Molecular Pathways and Key Genes Associated With Breast Width and Protein Content in White Striping and Wooden Breast Chicken Pectoral Muscle

Abstract

Growth-related abnormalities affecting modern chickens, known as White Striping (WS) and Wooden Breast (WB), have been deeply investigated in the last decade. Nevertheless, their precise etiology remains unclear. The present study aimed at providing new insights into the molecular mechanisms involved in their onset by identifying clusters of co-expressed genes (i.e., modules) and key loci associated with phenotypes highly related to the occurrence of these muscular disorders. The data obtained by a Weighted Gene Co-expression Network Analysis (WGCNA) were investigated to identify hub genes associated with the parameters breast width (W) and total crude protein content (PC) of Pectoralis major muscles (PM) previously harvested from 12 fast-growing broilers (6 normal vs. 6 affected by WS/WB). W and PC can be considered markers of the high breast yield of modern broilers and the impaired composition of abnormal fillets, respectively. Among the identified modules, the turquoise (r = -0.90, p < 0.0001) and yellow2 (r = 0.91, p < 0.0001) were those most significantly related to PC and W, and therefore respectively named “protein content” and “width” modules. Functional analysis of the width module evidenced genes involved in the ubiquitin-mediated proteolysis and inflammatory response. GTPase activator activity, PI3K-Akt signaling pathway, collagen catabolic process, and blood vessel development have been detected among the most significant functional categories of the protein content module. The most interconnected hub genes detected for the width module encode for proteins implicated in the adaptive responses to oxidative stress (i.e., THRAP3 and PRPF40A), and a member of the inhibitor of apoptosis family (i.e., BIRC2) involved in contrasting apoptotic events related to the endoplasmic reticulum (ER)-stress. The protein content module showed hub genes coding for different types of collagens (such as COL6A3 and COL5A2), along with MMP2 and SPARC, which are implicated in Collagen type IV catabolism and biosynthesis. Taken together, the present findings suggested that an ER stress condition may underly the inflammatory responses and apoptotic events taking place within affected PM muscles. Moreover, these results support the hypothesis of a role of the Collagen type IV in the cascade of events leading to the occurrence of WS/WB and identify novel actors probably involved in their onset.

Proteomic analyses on chicken breast meat with white striping myopathy

“…To understand the etiology, genetic susceptibility, gene and protein expression, and biochemical pathways associated with breast myopathies, including WS and WB meat, researchers have extensively used genomics ( Alnahhas et al, 2016 ; Pampouille et al, 2018 ), transcriptomics ( Mutryn et al, 2015 ; Marchesi et al, 2019 ; Maharjan et al, 2021 ), proteomics ( Kuttappan et al, 2017 ; Cai et al, 2018 ; Zhang et al, 2020a ; Zhang et al, 2020b ), metabolomics ( Abasht et al, 2016 ; Boerboom et al, 2018 ; Consolo et al, 2020 ), and other methodologies ( Abasht et al, 2021 ; Bordini et al, 2022 ; Bordini et al, 2021 ; Kong et al, 2021 ). Transcriptomics with WS meat identified differentially expressed genes associated with hypoxia, cell death, angiogenesis, immune system, and striated muscle contraction ( Marchesi et al, 2019 ).…”

Differential expression of miRNAs associated with pectoral myopathies in young broilers: insights from a comparative transcriptome analysis

“…Differences in the occurrence of myopathies were found among fast-growing commercial lines [ 20 , 21 ]. Several authors have reported that high-breast-yielding broilers are more affected by myopathies than standard broiler lines [ 7 , 10 , 18 , 19 , 22 – 25 ].…”

“…Transcriptomic analyses of the pectoralis major muscle (PMM) have provided the identification of the messenger RNA (mRNA) expression profile in broilers affected by myopathies [ 25 – 30 ]. These functional studies have pointed out several candidate genes for the development of these disorders.…”