A New Anaesthetic Protocol for Adult Zebrafish (Danio rerio): Propofol Combined with Lidocaine

Abstract

BackgroundThe increasing use of zebrafish model has not been accompanied by the evolution of proper anaesthesia for this species in research. The most used anaesthetic in fishes, MS222, may induce aversion, reduction of heart rate, and consequently high mortality, especially during long exposures. Therefore, we aim to explore new anaesthetic protocols to be used in zebrafish by studying the quality of anaesthesia and recovery induced by different concentrations of propofol alone and in combination with different concentrations of lidocaine.Material and MethodsIn experiment A, eighty-three AB zebrafish were randomly assigned to 7 different groups: control, 2.5 (2.5P), 5 (5P) or 7.5 μg/ml (7.5P) of propofol; and 2.5 μg/ml of propofol combined with 50, (P/50L), 100 (P/100L) or 150 μg/ml (P/150L) of lidocaine. Zebrafish were placed in an anaesthetic water bath and time to lose the equilibrium, reflex to touch, reflex to a tail pinch, and respiratory rate were measured. Time to gain equilibrium was also assessed in a clean tank. Five and 24 hours after anaesthesia recovery, zebrafish were evaluated concerning activity and reactivity. Afterwards, in a second phase of experiments (experiment B), the best protocol of the experiment A was compared with a new group of 8 fishes treated with 100 mg/L of MS222 (100M).ResultsIn experiment A, only different concentrations of propofol/lidocaine combination induced full anaesthesia in all animals. Thus only these groups were compared with a standard dose of MS222 in experiment B. Propofol/lidocaine induced a quicker loss of equilibrium, and loss of response to light and painful stimuli compared with MS222. However zebrafish treated with MS222 recovered quickly than the ones treated with propofol/lidocaine.ConclusionIn conclusion, propofol/lidocaine combination and MS222 have advantages in different situations. MS222 is ideal for minor procedures when a quick recovery is important, while propofol/lidocaine is best to induce a quick and complete anaesthesia.

Evaluation of anaesthetic protocols for laboratory adult zebrafish (Danio rerio)

“…Propofol is a sedative-hypnotic agent that is capable of anaesthesia induction in a rapid and smooth way and lacks cumulative effects due to its rapid metabolization. Moreover, the recovery from anaesthesia is also quick and complete [ 20 , 21 ]. Lidocaine hydrochloride, a local anaesthetic, induces anaesthesia quickly and the recovery is also relatively rapid [ 19 ], although, in zebrafish, it may present a high variability in the mean times to achieve a given anaesthetic stage or recovery [ 9 ].…”

Behavioural and physiological effects of methadone in the perioperative period on the Nile tilapia Oreochromis niloticus

“…Propofol, commonly used for mammals, was used as the anaesthetic agent in the present study. Propofol has demonstrated good anaesthetic effects on O. mykiss (Gomuka et al, ), C. auratus (GholipourKanani & Ahadizadeh, ), Gulf of Mexico sturgeon Acipenser desotoi (Fleming et al, ), silver catfish Rhamdia quelen (Gressler et al, ) and D. rerio (Valentim et al, ). For O. niloticus , low doses of propofol do not show genotoxic or mutagenic effects (Valença‐Silva et al, ).…”

Species specific anaesthetics for fish anaesthesia and euthanasia

“…Assessment of the practical aspects of using different anaesthetics, for different fish species have been reviewed in several papers 8 – 13 . These reviews generally focus on ease of delivery, rapid onset and stability, and not the potential welfare implications associated with induction.…”