Identification of biomarkers of meat quality by high throughput analyses of muscle transcripts and serum metabolites of two lines of broilers divergently selected on breast meat ultimate pH

The processing ability of chicken meat is very variable, which could impact on the competitiveness of the poultry industry. As in pig, high variations in ultimate pH lead to defects of appearance, conservation and processing yields. To understand the biological and genetic mechanisms involved in the control of poultry meat quality, two chicken lines were divergently selected on the breast meat ultimate pH (pHu): the pHu- and the pHu+ lines. Their average pHu diverges of 0.5 pH units in the breast Pectoralis major (PM), which corresponds to a 20% difference of muscle glycogen (pHu- > pHu+). The present study aims at identifying biomarkers of meat quality by using high throughput approaches for the profiling of the muscle transcriptome (8x60K custom Agilent microarray) and for the characterization of metabolome in muscle and serum (proton and phosphorus NMR analysis on muscle and proton NMR on serum). The analysis by Gene Ontology of the differentially expressed genes between muscles from the pHu- and the pHu+ lines indicates an over-representation of genes involved in 6 processes, i.e., the sarcomere organization, the positive regulation of phosphorylation, the pyruvate metabolism, the glycolysis, and the coenzyme and phosphorus metabolism. Most of the genes involved in the glycolysis pathway were over-expressed in the pHu- compared to the pHu+ line. The serum of the pHu- chickens was characterized by higher glucose level and lower concentrations in byproducts of purine degradation compared to the pHu+ line. These observations could help at a better understanding of the molecular pathways underlying the differential ability of the pHu- and pHu+ line to store glycogen in their muscle. By defining a set of pertinent biomarkers, our goal is to build a predictive model of the breast muscle ultimate pH to optimize the quality of poultry meat in relation to breeding and rearing factors.