Benzocaína e óleo de cravo como anestésicos para alevinos de peixe-rei (Odontesthes bonariensis).

Abstract

Pejerrey (Odontesthes bonariensis) is a native species from Rio Grande do Sul, Uruguay and Argentina, where it has great economic importance for artisanal fishing. This species is of great interest for aquaculture however, the studies related to its handling technique are rare. One difficulty in laboratory research with pejerrey is related to its sensitivity, as it presents higher basal cortisol levels than other freshwater species. For this reason, the aim of this work was to evaluate the efficiency of benzocaine and clove oil as anesthetics for pejerrey fingerlings. For which two experiments were made where fingerlings with average total length 57±7.8mm and average weight 1.1±0.44g were exposed to benzocaine with concentration between 40mg/l and 120mg/l and to clove oil with concentration between 12mg/l and 75mg/l. Survival, anesthesia induction time and recovery time for each one of the pharmaceutics were evaluated. The correlation between the concentration for each product and the anesthesia induction time was analyzed. Also, the correlation between the each product and the recovery time was analyzed. Both benzocaine and clove oil pharmaceutics showed efficiency as anesthetics for pejerrey fingerlings, with negative correlation between the dose of anesthetics and the anesthesia induction time. For benzocaine, the concentrations between 80mg/l and 100mg/l showed better result, as for clove oil the optimal concentrations were between 25mg/l and 50mg/l. On the other hand, the anesthesia recovery time did not present significant variation on the different concentrations of the tested products. These results show that the tested products are highly metabolizable by pejerrey.