Comparative effects of MS 222 and 2-phenoxyethanol on gilthead sea bream (Sparus aurata L.) during confinement

The effects of two anaesthetics, ethyl m-aminobenzoate methanosulphonate (MS 222) and 2-phenoxyethanol, at three different dosage levels, were examined on gilthead sea bream (Sparus aurata) during a confinement similar to that in transport. Changes in plasma cortisol, glucose, lactate and haematological parameters were analysed. Confinement without anaesthesia produces a smaller stress response than with the two anaesthetics. Exposure to MS 222 and 2-phenoxyethanol at a dose exceeding 25 mg 1-1 for MS 222 and 0.075 mg 1-1 for 2-phenoxyethanol, respectively, produces a stress response in gilthead sea bream. The greatest effect of anaesthetic stress in the cortisol level is found following the period of exposure. The effects on plasma glucose level and on plasma lactate continue until 24 hr of recovery time. When the anaesthetic body concentration decreases, as it is metabolically eliminated, a recovery of haematological parameters and cortisol levels is clearly noted. © 1995.