Effects of crating and transport on stress and meat quality characteristics in broilers

Dietary creatine nitrate enhances muscle creatine loading and delays postmortem glycolysis of broilers that experienced preslaughter transport

This study investigated the attenuating effects of dietary creatine nitrate (CrN), a novel form of creatine, on energy expenditure and rapid glycolysis in pectoralis major (PM) muscle of broiler induced by preslaughter transport. A total of 288 Arbor Acres broilers (28 day old) were randomly assigned into five dietary treatments, including a basal diet or the basal diet supplemented with 600 mg/kg guanidinoacetic acid (GAA), 300, 600, or 900 mg/kg CrN for 14 d, respectively. On the day of transportation, the broilers from basal diet group were divided into two equal groups: one group was transported for 0.5 h (Control group) and the other group was transported for 3 h (T3h group). Meanwhile, the birds from GAA and CrN supplementation groups were transported for 3 h (identified as GAA600, CrN300, CrN600, and CrN900 group, respectively). The results demonstrated that dietary supplementation of GAA or CrN from 28 to 42 d of age did not significantly affect the growth performance, carcass traits, and textural characteristics (P > 0.05) in PM muscle of transported broilers. Compared with T3h group, GAA600, CrN600, and CrN900 groups increased the pH45min (P < 0.01), and CrN600, CrN900 groups decreased the cooking loss (P < 0.05) of PM muscle. Meanwhile, the muscle of GAA600, CrN600, and CrN900 groups showed a higher glycogen content (P < 0.01) and a lower lactic acid content (P < 0.01). GAA600 and all CrN treatments enhanced muscle Cr content and reduced AMP/ATP ratio (P < 0.01). In addition, GAA600 and all CrN treatments downregulated the relative mRNA expression levels of LKB1 and AMPKα2 (P < 0.001) and the protein expression of p-AMPKαThr172 compared with the T3h group (P < 0.01). All CrN treatments showed lower protein expression levels of LKB1 and p-LKB1Thr189 than those of the T3h group (P < 0.05). In summary, dietary supplementation with GAA and CrN enhanced the content of muscle creatine, and inhibited transport-induced activation of LKB1/AMPK pathway, which is beneficial for delaying rapid muscle glycolysis and improving meat quality.

Transmission of antimicrobial resistance (AMR) during animal transport

The transmission of antimicrobial resistance (AMR) between food-producing animals (poultry, cattle and pigs) during short journeys (< 8 h) and long journeys (> 8 h) directed to other farms or to the slaughterhouse lairage (directly or with intermediate stops at assembly centres or control posts, mainly transported by road) was assessed. Among the identified risk factors contributing to the probability of transmission of antimicrobial-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs), the ones considered more important are the resistance status (presence of ARB/ARGs) of the animals pre-transport, increased faecal shedding, hygiene of the areas and vehicles, exposure to other animals carrying and/or shedding ARB/ARGs (especially between animals of different AMR loads and/or ARB/ARG types), exposure to contaminated lairage areas and duration of transport. There are nevertheless no data whereby differences between journeys shorter or longer than 8 h can be assessed. Strategies that would reduce the probability of AMR transmission, for all animal categories include minimising the duration of transport, proper cleaning and disinfection, appropriate transport planning, organising the transport in relation to AMR criteria (transport logistics), improving animal health and welfare and/or biosecurity immediately prior to and during transport, ensuring the thermal comfort of the animals and animal segregation. Most of the aforementioned measures have similar validity if applied at lairage, assembly centres and control posts. Data gaps relating to the risk factors and the effectiveness of mitigation measures have been identified, with consequent research needs in both the short and longer term listed. Quantification of the impact of animal transportation compared to the contribution of other stages of the food-production chain, and the interplay of duration with all risk factors on the transmission of ARB/ARGs during transport and journey breaks, were identified as urgent research needs.

Research Note: Sex difference in changes in heterophil to lymphocyte ratios in response to acute exposure of both corticosterone and cortisol in the Pekin duck

Poultry scientists have utilized both direct and indirect measures of stress hormones for monitoring the state of avian welfare. For decades, it has been assumed that the mammalian and avian hypothalamic pituitary adrenal (HPA) function similarly to one another. However, there are considerable differences between the 2. Further, it has been assumed that the predominate glucocorticoid (GC) in birds was corticosterone, but recent studies have suggested that both corticosterone and cortisol are secreted. GC release is associated with an increase in blood heterophils due to increased migration from the lymph nodes and a decrease in lymphocytes due to marginalization. Both actions account for an increase in heterophil to lymphocyte ratios (HLR). The goal of this project was to determine the effect of each GC on HLR over time. To achieve this, we intramuscularly injected 2.0 mg/kg of corticosterone or cortisol, a lower dose cortisol treatment (0.5 mg/kg), or safflower oil as vehicle control. Blood was collected prior to intramuscular (IM) injections and blood collected 3 more times at every hour. Blood smears were also collected to assess HLR at the same four time points. HLR assays were completed by avian pathologists from an independent lab who were unaware of the treatments. Data were analyzed by 3-way repeated measures ANOVA with a P < 0.05 considered significant. We found significant sex (P < 0.001) x treatment (P < 0.001) x time (P < 0.001) effects with significant interactions (P = 0.0055). In hens, both GC resulted in significant increase in HLR at 1 h after injection compared to controls. In drakes, however, both GC showed a significant increase in HLR but not until 2 h after injection. The low dose cortisol had no significant effect on HLR in either sex. These data suggest that sex differences need to be considered when assessing duck welfare, and that cortisol may play a role in the HPA axis in ducks.

Sex differences in glucocorticoid responses to shipping stress in Pekin ducks

Some concerns have been raised recently about the assay of corticosterone vs. cortisol in poultry species. Thus, we tested the hypothesis that ducks secrete both glucocorticoids. First, we validated two commercially ELISA kits for the two glucocorticoids by first charcoal stripping duck serum in order to remove all steroid hormones. We ran serial dilutions of spiked, charcoal-stripped serum on kits of opposite glucocorticoid as well as a serial dilution using the respective ELISA buffer of the opposite assay kit. We found that the glucocorticoid standard curve in duck serum matched the respective curve in that kit's own buffer. However, when the opposite hormone was run in each kit in both duck serum or ELISA buffer, a near zero slope was obtained. Second, we further validated the presence of both glucocorticoids using mass spectrometry. Third, we tested the hypothesis that exogenous ACTH would stimulate the release of both corticosterone and cortisol. And, fourth, we tested the hypothesis that each glucocorticoid would have different serum levels in response to shipping stress. To test this hypothesis, we collected serum from 10 drakes and 10 hens from 2 flocks (N = 20 per time point per sex): 24 h prior to shipping, at shipping as ducks were walked off the truck, 24 h after shipping, and 1 wk after shipping. Data were analyzed by 2-way repeated measures ANOVA. Surprisingly, we also observed a sex difference in both glucocorticoid levels in that hens showed higher (P < 0.01) serum levels than did drakes at all-time points in response to either ACTH or transportation. Finally, no differences were observed in either glucocorticoid levels associated with shipping in either sex. The fact that both glucocorticoids are released in measurable amounts lends to the possibility that they may be differentially regulated, or at least there is a sex difference in the neural pathways associated with glucocorticoid release in ducks. Although corticosterone is the likely predominate glucocorticoid in ducks, serious attention should be given to the role of cortisol in poultry. Further consideration of sex, age, and timing of blood collection to stressor needs to be considered when assessing glucocorticoid levels in any avian species.

Meat Quality and Cooking Characteristics in Broilers Influenced by Winter Transportation Distance and Crate Density

A study was conducted to determine the effect of transportation distance and crating density on meat quality traits during winter. ROSS-308 broilers aged 35 days were divided into 10 treatment groups based on three transportation distances (80, 160, and 240 km) with three crating densities (10, 12, and 15 birds per crate) along with birds slaughtered on farm without crating as a control group. Each treatment was replicated 10 times and placed at various locations in the truck. The birds were transported in plastic crates of 0.91 m×0.55 m×0.30 m at ambient temperature and relative humidity of 3.6–9.5°C and 63.3–78.8%, respectively. The breast meat quality parameters including pH, color, drip loss, shear force, marinade uptake and retention, cooking losses, and yield were determined. The results showed significantly higher pH 15 min post-slaughter (PS), drip loss, lightness, marinade uptake, raw meat cooking yield, and shear force in birds slaughtered on farm without any transportation. The birds transported for 240 km had significantly higher pH at 2 hours (h) PS, marinade retention, and cooking yield. Whereas, pH at 24 h PS, meat redness, yellowness, chroma, and marinated meat cooking yield were significantly higher in all transported treatments compared to the control group. Among different crating densities, the birds transported with 10 birds per crate showed significantly higher meat redness, marinade retention, and cooking yield. The crating density of 15 birds per crate had significantly higher lightness, hue, cooking loss, and shear force. However, no effect of crating density was observed on meat pH, drip loss, and marinade uptake. It can be concluded that an increase in transportation distance and low crating density during winter can negatively affect physical quality of meat with significant improvement in marination and cooking characteristics.

Validation of alternative behavioral observation methods in young broiler chickens

Continuous sampling provides the most complete data set for behavioral research; however, it often requires a prohibitive investment of time and labor. The objectives of this study were to validate behavioral observation methods of young broiler chickens using 1) 7 scan sampling intervals (0.5, 1, 3, 5, 10, 15, and 30 min) and 2) an automated tracking software program (EthoVision XT 14) compared to continuous behavioral observation, considered the gold standard for behavior observation. Ten 19-day-old Ross 708 broiler cockerels were included in this study. All behavior was video recorded over an 8-h period, and data were collected using a continuous sampling methodology. The same video files were utilized for analysis for scan sampling and automated tracking software analysis. For both analyses, the following criteria were used to identify which method accurately reflected the true duration and frequency for each behavior, as determined by continuous observation: R² ≥ 0.9, slope was not different from 1 (P > 0.05), and intercept was not different from 0 (P > 0.05). Active, eating, drinking, and maintenance behaviors were accurately estimated with 0.5-min scan sample intervals. Active, inactive, eating, and maintenance behaviors were accurately estimated with 1-min scan sample intervals. Inactive behavior was accurately estimated with 5-min scan sample intervals. The remainder of sampling intervals examined did not provide accurate estimates, and no scan sampling interval accurately estimated the number of behavior bouts. The automated tracking software was able to accurately detect true duration of inactive behavior but was unable to accurately detect activity. The results of this study suggest that high-frequency behaviors can be accurately observed with instantaneous scan sampling up to 1-min intervals. Automated tracking software can accurately identify inactivity in young broiler chickens, but further behavior identification will require refinement.

Slaughter of animals: poultry

The killing of poultry for human consumption (slaughtering) can take place in a slaughterhouse or during on-farm slaughter. The processes of slaughtering that were assessed, from the arrival of birds in containers until their death, were grouped into three main phases: pre-stunning (including arrival, unloading of containers from the truck, lairage, handling/removing of birds from containers); stunning (including restraint); and bleeding (including bleeding following stunning and bleeding during slaughter without stunning). Stunning methods were grouped into three categories: electrical, controlled modified atmosphere and mechanical. In total, 35 hazards were identified and characterised, most of them related to stunning and bleeding. Staff were identified as the origin of 29 hazards, and 28 hazards were attributed to the lack of appropriate skill sets needed to perform tasks or to fatigue. Corrective and preventive measures were assessed: measures to correct hazards were identified for 11 hazards, with management shown to have a crucial role in prevention. Ten welfare consequences, the birds can be exposed to during slaughter, were identified: consciousness, heat stress, cold stress, prolonged thirst, prolonged hunger, restriction of movements, pain, fear, distress and respiratory distress. Welfare consequences and relevant animal-based measures were described. Outcome tables linking hazards, welfare consequences, animal-based measures, origins, and preventive and corrective measures were developed for each process. Mitigation measures to minimise welfare consequences were also proposed.

Mode of Action of Dietary Dexamethasone May Not Be Dependent Upon Microbial Mechanisms in Broilers

Dexamethasone (Dex), a synthetic glucocorticoid (GC), in feed has been shown to increase gut permeability via stress-mediated mechanisms, but the exact mode of action on gut barrier function is not fully understood. Stress has been reported to alter the profile and virulence of intestinal flora predisposing for opportunistic disease. This study aimed to evaluate the relationship between dietary Dex and recoverable intestinal microbial profile in broilers to better understand mode of action and refine future uses of the model. Three experiments were conducted that administered Dex-treated feed for one week in conjunction with the antibiotics BMD (bacitracin methylene disalicylate) or Baytril^® (enrofloxacin) to evaluate if enteric microbial mechanisms were important in Dex-induced permeability. Serum fluorescein isothiocyanate-dextran (FITC-d) and bacterial translocation (BT) have been reported to increase after Dex treatment and were used to assess gut epithelial leakage. Shifts in bacterial profiles were also measured on selective agar. Combining Dex with BMD or Baytril resulted in increased (P < 0.05) serum FITC-d versus Dex-only. Additionally, Baytril did not reduce aerobic BT and bacterial profiles remained similar after Dex. These results suggest a minimal role of intestinal microbes in Dex-induced changes to intestinal barrier function.

The Influence of Welfare Training on Bird Welfare and Carcass Quality in Two Commercial Poultry Primary Processing Plants

The number of broilers slaughtered globally is increasing. Ensuring acceptable welfare conditions for birds at the time of slaughter is paramount in meeting legislative and retailer specifications, and in producing high quality meat. There is knowledge that welfare training programs for members of the farming and red meat slaughter industry can improve animal welfare measures and product quality, however there is little evidence of the effects of welfare training in poultry processing plants. In our study, a comprehensive welfare training program was introduced to a Costa Rican and a British commercial broiler primary processing plant, both of which slaughter birds by way of neck cut post electrical water bath stunning. The effects of this program on some welfare and product quality measures were investigated, both immediately and six months post training. The welfare measures that showed significant improvements post training included; flapping at shackling, pre-stun shocks, stun parameters and effective neck cut. Product quality measures including broken wings and red pygostyles also improved, however the positive effect of training was not seen in all quality measures. Welfare training does have the potential to improve broiler welfare and product quality at slaughter, and these data could help the development and targeting of future welfare training courses and encourage the uptake of welfare training in the poultry slaughter industry.

Effects of commercial hatchery processing on short- and long-term stress responses in laying hens

In commercial egg production, chicks are exposed to a potentially stressful procedure during their first day of life. Here, we investigated how this procedure affects the chickens in a short- as well as long-term perspective by conducting two behaviour tests and measuring corticosterone (CORT) and sex hormone levels at different time points. These results were compared with a group of control chickens from the same hatchery and incubator that did not go through the commercial hatchery routine. Chickens were continuously weighed, egg production data was collected and feather scoring was performed. We found that chicks have a significant increase in CORT during the hatchery process, which implies they are exposed to stress. During first weeks of life, these chicks were more fearful, had a higher CORT reactivity during restraint and weighed more than control chicks. Later in life, hatchery treated chickens had more feather damages and injuries on combs and wattles, a faster onset of egg laying and higher levels of estradiol. We conclude that processing at the commercial hatchery was a stressful event with short- and long-term effects on behaviour and stress reactivity, and potentially also positive effects on production. The results are relevant for a large number of individuals, since the chicken is by far the globally most common farm animal.

Mobile Poultry Processing Unit as a Resource for Small Poultry Farms: Planning and Economic Efficiency, Animal Welfare, Meat Quality and Sanitary Implications

Simple Summary

Poultry meat production is now based on fast-growing strains, with consequences for animal health and welfare. There is also an increasing demand for products from extensive rearing systems; there are, however, several criticisms including the difficulty of slaughtering chickens from a logistic, legislative and economic point of view. A possible solution could be represented by the use a Mobile Poultry Processing Unit (MPPU), which directly reaches the poultry farms. The aim of this review is to analyse the requisites and economic efficiency of a MPPU prototype in Italy; further, the related animal welfare aspects and the qualitative and sanitary implications are discussed.

Abstract

Nowadays there is an increasing demand for poultry products from alternative rearing systems. These systems, commonly named pastured poultry production (PPP), are more expensive than intensive rearing system but sustain biodiversity, local economies and farm multi-functionality besides providing meat to which consumers attribute high ethical value and quality. PPP generally uses large outdoor runs, small number of animals and requires chickens adapted to natural environment. One of the most relevant obstacles to further development of PPP systems is related to the slaughtering of animals economically and at the same time complying with the sanitary regulations to maintain food safety standards. A possible solution could be represented by a Mobile Poultry Processing Unit (MPPU), which directly reaches the poultry farms. MPPU can consider a good compromise for the niche production providing an opportunity to small farmers to exploit the full potential of their production system. The aim of this review is to analyse the essential requisites and MPPU economic viability in an Italian system. Qualitative, societal aspects are discussed together with bird welfare and hygiene implications. The case study indicates the viability of MPPUs but notes that up scaling to medium sized operations would not be permissible under current EU regulations.

Dietary resveratrol supplementation prevents transport-stress-impaired meat quality of broilers through maintaining muscle energy metabolism and antioxidant status

This experiment was to evaluate the effect of dietary resveratrol (Res) supplementation (0, 400 mg/kg) on growth performance, meat quality, and muscle anaerobic glycolysis and antioxidant capacity of transported broilers. A total of 360 21-day-old male Cobb broilers was randomly allotted to 2 dietary treatments (Res-free group and Res group) with 12 replicates of 15 birds each. On the morning of d 42, after a 9-hour fast, 24 birds (2 birds of each replicate) were selected from the Res-free group and then equally placed into 2 crates, and the other 12 birds (one bird of each replicate) were selected from the Res group and then placed into the other crate. All birds in the 3 crates were transported according to the following protocols: 0-hour transport of birds in the Res-free group (control group), 3-hour transport of birds in the Res-free group (T group), and 3-hour transport of birds in the Res group (T + Res group). The results showed that Res not only improved feed conversion ratio (P < 0.05) but also tended to improve birds’ final body weight (P < 0.10). In the Res-free group, a 3-hour transport increased serum corticosterone concentration, muscle malondialdehyde (MDA) and lactate contents, and muscle lactate dehydrogenase (LDH) activity, while it decreased muscle glycogen content, total superoxide dismutase (T-SOD), and glutathione peroxidase (GSH-PX) activities (P < 0.05), which induced decreased breast meat quality (lower pH_24h and higher drip loss and L*_24 h, P < 0.05). Nevertheless, compared with the T group, Res increased muscle glycogen content and T-SOD and GSH-PX activities (P < 0.05 or P < 0.10), while it decreased muscle MDA content and LDH activity (P < 0.05), which is beneficial to the meat quality maintenance of transported broilers (lower drip loss, L*_24 h, and higher pH_24h, P < 0.05 or P < 0.10). This study provides the first evidence that dietary resveratrol supplementation prevents transport-stress-impaired meat quality of broilers, possibly through decreasing the muscle anaerobic glycolysis metabolism and improving the muscle antioxidant capacity.

Different oxidative status and expression of calcium channel components in stress-induced dysfunctional chicken muscle

The objective of this study was to assess the effects of transport stress at high ambient temperatures on the oxidation status and the expression of essential elements responsible for the Ca transport (sarco- (endo-) plasmic reticulum Ca-ATPase (SERCA1) and the ryanodine receptor (RyR) in (PM) muscles of broilers. Briefly, Arbor Acres broiler chickens ( = 112) were randomly categorized into 2 treatments: unstressed control (C) and 0.5 h transport (T). Each treatment consisted of 8 replicates of 7 birds each. Birds were transported according to a designed protocol. PM muscle samples in T group were collected and classified as normal (T-NOR) or pale, soft, and exudative-like (T-PSE) using meat quality parameters. The results indicated that production of corticosterone (CORT) and reactive oxygen species (ROS) increased significantly after transportation ( < 0.05). Thiobarbituric acid reactive substance values and carbonyl contents increased significantly in the T group ( < 0.05). Moreover, the extent of lipid peroxidation and protein oxidation was more severe in the T-PSE group compared to the T-NOR group ( < 0.05). The mRNA and protein expression of SERCA1 and αRyR increased in the T-NOR group but decreased significantly in the T-PSE group compared to the CON group ( < 0.05). The mRNA expression of βRyR was found to be enhanced in the T-NOR group compared to the CON group, whereas there was no difference in the T-PSE group ( < 0.05). The results indicate that short-distance transport of broilers affects their physiological responses and biochemical changes which may lead to different oxidative states and, importantly, to different expressions of SERCA and RyR. These induced changes in abnormal sarcoplasmic Ca homeostasis have significant implications for the development of PSE-like meat.

Creatine Monohydrate Enhances Energy Status and Reduces Glycolysis via Inhibition of AMPK Pathway in Pectoralis Major Muscle of Transport-Stressed Broilers

Creatine monohydrate (CMH) contributes to reduce transport-induced muscle rapid glycolysis and improve meat quality of broilers, but the underlying mechanism is still unknown. Therefore, this study aimed to investigate the molecular mechanisms underlying the ameliorative effects of CMH on muscle glycolysis metabolism of transported broilers during summer. The results showed that 3 h transport during summer elevated chicken live weight loss and plasma corticosterone concentration; decreased muscle concentrations of ATP, creatine, and energy charge value; increased muscle AMP concentration and AMP/ATP ratio; and upregulated muscle mRNA expression of LKB1 and AMPKα2, as well as protein expression of p-LKB1^Thr189 and p-AMPKα^Thr172, which subsequently resulted in rapid glycolysis in the pectoralis major muscle and consequent reduction of meat quality. Dietary addition of CMH at 1200 mg/kg ameliorated transport-induced rapid muscle glycolysis and reduction of meat quality via enhancement of the energy-buffering capacity of intramuscular phosphocreatine/creatine system and inhibition of AMPK pathway.

Effects of water-misting sprays with forced ventilation on post mortem glycolysis, AMP-activated protein kinase and meat quality of broilers after transport during summer

Effects of water-misting sprays with forced ventilation on post mortem glycolysis, adenosine monophosphate-activated protein kinase (AMPK) and meat quality of broilers after transport during summer were investigated in the present paper. A total of 105 mixed-sex Arbor Acres broilers were divided into three treatment groups: (i) 45 min transport without rest (T); (ii) 45 min transport with 1 h rest (TR); and (iii) 45 min transport with 15 min water-misting sprays with forced ventilation and 45 min rest (TWFR). Each treatment consisted of five replicates with seven birds each. The results indicated that the water-misting sprays with forced ventilation could mitigate the stress caused by transport under high temperature conditions during summer, which reduced the energy depletion in post mortem Pectoralis major (PM) muscle. This resulted in a higher energy status compared to the T group, which would decrease the expression of phosphorylation of AMPK (p-AMPK). Furthermore, decreased the expression of p-AMPK then slowed down the rate of glycolysis in post mortem PM muscle during the early post mortem period, which in turn lessened the negative effects caused by transport on meat quality. In conclusion, water-misting sprays with forced ventilation may be a better method to control the incidence of the pale, soft and exudative meat in broilers.

Improving appearance and microbiologic quality of broiler carcasses with an allostatic modulator

An important priority of poultry producers is to guarantee animal welfare during animal production; however, broilers are exposed to unavoidable chronic stress (also known as allostasis) when they are captured, caged, and transported to the processing plant. This antemortem management causes allostatic load, animal injuries, and poor carcass quality. The aim of the present study was to evaluate the effects of an allostatic modulator (AM) on antemortem stress by measuring the appearance and microbiological quality of broiler carcasses. The AM consisted of a liquid formula containing ascorbic acid, acetyl salicylic acid, and electrolytes, administered orally 48 h before shipment to the processing plant. A total of 600 chickens (49-days-old) were used under a factorial arrangement 2 × 2 × 2 [2 commercial hybrid lines, 2 feed withdrawal programs (10 and 16 h), and 2 water treatments (control and AM)]. Each treatment included 25 chickens per pen and was carried out in triplicate. The broilers were shipped, slaughtered, and processed in a commercial processing plant where carcass defects (bruises and broken bones caused by antemortem management), crop pH, and carcass bacterial counts were evaluated in all experimental groups. Broilers under AM treatment showed a reduction in carcass defects (P = 0.015), crop pH (P = 0.0001), coliforms counts (P = 0.014), and total aerobic mesophilic bacteria (P = 0.0001) when compared to the control treatment. The present study indicates that the AM can be used to improve carcass quality in broilers. Our study provides a novel and economic alternative to reduce the allostatic load in broilers.

Induction of tissue- and stressor-specific kinomic responses in chickens exposed to hot and cold stresses

Defining cellular responses at the level of global cellular kinase (kinome) activity is a powerful approach to deciphering complex biology and identifying biomarkers. Here we report on the development of a chicken-specific peptide array and its application to characterizing kinome responses within the breast (pectoralis major) and thigh (iliotibialis) muscles of poultry subject to temperature stress to mimic conditions experienced by birds during commercial transport. Breast and thigh muscles exhibited unique kinome profiles, highlighting the distinct nature of these tissues. Against these distinct backgrounds, tissue- and temperature-specific kinome responses were observed. In breast, both cold and hot stresses activated calcium-dependent metabolic adaptations. Also within breast, but specific to cold stress, was the activation of ErbB signaling as well as dynamic patterns of phosphorylation of AMPK, a key regulatory enzyme of metabolism. In thigh, cold stress induced responses suggestive of the occurrence of tissue damage, including activation of innate immune signaling pathways and tissue repair pathways (TGF-β). In contrast, heat stress in thigh activated pathways associated with protein and fat metabolism through adipocytokine and mammalian target of rapamycin (mTOR) signaling. Defining the responses of these tissues to these stresses through conventional markers of pH, glycolytic potential, and meat quality offered a similar conclusion of the tissue- and stressor-specific responses, validating the kinome results. Collectively, the results of this study highlight the unique cellular responses of breast and thigh tissues to heat and cold stresses and may offer insight into the unique susceptibilities, as well as functional consequences, of these tissues to thermal stress.

Evaluation of a commercially available organic acid product on body weight loss, carcass yield, and meat quality during preslaughter feed withdrawal in broiler chickens: a poultry welfare and economic perspective

The effect of a commercial organic acid (OA) product on BW loss (BWL) during feed withdrawal and transportation, carcass yield, and meat quality was evaluated in broiler chickens. Two experiments were conducted in Brazil. Commercial houses were paired as control groups receiving regular water and treated groups receiving OA in the water. Treated birds had a reduction in BWL of 37 g in experiment 1 and 32.2 g in experiment 2. In experiment 2, no differences were observed in carcass yield between groups. Estimation of the cost benefit suggested a 1:16 ratio by using the OA. In experiment 3, conducted in Mexico, significant differences on water consumption, BWL, and meat quality characteristics were observed in chickens that were treated with the OA (P < 0.05). These data suggest this OA product may improve animal welfare and economic concerns in the poultry industry by reducing BWL and improving meat quality attributes.

Blood corticosterone levels in growing geese around feather gathering

Feather production is realised by gathering feathers from geese right as they start their natural moulting. The adequate gathering time coincides with the time of moulting. There is still scarce information as to whether or not gathering causes distress and pain to geese. A series of experiments was carried out by our research group to determine the effect of gathering on plasma corticosterone level in growing geese. In the present experiment, the reactions of five groups (two gathered and three not gathered groups) of 9-week-old Babat Hungarian Upgraded geese were compared regarding gathering. Blood samples were taken right before, during and 5 min, 1 and 3 h after gathering into heparinised tubes from all groups. The plasma concentration of corticosterone was determined by radioimmunoassay (RIA). The results show that the plasma concentration of corticosterone is high in the first sample of all groups but is significantly lower at subsequent blood samplings compared to the first samples, especially in gathered geese. Compared to the first sampling, we observed higher corticosterone levels in samples collected 1 and 3 h after gathering. This was true only for groups which were not gathered, especially for the group which was not given any antistress material. From these results it can be concluded that the handling of geese causes an elevation in plasma corticosterone level and that feather gathering does not result in a higher corticosterone level than the handling or catching of the bird. Therefore, it can be concluded that feather gathering - especially when it is done adequately in time - does not cause more distress than the handling or catching of the bird.

Interaction of transport distance and body weight on preslaughter stress and breast meat quality of broilers

1. The objective of the study was to investigate the effect of transport distance on blood metabolites and breast meat quality of broilers slaughtered at different weights. 2. The study was conducted on Ross 308 broilers from 27 different flocks reared under similar conditions. Slaughter weight was classified as <2·0 kg, 2·0-2·4 kg, and >2·4 kg. Transport distance was categorised as short (65 km), medium (115 km) and long (165 km) distance representing 90, 155 and 220 minutes at an average 45 km/h speed, for each slaughter weight. 3. Higher heterophils and heterophil:lymphocyte (H/L) ratios were obtained for broilers transported over a long distance. Long distance transport increased blood albumin, glucose, and triglycerides levels for <2·0 kg broilers, which did not differ from broilers slaughtered at >2·4 kg after long-distance transport. 4. Broilers slaughtered at >2·4 kg after long-distance transport had lower pH(u), and paler and tougher breast meat, than those broilers slaughtered at <2·0 kg after long-distance transport. 5. A negative correlation was obtained between pH(u) and L*, thawing loss and texture. The L* value was negatively correlated with a*; and positively correlated with b*, thawing and cooking losses. 6. It was concluded that the effect of transport distance could not be evaluated independently of slaughter weight. The interaction between transport distance and slaughter weight contributes to preslaughter stress and meat quality.

Broiler chicken thigh and breast muscle responses to cold stress during simulated transport before slaughter

The effect of acute cold exposure was assessed on broiler physiology, breast and thigh muscle metabolites, and meat quality. In total, 160 male birds at ages of 5 and 6 wk were exposed to temperatures of -9 to -15°C (cold stressed) and +20°C (control) in a simulated transport chamber for 3 h before slaughter followed by 0 or 2 h of lairage. Bird physiology parameters, including core body temperature, live shrink, blood glucose, and muscle temperature, were assessed. Core body temperature was monitored every minute using i-Button data loggers, and live shrink and blood glucose were assessed. Total glucose and lactate concentrations at 30 h postmortem, as well as ultimate pH (pH(u)), color, and water-holding attributes were evaluated on pectoralis major muscle of breast and iliotibialis muscle of thigh. Birds were grouped based on their microclimate temperature to control and cold-stressed groups (0 to -8, -8 to -11, and -11 to -14°C). Significant (P < 0.05) decreases in core body temperature and breast and thigh muscle temperatures were observed at simulated transport temperatures below 0°C. In addition, higher (P < 0.05) live shrink and lower blood glucose values were observed as a result of 3-h exposure to temperatures below 0°C, exacerbated as temperature decreased further below -8°C. Thigh muscle was almost depleted of glycogen reserve compared with a significant but small reduction in breast muscle glycogen when exposure temperature was below -8°C. Similarly, much greater effects were observed on thigh pH(u) and quality attributes compared with breast. In addition, 84% incidence of the dark, firm, dry quality defect was observed in thigh meat (pH(u) > 6.4, L* < 44) compared with 42% incidence of dark, firm, dry in breast meat (pH(u) > 6.1, L* < 46) when transportation temperature was below 0°C. Results of this study showed that thigh muscle was affected more severely than breast muscle by exposure to cold temperatures before slaughter.

Road transport of cattle, swine and poultry in North America and its impact on animal welfare, carcass and meat quality: a review

This paper reviews the effects of road transport on the welfare, carcass and meat quality of cattle, swine and poultry in North America (NA). The main effects of loading density, trailer microclimate, transport duration, animal size and condition, management factors including bedding, ventilation, handling, facilities, and vehicle design are summarized by species. The main effects listed above all have impacts on welfare (stress, health, injury, fatigue, dehydration, core body temperature, mortality and morbidity) and carcass and meat quality (shrink, bruising, pH, color defects and water losses) to varying degrees. It is clear that the effect of road transport is a multi-factorial problem where a combination of stressors rather than a single factor is responsible for the animal's well-being and meat quality post transport. Animals least fit for transport suffer the greatest losses in terms of welfare and meat quality while market ready animals (in particular cattle and pigs) in good condition appear to have fewer issues. More research is needed to identify the factors or combination of factors with the greatest negative impacts on welfare and meat quality relative to the species, and their size, age and condition under extreme environmental conditions. Future research needs to focus on controlled scientific assessments, under NA conditions, of varying loading densities, trailer design, microclimate, and handling quality during the transport process. Achieving optimal animal well-being, carcass and meat quality will entirely depend on the quality of the animal transport process.

Changes in selected biochemical indices related to transport of broilers to slaughterhouse under different ambient temperatures

The effect of transport distance on selected biochemical parameters (corticosterone, uric acid, triglycerides, total protein, glucose, and lactate) under various ambient temperatures was monitored in a group of unsexed Ross 308 broilers aged 42 d. Broilers were transported to the slaughterhouse over 3 different travel distances (10, 70, and 130 km). They were sampled before and after each transportation in 3 various periods with different ambient temperatures (-5 to +5°C, 10 to 20°C, and 25 to 35°C), which approximately correspond to temperature conditions during transport in individual seasons of the year (winter, fall, summer). The changes in biochemical parameters were specific in their dependence on the travel distance and the ambient temperature under which the broilers were transported. The highest corticosterone concentration was found in broilers before transport (i.e., immediately after catching, crating, and loading) at all ambient temperatures. The concentration of corticosterone was higher at winter temperatures than at summer and fall temperatures. Triglycerides decreased with travel distance, although this effect was detected under summer temperatures only. The concentration of total protein was higher only after 10 km of transport and then it decreased with travel distance at all monitored ambient temperatures. A highly significant decrease (P < 0.01) in the glucose level of broilers was observed after 130 km of transport when compared with broilers before transport at fall and winter temperatures. The effect of travel distance on lactate concentrations was the same at all monitored ambient temperatures, with the lactate level decreasing with travel distance. The results obtained indicate that pretransport handling procedures (catching, crating, and loading) may be more stressful for broilers than the transport itself. To improve broiler meat quality, it is necessary to meet the need for broilers to recover before being slaughtered. With regard to different seasons of the year, we can assume that transport under conditions of low ambient temperatures in winter represents a more stressful event than transport during fall and summer.

Effects of loading methods on rabbit welfare and meat quality

The effects of different loading methods on the welfare, carcass characteristics and meat quality traits of hybrid commercial rabbits were investigated. 384 male rabbits, 82 days old, were transported from the farm to the slaughterhouse. At the farm, 192 rabbits were loaded onto the truck smoothly (S) and 192 rabbits were loaded roughly (R). The S loading method consisted of carefully placing each rabbit into the transport crates. In the R method, the loading was hurriedly and carelessly executed by the transport operator, throwing each animal into the crates fixed on the truck. Live weight before and after transport as well as slaughter data were recorded for each rabbit, and a subset of 80 carcasses were evaluated for meat quality. Blood samples from 80 rabbits were analysed for haematological and biochemical parameters. A significant neutrophilia (P<0.001), lymphocytopaenia (P<0.001) and an increase in serum aspartate aminotransferase (AST) (P<0.01), alanine aminotransferase (ALT) (P<0.001) and creatine kinase (CK) activities (P<0.001) were recorded in all rabbits after transport, independent of the loading method. A twofold increase in serum corticosterone concentration (6.23 vs. 14.88 ng/mL; P=0.001) was observed in all rabbits following transport. Results suggest that the stress parameters analysed were more influenced by transport and handling itself rather than by the different loading methods. The results showed that there was no adverse effect of loading method on carcass traits. Furthermore, the stress condition evidenced by haematological and biochemical parameters prior to slaughter did not affect meat quality.

Corticosterone administration induces oxidative injury in skeletal muscle of broiler chickens

The present study had been conducted to explore the effect of corticosterone (CORT) on the induction of lipid peroxidation in skeletal muscle. The experimental chickens were subjected to 1 single s.c. injection of CORT (4 mg/kg of BW). Blood samples were obtained at the beginning and end of a 3-h experimental period. Muscle samples were obtained from musculus pectoralis major and musculus biceps femoris (BF) before and immediately after slaughter, and at 24- and 48-h time points postmortem. The result showed that plasma level of TBA reacting substances (TBARS) was significantly increased, whereas the activity of super-oxide dismutase was decreased after CORT injection. Plasma level of total antioxidant power, as reflected by the ferric reducing-antioxidant power, was increased by CORT administration. The preslaughter level of TBARS could be increased by CORT administration in pectoralis major. In contrast, although the preslaughter level of TBARS was not significantly changed by CORT administration in BF, the augmented TBARS level was detected at 48 h postmortem in BF of CORT chickens. During the period of storage, the concentrations of TBARS increased, whereas ferric reducing-antioxidant power level decreased over time regardless of treatment. In conclusion, the data suggest that elevated CORT due to preslaughter stress would affect the redox balance in skeletal muscle. The result suggested that the oxidative stability during storage of meat is associated with the alteration in muscle physiology induced by CORT administration.

Effects of Diet and Stress Mimicked by Corticosterone Administration on Early Postmortem Muscle Metabolism of Broiler Chickens

Three experiments were conducted to evaluate the effects of preslaughter physiological states mimicked by long- or short-term administration of corticosterone (CORT) and dietary energy sources on muscle glycogen contents and meat quality of broiler chickens. In experiment 1, the broilers were fed a high lipid diet (LD) or a normal diet (ND) that differed in carbohydrate (3.8%) and lipid (2.5%) contents from 21 d of age. From 28 d of age onwards, 50% of the chickens in each dietary treatment were subjected to CORT treatment (30 mg/kg of diet). At 7 and 11 d after CORT supplementation, musculus pectoralis major was sampled before and immediately after slaughter and analyzed for glycogen, pH, and R-value. In experiment 2, broilers, fed with the LD or ND diet from 21 d of age were subjected to 1 single s.c. injection of CORT (4 mg/kg of BW) for 3 h to mimicked acute stress at 46 d of age. In experiment 3, broiler chickens were supplied with water supplemented with glucose (30 g/L) for 1 wk before slaughter and were then subjected to the same CORT treatment as experiment 2. Blood and muscle samples were respectively obtained before and immediately after slaughter and analyzed for plasma glucose, urate and lactic acid, and muscle variables. Plasma concentrations of glucose and urate were significantly increased by acute CORT administration, whereas the lactic acid was not changed. Neither dietary energy source nor water glucose supplementation had any influence on the plasma variables. Dietary energy source or water glucose supplementation could not alter glycogen stores in musculus pectoralis major. Breast muscle glycogen stores were increased by stress mimicked by long-term CORT administration rather than by acute treatment. Preslaughter stress reactions had no relation to the depletion of breast muscle glycogen during the initial postmortem period. The initial breast muscle pH was significantly decreased by long-term CORT administration. The result suggests that short-term upregulation of circulating CORT is not involved in the elevated drip loss induced by preslaughter stress.

Effects of Travel Distance and the Season of the Year on Death Rates of Broilers Transported to Poultry Processing Plants

Death losses among broilers transported to processing plants are caused by poor welfare. The number of birds dying during transport and in processing plants shortly after arrival there may serve as an indicator of the quality of welfare during loading and transport. In the Czech Republic, shipments of broilers to processing plants were monitored from 1997 to 2004. It was found that the mortality of broilers during transport was 0.247%, but it varied according to the transport distance to the processing plant from 0.146% (50 km maximum) to 0.862% (>300 km). The broiler mortality in transit was also influenced by the season of the year. The highest mortality was found in summer months, especially in June, July, and August, and in winter months, especially in December, January, and February. A comparison between period 1 (1997 to 2000) and period 2 (2001 to 2004) showed a long-term adverse trend in the number of broilers dying during transport to processing plants for all of the distances monitored (except transport distances <50 km), because the overall number of dead birds on arrival to processing plants increased from 0.224 to 0.265% (index of 1.18). This difference is statistically significant (P = 0.000). The stress caused to broilers by transport to processing plants is reflected in higher transport-related mortality of the birds. Long-term trends point to an increase in death losses of broilers. Longer transport distances and transportation in summer and winter months have led to an increase in death losses among broilers transported to processing plants.

Effects of Temperature During Rearing and Crating on Stress Parameters and Meat Quality of Broilers

Two trials were conducted to study the effects of heat stress during rearing (trial 1) and crating (trial 2) on broiler stress parameters and fear, breast meat quality, and nutrient composition. The relationships between stress parameters and meat quality traits were also determined. Trial 1 consisted of 3 temperature treatments from 3 to 7 wk: control (temperature was 22 degrees C); diurnal cyclic temperature (temperature was 28 degrees C from 1000 to 1700 h and 22 degrees C from 1700 to 1000 h); and constant high temperature (34 degrees C; temperature was 34 degrees C). In trial 2, broilers from the control and 34 degrees C groups in trial 1 were used. Broilers in each group were placed in transport cages. The 9 cages from the control group were divided into 3 groups and placed into 3 rooms at 15, 22, or 34 degrees C for 2 h. The 3 cages from the 34 degrees C group were also held in the room at 34 degrees C (34-34 degrees C). Diurnal cyclic temperature had no effect on BW up to 5 wk of age. The effect of 34 degrees C constant temperature on BW of broilers increased with age. Plasma levels of glucose and albumin increased by 34 degrees C, but no dramatic change in levels occurred when those broilers were crated at 34 degrees C. The heterophil:lymphocyte (H:L) was higher for the 34-34 degrees C broilers and the control broilers in the 34 degrees C room than those from the 22 and 15 degrees C room. Breast muscle glycogen level decreased in broilers reared under diurnal cyclic or high temperatures. A lower pH and higher lightness (L*) and redness values and redness:yellowness were found in meat for broilers from both 34 degrees C and 34-34 degrees C groups. Higher H:L was associated with breast muscle pH according to first-order polynomial regression. The H:L had a significant effect on L* values, which were described by a second-order polynomial regression. Blood glucose level was positively correlated with L* and redness values. Duration of tonic immobility was neither influenced by rearing and crating temperatures nor associated with meat quality parameters.

Variations in chicken breast meat quality: implications of struggle and muscle glycogen content at death

1. Pectoralis major (P. major) muscle pH and meat quality traits were studied in relation to bird response to ante-mortem stress in three chicken lines: a fast-growing standard line (FGL), a slow-growing French 'Label Rouge' line (SGL) and a heavy line (HL). Ninety-nine birds of the three genetic types were slaughtered at their usual marketing age (6, 12 and 6 weeks for FGL, SGL and HL birds, respectively) on the same day. The birds of each line were divided into three different ante-mortem treatment groups: minimum stress (shackling for 10 s) (C), shackling for 2 min (SH) and acute heat plus shackling stress (exposure to 35 degrees C for 3.5 h and shackling for 2 min before stunning) (H + SH). 2. Regardless of chicken line, wing flapping duration (WFD) between hanging and stunning was strongly negatively related to P. major muscle pH at 15 min post-mortem. It was also moderately negatively related to P. major muscle glycolytic potential (GP), which represents glycogen level at death. Increasing WFD induced an increased ultimate pH (pHu) only in HL. The consequences of increased WFD for breast meat traits were dependent on the chicken line: it induced lower L* and b* and higher a* and drip loss in SGL while it only increased breast a* in HL birds. By contrast, WFD variations did not alter breast meat quality traits of FGL birds. Regardless of the chicken line, increased GP was associated with lower pHu and higher L* and drip loss. In SGL, it also increased b* and decreased curing-cooking yield of breast meat. 3. Struggling activity on the shackle line and muscle glycogen content at death could partly explain line and pre-slaughter variations in breast meat pH and quality traits. The water holding capacity of the raw and cooked meat was impaired by long shackling in the case of SGL birds while it was barely affected by ante-mortem conditions in the two standard lines. In conditions which minimised bird struggling (C), SGL and FGL birds had meat with a better water holding ability than that of broilers from the heavy line. However, when broilers were subjected to SH or H + SH conditions, the breast meat water holding capacity of SGL birds was lowered to the same level as that of the heavy line birds.

Breed differences in the biochemical determinism of ultimate pH in breast muscles of broiler chickens--a key role of AMP deaminase?

The biochemical determinism of ultimate pH (pHu) was studied in the pectoralis muscle of broiler chickens. Thirty birds of 3 genetic types (a fast-growing standard (FG), a slow-growing French "Label Rouge" (SG), and a heavy line type (HL)) were kept under conventional breeding methods until the usual marketing age (6, 12, and 6 wk for FG, SG, and HL birds, respectively). The birds were divided into 3 different antemortem treatment groups: minimum stress, shackling for a longer time (2 min), and heat stress (exposure to 35 degrees C for 3.5 h and shackling for 2 min before stunning). The birds were slaughtered on the same day. The pHu differed (P < 0.001) among the 3 genetic types, ranking as follows: FG (5.95+/-0.01) > HL (5.85+/-0.02) > SG (5.73+/-0.02). In SG and HL birds, pHu was strongly correlated with muscle glycogen content at slaughter (r = -0.74 and -0.82; P < 0.01 respectively), whereas this correlation was weak in FG birds. Regardless of genetic type, neither buffering capacity nor lactate accumulation significantly contributed to pHu variations (P > 0.05). The activity of adenosine monophosphate deaminase (AMPd) was significantly higher in FG chickens (0.98+/-0.31; P < 0.05) than in HL and SG birds (0.46+/-0.24 and 0.34+/-0.18, respectively). Significant correlations were found between AMPd activity, pHu, and glycolytic potential (GP) at slaughter (r = 0.34 and -.29; P < 0.01, respectively). Further research is needed to study in more detail the role of AMPd in the determinism of pHu, particularly in fast-growing broilers.