Transport Stress in Common Carp (Cyprinus carpio) with benzocaine hydrocholoride

Objectives:   The purpose of the present study was to investigate the effects of a 3 hours transport on Common Carp with and without a benzocaine hydrocholoride solution and the recovery of these fishes. Stages of anaesthesia such as erratic swimming, increased respiration, and reduced and also ability of fish handling were monitored.Materials Methods:  50 fish of 50 g average weight were obtained from a commercial fish farm. The fish were anaesthetized with 10 mg/l benzocaine hydrocholoride and given a 3-h transport. The effects of benzocaine hydrocholoride anaesthesia on levels of glucose, haematocrit, plasma cortisol in carps, after a 3-h transport and during a 24 hours recovery period were investigated.Results Conclusion:  Plasma cortisol levels were significantly higher for fish in the control group at time=0, 1, 12 hours after transport. Fish in the experimental group reached significantly higher plasma cortisol levels 4 and 8 h after transport. 24 hours after transport, mean plasma cortisol values were 286.6 ± 52.2 nM (control) and 62.0 ± 42.6 nM (experimental group). Significantly higher glucose values were measured in the experimental group at time = 0 and 1 h after transport. 24 hours after transport, mean plasma glucose values were 10.2 ± 0.6 mM (control) and 5.8 ± 0.2 mM (experimental group). The use of benzocaine anaesthesia during transport led to a reduced release of cortisol and significantly lowers levels of plasma cortisol after 24 hours recovery period. Plasma glucose did not return to basal level after 24-hours period, indicating that even longer recovery may be needed for the fish to return to a pre-stress state. In conclusion, in common carp, benzocaine hydrocholoride at a concentration of 10 mg/l made satisfactory induction and recovery. Also, the results demonstreated that benzocain anaesthesia combined with a recovery period lessens the stress burden imposed by transport.