Metabolite profile based on 1H NMR of broiler chicken breasts affected by wooden breast myodegeneration

The objective was to characterize the effect of wooden breast (WB) myodegeneration on the metabolite profile of chicken meat by ¹H NMR and multivariate data analysis. The results displayed that the metabonome of chicken breast consisted predominantly of 30 metabolites, including amino acids, organic acids, carbohydrates, alkaloids, nucleosides and their derivatives. WB-affected samples showed higher leucine, valine, alanine, glutamate, lysine, lactate, succinate, taurine, glucose, and 5'-IMP levels, but lower histidine, β-alanine, acetate, creatine, creatinine, anserine and nicotinamide adenine dinucleotide levels compared to normal fillets (p < 0.05). In conclusion, results indicated that WB-affected fillets possessed a unique biochemical signature. This unique profile could identify candidate biomarkers for diagnostic utilization and provide mechanistic insight into biochemical processes leading to WB myopathy in commercial broiler chickens.

Detection of razor shear force differences in broiler breast meat due to the woody breast condition depends on measurement technique and meat state1

Broiler breast meat with the woody breast (WB) myopathy exhibits abnormal tissue hardness and muscle rigidity in the raw state. The effectiveness of using instrumental shear measurements to characterize texture in WB fillets before and after cooking is not well understood. The objective of this study was to determine the influence of WB on razor shear force measurements in fresh never-frozen and frozen-thawed broiler breast fillets in both the raw and cooked state. Deboned breast fillets (n = 234) were collected from a commercial processing plant and categorized as normal (n = 78), moderate WB (n = 86), or severe WB (n = 70). At 24 h postmortem fillets were either used for texture analysis directly or frozen-thawed prior to analysis. Each fillet was measured before and after cooking using either the blunt blade (BMORS) or sharpened blade (MORS) versions of the Meullenet-Owens razor shear test. The ability of BMORS to distinguish between normal and WB fillets was different between raw and cooked fillets. In both fresh and frozen-thawed fillets, raw BMORS shear values (peak shear force and shear energy) increased (P < 0.0001) with WB severity. In fresh fillets, cooked BMORS values were similar between normal, moderate WB, and severe WB fillets. In frozen-thawed fillets, cooked BMORS values were greater (P < 0.001) in severe WB compared to normal fillets but were similar between normal and moderate WB fillets. Cooking had less impact on the ability of MORS to distinguish between normal and WB fillets. For both fresh and frozen-thawed fillets, MORS shear values (peak shear force and shear energy) were greater (P < 0.05) in WB fillets than normals in both the raw and cooked states. Data from this study demonstrate that the WB myopathy influences razor shear measurements in raw broiler breast fillets, but suggest that the ability to objectively detect texture differences in cooked WB meat is strongly dependent upon razor shear technique.

Differential expression and co-expression gene network analyses reveal molecular mechanisms and candidate biomarkers involved in breast muscle myopathies in chicken

The broiler industry is facing an increasing prevalence of breast myopathies, such as white striping (WS) and wooden breast (WB), and the precise aetiology of these occurrences remains poorly understood. To progress our understanding of the structural changes and molecular pathways involved in these myopathies, a transcriptomic analysis was performed using an 8 × 60 K Agilent chicken microarray and histological study. The study used pectoralis major muscles from three groups: slow-growing animals (n = 8), fast-growing animals visually free from defects (n = 8), or severely affected by both WS and WB (n = 8). In addition, a weighted correlation network analysis was performed to investigate the relationship between modules of co-expressed genes and histological traits. Functional analysis suggested that selection for fast growing and breast meat yield has progressively led to conditions favouring metabolic shifts towards alternative catabolic pathways to produce energy, leading to an adaptive response to oxidative stress and the first signs of inflammatory, regeneration and fibrosis processes. All these processes are intensified in muscles affected by severe myopathies, in which new mechanisms related to cellular defences and remodelling seem also activated. Furthermore, our study opens new perspectives for myopathy diagnosis by highlighting fine histological phenotypes and genes whose expression was strongly correlated with defects.

Quantum Blue Reduces the Severity of Woody Breast Myopathy via Modulation of Oxygen Homeostasis-Related Genes in Broiler Chickens

The incidence of woody breast (WB) is increasing on a global scale representing a significant welfare problem and economic burden to the poultry industry and for which there is no effective treatment due to its unknown etiology. In this study, using diffuse reflectance spectroscopy (DRS) coupled with iSTAT portable clinical analyzer, we provide evidence that the circulatory- and breast muscle-oxygen homeostasis is dysregulated [low oxygen and hemoglobin (HB) levels] in chickens with WB myopathy compared to healthy counterparts. Molecular analysis showed that blood HB subunit Mu (HBM), Zeta (HBZ), and hephaestin (HEPH) expression were significantly down regulated; however, the expression of the subunit rho of HB beta (HBBR) was upregulated in chicken with WB compared to healthy counterparts. The breast muscle HBBR, HBE, HBZ, and hypoxia-inducible factor prolyl hydroxylase 2 (PHD2) mRNA abundances were significantly down regulated in WB-affected compared to normal birds. The expression of HIF-1α at mRNA and protein levels was significantly induced in breasts of WB-affected compared to unaffected birds confirming a local hypoxic status. The phosphorylated levels of the upstream mediators AKT at Ser473 site, mTOR at Ser2481 site, and PI3K P85 at Tyr458 site, as well as their mRNA levels were significantly increased in breasts of WB-affected birds. In attempt to identify a nutritional strategy to reduce WB incidence, male broiler chicks (Cobb 500, n = 576) were randomly distributed into 48 floor pens and subjected to six treatments (12 birds/pen; 8 pens/treatment): a nutrient adequate control group (PC), the PC supplemented with 0.3% myo-inositol (PC + MI), a negative control (NC) deficient in available P and Ca by 0.15 and 0.16%, respectively, the NC fed with quantum blue (QB) at 500 (NC + 500 FTU), 1,000 (NC + 1,000 FTU), or 2,000 FTU/kg of feed (NC + 2,000 FTU). Although QB-enriched diets did not affect growth performances (FCR and FE), it did reduce the severity of WB by 5% compared to the PC diet. This effect is mediated by reversing the expression profile of oxygen homeostasis-related genes; i.e., significant down regulation of HBBR and upregulation of HBM, HBZ, and HEPH in blood, as well as a significant upregulation of HBA1, HBBR, HBE, HBZ, and PHD2 in breast muscle compared to the positive control.

The metabolic characteristics of susceptibility to wooden breast disease in chickens with high feed efficiency

This study was conducted to characterize metabolic differences between high feed efficiency (HFE) and low feed efficiency (LFE) chickens to investigate why feed efficient chickens are more susceptible to muscle abnormalities such as wooden breast disease. Gene expression profiles were generated by RNA sequencing of pectoralis major muscle samples from 10 HFE and 13 LFE broiler chickens selected from a modern broiler population. Metabolism-associated differentially expressed genes were identified and interpreted by Ingenuity Pathway Analysis and literature mining. Our RNA-seq data indicate decreased glycolytic capacity, increased fatty acid uptake, mitochondrial oxidation of fatty acids, and several other metabolic alterations in the pectoralis major muscle of HFE chickens. We also quantified glycogen content of the pectoralis major muscle and found that the HFE chickens had a significantly (P ≤ 0.05) lower glycogen content. Collectively, this study indicates extensive metabolic differences in the pectoralis major muscle between HFE and LFE chickens and helps identify metabolic features of susceptibility to muscle disorders in modern broiler chickens.

Absolute expressions of hypoxia-inducible factor-1 alpha (HIF1A) transcript and the associated genes in chicken skeletal muscle with white striping and wooden breast myopathies

Development of white striping (WS) and wooden breast (WB) in broiler breast meat have been linked to hypoxia, but their etiologies are not fully understood. This study aimed at investigating absolute expression of hypoxia-inducible factor-1 alpha subunit (HIF1A) and genes involved in stress responses and muscle repair using a droplet digital polymerase chain reaction. Total RNA was isolated from pectoralis major collected from male 6-week-old medium (carcass weight ≤ 2.5 kg) and heavy (carcass weight > 2.5 kg) broilers. Samples were classified as “non-defective” (n = 4), “medium-WS” (n = 6), “heavy-WS” (n = 7) and “heavy-WS+WB” (n = 3) based on abnormality scores. The HIF1A transcript was up-regulated in all of the abnormal groups. Transcript abundances of genes encoding 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 4 (PFKFB4), lactate dehydrogenase-A (LDHA), and phosphorylase kinase beta subunit (PHKB) were increased in heavy-WS but decreased in heavy-WS+WB. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was up-regulated in non-defective samples. The muscle-specific mu-2 isoform of glutathione S-transferases (GSTM2) was up-regulated in the abnormal samples, particularly in the heavy groups. The genes encoding myogenic differentiation (MYOD1) and myosin light chain kinase (MYLK) exhibited similar expression pattern, of which medium-WS and heavy-WS significantly increased compared to non-defective whereas expression in heavy-WS+WB was not different from either non-defective or WS-affected group. The greatest and the lowest levels of calpain-3 (CAPN3) and delta-sarcoglycan (SCGD) were observed in heavy-WS and heavy-WS+WB, respectively. Based on micrographs, the abnormal muscles primarily comprised fibers with cross-sectional areas ranging from 2,000 to 3,000 μm². Despite induced glycolysis at the transcriptional level, lower stored glycogen in the abnormal muscles corresponded with the reduced lactate and higher pH within their meats. The findings support hypoxia within the abnormal breasts, potentially associated with oversized muscle fibers. Between WS and WB, divergent glucose metabolism, cellular detoxification and myoregeneration at the transcriptional level could be anticipated.

Effect of breast myopathies on quality and microbial shelf life of broiler meat

To evaluate the impact of emerging myopathies on meat quality and microbial shelf life, 48 normal, 48 white striped (WS), and 48 wooden breasts (WB) were stored for 11 d at 4°C aerobically and analyzed at 24, 72, 120, 168, 216, and 264 h post-mortem. Normal breasts showed lower (P < 0.001) redness index (-0.88 vs. -0.41 and -0.43) and cooking losses (22.0 vs. 23.8 vs. 26.9%) than those of WS and WB meat. Normal and WS breasts exhibited higher protein content than that in WB meat (23.9 and 23.2 vs. 21.4%; P < 0.001). Normal meat also had a lower ether extract content than that in WB meat (1.09 vs. 1.88%; P < 0.001), with intermediate values for WS meat. Normal breasts exhibited higher saturated fatty acid (FA) rate (31.3 vs. 28.0% of total FA on average) and lower unsaturated FA rate (68.7 vs. 72.0%) than those in WS and WB meat (P < 0.001). Differences were mainly due to polyunsaturated FA (30.5% in normal vs. 35.3 and 35.4% in WS and WB meat; P < 0.001). Normal breasts had higher initial total viable count (TVC) and a shorter TVC lag phase than those of WS and WB meat (46.3 vs. 85.2 and 77.8 h). The microbial shelf life threshold (7 log10 CFU TVC/g) was achieved first in normal (130 h) and then in WS (149 h) and WB (192 h) meat. TVC and Pseudomonas spp. counts were significantly higher in normal than those in the affected breasts between 72 and 216 h of storage. Enterobacteriaceae spp. and lactic acid bacteria counts were significantly higher in normal meat, lower in WB meat, and intermediate in WS meat until 216 h. All differences in microbial targets across meat types disappeared by 264 h of storage. Further studies are necessary to elucidate the factors and the mechanisms that may modulate microbial growth and composition during storage in broiler breast meat affected by myopathies.

Evaluation of Bone Marrow Adipose Tissue and Bone Mineralization on Broiler Chickens Affected by Wooden Breast Myopathy

In humans, alterations in bone metabolism have been associated with myopathies. We postulate the hypothesis that perhaps similar pathologies can also be associated in modern chickens. Hence, this study aimed to assess the fat infiltration in bone marrow and its repercussion on broiler chicken affected by Wooden Breast (WB) myopathy. Ten Cobb 500 live birds with extreme rigidity of the Pectoralis major (PM) muscle were selected as WB affected chickens by physical examination of the muscle at 49 days of age, whereas ten chickens healthy with no physical signs of hardness in the breast muscle were considered to be unaffected. Macroscopic lesions in affected chickens included areas of firm and inflamed muscle with pale appearance, hemorrhaging, and viscous exudate on the surface. Bone marrow and sections of the PM muscle were collected and analyzed for light microscopy. Additionally, transmission electron microscopy was conducted in affected or unaffected muscle. Chickens affected with WB showed significant reductions (P < 0.05) in femur diameter, calcium, and phosphorous percentage but increased breast weight, compression force and filet thickness when compared with non-affected chickens. Interestingly, bone marrow from WB chicken had subjectively, more abundant infiltration of adipose tissue, when compared with non-affected chickens. Histology of the Pectoralis major of birds with WB showed abundant infiltration of adipose tissue, muscle fibers degeneration with necrosis and infiltration of heterophils and mononuclear cells, connective tissue proliferation, and vasculitis. Ultrastructural changes of WB muscle revealed lack definition of bands in muscle tissue, or any normal ultrastructural anatomy such as myofibrils. The endomysium components were necrotic, and in some areas, the endomysium was notable only as a string of necrotic tissue between degraded myofibrils. The fascia appeared hypertrophied, with large areas of necrosis and myofiber without structural identity with degraded mitochondria adjacent to the disrupted muscle tissue. As far as we know, this is the first study that describes a subjective increase in adipose tissue in the bone marrow of chickens affected with WB when compared with non-affected chickens, and reduced bone mineralization.

The impaired quality of chicken affected by the wooden breast myopathy is counteracted in emulsion-type sausages

The aim of this study was to evaluate the suitability of using chicken meat affected by wooden breast (WB) myopathy in the production of chicken sausages. Compare the technological and sensory properties of such sausages were compared with those produced from normal (N) breast meat. Three types of chicken sausages were elaborated: 100% containing N chicken meat, 100% of WB chicken meat and 50% N/50% of WB meat. The WB chicken meat presented higher values for pH, L*, moisture, cooking loss, shear force, hardness, chewiness, adhesiveness and gumminess; while WHC and protein content were higher for N chicken meat. N and WB chicken sausages presented similar values of WHC, a*, b* color values, protein content and TBARS. QDA indicated no sensory differences between the three sausage formulations, so did the acceptability and purchase intention. Therefore, WB chicken meat may be used to produce chicken sausages combined or not with N chicken meat. Further studies, however, may be required to investigate the nutritional value and digestibility of WB meat and derived products.

Near-infrared spectroscopy detects woody breast syndrome in chicken fillets by the markers protein content and degree of water binding

The muscle syndrome woody breast (WB) impairs quality of chicken fillets and is a challenge to the poultry meat industry. There is a need for online detection of affected fillets for automatic quality sorting in process. Near-infrared spectroscopy (NIRS) is a promising method, and in this study we elucidate the spectral properties of WB versus normal fillets. On a training set of 50 chicken fillets (20 normal, 30 WB), we measured NIR, nuclear magnetic resonance (NMR) T2 relaxation distributions, and crude chemical composition. NIRS could estimate protein in the fillets with an accuracy of ±0.64 percentage points. T2 distributions showed that there was a larger share of free water in WB fillets. This difference in water binding generated a shift and narrowing of the water absorption peak in NIR around 980 nm, quantified by a bound water index (BWI). The correlation between BWI and T2 distributions was 0.78, indicating that NIRS contains information about degree of water binding. Discriminant analysis showed that NIRS obtained 100% correct classification of normal versus WB on the training set, and 96% correct classification on a test set of 52 fillets. The main reason for why NIRS can successfully discriminate between WB and normal fillets is the methods sensitivity to both protein content and degree of water binding in the muscle, both established markers for WB. The classification model can be based on NIR spectra only, calibration against protein is not needed. The affected muscle tissue associated with the WB syndrome is unevenly distributed in the fillets, and this heterogeneity was characterized by NIRS and NMR. Clear differences in water binding properties were found between the superficial 1 cm layer and the deeper layer at 1 to 2 cm depth. Significant differences in protein estimates by NIRS at different measurement points along the chicken fillets were obtained for WB fillets. The findings suggest how to obtain optimal sampling with NIRS for best possible discrimination between WB and normal breast fillets.

Wooden-Breast, White Striping, and Spaghetti Meat: Causes, Consequences and Consumer Perception of Emerging Broiler Meat Abnormalities

Ten years ago, the occurrence of macroscopic defects in breasts muscles from fast-growing broilers challenged producers and animal scientists to label and characterize myopathies wholly unknown. The distinctive white striations in breasts affected by white striping disorder, the presence of out-bulging and pale areas of hardened consistency in the so-called wooden breast, and the separation of the fiber bundles in breasts labelled as spaghetti meat, made these myopathies easily identified in chicken carcasses. Yet, the high incidence of these myopathies and the increasing concern by producers and retailers led to an unprecedented flood of questions on the causes and consequences of these abnormal chicken breasts. This review comprehensively collects the most relevant information from studies aimed to understand the pathological mechanisms of these myopathies, their physicochemical and histological characterization and their impact on meat quality and consumer's preferences. Today, it is known that the occurrence is linked to fast-growth rates of the birds and their large breast muscles. The muscle hypertrophy along with an unbalanced growth of supportive connective tissue leads to a compromised blood supply and hypoxia. The occurrence of oxidative stress and mitochondrial dysfunction leads to lipidosis, fibrosis, and overall myodegeneration. Along with the altered appearance, breast muscles affected by the myopathies display poor technological properties, impaired texture properties, and reduced nutritional value. As consumer's awareness on the occurrence of these abnormalities and the concerns on animal welfare arise, efforts are made to inhibit the onset of the myopathies or alleviate the severity of the symptoms. The lack of fully effective dietary strategies leads scientists to propose whether "slow" production systems may alternatively provide with poultry meat free of these myopathies.

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.

Comparison of quality traits among breast meat affected by current muscle abnormalities

Over the past several decades, as a result of the increasing growth rate and body size of modern hybrid birds, poultry industry has been facing up the occurrence of many breast meat abnormalities, such as White Striping (WS), Wooden Breast (WB) and Spaghetti Meat (SM), whose incidence has recently reached alarming levels. Thus, the present study aimed at simultaneously investigating the implications of WS, WB and SM abnormalities on meat colour, pH, proximate composition, fatty acid profile, collagen, thermal properties as well as texture and water mobility, assessed on both superficial and deep section of Pectoralis major muscle. Overall, the occurrence of breast abnormalities is associated with a higher ultimate pH and a significant increase in moisture and fat level, coupled with a decrease in protein and ash content with WB showing the most detrimental effect. However, fatty acid profile resulted to be mildly modified only by WS. Moreover, WB fillets showed significantly higher (P < .001) collagen content and stromal protein denaturation enthalpy associated with an altered water distribution and mobility within the muscle tissue. On the contrary, SM samples displayed a lower (P < .001) collagen cross-linking and a softer texture after the cooking. Overall, these findings reveal that the occurrence of WB abnormality exerts a more profound and prominent effect on meat quality traits rather than the presence not only of WS, but also of SM.

Unraveling the cause of white striping in broilers using metabolomics

White striping (WS) is a major problem affecting the broiler industry. Fillets affected by this myopathy present pathologies that compromise the quality of the meat, and most importantly, make the fillets more prone to rejection by the consumer. The exact etiology is still unknown, which is why a metabolomics analysis was performed on breast samples of broilers. The overall objective was to identify biological pathways involved in the pathogenesis of WS. The analysis was performed on a total of 51 muscle samples and distinction was made between normal (n = 19), moderately affected (n = 24) and severely affected (n = 8) breast fillets. Samples were analyzed using gas chromatographic mass spectral analysis and liquid chromatography quadrupole time-of-flight mass spectrometry. Data were subsequently standardized, normalized and analyzed using various multivariate statistical procedures. Metabolomics allowed for the identification of several pathways that were altered in white striped breast fillets. The tricarboxylic acid cycle exhibited opposing directionalities. This is described in literature as the backflux and enables the TCA cycle to produce high-energy phosphates through matrix-level phosphorylation and, therefore, produce energy under conditions of hypoxia. Mitochondrial fatty acid oxidation was limited due to disturbances in especially cis-5-14:1 carnitine (log2 FC of 2, P < 0.01). Because of this, accumulation of harmful fatty acids took place, especially long-chain ones, which damages cell structures. Conversion of arginine to citrulline increased presumably to produce nitric oxide, which enhances blood flow under conditions of hypoxia. Nitric oxide however also increases oxidative damage. Increases in taurine (log2 FC of 1.2, P < 0.05) suggests stabilization of the sarcolemma under hypoxic conditions. Lastly, organic osmolytes (sorbitol, taurine, and alanine) increased (P < 0.05) in severely affected birds; likely this disrupts cell volume maintenance. Based on the results of this study, hypoxia was the most likely cause/initiator of WS in broilers. We speculate that birds suffering from WS have a vascular support system in muscle that is borderline adequate to support growth, but triggers like activity results in local hypoxia that damages tissue.

The Incidence of Muscle Abnormalities in Broiler Breast Meat - A Review

The dramatic improvements in the growth rate and breast muscle size and yield in broilers through the intensive genetic selection, and the improvement in nutrition and management over the past 50 years have introduced serious abnormalities that influenced the quality of breast meat. The abnormalities include pale-soft-exudative (PSE) conditions, deep pectoral muscle (DPM) myopathy, spaghetti meat (SM), white striping (WS), and woody breast (WB) that have serious negative implications to the broiler meat industry. The incidences of PSE and DPM have been known for several decades, and their prevalence, etiology and economic impact have been well discussed. However, other abnormalities such as SM, WS and WB conditions have been reported just for few years although these conditions have been known for some time. The newly emerging quality issues in broilers are mainly associated with the Pectoralis major muscles, and the incidences have been increased dramatically in some regions of the world in recent years. As high as 90% of the broilers are affected by the abnormalities, which are expected to cause from $200 million to $1 billion economic losses to the U.S. poultry industry per year. So, this review mainly discusses the histopathological characteristics and biochemical changes in the breast muscles with the emphasis on the newly emerging abnormalities (SM, WS, and WB) although other abnormalities are also discussed. The impacts of the anomalies on the nutritional, functional, mechanical and sensory quality of the meat and their implications to the poultry industry are discussed.

Marination and cooking performance of portioned broiler breast fillets with the wooden breast condition

The wooden breast (WB) condition in broiler breast meat negatively influences technological meat quality. However, it is unknown if the WB effects are uniform throughout the Pectoralis major. The objective of this study was to determine the effects of WB on the marination and cooking performance of the dorsal and ventral portions of broiler breast fillets. Sixty butterfly breast fillets were collected from the deboning line of a commercial plant and sorted into normal (no WB) and severe WB categories. Each fillet was horizontally portioned into dorsal and ventral halves. Portions from one side of each butterfly were used as non-marinated controls, while portions from the other side were vacuum-tumble marinated (16 rpm, -0.6 atm, 4°C, 20 min) with 20% (wt/wt) marinade to meat ratio. Marinade was formulated to target a final concentration of 0.75% salt and 0.45% sodium tripolyphosphate in the final product. Samples were cooked to 78°C in a combination oven. Marinade uptake and retention were lower (P < 0.001) in both the ventral and dorsal portions of the WB fillets. The dorsal portions had greater (P < 0.001) marinade uptake and retention than the ventral portions in both normal and WB fillets. For non-marinated samples, cook loss was greater (P < 0.05) in both the ventral and dorsal portions of WB fillets. In marinated samples, however, cook loss was similar between the dorsal portions of normal and WB fillets. Final cooked product yield was calculated based on pre-marination and post-cook weights. Non-marinated WB samples exhibited lower (P < 0.001) cooked product yields than normal samples in both portions. For marinated samples, cooked product yields were greater (P < 0.001) in the dorsal portions. Data demonstrated that the dorsal portion of the Pectoralis major more readily absorbs and retains marinade during vacuum tumbling and storage than the ventral portion. Although the WB condition negatively influenced marination and cooking performance in both fillet portions, the effects were less severe in the dorsal portion.

Descriptive sensory analysis of marinated and non-marinated wooden breast fillet portions

The wooden breast (WB) myopathy influences muscle composition and texture characteristics in broiler breast meat. It is unknown if marination reduces the negative influence of WB on meat sensory quality or if WB effects are uniform throughout the Pectoralis major. The objective of this study was to determine the effects of marination on the sensory attributes and instrumental shear force measurements of the ventral (skin-side) and dorsal (bone-side) portions of normal and severe WB meat. Sixty butterfly fillets (30 normal and 30 severe WB) were selected from the deboning line of a commercial processing plant. Individual fillets were portioned into ventral and dorsal halves. Portions from one side of each butterfly were used as non-marinated controls, and portions from the other side were vacuum-tumble marinated (16 rpm, -0.6 atm, 4°C, 20 min) with 20% (wt/wt) marinade to meat ratio. Marinade was formulated to target a concentration of 0.75% (w/v) salt and 0.45% (w/v) sodium tripolyphosphate in the final product. Descriptive sensory analysis (9 trained panelists) was conducted to evaluate visual, texture, and flavor attributes (0-15 point scale) of breast portions along with Warner-Bratzler shear force. Significant interaction effects between WB and marination were not observed for the sensory attributes. Greater springiness, cohesiveness, hardness, fibrousness, and chewiness scores were observed in WB samples (P < 0.001). Marination decreased cohesiveness, hardness, and chewiness (P < 0.05) and increased juiciness (P = 0.002). The effects of WB on sensory texture attributes were more apparent in the ventral portions of the breast fillets. Flavor attributes (salty and brothy) increased (P < 0.001) with marination. In non-marinated samples, shear force was similar between normal and WB samples. In marinated samples, however, shear force was greater (P < 0.001) in WB samples. Data suggest that the WB effect on meat sensory quality is not uniform throughout the Pectoralis major and that WB-related differences in cooked meat sensory texture attributes are lessened but not eliminated by vacuum-tumbling marination.

Monitoring of white striping and wooden breast cases and impacts on quality of breast meat collected from commercial broilers (Gallus gallus)

Objective

This study aimed at investigating white striping (WS) and wooden breast (WB) cases in breast meat collected from commercial broilers.

Methods

A total of 183 breast samples were collected from male Ross 308 broilers slaughtered at the age of 6 weeks (n = 100) and 7 weeks (n = 83). The breasts were subjected to meat defect inspection, meat quality determination and histology evaluation.

Results

Of 183, 4 breasts from 6-week-old broilers were classified as non-defective while the others exhibited the WS lesion. Among the 6-week-old birds, the defective samples from the medium size birds (carcass weight ≤2.5 kg) showed mild to moderate WS degree with no altered meat quality. Some of the breasts from the 6-week-old birds with carcass weight above 2.5 kg exhibited WB in accompanied with the WS condition. Besides of a reduction of protein content, increases in collagen matter and pH values in the defective samples (p<0.05), no other impaired quality indices were detected within this group. All 7-week-old broilers yielded carcasses weighing above 2.5 kg and showed abnormal characteristics with progressive severity. The breasts affected with severe WS and WB showed the greatest cook loss, hardness, springiness and chewiness (p<0.05). Development of WB induced significantly increased drip loss in the samples (p<0.05). Histology indicated necrotic events in the defective myofibers. Based on logistic regression, increasing percent breast weight by one unit enhanced the chance of WS and WB development with advanced severity by 50.9% and 61.0%, respectively. Delayed slaughter age from 6 to 7 weeks increased the likelihood of obtaining increased WS severity by 56.3%.

Conclusion

Cases of WS and WB defects in Southeast Asia have been revealed. Despite few cases of the severe WS and WB, such abnormal conditions significantly impaired technological properties and nutritional quality of broiler breasts.

Meat quality traits and proteome profile of woody broiler breast (pectoralis major) meat

Woody breast meat has recently become prevalent in the broiler industry in both the United States and European Union. Recent publications have described the meat quality characteristics of woody breast meat as having hardened areas and pale ridge-like bulges at both the caudal and cranial regions of the breast. The present study investigated the meat quality (pH, color, cooking loss, and shear force) and protein quality characteristics (protein and salt-soluble protein content) in woody breast meat as compared to normal breast meat. In addition, the differences in the muscle proteome profiles of woody and normal breast meat were characterized. Results indicated that woody breast meat had a greater average pH (P < 0.0001) and cooking loss (P = 0.001) than normal breast meat, but woody breast meat did not differ in shear force (P > 0.05) in comparison to normal breast meat samples. The L*, a*, and b* values of woody breast fillets were greater than normal breast fillets (P < 0.0001 to L*; P = 0.002 to a*; P = 0.016 to b*). The woody breast meat had more fat (P < 0.0001) and moisture (P < 0.021) and less protein (P < 0.0001) and salt-soluble protein (P < 0.0001) when compared with normal breast fillets. Whole muscle proteome analysis indicated 8 proteins that were differentially expressed (P < 0.05) between normal and woody breast meat samples. The differences in muscle proteome between normal and woody breast meat indicated an increased oxidative stress in woody breast meat when compared to normal meat. In addition, the abundance of some glycolytic enzymes, which are critical to the regeneration of adenosine triphosphate (ATP) in postmortem muscles, was lower in woody breast meat than in normal breast meat. Proteomic differences provide additional information on the biochemical pathways and genetic variations that lead to woody breast meat. Further research should be conducted to elucidate the genetic and nutritional contributions to the proliferation of woody breast meat in the United States.

Descriptive texture analyses of cooked patties made of chicken breast with the woody breast condition

The woody breast (WB) condition negatively influences the texture characteristics and quality of intact broiler breast fillets (Pectoralis major). But the impact of WB on ground meat is unknown. The objective of this study was to evaluate the effects of WB on the texture and cook loss of ground meat made of broiler breast fillets. Broiler breasts (deboned 3 h postmortem) were collected on 3 separate trial d from the commercial deboning line and classified into normal and severe WB fillet categories. Individual fillets were either ground and formed into patties or left intact prior to being stored for 7 d at -20°C. Samples were then cooked directly from the frozen state to an endpoint temperature of 76 °C for cook loss, instrumental (patties: Allo-Kramer shear; fillets: Warner-Bratzler shear), and descriptive sensory analysis of texture. Cook loss was greater (P < 0.05) in intact WB fillets compared to that in intact normal fillets, but there was no difference (P > 0.05) between WB and normal patties. There was no difference (P > 0.05) in shear force between normal and WB samples regardless of meat type. Sensory analysis showed that average scores of springiness and hardness of intact WB fillets were greater than those of normal fillets (P < 0.05). However, there were no significant differences (P > 0.05) in average scores for sensory attributes cohesiveness, hardness, juiciness, fibrous, and rate of breakdown between WB and normal patties. WB patties exhibited lower springiness and chewiness scores (P < 0.05) than normal patties. Data suggest that undesirable differences in sensory texture characteristics between cooked intact WB and normal breast meat can be minimized in a ground product.

Freezing-thawing and sub-sampling influence the marination performance of chicken breast meat

Vacuum-tumbling marination is often used to improve the yield and quality of whole or portioned broiler breast fillets. The relationship between the marination performance of whole Pectoralis major muscles and breast fillet sub-samples is not well understood. The objective was to determine the effects of sub-sampling and freezing-thawing on the marination performance and cook loss of broiler breast meat. Paired right and left breast fillets were marinated as whole fillets or sub-samples (cranial and mid-caudal portions). Samples were marinated at 48 h postmortem (fresh) or stored at -20°C and then thawed prior to marination (frozen-thawed). Samples were vacuum-tumbled in 20% wt/wt brine (5% NaCl, 3% STP) and weighed pre-marination, during marination (15, 30, and 45 min), and 24 h post-marination. Samples were then cooked to 75°C for determination of cook loss. Marinade uptake was greater in caudal sub-samples than intact fillets and cranial sub-samples after 15 min of marination (P < 0.0001). After 30 min, marinade uptake was greater in caudal sub-samples and intact fillets than cranial sub-samples (P < 0.05). After 45 min, marinade uptake for fresh samples was greatest in intact fillets and lowest in cranial sub-samples. For frozen-thawed samples, marinade uptake at 45 min was greater in caudal sub-samples and intact fillets than cranial sub-samples (P < 0.0001). Marinade uptake in sub-samples at 30 min was greater in frozen-thawed versus fresh fillets (P < 0.05). Differences in marinade retention were not observed. Cook loss was similar between fresh and frozen-thawed samples but was greater in sub-samples compared to intact fillets (P < 0.0001). Correlations between marinade uptake in intact fillets and cranial sub-samples were greater in fresh (r = 0.64 to 0.78) than frozen-thawed samples (r = 0.39 to 0.59). Correlations between marinade uptake in intact fillets and caudal sub-samples were greater in frozen-thawed (r = 0.79 to 0.82) than fresh samples (r = 0.46 to 0.63). Data suggest that the relationships between marination performance of whole breast fillets and fillet sub-samples are dependent upon prior sample handling and intra-fillet sampling location.

Rapid growth rate results in remarkably hardened breast in broilers during the middle stage of rearing: A biochemical and histopathological study

The high incidence of meat of impaired quality poses a serious problem in the poultry industry. In recent years, the incidence of the pectoralis major muscle that appeared pale colored, remarkably hardened, and exudative, called "wooden breast" or "woody breast" has increased in slaughter houses. In the present study, 19-day-old Ross 308 broiler chickens affected (n = 10) and unaffected (n = 10) with remarkably hardened breast were selected from a commercial broiler farm, and reared to 55 days of age under a controlled environment. Among the affected birds, 5 of 10 birds appeared exhausted with markedly suppressed weight gain and 4 of 10 birds died during the rearing period. In contrast, all unaffected birds survived and most gained weight. Four of 10 unaffected birds lost the ability of back-to-back wing contact by the late stage of rearing. The biochemical analysis of blood plasma samples of 20-day-old birds revealed that creatine kinase and L-aspartate aminotransferase values in most affected birds were higher than those in unaffected birds; however, these values in unaffected birds increased rapidly with lost wing contactability and increasing age. Postmortem examinations revealed that the mean diameter of myofibers in affected birds was smaller than that in unaffected birds. Moreover, symptoms of degenerative and regenerative muscles were observed in most birds in both groups. Among them, a decrease in, or defect of, the characteristic polygonal shape of myofibers was the most common change within the pectoralis major muscles in both groups. The present study demonstrated that broilers affected with remarkably hardened breast during the middle stage of rearing would have suppressed physical status and weight gain, or would die. It was suggested that rapid growth in broilers might be a cause of remarkably hardened breast.

Onset of white striping and progression into wooden breast as defined by myopathic changes underlying Pectoralis major growth. Estimation of growth parameters as predictors for stage of myopathy progression

The broiler industry has incurred significant economic losses due to two muscle myopathies, white striping (WS) and wooden breast (WB), affecting the Pectoralis major (P. major) of commercial broilers. The present study documented macroscopic changes occurring with age/growth in the P. major and P. minor muscles of commercial broilers from day 2 through day 46 (n = 27/day). Distinct myopathic aberrations observed in both breast muscles corresponded to the onset of WB. These distinct morphological changes were used as determinants in developing a ranking system, defining the ontogeny of WB as the following four stages: (1) WS, (2) petechial epimysium haemorrhages, (3) intramuscular haemorrhages and (4) ischaemia. A cumulative logit proportional odds model was used to relate the rank probabilities with the following growth parameters: body weight, P. major and P. minor weight/yield/length/width/depth. The best-fit model included P. major length/width/depth, P. minor width, P. major and P. minor yield as predictors for rank. Increasing P. major depth, P. minor width and P. major yield increased the odds of falling into higher ranks (more severe myopathy). Conversely, increasing P. major length, P. major width and P. minor yield increased the odds of falling into smaller ranks (less severe myopathy). This study describes the macroscopic changes associated with WB ontogeny in the development of a ranking system and the contribution of growth parameters in the determination of rank (WB severity). Results suggest that physical measurements inherent to selection for high-yielding broiler genotypes are contributing to the occurrence and severity of WS and WB.

Implications of white striping and spaghetti meat abnormalities on meat quality and histological features in broilers

During the past few years, there has been an increasing prevalence of broiler breast muscle abnormalities, such as white striping (WS) and wooden breast conditions. More recently, a new muscular abnormality termed as spaghetti meat (SM) because of the altered structural integrity of the Pectoralis major muscle often associated with WS has emerged. Thus, this study aimed at evaluating the effects of WS and SM conditions, occurring alone or combined within the same P. major muscle, on meat quality traits and muscle histology. In two replications, 96 P. major muscles were classified into four classes: normal (N), WS, SM and WS/SM. The whole fillet was used for weight assessment and morphometric measurements, then each sample was cut in order to separate the superficial layer from the deep one and used to evaluate proximate composition, histological features, nuclear magnetic resonance relaxation times, functional properties and both myofibrillar and sarcoplasmic proteins profile. Fillets affected by WS and SM abnormalities exhibited higher weights and increased thickness and length. SM condition was associated with a relevant decrease in protein content coupled with a significant increase in moisture level, whereas fat content was affected only by the simultaneous presence of WS. Histological evaluations revealed that abnormal samples were characterized by several degenerative aspects that almost completely concerned the superficial layer of the fillets. White striped fillets exhibited necrosis and lysis of fibers, fibrosis, lipidosis, loss of cross striation and vacuolar degeneration. Moreover, SM samples were characterized by poor fiber uniformity and a progressive rarefaction of the endo- and peri-mysial connective tissue, whereas WS/SM fillets showed intermediate histological features. Nuclear magnetic resonance relaxation analysis revealed a higher proportion of extra-myofibrillar water in the superficial section of all the abnormal fillets, especially in SM samples, which consequently led to a reduction of the water holding capacity of meat. As for functional properties, abnormal fillets exhibited a lower protein solubility and higher ultimate pH values on both the superficial and deep sections. Although abnormal fillets exhibited higher yellowness values, no relevant effect on meat color was observed. The occurrence of WS and SM abnormalities led to increased carbonylation levels and more intense proteolytic processes. Overall, muscle abnormalities mainly affect the superficial layer of P. major muscle and particularly the occurrence of SM myopathy seems to implicate a more pronounced modification of meat quality traits than the mere presence of WS.

Proteomic approach to characterize biochemistry of meat quality defects

Proteomics can be used to characterize quality defects including pale, soft, and exudative (PSE) meat (pork and poultry), woody broiler breast meat, reddish catfish fillets, meat toughness, and beef myoglobin oxidation. PSE broiler meat was characterized by 15 proteins that differed in abundance in comparison to normal broiler breast meat, and eight proteins were differentially expressed in woody breast meat in comparison to normal breast meat. Hemoglobin was the only protein that was differentially expressed between red and normal catfish fillets. However, inducing low oxygen and/or heat stress conditions to catfish fillets did not lead to the production of red fillets. Proteomic data provided information pertaining to the protein differences that exist in meat quality defects. However, these data need to be evaluated in conjunction with information pertaining to genetics, nutrition, environment of the live animal, muscle to meat conversion, meat quality analyses and sensory attributes to understand causality, protein biomarkers, and ultimately how to prevent quality defects.