Different benzocaine concentrations on anesthetic induction in lambari (“Astyanax altiparanae”)

Abstract

Intensive fish production processes realized during routine management or experimental samplings are indispensable procedures that may cause damages of several proportions, impairing the sampling and causing death to biological model. To avoid damages on fish it is common the use of anesthetic to facilitate the processes. A limiting factor to use these products is the lack of knowledge about concentrations and appropriate time exposition for each species including lambari-do-rabo-amarelo ("Astyanax altiparanae"). To evaluate those parameters, lambaris were exposed to different benzocaine concentrations (50, 75, 100 and 125 mg/L) in four liters aquarium (1 fish/aquarium, 9 fish/concentration). Water quality was monitored during anesthetic induction in each aquarium. It was observed that fish exposed to 125 mg/L reached deep anesthesia quickly, but higher mortality occurred seven days after induction. And for 100 mg/L it was observed deep anesthesia reached quickly, without effects on water parameters and resulting in low mortality. Thus, benzocaine concentration of 100 mg/L is indicated for anesthetic induction of lambari-do-rabo-amarelo ("Astyanax altiparanae").