Expressed microRNA associated with high rate of egg production in chicken ovarian follicles

Summary Micro RNA (mi RNA ) is a highly conserved class of small noncoding RNA about 19–24 nucleotides in length that function in a specific manner to post‐transcriptionally regulate gene expression in organisms. Tissue mi RNA expression studies have discovered a myriad of functions for mi RNA s in various aspects, but a role for mi RNA s in chicken ovarian tissue at 300 days of age has not hitherto been reported. In this study, we performed the first mi RNA analysis of ovarian tissues in chickens with low and high rates of egg production using high‐throughput sequencing. By comparing low rate of egg production chickens with high rate of egg production chickens, 17 significantly differentially expressed mi RNA s were found ( P < 0.05), including 11 known and six novel mi RNA s. We found that all 11 known mi RNA s were involved mainly in pathways of reproduction regulation, such as steroid hormone biosynthesis and dopaminergic synapse. Additionally, expression profiling of six randomly selected differentially regulated mi RNA s were validated by quantitative real‐time polymerase chain reaction ( RT ‐ qPCR ). Some mi RNA s, such as gga‐miR‐34b, gga‐miR‐34c and gga‐miR‐216b, were reported to regulate processes such as proliferation, cell cycle, apoptosis and metastasis and were expressed differentially in ovaries of chickens with high rates of egg production, suggesting that these mi RNA s have an important role in ovary development and reproductive management of chicken. Furthermore, we uncovered that a significantly up‐regulated mi RNA —gga‐miR‐200a‐3p—is ubiquitous in reproduction‐regulation‐related pathways. This mi RNA may play a special central role in the reproductive management of chicken, and needs to be further studied for confirmation.