miRNA expression profiling in liver of juvenile and egg-laying hens

A total of 565 miRNAs annotated in miRBase 20.0 were identified to be expressed in the liver of hen by high-throughput sequencing three biological reduplication libraries in juvenile and egg-laying hens, respectively. Compared with juvenile hen, 80 miRNAs (67 down-regulated and 13 up-regulated) were verified to be significant differential expression (SDE) in egg-laying physiological stage. Among these, miR-22-3p has the highest abundant expression, and miR-146b-5p has the highest fold-change. Additionally, 19 of the 71 novel miRNAs was significantly expressed. Furthermore, 648 putative target genes of the SDE miRNAs were obtained, and among these, FADS1, FADS2, ELOVL6, ACSL5, etc which are lipid metabolism related critical regulators are targeted by some SDE miRNAs. Gene Ontology (GO) analyses to the putative target genes of all the SDE miRNAs showed significantly enriched in Steroid biosynthesis, Glycerophospholipid metabolism, Biosynthesis of unsaturated fatty acids, and PPAR signaling pathway (P ≤ 0.05). Meanwhile, GO terms are also significantly enriched in lipid related biological processes. Total two groups juvenile and egg-laying hens were included,and three replications for each group.Juvenile stage was designed as the reference group.The liver miRNAs expression profile of juvenile hens and laying hens were generated by Solexa microRNA-Seq