Abstract
BACKGROUND: Growth-related myopathies, including white striping (WS), wooden breast (WB), and spaghetti meat (SM), compromise broiler meat quality, causing significant economic losses. Although these myopathies share some histological features, their molecular mechanisms remain incompletely understood, particularly regarding sex-specific differences. This study aimed to compare transcriptomic profiles of normal and defective pectoralis major muscles to identify biological pathways underlying male and female myopathies. Transcriptomic analysis was performed on RNA-seq data from pectoralis major muscles of male and female Ross 308 broilers. Then, differentially expressed genes (DEGs) and enriched pathways were identified using edgeR and functional annotation tools. RESULTS: SM samples exhibited the most extensive transcriptional alterations, particularly in males, with significant disruption of pathways related to hypoxia, energy metabolism, calcium signaling, and extracellular matrix remodeling. Compared to normal meat, WB meat demonstrated moderate molecular changes, while WS meat showed minimal transcriptomic impact. Males displayed pronounced metabolic dysregulation and increased activation of pathways associated with inflammation, fibrosis, and vascular remodeling compared to females, where transcriptional changes were generally less pronounced across all myopathies. Shared pathways among myopathies included oxidative phosphorylation, cytoskeletal organization, and inflammatory responses, though their expression patterns varied between sexes and conditions. CONCLUSIONS: This study highlights marked sex-specific differences in molecular responses to WS, WB, and SM, with males exhibiting more pronounced transcriptomic alterations. These findings underscore the importance of sex-specific approaches to mitigate the economic and welfare impacts of these myopathies in broiler production.