Effect of Gaseous Preslaughter Environment on Chicken Broiler Meat Quality

Abstract

The effect of preslaughter exposure to ammonia, carbon dioxide, or carbon monoxide on broiler carcass quality was studied in specially designed environmental chambers. Seventy-five birds were randomized into 15 treatments with 5 birds/treatment group and replicated, giving a grand total of 150 birds. The ammonia study included a control group, 25, 50, 75, and 100 ppm of ammonia exposure for 7 days prior to slaughter. Carbon dioxide treatments included a control group and 2,500, 5,000, 7,500, and 10,000 ppm exposure for 7 days. Carbon monoxide preslaughter exposure was for 2 hr using a control and 250, 500, 750, and 1,000 ppm of carbon monoxide. When compared to the control treatments, the following results were noted. Preslaughter exposure to ammonia of 75 ppm, or carbon dioxide of 5,000 ppm or greater, and carbon monoxide at 750 ppm significantly increased breast muscle shear values. Breast muscle pH was significantly increased at all levels of carbon dioxide, or 1,000 ppm of carbon monoxide, and significantly decreased at 25 ppm ammonia. The expressible moisture of the breast muscle was significantly increased at carbon monoxide exposures of 250, 500, and 750 ppm. Hunterlab aL values in the raw breast muscle were significantly higher at all levels of carbon monoxide exposure. Reflectance spectra of the thigh muscle from the 1,000-ppm carbon monoxide preslaughter treatment indicated a shift in the 580-nm oxymyoglobin peak to 570 nm, which likely corresponds to carboxymyoglobin. As shown by these data, the preslaughter gaseous environment influences muscle characteristics.