title: Survival rate and carcase downgrading after the stunning of broilers with carbon dioxide-argon mixtures.
abstract: As chickens may rapidly regain consciousness after gas stunning, the effects of a two minute exposure to a carbon dioxide-argon mixture on survival rate were investigated. Broilers were stunned in batches of 10 per transport crate with a mixture of 10, 20 or 30 per cent carbon dioxide in argon with 5 per cent residual oxygen. The birds were exposed to the gaseous atmosphere for two minutes. A control group of birds was electrically stunned (120 mA for four seconds; 50Hz sinusoidal waveform). In addition, the incidence of carcase downgrading conditions after stunning with 20 per cent or 30 per cent carbon dioxide in argon with 5 per cent residual oxygen was compared with the incidence after electrical stunning. The results showed that stunning with 10 and 20 per cent carbon dioxide in argon with 5 per cent residual oxygen resulted in survival rates of 24 and 1 per cent, respectively. Stunning with 30 per cent carbon dioxide in argon with 5 per cent residual oxygen resulted in the death of all the broilers. Electrical stunning resulted in a significantly (P less than 0.001) larger number of broilers with breast muscle haemorrhaging and broken furculum and coracoid bones, whereas stunning with gas mixtures resulted in a significantly (P less than 0.001) higher incidence of broilers with damaged wing bones. Electrical stunning of broilers resulted in a significantly higher pH in the breast muscles 20 minutes post mortem than stunning with carbon dioxide-argon mixtures.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Meat Animal Science, School of Veterinary Science, University of Bristol, Langford.
authors.forename: A B
authors.initials: AB
authors.lastname: Raj
authors.forename: N G
authors.initials: NG
authors.lastname: Gregory
authors.forename: L J
authors.initials: LJ
authors.lastname: Wilkins
mesh_terms: D000003:Abattoirs; D000818:Animals; D001128:Argon; D001842:Bone and Bones / Q000293:injuries / Q000473:pathology; D002245:Carbon Dioxide; D002645:Chickens / Q000293:injuries / Q000502:physiology*; D004558:Electric Stimulation; D006863:Hydrogen-Ion Concentration; D007103:Immobilization; D008460:Meat / Q000592:standards*; D009132:Muscles / Q000737:chemistry / Q000473:pathology; D014921:Wings, Animal / Q000293:injuries / Q000473:pathology
chemical_list: D002245:Carbon Dioxide; D001128:Argon