Advances in the use of dexmedetomidine in green iguanas (Iguana iguana)

• Grant number: 21/02433-8
• Support Opportunities: Regular Research Grants
• Duration: August 01, 2021 - July 31, 2023
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Clinics and Surgery
• Principal Investigator: Adriano Bonfim Carregaro
• Grantee: Adriano Bonfim Carregaro
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil

Abstract

The study aims to assess the effects of dexmedetomidine as a sedative, analgesic and the sparing-effect on sevoflurane anaesthesia in green iguanas (Iguana iguana). Seven adult green iguanas, four males and three females weighing 600 to 1000 gr, will be used in all of the four stages of this project. To validation of a sedative scale for iguanas, animals will be given 2 mg/kg midazolam IM and footages will be recorded at baseline (0 min) and 15, 30, 90, 180 and 300 minutes post-injection. Three experienced observers on lizards' management will score the footages, according to the characteristics of a sedative scale, which has already been used by the group. The intra-observer and inter-observer reliability, specificity and sensitivity in the detection of sedation in iguanas will be evaluated. To the evaluation of sedative and antinociceptive effects of dexmedetomidine, animals will be subjected to five treatments: 2 mg/kg midazolam (MID), 100 µg/kg (D100), 200 µg/kg (D200), 400 µg/kg dexmedetomidine and 0.8 mL/kg saline solution (Control), all of them given by IM route. The sedative effect will be assessed by the scale, which will be validated in the previous stage. Antinociception will be assessed by measurement of the latency of limb withdrawal reflex to thermal stimulus, a technique that has been commonly used by the group in lizard studies. Finally, the sparing-effect of dexmedetomidine on sevoflurane anaesthesia will be evaluated. The minimum anaesthetic concentration (MAC) of each iguana will be determined, by bracketing method. In a second moment, the animals will be given dexmedetomidine, 30 minutes before anaesthetic induction, and the MAC of sevoflurane will be evaluated again, by the same method. At the end of this study, we hope to provide consistent data enough to recommend at least one dose of dexmedetomidine as an analgesic, sedative and also as a part of inhalation anaesthesia protocols, contributing to the advancement of anaesthesia and analgesia in this species. (AU)