Transcriptomic Insights into the Age-Dependent Regulation of Breast Muscle Growth in Broiler Chickens

Abstract

The poultry industry is an excellent model for understanding the effects of human-driven selective pressure on animal genomes. One such system is modern poultry breeding, which uses intensive genetic selection for meat production in broilers. While the mRNA levels in broilers between days 6 and 21 post-hatch have been compared, the transcriptome of older chickens is not well defined, particularly for growth-related mRNAs. Here, RNA sequencing was used to compare the transcriptomes of 2-, 6-, 10-, and 14-week-old broilers to identify differentially enriched genes in the breast muscle. Among the genes analyzed, 445 were upregulated, and 237 were downregulated. We identified the differentially enriched genes that regulate breast muscle growth and differentiation in chickens of different ages. Our results indicated that most growth hormone and insulin-like growth factor genes were downregulated as growth proceeded. Furthermore, differences in the ratios of several positive myogenic growth regulators (IGF2BP1, IGF2BP3, MYOD1, mTOR, SHC, IRS, SOCS, GK, and MNK) may help to explain the different growth characteristics of different aged broilers.