Objective—To evaluate isoeugenol as an anesthetic agent in koi carp.
Animals—216 juvenile koi carp (Cyprinus carpio).
Procedures—Fish were randomly allocated to 9 groups of 24, and each group was randomly exposed to isoeugenol concentrations ranging from 0 to 500 mg/L. General activity, excitement, fin and gill color changes, opercular movement rate, loss of equilibrium, muscle tone, jaw tone, and handleability were assessed. Five fish from the control (0 mg/L), 200 mg/L, and 500 mg/L groups were randomly selected prior to anesthetic recovery and again 24 hours after recovery for euthanasia, gross necropsy, and histologic assessment of gills, internal viscera, and skeletal muscles.
Results—Mean ± SD interval to achieve stage 2 anesthesia with isoeugenol ranged from 22.4 ± 6.2 minutes at 20 mg/L to 0.25 ± 0.4 minutes at 500 mg/L, whereas the mean interval to stage 3 anesthesia ranged from 28.1 ± 3.9 minutes at 20 mg/L to 0.33 ± 0.48 minutes at 500 mg/L. With the exception of the 500 mg/L group, opercular movements were maintained throughout. Death was observed only in the 500 mg/L group, in which 50% of the fish either failed to recover or died within 24 hours after anesthetic exposure. There were no pathological differences between fish exposed to isoeugenol at 0 or 500 mg/L.
Conclusions and Clinical Relevance—Isoeugenol appeared to have a wide margin of safety with predictable dose-related effects. Concentrations of 40 to 80 mg/L induced anesthesia within 4 to 11 minutes and were considerably less than the concentration associated with fish death.
Objective—To evaluate endoscopic liver biopsy and compare that technique with a standard coeliotomy biopsy technique in fish.
Design—Randomized controlled clinical trial.
Animals—30 channel catfish (Ictalurus punctatus).
Procedures—10 fish were randomly assigned into control, coeliotomy, and coelioscopy groups. Anesthesia was performed with a recirculating anesthesia machine. Body weight, PCV, and total protein (TP) concentration in blood as well as plasma activities of aspartate aminotransferase, creatinine phosphokinase, lactate dehydrogenase, and sorbitol dehydrogenase were measured before and after surgery. Standard ventral coeliotomy or coelioscopy was performed, and the biopsy specimens were scored histologically.
Results—Coeliotomy and coelioscopy procedures were well tolerated without acute deaths. Blood TP concentration and PCV decreased after surgery in the coelioscopy group because of intracoelomic fluid administration to aid visualization. Minor changes in activities for hepatic and muscular enzyme activities were apparent, but were not significantly different between the coelioscopy and coeliotomy groups. Coelioscopy and coeliotomy yielded biopsy specimens of similar diagnostic quality. However, coelioscopy permitted a more extensive evaluation of the viscera, and all 10 surgical wounds healed completely, compared with severe wound dehiscence in 3 of 10 fish that underwent coeliotomy.
Conclusions and Clinical Relevance—Both coelioscopy and coeliotomy were capable of yielding antemortem liver biopsy specimens of diagnostic quality in catfish. Coelioscopy permitted a more detailed examination of the coelomic viscera through a smaller surgical incision, was less traumatic, and resulted in decreased wound dehiscence.