USE OF PROPOFOL ASSOCIATED WITH METHADONE AND LOCAL BLOCKADE WITH LIDOCAINE IN SIX SPECIMENS OF FRESHWATER STINGRAYS (Potamotrygon spp.)

Abstract

Fish are the most diverse group of vertebrates, and their main characteristic is their aquatic habitat, with primary respiration through gills and ectothermy. The Potamotrygonidae is a family of cartilaginous fish that includes freshwater rays from South America. As they are restricted to freshwater environments, they possess anatomic and physiological particularities that differentiate them from other elasmobranchs. Potamotrygon is the most diverse genus, and although they are not aggressive fish, stingrays of this genus have a retro-serrated barb covered by a venom-producing glandular epithelium. This work aims to report the anesthetic protocol for barb resection from stingrays of two species from the genus Potamotrygon. Six stingrays (Potamotrygon falkneri, n = 3; P. leopoldi, n = 3) were sent to the Veterinary Hospital of the Federal University of Uberlândia (HVET-UFU) for surgical removal of the barb. The anesthetic protocol consisted of premedication with methadone administered intramuscularly, induction with propofol in the spiracles and local blockade with lidocaine without vasoconstriction. Trans-anesthetic monitoring was performed regarding the animals' water temperature, respiratory rate, and heart rate. All animals had fully recovered from anesthesia within five minutes, and no complications were recorded. Although the anesthesiology of elasmobranch fishes is still uncertain due to the scarcity of experimental models, the launched protocol yielded satisfactory results for promoting relaxation, analgesia, and rapid recovery.