Stunning pigs with nitrogen and carbon dioxide mixtures: effects on animal welfare and meat quality
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Publication date
2011-10-10ISSN
1751-7311
Abstract
The aim of this study was to assess the effect of exposure to the gas mixtures of 70% nitrogen (N2) and 30% carbon dioxide (CO2;
70N30C), 80% N2 and 20% CO2 (80N20C) and 85% N2 and 15% CO2 (85N15C) on aversion, stunning effectiveness and carcass, as well
as meat quality in pigs, and to compare them with the commercial stunning of 90% CO2 (90C). A total of 68 female pigs were divided
into four groups and stunned with one of the gas mixtures. During the exposure to the gas, behavioural variables (retreat attempts,
escape attempts, gasping, loss of balance, muscular excitation and vocalizations) were recorded, and at the end of the stunning, corneal
reflex and rhythmic breathing were assessed. After slaughter, meat quality parameters such as pH at 45 min post mortem (pH45) and at
24 h post mortem (pHu), electrical conductivity, drip loss and colour, in the Longissimus thoracis (LT) and Semimembranosus (SM) muscles
were measured, and the presence of ecchymosis on the hams was noted. The PROC MIXED and the PROC GENMOD of SAS R were
used to analyse the parametric and binomial variables, respectively. The ‘gas mixture’ was always considered a fixed effect and the
‘live weight’ as a covariate. To assess the correlation between meat quality and behaviour measures, PROC CORR was used. Pigs
exposed to 90C showed a higher percentage of escape attempts and gasping, a lower percentage of vocalization and shorter muscular
excitation phase than pigs exposed to the other N2 and CO2 mixtures (P , 0.05). After stunning, no pig exposed to 90C showed
corneal reflex or rhythmic breathing, whereas 85% and 92% of the animals exposed to N2 and CO2 mixtures showed corneal reflex and
rhythmic breathing, respectively. Animals stunned with 80N20C and 85N15C had a lower pH45 (P , 0.01) than animals exposed to 90C.
Electrical conductivity in the SM muscle was lower (P , 0.001) in 90C and 70N30C pigs than in 80N20C and 85N15C pigs, whereas in
LT, it was lower (P , 0.05) in 90C pigs than in 85N15C. As the CO2 concentration of the gas mixture was decreased, the prevalence of
exudative pork increased. Twenty-five percent of animals exposed to N2 and CO2 mixtures (n 5 68) had ecchymosis in their carcasses,
whereas no animal stunned with 90C had ecchymosis. In conclusion, although N2 and CO2 stunning exhibit fewer signs of aversion
than 90C, their induction time to unconsciousness is longer, and this may negatively affect meat and carcass quality.
Document Type
Article
Document version
Published version
Language
English
Subject (CDU)
636 - Animal husbandry and breeding in general. Livestock rearing. Breeding of domestic animals
663/664 - Food and nutrition. Enology. Oils. Fat
Pages
8
Publisher
Cambridge University Press
Is part of
Animal
Citation
Llonch, P., P. Rodríguez, M. Gispert, A. Dalmau, X. Manteca, and A. Velarde. 2012. “Stunning Pigs With Nitrogen and Carbon Dioxide Mixtures: Effects on Animal Welfare and Meat Quality.” Animal 6 (4): 668–675. doi: 10.1017/s1751731111001911
Grant agreement number
INIA/ /AGL2005-06671-C02-01/ES/Efecto del aturdimiento con nitrogeno sobre la calidad de la canal y de la carne en porcino/GAN
Program
Benestar Animal
Qualitat i Tecnologia Alimentària
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- ARTICLES CIENTÍFICS [2646]
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