Identification of genes related to growth and amino acid metabolism from the transcriptome profile of the liver of growing laying hens

The growing period is a critical period for the growth and development of hens and affects their production performance during the laying period. Dur-ing the early stage of growing, bone and muscle growth is rapid, making it necessary to provide sufficient amino acids (AA) to support the growth and development of laying hens. In this experiment, RNA-Sequencing (RNA-Seq) was applied to compare the liver tissues from 6-to 12-wk-old growing laying hens to identify can-didate genes related to growth and AA transport and metabolism. In the liver tissues, 596 differentially expressed genes (DEG) were identified, of which 424 genes were up-regulated and 172 were down-regulated. Through enrichment analysis and DEGs analysis, some DEGs and pathways related to AA transport and metabolism were identified. Additionally, there were significantly increased activities in the liver of glutamate dehydrogenase (GDH), glutamic oxaloacetic transami-nase (GOT), and glutamate pyruvate transaminase (GPT). Meanwhile, the level of serum insulin-like growth factor binding protein-5 (IGFBP-5) signifi-cantly elevated, and insulin-like growth factor-1 (IGF-1) levels significantly reduced at 12 wk compared to 6 wk. The AA contents in the breast muscle were not sig-nificantly altered, while the levels of the free AA in the serum underwent significant changes. This study discov-ered that the transport and metabolism of AAs in grow-ing laying hens at different ages changed, which influenced the growth and development of growing lay-ing hens. This contributes to future research on the mechanisms of growth and AA metabolism during the growing period of laying hens.

Automated summary

This study compared the gene expression differences in liver tissues of laying hens at different ages using RNA sequencing, and found that the transport and metabolism of amino acids changed during the growing period, which influenced the growth and development of the hens.