Clinical and cardiopulmonary effects of propofol in the spotted bamboo shark (Chylloscyllium plagiosum)

Abstract

Sharks are important exhibit animals at aquariums worldwide. Restraint is often necessary for physical examination, diagnostic evaluation, medical treatment and/or surgical procedures. Manual restraint is often used for simple procedures but may result in dangerous contact for the shark and the handler and, when used alone, is not sufficient for painful procedures. Limited reports describe the use of tricaine methane sulfonate, ketamine, or tiletamine–zolazepam in sharks. This study evaluates the clinical and cardiorespiratory effects of propofol in spotted bamboo sharks (Chylloscyllium plagiosum). Nine, wild-caught, adult female spotted bamboo sharks weighing 1.75–2.5 kg were used in this study. The sharks were housed in individual portable plastic containers during data collection. Water chemistries and temperature were maintained within normal limits. An initial physical examination was performed using manual restraint. Propofol (2.5 mg kg−1) was administered IV in the caudal tail vein over 30 seconds. The HR, RR, time to relaxation, resistance to handling, fin movement, loss of righting reflex, and response to painful stimuli (fin pinch) were evaluated and recorded at baseline and 5, 10, 15, 30, 45, 60, and 75 minutes after propofol administration. Surgical anesthesia was thought to be achieved when a shark lost its righting reflex, did not respond to painful stimuli, and no longer resisted handling. The HR and RR were evaluated over time using Friedman's nonparametric analysis of repeated data. A significant difference was determined at p < 0.05. Where differences were apparent, Rhyne and Steels method for comparison of related samples to a control (time 0) was used with an experimental-wise error of alpha = 0.05. HR and RR did not change significantly over time. Respective values (mean ± SD) for each data collection point were T (0), HR 37 ± 10 beats minute−1, RR 38 ± 7 breaths minute−1; T (5), HR 40 ± 5, RR 44 ± 15; T (10), HR 41 ± 6; RR 41 ± 15; T (15), HR 43 ± 7, RR 38 ± 13; T (30), HR 39 ± 50, RR 39 ± 14; T (45), HR 43 ± 9, RR 37 ± 14; T (60), HR 45 ± 9, RR 38 ± 11; T (75), HR 44 ± 6, RR 38 ± 12. The righting response was lost in all sharks within 5 minutes of propofol administration. A surgical plane of anesthesia was observed in all nine sharks. The righting response returned within 60 minutes in 4/9 sharks, 75 minutes in 2/9 sharks, and over 200 minutes in 3/9 sharks. All nine animals had uneventful recoveries. Propofol provided a safe alternative for immobilization of spotted bamboo sharks. However, manual restraint is required for IV administration. Further studies are necessary to determine an ideal dose and further evaluate propofol's suitability as a general anesthetic for painful procedures.