Augmentation of the anesthetic potency of clove oil for immersion anesthesia in fishes

Pharmaceutical incompatibility of clove oil due to its immiscibility in water may affect the safety, efficacy, appearance, and stability of the drug during immersion anesthesia. Though there are reports of using ethanol to enhance the anesthetic efficacy of clove oil, there are no reports of quantitative calculations of anesthetic efficacy and stages of anesthesia for this combination. To overcome this issue, a study was designed to enhance the miscibility of clove oil in water by incorporating ethanol as an interphase. Two trials were conducted using clove oil at concentrations of 50 and 100 mg/L, respectively, dissolved in ethanol at a 1:10 ratio. These trials were performed on tilapia fishes ( Oreochromis mossambicus ) to evaluate the time required for anesthesia induction, duration (maintenance time), and recovery from anesthesia. The results of the study showed an induction time of 1 min for the 100 mg/L concentration and 10 min for the 50 mg/L concentration. The duration of action was observed to be 12 min for the 100 mg/L concentration and 31 min for the 50 mg/L concentration, respectively. The recovery times were 10 min and 3 min for the 100 mg/L and 50 mg/L doses, respectively. Changes associated with various stages and planes for surgical anesthesia were also documented in this study. This study concludes that the mixture of clove oil and ethanol serves as a more effective general anesthetic for fish compared to conventional clove oil immersion anesthesia.