Fig 1.
Scheme of the study workflow, groups used and the comparisons made between groups concerning the assessments performed.
The post-anaesthetic recovery was assessed by the fish reactivity to the approach of the observer in experiment A, and by the fish activity (number of crossings per minute made in a virtual line) in both experiments.
Fig 2.
Anaesthetic parameters of adult zebrafish when treated with propofol alone or combined with lidocaine.
a) equilibrium loss, b) loss of touch reaction, c) loss of reaction to a painful stimulus, and d) equilibrium recovery of adult zebrafish after being placed in an anaesthetic bath of 2.5, 5 or 7.5 μg/ml of propofol alone (P) or 2.5 μg/ml of propofol combined with 50, 100 or 150 μg/ml of lidocaine (P/L). Each point represents an animal. n = 10. Data are expressed as median [interquartile range]. * p< 0.05 compared with 2.5 μg/ml of propofol; ° p< 0.05 compared with all groups except with 5 μg/ml of propofol; #p< 0.05 compared with 5 μg/ml of propofol.
Table 1.
Proportion of animals that responded to the light and painful stimuli after 5 minutes of anaesthesia, and proportion of animals that died in each treatment group.
Fig 3.
Respiratory rate per minute (RR) of adult zebrafish treated with the different anaesthetic protocols.
a) RR after loss of equilibrium (equilibrium-), and b) RR after loss of light stimulus response (light-) of adult zebrafish treated with different concentrations (2.5, 5 or 7.5 μg/ml) of propofol alone (P) or 2.5 μg/ml of propofol combined with 50, 100 or 150μg/ml of lidocaine (P/L), or treated with 100 mg/L of MS222. Each point represents an animal; we were not able to count the respiratory movements of all animals. Data are presented as median [interquartile range].
Fig 4.
Number of crossings per minute of adult zebrafish through the middle/ longitudinal line of the tank 5 and 24 hours after being treated with the different anaesthetic protocols, and the control groups.
Zebrafish were treated with 2.5, 5 or 7.5 μg/ml of propofol alone (P) (n = 10, except 2.5P with n = 11), 2.5 μg/ml of propofol combined with 50, 100 or 150 μg/ml of lidocaine (P/L) (n = 10), or treated with 100 mg/L of MS222 (100M, n = 8), and respective unanaesthetized controls (control A, n = 12; and control B, n = 4). Data are presented as a box plot (the median is indicated by the horizontal bar inside the box; the 25th and 75th percentile are the boxes’ borders; and the whiskers are the lowest and highest values for the 5th and 95th percentiles, respectively). P and P/L groups were compared with control A, and 100M group was compared with control B. * p< 0.05 compared with control A.
Fig 5.
Anaesthetic parameters of adult zebrafish treated with propofol combined with lidocaine or treated with MS222.
a) equilibrium loss, b) loss of touch reaction, c) loss of reaction to a painful stimulus, and d) equilibrium recovery of adult zebrafish after being placed in an anaesthetic bath of 2.5 μg/ml of propofol combined with 50, 100 or 150 μg/ml of lidocaine (P/L; n = 10), and of 100 mg/L of MS222 (100M; n = 8). Each point represents an animal. Data are expressed as median [interquartile range]. * p≤ 0.016 compared with 100 mg/L of MS222.