Water-bath stunning process in broiler chickens: Effects of voltage and intensity

The effect of electrical parameters (intensity and voltage) to obtain an effective water-bath stunning in a commercial poultry slaughterhouse was studied. A total of 390 broilers were randomly divided into six experimental groups according to the intensity (150 and 200 mA) and voltage (51-60, 61-80 and 81-100 V). Statistical analysis showed a significant ( p <0.001) effect of electrical parameters on the cloacal reflex since the response rate was 8 s for 96% of broilers. On the other hand, the stunning treatments suppressed the palpebral reflex up to 12 s in 80% of broilers. All stun-treated broilers showed breathing response after 27 s with an average time between 45 and 50 s depending on voltage and intensity of the current. Regarding voltage, the percentage of complete neck cutting increased with the increase of voltage, presenting the highest levels in broilers stunned at 81-100 V (100 and 92.8%, for 150 and 200 mA, respectively). Concerning to intensity, the best results were obtained in broilers stunned at 150 mA, showing mean percentages of 94.83 and 87.30%, for 150 and 200 mA, respectively. The bruises on wings were significantly ( p <0.001) affected by voltage, observing the highest values in broilers slaughtered at lower voltages. An opposite trend was observed on bruises under the wings since the lowest voltages showed ( p <0.001) lower levels (1.34 and 1.42%, for 150 and 200 mA, respectively). Finally, bruises on dorsal winds and on back were significantly ( p <0.001) influenced by intensity level, showing the lowest percentages in broilers stunned at 150 mA.