Anesthesia with intramuscular administration of alfaxalone in Spanish ribbed newt (Pleurodeles waltl)

Abstract

The objective of this investigation was to assess the usefulness of three different doses of alfaxalone administered intramuscularly in amphibian species. Thirty-two healthy, adult (5–9 years old) captive Spanish ribbed newts (Pleurodeles waltl) were used. Alfaxalone at a dose of 15, 20, and 30 mg/kg was administered into the muscles of the front legs of each newt, with a 4-week washout period between trials. Heart rate and depth of sedation were assessed for each animal prior to the administration of anesthetic (T0), and at 2-minute intervals over the initial 20 minutes, then at 5-minute intervals over 60 minutes, and at 15-minute intervals until a full duration of 120 minutes for each trial. The average induction time was reduced with increasing doses. The recovery period was prolonged with increasing doses. Intramuscular administration of alfaxalone proved a feasible method for immobilization and sedation in Spanish ribbed newts and resulted in loss of both the escape reflex and righting reflex.