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Rapidly growing broilers experience a significant increase in body weight and undergo metabolic changes at an accelerated rate over a very short period. As broiler chickens rapidly grow, the excessive yield and quality of breast muscle become significant concerns because breast muscle is the most preferred portion in the U.S. It is important to recognize the age dependent differences age dependent differences within the grower phase for the purpose of maximizing lean mass. To understand the differences in gene expression of breast muscle across different ages during the grower phase in the broiler chickens, we compared the transcriptomic profiles of breast muscle at 20-d-old (D20) and 28-d-old (D28) of age in broiler chickens using RNA-seq. We identified a total of 1,536 differentially expressed genes (DEGs), of which 990 genes were up-regulated and 546 genes were down-regulated in the D28 group compared with the D20 group. According to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, the up-regulated DEGs indicated that MAPK signaling pathway, ErbB signaling pathway, Insulin signaling pathway, and Regulation of actin cytoskeleton, whereas Ribosome and Cell cycle pathways were enriched in the down-regulated DEGs. Gene set enrichment analysis and protein-protein interaction network analysis revealed that the breast muscle of the D20 group showed metabolic pathways focusing on muscle proliferation and differentiation. In contrast, the breast muscle of the D28 group was primarily focused on metabolic pathways related to muscle fiber maintenance and functional enhancement. These findings may serve as a basis for further research into metabolic differences in breast muscle during the grower phase of broiler chickens and could be valuable for improving genetic feeding strategies in the future.
Han et al. (Mon,) studied this question.