Controlled atmosphere stunning of broiler chickens. II. Effects on behaviour, physiology and meat quality in a commercial processing plant

McKeegan, Dorothy; Abeyesinghe, Siobhan; McLeman, Morven A.; Lowe, John C.; Demmers, T. G. M.; White, R.P.; Kranen, R.W.; Bemmel, H van; Lankhaar, J.; Wathes, C. M.

doi:10.1080/00071660701543097

Cited by 45 publications

(30 citation statements)

References 18 publications

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“…Slow exposure to hypoxia has been associated with increased heart rate responses in laying hens [4], and exposure to altitude in man also causes tachycardia [53]. The bradycardia observed here in broilers may relate to their compromised cardiovascular physiology [28] but in any case is consistent with exposure to relatively rapid hypoxia, as also seen during controlled atmosphere stunning in broilers [45,[36][37][38].…”

Section: Accepted M Manuscriptmentioning

confidence: 51%

“…Baseline points refer to signal collected prior to LAPS (3 outside chamber, 3 inside chamber). The coloured horizontal lines correspond to mean F50 previously recorded in chickens during sedation (<14 Hz [50], non-responsive to toe pinch after rapid anaesthetic 'knock down' (<12 Hz [33,36]) and surgical plane of general anaesthesia (<7 Hz [33,36,50] …”

Section: Figurementioning

confidence: 99%

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Behavioural, brain and cardiac responses to hypobaric hypoxia in broiler chickens

Martin

Christensen

Vizzier-Thaxton

et al. 2016

Physiology & Behavior

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A novel approach to pre-slaughter stunning of chickens has been developed in which birds are rendered unconscious by progressive hypobaric hypoxia. Termed Low Atmospheric Pressure Stunning (LAPS), this approach involves application of gradual decompression lasting 280 s according to a prescribed curve. We examined responses to LAPS by recording behaviour, electroencephalogram (EEG) and electrocardiogram (ECG) in individual male chickens, and interpreted these with regards to the welfare impact of the process. We also examined the effect of two temperature adjusted pressure curves on these responses. Broiler chickens were exposed to LAPS in 30 triplets (16 and 14 triplets assigned to each pressure curve). In each triplet, one bird was instrumented for recording of EEG and ECG while the behaviour of all three birds was observed. Birds showed a consistent sequence of behaviours during LAPS (ataxia, loss of posture, clonic convulsions and motionless) which were observed in all birds. Leg paddling, tonic convulsions, slow wing flapping, mandibulation, head shaking, open bill breathing, deep inhalation, jumping and vocalisation were observed in a proportion of birds. Spectral analysis of EEG responses at 2 s intervals throughout LAPS revealed progressive decreases in median frequency at the same time as corresponding progressive increases in total power, followed later by decreases in total power as all birds exhibited isoelectric EEG and died. There was a very pronounced increase in total power at 50-60 s into the LAPS cycle, which corresponded to dominance of the signal by high amplitude slow waves, indicating loss of consciousness.Slow wave EEG was seen early in the LAPS process, before behavioural evidence of loss of consciousness such as ataxia and loss of posture, almost certainly due to the fact that it was completely dark in the LAPS chamber. ECG recordings showed a pronounced bradycardia (starting on average 49.6 s into LAPS), often associated with arrhythmia, until around 60 s into LAPS when heart rate levelled off. There was a good correlation between behavioural, EEG and cardiac measures in relation to loss of consciousness which collectively provide a loss of consciousness estimate of around 60 s. There were some effects of temperature A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPTadjusted pressure curves on behavioural latencies and ECG responses, but in general responses were consistent and very similar to those reported in previous research on controlled atmosphere stunning with inert gases. The results suggest that the process is humane (slaughter without avoidable fear, anxiety, pain, suffering and distress). In particular, the maintenance of slow wave EEG patterns in the early part of LAPS (while birds are still conscious) is strongly suggestive that LAPS is non-aversive, since we would expect this to be interrupted by pain or discomfort. Highlights A novel stunning system uses hypobaric hypoxia to render poultry unconscious  We measured electroencephalogram, electrocardiogram and...

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Section: Accepted M Manuscriptmentioning

confidence: 51%

Section: Figurementioning

confidence: 99%

Behavioural, brain and cardiac responses to hypobaric hypoxia in broiler chickens

Martin

Christensen

Vizzier-Thaxton

et al. 2016

Physiology & Behavior

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“…2,28 Headshaking has also been observed in birds stunned with hypercapnic anoxic systems 2,10,28 but may occur to a lesser degree than in birds stunned with hypercapnic hyperoxygenation systems. 2,28 Headshaking has also been observed in birds stunned with hypercapnic anoxic systems 2,10,28 but may occur to a lesser degree than in birds stunned with hypercapnic hyperoxygenation systems.…”

Section: Behavioral Reactionsmentioning

confidence: 99%

A review of bird welfare during controlled atmosphere and electrical water-bath stunning

Johnson¹

2014

javma

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“…In recent experiments using several different gas mixtures, McKeegan, Abeyesinghe, et al (2007) concluded that a two-step system using 40% CO 2 , 30% O 2 , and 30% N in the first phase and 80% CO 2 , 5% O 2 , and 15% N in the second phase was best compared with a one-step system using either argon or argon mixed with 30% carbon dioxide from both a bird welfare and a meat quality perspective McKeegan, Abeyesinghe, et al, 2007). Not unexpectedly, behavioral observations at the slaughter plant showed that wing flapping and jumping associated with convulsions were greater in the gas mixture tested that contained argon, and this led to fractured wings and hemorrhages, whereas the transition to a motionless state was longer but occurred without convulsions while using the 40% CO 2 , 30% O 2 , and 30% N in the induction phase .…”

Section: Current Research On Gas Mixturesmentioning

confidence: 97%

A Critical Review of Electrical Water-Bath Stun Systems for Poultry Slaughter and Recent Developments in Alternative Technologies

Shields¹,

Raj

2010

Journal of Applied Animal Welfare Science

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Prior to slaughter, most farmed birds move through a constant-voltage, multiple-bird, electrical water-bath stun system. Using this system subjects live birds to stressful and painful shackling, and the potential exists for them to receive prestun electric shocks and induction of seizures while still conscious. The existing electrical water-bath stunner settings, particularly those used in U.S. slaughter plants, are not necessarily based on sound scientific data that they produce a consistent, immediate stun, and research indicates that they are not effective in all birds. Further, in multiple-bird, electrical water-bath systems, birds may miss the stunner completely. Evidence suggests that some birds may still be alive when they reach the scald vat. For these reasons, electrical water-bath systems are increasingly under scrutiny on nonhuman-animal welfare grounds. Controlled Atmosphere Killing (CAK), a promising alternative technology, uses gas mixtures to render birds unconscious. CAK systems that stun birds while they are still in their transport crates avoid many of the welfare problems associated with the live-hang process and electrical water-bath stunning.

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Controlled atmosphere stunning of broiler chickens. II. Effects on behaviour, physiology and meat quality in a commercial processing plant

Cited by 45 publications

References 18 publications

Behavioural, brain and cardiac responses to hypobaric hypoxia in broiler chickens

Behavioural, brain and cardiac responses to hypobaric hypoxia in broiler chickens

A review of bird welfare during controlled atmosphere and electrical water-bath stunning

A Critical Review of Electrical Water-Bath Stun Systems for Poultry Slaughter and Recent Developments in Alternative Technologies

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