Impact of Different Gas-Stunning Conditions on Slaughter Stress and Quality Properties of Laying Hens Breast Meat

This study was conducted to investigate the impact of stunning using carbon dioxide (CO2), argon (Ar) and nitrogen (N2) in the slaughtering process on the slaughter stress and the quality characteristics of breast meat in laying hens. In the experiment, 70 laying hens at 30 weeks of age were used and subjected to various stunning conditions. These conditions included halal method, CO2 (70%, 80%, 90%) gas, Ar (80%, 90%) gas, and 90% N2. Blood was immediately collected after slaughter and serum was separated and rapidly frozen at -70°C, while breast meat was vacuum-packed and stored in a 4°C refrigerator for 4 days before being used in the experiment. The pH of breast meat was highest in the N2 treatment, while the Ar treatments showed results similar to the Halal and CO2 treatments. Lightness was higher in the CO2 treatments compared to other gas treatments, and redness was highest in the N2 treatment, with no significant difference between the Ar and CO2 treatments. Furthermore, the drip loss was highest in the 90% Ar treatment and lowest in the N2 treatment. Drip loss and cooking loss were influenced by water-holding capacity, and shear force was higher in the CO2 treatments compared to the Halal and Ar treatments. These results suggest that in the slaughter process of laying hens, the use of Ar and N2 for stunning can be an alternative to CO2.