Hematological effects of etomidate and tricaine in common carp


Abstract: Hematological effects of etomidate and tricaine at concentrations causing general anesthesia or sedation of carp juveniles were compared. Recovery of body balance took similar time in the case of both anesthetics, but fish treated with etomidate were depressed for several hours, while those subjected to tricaine immediately regained normal behavior. Immediately after exposure anesthetics caused minor hematological changes; the only statistically significant effects (decrease of hematocrit and plasma glucose) occurred after sedation with etomidate. One week after exposure a significant increase in mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration occurred in all groups of fish compared to the previous values, with slight increase in hemoglobin and decrease in red blood cell count. The mean corpuscular volume values tended to increase in all groups except for the control. Oxidative metabolic activity of phagocytes was significantly higher in both groups treated with etomidate compared to the control and tricaine groups. The results revealed that etomidate was less aversive and better prevented a delayed immunosuppressive effect of stress caused by handling and bleeding, while very quick complete recovery was the benefit of tricaine. These findings suggest that etomidate is better when long-term stress prevention is required, while tricaine is more useful for short-term immobilization of fish when rapid recovery of normal behavior is needed.

Keywords: Anesthesia, blood, erythrocytes, leukocytes, fish

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