Molecular Phenotyping of White Striping and Wooden Breast Myopathies in Chicken

Abstract

The White Striping (WS) and Wooden Breast (WB) defects are two myopathic syndromes whose occurrence has recently increased in modern fast-growing broilers. The impact of these defects on the quality of breast meat is very important, as they greatly affect its visual aspect, nutritional value, and processing yields. The research conducted to date has improved our knowledge of the biological processes involved in their occurrence, but no solution has been identified so far to significantly reduce their incidence without affecting growing performance of broilers. This study aims to follow the evolution of molecular phenotypes in relation to both fast-growing rate and the occurrence of defects in order to identify potential biomarkers for diagnostic purposes, but also to improve our understanding of physiological dysregulation involved in the occurrence of WS and WB. This has been achieved through enzymatic, histological, and transcriptional approaches by considering breast muscles from a slow- and a fast-growing line, affected or not by WS and WB. Fast-growing muscles produced more reactive oxygen species (ROS) than slow-growing ones, independently of WS and WB occurrence. Within fast-growing muscles, despite higher mitochondria density, muscles affected by WS or WB defects did not show higher cytochrome oxidase activity (COX) activity, suggesting altered mitochondrial function. Among the markers related to muscle remodeling and regeneration, immunohistochemical staining of FN1, NCAM, and MYH15 was higher in fast- compared to slow-growing muscles, and their amount also increased linearly with the presence and severity of WS and WB defects, making them potential biomarkers to assess accurately their presence and severity. Thanks to an innovative histological technique based on fluorescence intensity measurement, they can be rapidly quantified to estimate the injuries induced in case of WS and WB. The muscular expression of several other genes correlates also positively to the presence and severity of the defects like TGFB1 and CTGF , both involved in the development of connective tissue, or Twist1 , known as an inhibitor of myogenesis. Finally, our results suggested that a balance between TGFB1 and PPARG would be essential for fibrosis or adiposis induction and therefore for determining WS and WB phenotypes.

Physical, Chemical and Histological Characterization of Pectoralis major Muscle of Broilers Affected by Wooden Breast Myopathy

“…The same authors say that molecular phenotyping will allow progress in understanding the etiology of these defects but also by refining the diagnosis of injuries accelerate the development of non-invasive prediction tools at the service of breeders and producers. The present work is an additional contribution in line with recent reports [54,55].…”

“…Histological results of the present work are similar to those presented by [54] who raised the hypothesis that the damage to mitochondria mediated by hypoxia serves as the first step in Wooden Breast pathogenesis, followed by muscle pathology such as hypertrophy and fibrosis. Praud et al [55] worked with molecular phenotyping of white striping and wooden breast myopathies in chicken and propose the use of histological and molecular tools allowing for precise quantification of the different lesions present in muscles affected by white striping or wooden breast. The same authors say that molecular phenotyping will allow progress in understanding the etiology of these defects but also by refining the diagnosis of injuries accelerate the development of non-invasive prediction tools at the service of breeders and producers.…”

Serum Creatine Kinase as a Biomarker to Predict Wooden Breast in vivo for Chicken Breeding

“…Fibrosis was also one of the main features of WB and this may be related to the activation of transforming growth factor-beta signaling and the dysregulation of the matrix metalloproteinases and tissue inhibitor of metalloproteinases system ( Xing et al, 2021 ). Besides, Praud et al (2020) suggested that a balance between TGFB1 and PPARG would be essential for fibrosis or adiposis induction during the development of WB and WS. All the results suggested that there are several biological pathways, as well as response mechanisms involved in the development of WB.…”

Insights Into Transcriptome Profiles Associated With Wooden Breast Myopathy in Broilers Slaughtered at the Age of 6 or 7 Weeks

“…Widely distributed in inflammatory lesions, fibronectins, a group of fibroblast surface glycoproteins, generally binds to ECM proteins, were also found to play a major role during wound healing ( Grinnell et al, 1981 ). An extensive localization of FN1 at endomysial and perimysial levels was found in WB coupled with an increased content of this glycoprotein ( Praud et al, 2020 ). In addition, grouped in phagosome, FA ( Table 4 ), and ECM receptor interaction ( Supplementary Table 4 ), thrombospondin 2 ( THBS2 ), disulfide-linked homotrimeric glycoprotein, was highlighted as one of the most highly increased transcripts (FC = 15) in 7wk WB-affected broilers if compared to their non-WB counterparts ( Table 2 ).…”