole) for yarrow oil. In general, anesthesia induction time of fish decreased with increasing the concentration for both oils. The lowest effective doses of melisa and yarrow for deep anesthesia (Stage 4) in fish were determined as 200 mg L-1 and 400 mg L-1, respectively. At these doses, anesthesia induction and recovery times were 117.67 and 96.33 s for melisa oil, 132.00 and 225.67 s for yarrow oil, respectively. No histopathological findings in gill, skin and liver tissues were observed in anesthetized fish. In light of these findings, it was determined that melisa and yarrow oils can be used as a safely effective natural anesthetic for rainbow trout.