Sammendrag
The effects of 40 mg/L metomidate and 300 mg/L
iso-eugenol (i.e. 600 mg/L Aqui-S vet.) anaesthesia
on the stress response in European silver eel
during a process of complete anaesthesia, recovery
and long-term survival were studied. Metomidate
is a hypnotic agent with no analgesia,
whereas Aqui-S vet. is a true anaesthetic. There
was no difference between fish exposed to Aqui-S
vet. and metomidate, with respect to time to
anaesthesia (mean 3.8 and 2.6 min respectively)
and recovery (mean 7.6 and 6.5 min respectively).
For the metomidate group, the plasma
cortisol concentration increased to a peak during
the recovery phase, and was significantly higher
than for the Aqui-S vet. group, which showed no
such increase. Fish were kept in tanks with seawater
for monitoring of long-term survival
(4 months) after anaesthesia treatment, and no
mortality was observed in either group. The
results indicate that metomidate is a potential
stressor to European eels during exposure, and we
do not recommend using metomidate in this species.
Aqui-S vet., however, seems promising as a
stress-reducing anaesthetic for European eel, and
if used properly could improve animal welfare
and survivability during and after common ecology-
related procedures, as capture, tagging and
size measuring.
Vis fullstendig beskrivelse
