Untitled - CNR

Marine research at CNR4.2 Impact on animal wellbeingof the anaesthetic pretreatmentAn ideal method of stunning/killing shoulddetermine the conditions to induce permanentunconsciousness and insensibilityof animals until death [31]. Many studieshave demonstrated that, even if lesswell developed than in other farmed animals,fish also have sense organs ableto detect painful stimuli, sensory substratefor processing stimuli and brain pathwaysthat process this information able to generatebehavioural responses [32, 33, 34].As stated initially, our study analyzed thepossibility of using anaesthetics as a pretreatmentmethod for subjects intended tobe immersed in water and ice, in order toevaluate a possible contribution to the protectionof animal well-being. In this context,as already described in our results,the behaviour of the fish which were subsequentlyimmersed in water and ice afterbeing anaesthetized was reassuring. In fact,the fish pre-treated died without violent reactionsor evident muscular spasms and inshorter times. The most important issuefor the assessment at time of slaughter isanimal suffering, which is also difficult tomeasure. The results of this work evidencethat the behaviour represent a goodnoninvasive indicator of fish welfare as itoften responds rapidly to multiple stimulifrom the environmental changes includedthe stunning/killing phases, in agreementwith other studies [35, 36, 37]. However,in order to evaluate the impact ofanaesthetic techniques on the well-beingof farmed fish using enable objective andmore measurable assessments of the fishconditions, it would be desirable in futureto perform further studies with a multidisciplinaryapproach that, together withthe study of fish behaviour, takes into accountthe different biochemical and physiologicalprocesses (brain function, haematologicaland endocrine responses) involved.In conclusion, the behavioural evidenceand mortality times of the fish recordedin the present survey allow us to identifythe anaesthetic pre-treatment as a validtool for the protection of the well-being offish during the stunning/killing phases. Infact, both Eugenol and 2-Phenoxyethanolcould potentially represent, for their anaestheticcharacteristics, an important additionto the classic stunning/killing method ofimmersion in water and ice. Moreover, thecomparison between the two anaestheticsshowed that the Eugenol, the only anestheticthat does not pose any threat forthe public health if used in aquaculture,provides better induction performance withsignificantly shorter times of deep anaesthesiacompared to 2-Phenoxyethanol. Inconsideration of these excellent inductivecharacteristics of Eugenol and the equallyvalid characteristics of 2-Phenoxyethanolat recovery, we can consider the formermore suitable for pre-treatment of famedfish during stunning/killing practice andthe latter more suitable for short manipulation,surgery or transport of fish.5 AcknowledgmentsWe would like to thank the team atthe Department of Experimental Sciencesand Applied Biotechnologies of the Facultyof Veterinary Medicine, University ofMessina for their technical and logisticsupport.1951