Project description:Broiler industry is facing an increasing prevalence of breast myopathies such as white striping (WS) and wooden breast (WB), whose precise etiology remains poorly understood. In order to progress in the understanding of the structural changes and the molecular pathways involved in these myopathies, and identify biomarkers, a transcriptomic analysis using an 8×60K Agilent chicken microarray was performed. The study used pectoralis major muscles from three groups: slow-growing animals (n=8), fast-growing animals visually free from defects (n=8) or severely affected by both WS and WB (n=8). In addition, a weighted correlation network analysis was performed to investigate the relationship between modules of co-expressed genes and histological traits.
Project description:Wooden Breast (WB) is a novel myopathy affecting the pectoralis major muscle of modern broiler chickens. We selected pectoralis fillet samples, a normal(healthy) fillet and a WB fillet.
Project description:White Striping and Wooden Breast (WS/WB) are abnormalities increasingly occurring in the fillets of high breast yield and growth rate chicken hybrids. These defects lead to consistent economic losses for poultry meat industry, as affected broilers fillets present an impaired visual appearance that negatively affects consumers’ acceptability. Previous studies have highlighted in affected fillets a deeply damaged muscle, showing profound inflammation, fibrosis and lipidosis. The present study investigated the differentially expressed genes and pathways linked to the compositional changes observed in WS/WB breast muscles, in order to outline a more complete framework of the gene networks related to the occurrence of this complex pathological picture. The biochemical composition was performed on 20 Pectoralis major samples obtained from high breast yield and growth rate broilers (10 affected vs. 10 normal) and 12 out of the 20 samples were used for the microarray gene expression profiling (6 affected vs. 6 normal). The obtained results indicate strong changes in muscle mineral composition, coupled to an increased deposition of fat. In addition, 204 differentially expressed genes (DEG) were found: 102 up-regulated and 102 down-regulated in affected breasts. The gene expression pathways found more altered in WS/WB muscles are those related to muscle development, polysaccharide metabolic processes, proteoglycans synthesis, inflammation and calcium signaling pathway. On the whole, the findings suggest that a multifactorial and complex etiology is associated with the occurrence of WS/WB muscle abnormalities, contributing to further define the transcription patterns associated to these myopathies.
Project description:We report the results of comparative transcriptional profiling in the pectoralis major muscle of a modern production broiler line (Ross 708) and a legacy broiler line inbred since the late 1940s (Illinois) focusing on metabolic differences and differences in myogenic growth regulators Differential gene expression analysis between Ross 708 and Illinois pectoralis major at two post-hatch time points (D6 and D21) that bracket critical inflection point in the allometric growth characteristics of the muscle
Project description:RNA-seq analysis reveals spatial and sex differences in pectoralis major muscle of broiler chickens contributing to difference in susceptibility to wooden breast disease
Project description:Breast muscle myopathies in broilers compromise meat quality and continue to plague the poultry industry. Broiler breast muscle myopathies are characterized by impaired satellite cells (SC)-mediated repair, and localized tissue hypoxia and dysregulation of oxygen homeostasis have been implicated as contributing factors. The present study was designed to test the hypothesis that hypoxia disrupts the behavior of SC essential for multinucleated myotube formation in vitro, and to determine the extent to which effects are reversed by restoration of oxygen tension. Primary SC was isolated from pectoralis major of young (5 d) Cobb 700 chicks and maintained in growth conditions or induced to differentiate under normoxic (20% O2) or hypoxic (1% O2) conditions for up to 48 h. Hypoxia enhanced SC proliferation while inhibiting myogenic potential, with decreased fusion index and suppressed myotube formation. Reoxygenation after hypoxia partially reversed effects on both proliferation and myogenesis. Western blotting showed that hypoxia diminished myogenin expression, activated AMPK, upregulated proliferation markers, and increased molecular signaling of cellular stress. Hypoxia also promoted accumulation of lipid droplets in myotubes. Targeted RNAseq identified numerous differentially expressed genes across differentiation under hypoxia, including several genes that have been associated with myopathies in vivo. Altogether, these data demonstrate localized hypoxia may influence SC behavior in ways that disrupt muscle repair and promote the formation of myopathies in broilers.
Project description:We report the results of comparative transcriptional profiling in the pectoralis major muscle of a modern production broiler line (Ross 708) and a legacy broiler line inbred since the late 1940s (Illinois) focusing on metabolic differences and differences in myogenic growth regulators
