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Stress-preventing effects of the anaesthetic agents 2-phenoxyethanol, MS-222, clove oil and metomidate in the Senegalese sole Solea senegalensis
Authors: Robilson Antonio Weber, Jorge José Pérez Maceira, María José Aldegunde, Leopoldo Oscar García Martín, Manuel Aldegunde
Number of views: 453
Objective: To determine the effectiveness of the anaesthetic agents 2-phenoxyethanol, MS-
222, clove oil and metomidate in attenuating acute handling stress in juvenile specimens of
Solea senegalensis subjected to two routine stressful events specific to aquaculture and/or fish
research.
Methods: The stress-preventing effects of four anaesthetic agents (2-phenoxyethanol, 600
mg/L; metomidate, 5 mg/L; clove oil, 30 mg/L and MS-222, 75 mg/L) were evaluated in
juvenile specimens of Senegalase sole (Solea senegalensis) subjected to two different types
of acute (handling-related) stress: air exposure and net handling (chasing). To assess the
stress-preventing effects of the four anaesthetic agents, diverse blood and plasma parameters
(haematocrit, haemoglobin, glucose, lactate and cortisol levels) were determined as stress
indicators. Fish were treated with the anaesthetic agents before being subjected to the different
types of acute stress, and they were sacrificed 30 min, 2 and 24 h later. Control fish were
processed in the same way without pretreatment with the anaesthetic agents.
Results: The net handling stress was of sufficient intensity to cause a significant increase in the
levels of most of the stress indicators considered. By contrast, air exposure stress only induced
significant increases in cortisol and haemoglobin levels.
Conclusions: The stress-preventing effects of the anaesthetic agents tested were ranked on the
basis of their capacity to prevent increases in the haematocrit, haemoglobin, glucose, lactate
and cortisol levels, as follows: metomidate (5 mg/L) > clove oil (30 mg/L) > MS-222 (75 mg/L)
> 2-phenoxyethanol (600 mg/L).