Potencial anestésico com óleo essencial de Ocimum basilicum em pacu Piaractus mesopotamicus

Abstract

The aim of this study was to evaluate the anesthetic induction and recovery time of pacu juveniles (Piaractus mesopotamicus) submitted to different concentrations of Ocimum basilicum essential oil. A total of 54 juvenile pacu P. mesopotamicus with an average weight of 319.08 ± 9.14 g and an average total length of 21.59 ± 2.59 cm were acquired from a commercial fish farm for this experiment. The fish were fed a commercial diet three times a day until apparent satiety. After the acclimatization period, the juvenile pacu fish were evaluated in terms of the time taken to induce and recover from anesthesia. The fish were transferred to three aquariums (8 L) filled with water from the acclimatization tanks. The fish were exposed to the following treatments with different concentrations of O. basilicum essential oil: 150, 180, 210, 240, 270 and 300 mg L-1. To evaluate the anaesthetic induction time, nine fish were used per concentration, with three fish being anaesthetized per tank, one after the other (3 fish x 3 repetitions per treatment). All the fish exposed to the different concentrations of O. basilicum satisfactorily reached stage III of anaesthetic induction, characterized by "belly - up" swimming, a change that did not occur when the fish were exposed to the vehicle, 95% ethanol. The results showed that for Ocimum basilicum oil, the concentration that promoted anesthetic induction in the shortest time was 300 µl L-1 and also led to a longer recovery time compared to the 150mg L-1 concentration. Alcohol, on the other hand, was unable to induce anesthesia.