A critical appraisal of electrical stunning in chickens

Abstract

Chickens, unlike red meat species, do not show grand mal epilepsy in the brain following electrical stunning. The underpinning causes of this and the brain mechanisms associated with the induction and maintenance of electrical stunning induced unconsciousness in chickens have not been elucidated. However, the changes occurring in the electroencephalogram (EEG), abolition of somatosensory evoked potentials (SEPs), induction of seizure and loss of muscle tone or physical reflexes following electrical stunning have been used in the past to ascertain the effectiveness of waterbath electrical stunning in chickens.The purpose of this appraisal is to evaluate scientifically the relative merits of some of the criteria that have been used for ascertaining the effectiveness of electrical stunning in chickens. Scientific literature suggests that, unlike red meat species, the electrical stunning-induced release of monoamines and inhibitory amino acid neurotransmitter(s) in the chicken brain may play prominent roles in the induction and maintenance of unconsciousness following electrical stunning. These mechanisms would also appear to be relevant to the manifestation of a profoundly suppressed EEG and abolition of SEPs following electrical stunning, which are suggested to be meaningful indicators of an effective electrical stunning in chickens.