Impact of alternative electrical stunning parameters on the ability of broilers to recover consciousness and meat quality

Authors: Bourassa, Dianna; Bowker, Brian; Zhuang, Hong; WILSON, KIMBERLY - University Of Georgia; HARRIS, CAITLIN - University Of Georgia; Buhr, Richard - Jeff

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/29/2017
Publication Date: 6/17/2017
Citation: Bourassa, D.V., Bowker, B.C., Zhuang, H., Wilson, K.M., Harris, C.E., Buhr, R.J. 2017. Impact of alternative electrical stunning parameters on the ability of broilers to recover consciousness and meat quality. Poultry Science. 96(9):3495-3501. doi:10.3382/ps/pex120.

Interpretive Summary: Broilers in the United States are typically electrically stunned (temporary unconscious) using low voltage-high frequency (12-38V, =400Hz) DC or AC water bath stunners. In the European Union, however, broilers are required to be electrocuted (terminally unconscious) using high voltage-low frequency (50-150V, 50-350Hz) AC. By definition and practice, stunned broilers should be able to regain consciousness in the absence of bleeding. In contrast, electrocuted broilers die due to the induction of cardiac fibrillation. For broilers stunned with low voltage systems, concerns have been raised regarding animal welfare (unconscious status) during the bleeding period. This work evaluated the impact of extended DC stunning duration and alternative stunning methods (DC+AC combination) on the recovery of consciousness and carcass meat quality. In the absence of bleeding, broilers that were DC stunned for extended times (60, 90, or 120 s), were able to recover consciousness 63, 10, or 0%. Alternative stunning protocols included waterbath stunning broilers at 15 or 25V DC for 10 s followed by plate stunning at 100, 110, or 120V AC for 5 s. During the application of the stun the maximum current in milli-Amps (mA) for both DC and AC stuns were recorded. All six of the alternative stunning protocols were successful in rendering the broilers unable to regain consciousness. The maximum mA recorded during both DC and AC stunning were moderately-strongly (r=0.54–0.81) correlated to body weight and poorly-moderately (r=0.27–0.74) correlated to shank width. No significant differences for carcass or meat quality characteristics (hemorrhages, red wing tips, broken clavicles, meat pH, cook loss, color values, or shear) were detected between control (15 or 25V DC only) and treatment groups (DC+AC combination stunning). The only significant different meat quality parameter was lightness values where the lowest voltage group (15V DC) had the darkest breast meat fillets (53.27L*) and the 15V DC+100V AC group had the lightest breast meat fillets (55.61L*) with all other groups intermediate. These results indicate that stunning parameters combining DC and AC stunning are viable and do not impact carcass or meat quality and could be used when a stun-to-death protocol is desired. Further investigations on a larger, commercial scale should be conducted to validate these stunning parameters.

Technical Abstract: Broilers in the United States are typically electrically stunned using low voltage-high frequency (12-38V, =400Hz) DC or AC water bath stunners. In the European Union, however, broilers are required to be electrocuted using high voltage-low frequency (50-150V, 50-350Hz) AC. Low voltage stunned broilers regain consciousness in the absence of bleeding. In contrast, high voltage stunned broilers die due to induction of cardiac fibrillation. For birds stunned with low voltage systems, concerns have been raised regarding animal welfare during bleeding. This work evaluated the impact of extended DC stunning duration and alternative stunning methods (DC+AC combination) on the recovery of bird consciousness and meat quality. In the absence of bleeding, broilers that were DC stunned for extended times (60, 90, or 120 s), were able to recover consciousness 63, 10, or 0%. Alternative stunning protocols included waterbath stunning broilers at 15 or 25V DC for 10 s followed by plate stunning at 100, 110, or 120V AC for 5 s. Prior to shackling, live body weight and shank width were measured and during stunning, maximum mA for both DC and AC stuns were recorded. All of the alternative stunning protocols were successful in rendering the broilers unable to regain consciousness. The maximum mA recorded during both DC and AC stunning were moderately-strongly (r=0.54–0.81) correlated to body weight and poorly-moderately (r=0.27–0.74) correlated to shank width. No significant differences for carcass or meat quality characteristics (hemorrhages, red wing tips, broken clavicles, pH, cook loss, a* and b* color values, and MORS shear energy) were detected between control (15 or 25V DC only) and treatment groups (DC+AC combination stunning). The only significant different meat quality parameter was L* values where the lowest voltage group (15V DC) had the darkest fillets (53.27) and the 15V DC+100V AC group had the lightest fillets (55.61) with all other groups intermediate. These data indicate that stunning parameters combining DC and AC stunning may be viable protocols when a stun-to-death is desired.