Plasma variables, meat quality, and glycolytic potential in broilers stunned with different carbon dioxide...

This study aimed to investigate the effects of different CO(2) concentrations on blood variables, glycolytic potential (GP), and meat quality of hot-boned muscles in broilers. Thirty broilers were exposed to one of the following 5 gas mixtures for 90 s: 40% CO(2) + 30% O(2) + N(2) (control), 30% CO(2) + 21% O(2) + N(2) (G30%), 40% CO(2) + 21% O(2) + N(2) (G40%), 50% CO(2) + 21% O(2) + N(2) (G50%), and 60% CO(2) + 21% O(2) + N(2) (G60%). Samples were taken from the pectoralis major (PM), musculus iliofibularis (MI), and tibialis anterior muscles 45 min postmortem. The ultimate pH in both the PM (vs. G30% and G40%) and MI (vs. G40%) was decreased with G60% (P < 0.05), whereas drip loss in the PM (vs. G30%, P = 0.01) was increased with G60%. Drip loss in the MI (vs. control and G30%, P < 0.01) was increased with G50%. Lightness after 24 h in PM (vs. G30% and G40%, P < 0.01) was increased with G50%. In MI, lightness after 24 h was slightly decreased with G40% compared with the control (P < 0.10). The GP value in the PM was lower in the G30% and G40% than in G60% (P < 0.05), and the GP value in the tibialis anterior was the lowest in G30% (P < 0.01). Plasma corticosterone, plasma glucose, and meat quality (pH, lightness, redness, yellowness) 45 min postmortem were not affected by CO(2) levels (P > 0.05). In conclusion, stunning broilers with low CO(2) levels (30 and 40%) improved meat quality but had no advantage in animal welfare compared with high CO(2) levels (50 and 60%).