A COMPARISON OF ARGON, CARBON-DIOXIDE, AND NITROGEN IN A BROILER KILLING SYSTEM

Argon, CO2, and N-2 gasses were each evaluated in a broiler chicken ga s killing system. Birds were killed by individual exposure to one of t he three gasses for 2 min in a flow-through system. The gasses were ev aluated by determining the time, in seconds, for the following respons es: first reaction to the gas, loss of posture, eye closure, initiatio n of death struggle, and cessation of respiration. Percentage blood lo ss over a 3-min bleed time was determined by weight loss. Breast muscl e pH values were determined at 15 min and 24 h post-mortem on the Pect oralis major muscle. Carbon dioxide resulted in the earliest first rea ction, loss of posture, eye closure, and initiation of struggle. Argon and N-2 exhibited a delayed first reaction, a less severe early react ion, but a more severe unconscious death struggle. All birds died in a pproximately 75 s. Results indicate that the flow-through gas system t akes longer to kill broilers than the immersion systems previously rep orted. Gas killing resulted in lower (P <.05) blood loss. Initial brea st muscle pH values were significantly highest for the birds killed wi th CO2, followed by the control treatment, which was significantly hig her than the values for broilers killed with either Ar or N-2 After 24 h of chilling, there were no differences in broiler breast muscle pH among the four treatments. These results indicated that a flow-through gassing chamber may be a feasible, although slower, method of perform ing gas killing as compared to an immersion system.