Cone restraining and head-only electrical stunning in broilers: Effects on physiological responses and meat quality

Abstract

Two experiments were conducted to evaluate a new electrical stunning system for broilers. The objective of the first experiment was to evaluate the behavioral, neural, and physiological responses of 27 broilers after head-only electrical stunning while their bodies were restrained in cone-shaped holders. In the second experiment, quality of meat from 30 broilers after head-only electrical stunning in a cone-shaped restrainer was compared with that from 30 broilers stunned in a conventional water bath. Broilers were restrained in the cone with their heads positioned to facilitate a correct stun, followed by a neck cut by hand. After stunning, each broiler displayed a tonic phase, followed by minimal brain activity during bleeding. On average, heart rate was 258 ± 51 beats/min before stunning. The heart was observed to malfunction after cutting. According to the correlation dimension analyses, the score remained low. Within a confidence limit of 95%, taking into account the number of birds with a reliable electroencephalogram (n = 27), the chance of an effective stun and exsanguination with all broilers lies between 0.90 and 1.00 using a sinusoidal AC current of 264 ± 29 mA (∼130 V). After a brief learning period, operators were able to easily position the broilers in the cone in a commercial setting. The pH after chilling was 0.5 units lower (P < 0.05) in the head-only stunned group compared with the group stunned in a conventional water bath. After head-only stunning, 60% of breast fillets showed no blood splashes and 3% showed severe blood splashes compared with 20 and 27% after conventional water bath stunning. No differences in temperature and color were observed between the 2 groups. It is concluded that broilers could be restrained in a cone, followed by correct head-only stunning, neck-cutting, and unconscious shackling afterward under laboratory and commercial slaughterhouse conditions. When this procedure was used, meat quality was better compared with broilers stunned in the conventional water bath.