Preliminary Comparative Transcriptome Profiling of Ovary Tissue in White Muscovy Duck with High- and Low-Egg Production

Background: The egg-laying rate is an important indicator for evaluating fertility of poultry, in which the growth and development of ovarian granulosa cells are essential for the egg production performance of poultry. In this study, to understand the mRNA expression regulations and pathways of ovarian granulosa cells organization, we sequenced the white Muscovy ducks of different fecundity at egg production peak using RNA-Seq, further, improve the reproduction character and economic efficiency. Three high-yield and three low-yield Muscovy ducks in the peak egg-laying period were selected according to the egg-laying record in the peak egg-laying period. The ovarian tissues of Muscovy ducks were collected, and the differentially expressed genes (DEGs) were screened by RNA-seq analysis. The main signaling pathways were analyzed by Gene Ontology (GO) annotations enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations enrichment, and verified by qRT-PCR. Results The results showed that the ratio of sequencing reads generated by high-yield and low-yield white Muscovy ducks to the reference genome of green head ducks ranged from 60.28–65.58%; Further analysis showed 296 differentially expressed genes (DEGs) were screened. Compared with low-yield white Muscovy ducks, 160 genes were up-regulated and 136 genes were down-regulated in high-yield white Muscovy ducks ovary; GO annotations are mainly enriched in oxygen binding and oxygen transport activities at the molecular level, but not in GO Terms of biological processes and cell components; KEGG pathway was enriched in phagosome, cancer proteoglycan pathway, actin cytoskeleton regulation, cell adhesion molecules, Rap1 signaling pathway and PI3K-Akt signaling pathway. PI3K-Akt signaling pathway was closely related to animal reproductive performance; based on the GO terms and KEGG pathways results, seven genes closely related to ovarian granulosa cell differentiation and proliferation were screened and RNA-seq was used., qRT-PCR results showed that the expression trends of seven randomly selected DEGs were consistent with RNA-seq results. Conclusion In summary, this study should serve as an important resource revealing a theoretical basis on the molecular regulation mechanism of reproductive traits genes in granulosa cells of white Muscovy duck ovary.