Yvonne Vizzier-Thaxton

The effects of low atmosphere stunning and deboning time on broiler breast meat quality.

Research was conducted to determine the effect of stunning method (low atmosphere pressure, LAPS, and electrical stunning, ES) and deboning time (0.75 and 4 h) on breast meat quality (n = 576, 144 birds per treatment) in a commercial processing plant. Breast meat quality was evaluated through determining pH, Commission Internationale dEclairage L*a*b*, cooking yield, shear force, and consumer acceptability. The onset of rigor mortis was more rapid (P < 0.05) in breast meat from LAPS-stunned birds compared with ES-stunned birds, but no differences existed (P > 0.05) among stunning methods with respect to final pH at 24 h. As expected, breast meat that was deboned at 4 h required less shear force (P < 0.05) to cut through the breast than samples that were deboned at 0.75 h postmortem, but no differences existed between breast meat from LAPS or ES broilers that were deboned at the same time postmortem. However, when samples were marinated with 2% NaCl and 0.5% phosphate, there was no difference in Allo-Kramer shear force between ES 4 h and LAPS 4-h samples, but the ES 0.75-h samples had lower shear force values (P < 0.05) than the LAPS 0.75-h samples. On average, the LAPS 4-h treatment had greater overall acceptability ratings (P < 0.05) than other treatments, and the ES and LAPS 4-h treatments had more acceptable (P < 0.05) texture than the ES and LAPS 0.75-h treatments. Cluster analysis revealed that the 2 largest consumer groups liked all chicken breast fillet treatments, but a larger proportion of consumers liked the 4-h LAPS and ES treatments compared with the 0.75-h LAPS and ES treatments. In addition, consumers who rated baked chicken breast as at least moderately acceptable preferred (P < 0.05) the 4-h LAPS samples over the 4-h ES samples. The present study revealed that both the LAPS and ES systems can be successfully used in commercial poultry plants without detrimental breast fillet quality problems with respect to color, texture, and consumer acceptance.

Broiler stunning methods and their effects on welfare, rigor mortis, and meat quality

Broiler stunning is conducted to produce a rapid onset of insensibility prior to slaughter. Though most broiler plants use electrical stunning applications, gas stunning, and low-atmosphere pressure stunning are also available for commercial applications. All three of these stunning methods are able to meet animal welfare requirements and produce meat with acceptable quality. However, each method differs in their mechanisms of stunning, rigor mortis patterns, and physical meat characteristics. In addition, gas stunning and low-atmosphere pressure stunning have received interest over the past decade as part of an effort to further improve animal welfare. Researchers have reported that gas and low-atmosphere pressure stunning both have potential advantages over electrical stunning with respect to broiler welfare and deboning time, which has been attributed to shackling post-stunning. This review paper will focus on these three stunning methods and their impact on animal welfare, physiology, rigor mortis patterns, carcass characteristics, and meat quality.

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

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 280s 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 regard 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 2s 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 50-60s 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 49.6s into LAPS), often associated with arrhythmia, until around 60s 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 60s. There were some effects of temperature adjusted 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.

Effects of light on responses to low atmospheric pressure stunning in broilers

Abstract Low atmospheric pressure stunning (LAPS) is a novel approach to poultry stunning involving the application of gradual decompression lasting 280 s according to a prescribed pressure curve. The aim of this study was to determine how behavioural, electroencephalogram (EEG) and electrocardiogram (ECG) responses to LAPS are influenced by illumination of the decompression chamber. A secondary aim was to examine responses to the decompression chamber without LAPS being applied, as such a “sham” control has been absent in previous studies. A two by two factorial design was employed, with LAPS/light, LAPS/dark, sham/light and sham/dark treatments (N = 20 per treatment). Broilers were exposed to each treatment in pairs, in each of which one bird was instrumented for recording EEG and ECG. Illumination was applied at 500 lx, and in sham treatments, birds were identically handled but remained undisturbed in the LAPS chamber without decompression for 280 s. Birds which underwent the sham treatment exhibited behaviours which were also observed in LAPS (e.g. sitting) while those exposed to LAPS exhibited hypoxia-related behaviours (e.g. ataxia, loss of posture). Behavioural latencies and durations were increased in the sham treatments, since the whole cycle time was available (in LAPS; birds were motionless by 186 s). Within the sham treatments, illumination increased active behaviour and darkness induced sleep, but slow-wave EEG was seen in both. The pattern of EEG response to LAPS (steep reduction in median frequency in the first 60 s and increased total power) was similar, irrespective of illumination, though birds in darkness had shorter latencies to loss of consciousness and isoelectric EEG. Cardiac responses to LAPS (pronounced bradycardia) closely matched those reported previously and were not affected by illumination. The effects of LAPS/sham treatment primarily reflected the presence/absence of hypoxia, while illumination affected activity/sleep levels in sham-treated birds and slowed time to unconsciousness in birds undergoing LAPS. Therefore, it is recommended that LAPS be conducted in darkness for poultry.

Sensory quality of broiler breast meat influenced by low atmospheric pressure stunning, deboning time and cooking methods

Stunning method (low atmospheric pressure stunning, LAPS and electrical stunning, ES), deboning time (0.75 h and 4 h), and cooking method (baking, frying, and sous vide) were evaluated for their impact on the descriptive sensory characteristics and consumer acceptability of breast meat (n=576, 144 birds per stunning × deboning time combination). Sensory evaluation was conducted by trained descriptive (n=8) and consumer (n=185) panels. On average, no differences (P>0.05) existed in the sensory acceptability of fried and sous vide cooked broiler breast treatment combinations. However, for oven-baking, the LAPS treatment that was deboned at 4 h was more acceptable (P<0.05) than other treatments and the ES and LAPS 4 h samples had greater (P<0.05) acceptability for texture than their ES and LAPS 0.75 h counterparts. Since consumers were highly variable in their liking of chicken breast treatments, consumers were grouped into clusters for each cooking method based on liking and preference. Cluster analysis data revealed that the largest groups of consumers liked (score≥6.0) all chicken breast treatments, but a larger proportion of consumers liked the 4 h LAPS and ES treatments when compared to the 0.75 h LAPS and ES treatments for all cooking methods. In addition, the consumers who indicated that baked chicken breast was highly acceptable preferred (P<0.05) 4 h LAPS over the 4 h ES samples. Based on sensory results, chicken breast meat from all stunning and deboning method combinations was highly acceptable to the majority of consumers, but the LAPS 4 h treatment had enhanced sensory characteristics when baked.

An evaluation of methods for measuring stress in broiler chickens

There are potential advantages for using noninvasive methods instead of conventional approaches for measuring corticosterone (CORT) as a metric of stress. Two studies compared blood heterophil: lymphocyte (H:L) ratios, serum CORT, cecal content CORT (Study 1), colon content CORT (Study 2), and feather CORT concentrations for broiler chicks receiving drinking water with or without added CORT. On day 28, male broilers (N = 140) were provided tap water (Control group) or water containing 20xa0mg/L of CORT (CORT group) for up to 72xa0h. Body weight (BW), blood, feather, cecal, and colon content samples were collected from 10 birds from each treatment group at 0, 6, 12, 24, 30, 48, and 72xa0h. Data were analyzed with a JMP Pro ANOVA. Mean comparisons were analyzed on significant treatment effects using post hoc t-tests to compare control and CORT measures within each sampling time point. Pearsons pairwise correlations for all data were performed. A treatment by time interaction affected all measures in both studies. In both studies, CORT treatment reduced body weight and increased H:L ratios at later time points. In study 1 cecal content CORT concentrations were elevated with CORT treatment after 24xa0h, whereas in study 2 colon content CORT concentrations were elevated after 6xa0h. CORT treatment increased body and primary feather CORT and primary feather CORT increased with time in control groups in both studies. Serum CORT exhibited the lowest variability compared with all other sample sources used for determining CORT. Estimates of CORT by different methods were positively correlated. These results indicate that serum CORT concentrations most reliably reflect the CORT status of broilers, and that feather CORT concentrations demonstrated potential for estimating stress in broilers.

Proceedings of the 50th Congress of the International Society for Applied Ethology 12-15th July, 2016, Edinburgh, United Kingdom

Antibiotic (AB) resistance is a major concern worldwide. Knowledge about potential drivers of AB use and prescribing practices in the pig industry is required to address problems of mis and over use. We hypothesised that pig farmers attitudes towards the treatment and care of injured or sick pigs may influence their use of AB. Semi-structured face-to-face interviews were conducted with 30 producers who managed integrated pig units in Ireland and which supplied records to the Teagasc PigSys database. Ethical approval was obtained and pig producers were invited for interview by their Teagasc pig advisor. Consent was obtained at the time of the interview. Interviews with participants were recorded and transcribed using random numbers from 1 to 30, one per participant to ensure anonymity. Themes were then identified from the data. The importance of comfort and care in the rehabilitation of animals following injury was only expressed in relation to sows. Here the importance of straw bedding and a solid floor innensuring recuperation from lameness/injury was mentioned by several producers (n=7). The relevance of analgesics to recovery from illness or injury was only mentioned by 2 producers who used pain relief for sows that were ‘sick after farrowing’. Injectable ABs were the most common method of treating illness or injury (n=12), followed by euthanasia (n=7). The practice of euthanising pigs was driven by economic (n=6) or humane grounds (n=9). The latter also expressed the belief that it was more humane to euthanise than to hospitalise sick or injured pigs. However, there was a general dislike for the practice of euthanasia. Many producers mentioned that it is too expensive to call a vet to treat or to euthanise sick or injured pigs. Only one producer used a vet to euthanise pigs. Several producers did not agree with the use of hospital pens (n=7) either because they believed that pigs are usually abandoned/forgotten in such pens (n=2) or because hospital pens are places where diseases are harbored and recirculated through the herd. Almost half of the producers expressed the view that medications (in-feed and/or injections) were the only solution to deal with pig health problems and to ensure good welfare. A 3rd of producers believed that the only solution to serious diseases challenges was to de-stock the herd. Low profit margins and lack of awareness of the role which husbandry and the environment have to play in the prevention of diseases as well as the role which comfort and care of pigs play in the recovery process are major barriers to reducing the reliance on medication in the pig industry

Welfare assessment of low atmospheric pressure stunning in chickens

Antibiotic (AB) resistance is a major concern worldwide. Knowledge about potential drivers of AB use and prescribing practices in the pig industry is required to address problems of mis and over use. We hypothesised that pig farmers attitudes towards the treatment and care of injured or sick pigs may influence their use of AB. Semi-structured face-to-face interviews were conducted with 30 producers who managed integrated pig units in Ireland and which supplied records to the Teagasc PigSys database. Ethical approval was obtained and pig producers were invited for interview by their Teagasc pig advisor. Consent was obtained at the time of the interview. Interviews with participants were recorded and transcribed using random numbers from 1 to 30, one per participant to ensure anonymity. Themes were then identified from the data. The importance of comfort and care in the rehabilitation of animals following injury was only expressed in relation to sows. Here the importance of straw bedding and a solid floor innensuring recuperation from lameness/injury was mentioned by several producers (n=7). The relevance of analgesics to recovery from illness or injury was only mentioned by 2 producers who used pain relief for sows that were ‘sick after farrowing’. Injectable ABs were the most common method of treating illness or injury (n=12), followed by euthanasia (n=7). The practice of euthanising pigs was driven by economic (n=6) or humane grounds (n=9). The latter also expressed the belief that it was more humane to euthanise than to hospitalise sick or injured pigs. However, there was a general dislike for the practice of euthanasia. Many producers mentioned that it is too expensive to call a vet to treat or to euthanise sick or injured pigs. Only one producer used a vet to euthanise pigs. Several producers did not agree with the use of hospital pens (n=7) either because they believed that pigs are usually abandoned/forgotten in such pens (n=2) or because hospital pens are places where diseases are harbored and recirculated through the herd. Almost half of the producers expressed the view that medications (in-feed and/or injections) were the only solution to deal with pig health problems and to ensure good welfare. A 3rd of producers believed that the only solution to serious diseases challenges was to de-stock the herd. Low profit margins and lack of awareness of the role which husbandry and the environment have to play in the prevention of diseases as well as the role which comfort and care of pigs play in the recovery process are major barriers to reducing the reliance on medication in the pig industry

SLAUGHTER-LINE OPERATION | Poultry

This article includes information about the processing line in poultry plants in which the live birds are slaughtered and the muscle tissue is converted to meat. The steps in the process include crating, unloading, stunning, bleeding, scalding, picking, evisceration, inspection, chilling, and packaging. Each step must be optimized for efficiency, food safety, and quality to insure that the broilers that are produced are economical, safe, and acceptable to consumers.