Sedative Efficacy of Tobacco Extract, Clove Oil, Tricaine Methanesulfonate, and Ketamine: Effects on Hematological Parameters and Blood Biochemical Profile in Sterlet

Abstract

This study was carried out to evaluate the efficacy of four sedatives, including tobacco extract, clove oil, tricaine methanesulfonate (MS‐222), and ketamine, in juvenile Sterlet Acipenser ruthenus by use of two experiments. First, fish with an average weight (±SD) of 64.1 ± 3.4 g were exposed to immersion at six concentrations of each sedative, including clove oil at 14, 35, 56, 77, 98, and 119 mg/L; MS‐222 at 45, 50, 55, 60, 65, and 70 mg/L; ketamine at 35, 37.5, 40, 42.5, 45, and 50 mg/L; and tobacco extract at 375, 450, 525, 600, 675, and 700 mg/L. Induction time (deep induction) and recovery time were measured, and the concentrations inducing lower induction time and recovery (i.e., optimum concentrations) of each sedative were obtained as follows: 56 mg/L for clove oil, 60 mg/L for MS‐222, 45 mg/L for ketamine, and 675 mg/L for tobacco extract. To evaluate the impact of the selected concentration of each sedative on physiological responses of Sterlet, the hematological indices, plasma cortisol, glucose, and lactate concentrations were measured. Additionally, one nonexposed group was considered as a control group. Significant changes were revealed in all hematological parameters except for mean corpuscular hemoglobin concentration and monocytes percent. Biochemical parameters were measured at 0, 1, 3, and 6 h after induction. Significant changes were found in cortisol and lactate levels for all treatments except clove oil. Glucose concentration changed significantly only in the control group. Given that fish sedated with clove oil did not indicate changes in blood chemistry, clove oil may be the more effective sedative according to our results.