White striping (WS) is a pathological modification typical of heavy broiler breast, macroscopically characterized by white striation running parallel to muscle fibers. This lesion changes breast characteristics and can cause a meat downgrade with related economic losses.The aim of this study was to develop a histological score for WS lesions in broilers and the evaluation of the evolution of macroscopic and microscopic lesions during a production cycle. For this study, superficial pectoral muscle of 138 broilers, euthanized at different ages (12, 25 and 51 days), were scored macroscopically for WS (0=absence, 1=mild, 2=severe), and sampled for histopathology analysis. Sections were cut at a thickness of 4 μm and stained with hematoxylin-eosin, then firstly observed to set up a grading of peculiar lesions. The following lesions were selected and scored: myocyte degeneration (score 1-4), presence of adipocytes (score 0-3), fibrosis (score 0-3), diffused inflammation (score 0-3) or vasculitis (score 0-3). The degree of association between WS macroscopic scores and the presence of each histological lesion selected was evaluated using the rank correlation by means of the Spearman’s Rho coefficient. A strong correlation was found between WS and myocyte degeneration (Rho= 0,543 P=0,000), WS and presence of adipocytes (Rho= 0,683 P=0,000), WS and fibrosis (Rho= 0,406 P=0,000). Because of these results only these parameters were used to calculate an histological overall score. The overall score resulted to increase with time, as a result of the evolution of single lesions. At 12 and 25 days, myocytes resulted swollen and degenerated (average score 1.8 and 2.2), other lesions are rare (average score under 1). The absence of inflammation in this period led to suppose that the lesion originates from an apoptotic phenomena instead of an autoimmune mechanism. At 51 days, after degeneration, myocytes seems to be substituted by adipocytes and connective tissue, and the pathology becomes chronic. Diffused inflammation and vasculitis worsen progressively, but they are not strongly correlated with WS. In conclusion WS is confirmed to be a chronic alteration of muscle fibers beginning before the second week of age and immune system seems not to be involved in the onset of the pathology, but further studies will be necessary to better understand the pathogenesis of this disease.

Evolution of macroscopic and microscopic broiler breast alteration related to white striping.

Drigo M.
Formal Analysis
;
Dalle Zotte A.
Membro del Collaboration Group
;
Cecchinato M.
Project Administration
2018

Abstract

White striping (WS) is a pathological modification typical of heavy broiler breast, macroscopically characterized by white striation running parallel to muscle fibers. This lesion changes breast characteristics and can cause a meat downgrade with related economic losses.The aim of this study was to develop a histological score for WS lesions in broilers and the evaluation of the evolution of macroscopic and microscopic lesions during a production cycle. For this study, superficial pectoral muscle of 138 broilers, euthanized at different ages (12, 25 and 51 days), were scored macroscopically for WS (0=absence, 1=mild, 2=severe), and sampled for histopathology analysis. Sections were cut at a thickness of 4 μm and stained with hematoxylin-eosin, then firstly observed to set up a grading of peculiar lesions. The following lesions were selected and scored: myocyte degeneration (score 1-4), presence of adipocytes (score 0-3), fibrosis (score 0-3), diffused inflammation (score 0-3) or vasculitis (score 0-3). The degree of association between WS macroscopic scores and the presence of each histological lesion selected was evaluated using the rank correlation by means of the Spearman’s Rho coefficient. A strong correlation was found between WS and myocyte degeneration (Rho= 0,543 P=0,000), WS and presence of adipocytes (Rho= 0,683 P=0,000), WS and fibrosis (Rho= 0,406 P=0,000). Because of these results only these parameters were used to calculate an histological overall score. The overall score resulted to increase with time, as a result of the evolution of single lesions. At 12 and 25 days, myocytes resulted swollen and degenerated (average score 1.8 and 2.2), other lesions are rare (average score under 1). The absence of inflammation in this period led to suppose that the lesion originates from an apoptotic phenomena instead of an autoimmune mechanism. At 51 days, after degeneration, myocytes seems to be substituted by adipocytes and connective tissue, and the pathology becomes chronic. Diffused inflammation and vasculitis worsen progressively, but they are not strongly correlated with WS. In conclusion WS is confirmed to be a chronic alteration of muscle fibers beginning before the second week of age and immune system seems not to be involved in the onset of the pathology, but further studies will be necessary to better understand the pathogenesis of this disease.
2018
Proceedings of the XVth European poultry conference
978-90-829157-0-9
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/3281402
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