scholarly journals Wooden Breast Myodegeneration of Pectoralis Major Muscle Over the Growth Period in Broilers

2016 ◽  
Vol 54 (1) ◽  
pp. 119-128 ◽  
Author(s):  
H.-K. Sihvo ◽  
J. Lindén ◽  
N. Airas ◽  
K. Immonen ◽  
J. Valaja ◽  
...  

Wooden breast (WB) myopathy of broiler chickens is a myodegenerative disease of an unknown etiology and is macroscopically characterized by a hardened consistency of the pectoralis major muscle. Our aim was to describe the development and morphology of WB over the growth period in broilers. Additionally, the effect of restricted dietary selenium on the occurrence of WB was examined by allocating the birds in 2 dietary groups: restricted and conventional level of selenium. The experiment included 240 male broilers that were euthanized at ages of 10, 18, 24, 35, 38, or 42 days and evaluated for WB based on abnormal hardness of the pectoralis major muscle. The severity and the distribution of the lesion and presence of white striping were recorded. The first WB cases were seen at 18 days; 13/47 birds (28%) were affected and the majority exhibited a mild focal lesion. In subsequent age groups the WB prevalence varied between 48% and 73% and the lesion was usually diffuse and markedly firm. White striping often coexisted with WB. Histological evaluation performed on 111 cases revealed a significant association of myodegeneration and lymphocytic vasculitis with WB. Vasculitis and perivascular cell infiltration were restricted to the veins. Restricted dietary selenium did not affect the occurrence of WB ( P = .44). Our results indicate that WB starts focally and spreads to form a diffuse and more severe lesion.

2016 ◽  
Vol 95 (12) ◽  
pp. 2771-2785 ◽  
Author(s):  
Paolo Zambonelli ◽  
Martina Zappaterra ◽  
Francesca Soglia ◽  
Massimiliano Petracci ◽  
Federico Sirri ◽  
...  

Author(s):  
Juniper A. Lake ◽  
Michael B. Papah ◽  
Behnam Abasht

Wooden breast is a muscle disorder affecting modern commercial broiler chickens that causes a palpably firm pectoralis major muscle and severe reduction in meat quality. Most studies have focused on advanced stages of wooden breast apparent at market age, resulting in limited insights into the etiology and early pathogenesis of the myopathy. Therefore, the objective of this study was to identify early molecular signals in the wooden breast transcriptional cascade by performing gene expression analysis on the pectoralis major muscle of two-week-old birds that may later exhibit the wooden breast phenotype by market age at 7 weeks. Biopsy samples of the left pectoralis major muscle were collected from a subset of 101 birds randomly selected from a total of 302 birds at 14 days of age, after which all birds were raised to 7 weeks of age for scoring of wooden breast. RNA sequencing was performed on 5 unaffected and 8 affected female chicken samples, selected based on wooden breast scores (0 to 4) assigned at necropsy where affected birds had scores of 2 or 3 (mildly or moderately affected) while unaffected birds had scores of 0 (no apparent gross lesions). Differential expression analysis identified 60 genes found to be significant at an FDR-adjusted p value of 0.05. Of these, 26 were previously demonstrated to exhibit altered expression or genetic polymorphisms related to glucose tolerance or diabetes mellitus in mammals. Additionally, 9 genes have functions directly related to lipid metabolism and 11 genes are associated with adiposity traits such as intramuscular fat and body mass index. This study suggests that wooden breast disease is first and foremost a metabolic disorder characterized primarily by ectopic lipid accumulation in the pectoralis major.


Genes ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 746 ◽  
Author(s):  
Juniper A. Lake ◽  
Michael B. Papah ◽  
Behnam Abasht

Wooden breast is a muscle disorder affecting modern commercial broiler chickens that causes a palpably firm pectoralis major muscle and severe reduction in meat quality. Most studies have focused on advanced stages of wooden breast apparent at market age, resulting in limited insights into the etiology and early pathogenesis of the myopathy. Therefore, the objective of this study was to identify early molecular signals in the wooden breast transcriptional cascade by performing gene expression analysis on the pectoralis major muscle of two-week-old birds that may later exhibit the wooden breast phenotype by market age at 7 weeks. Biopsy samples of the left pectoralis major muscle were collected from 101 birds at 14 days of age. Birds were subsequently raised to 7 weeks of age to allow sample selection based on the wooden breast phenotype at market age. RNA-sequencing was performed on 5 unaffected and 8 affected female chicken samples, selected based on wooden breast scores (0 to 4) assigned at necropsy where affected birds had scores of 2 or 3 (mildly or moderately affected) while unaffected birds had scores of 0 (no apparent gross lesions). Differential expression analysis identified 60 genes found to be significant at an FDR-adjusted p-value of 0.05. Of these, 26 were previously demonstrated to exhibit altered expression or genetic polymorphisms related to glucose tolerance or diabetes mellitus in mammals. Additionally, 9 genes have functions directly related to lipid metabolism and 11 genes are associated with adiposity traits such as intramuscular fat and body mass index. This study suggests that wooden breast disease is first and foremost a metabolic disorder characterized primarily by ectopic lipid accumulation in the pectoralis major.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 96-96
Author(s):  
Alexander M Stelzleni

Abstract Wooden breast (WB) and white striping (WS) are two myopathies impacting the broiler market. Wooden breast and WS may occur individually or in concert with each other. Wooden breast is characterized by increased rigidity and firmness in the pectoralis major and has been associated with breast meat from larger, faster growing broilers. It begins in the ventral-cranial region and increases in severity, moving toward the deeper and more caudal portions of the muscle. Although the etiology is not fully understood, compositional characteristics of WB include increased collagen and lipid deposition and decreased water holding capacity. Breast fillets exhibiting WS are characterized by the size and amount of striping that occurs on the surface of the pectoralis major. These breasts express similar compositional characteristics to those with WB. Both WB and WS have been associated with decreased organoleptic and rheological properties, causing industry losses estimated in excess of $200 million annually through value downgrades, trim loss, and diversion to rendering. Although WB and WS meat have decreased rheological properties, some lost value may be recaptured through further processing. Recent studies have shown that both blade tenderization and marination improved the textural properties of afflicted breast meat, but neither were able to overcome the differences between afflicted and normal breast meat. Research investigating comminuted and emulsified products containing WB or WS meat have shown similar results due to the lower extraction of salt-soluble proteins and subsequent low bind and gelation properties. When WB/WS meat was included as a portion of the meat block with normal breast meat, textural and rheological differences were ameliorated. Using WB or WS meat in further processed products may give processors an alternative use for afflicted breast meat. Additional research should continue to explore how WB and WS meat can be incorporated into further processed and value-added products.


Author(s):  
Juniper A. Lake ◽  
Michael B. Papah ◽  
Behnam Abasht

Wooden breast is a muscle disorder affecting modern commercial broiler chickens that causes a palpably firm pectoralis major muscle and severe reduction in meat quality. Most studies have focused on advanced stages of wooden breast apparent at market age, resulting in limited insights into the etiology and early pathogenesis of the myopathy. Therefore, the objective of this study was to identify early molecular signals in the wooden breast transcriptional cascade by performing gene expression analysis on the pectoralis major muscle of two-week-old birds that may later exhibit the wooden breast phenotype by market age at 7 weeks. Biopsy samples of the left pectoralis major muscle were collected from 101 birds at 14 days of age. Birds were subsequently raised to 7 weeks of age to allow sample selection based on the wooden breast phenotype at market age. RNA sequencing was performed on 5 unaffected and 8 affected female chicken samples, selected based on wooden breast scores (0 to 4) assigned at necropsy where affected birds had scores of 2 or 3 (mildly or moderately affected) while unaffected birds had scores of 0 (no apparent gross lesions). Differential expression analysis identified 60 genes found to be significant at an FDR-adjusted p value of 0.05. Of these, 26 were previously demonstrated to exhibit altered expression or genetic polymorphisms related to glucose tolerance or diabetes mellitus in mammals. Additionally, 9 genes have functions directly related to lipid metabolism and 11 genes are associated with adiposity traits such as intramuscular fat and body mass index. This study suggests that wooden breast disease is first and foremost a metabolic disorder characterized primarily by ectopic lipid accumulation in the pectoralis major.


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