Transcriptome Profiling of Hypothalamus-Pituitary-Ovary Axis Provides Insights into Egg-Laying Interval Differences Between European Meat Pigeons and Shiqi Pigeons

Wang Xinlei^1*liyu yang¹Ruiting LI¹Liheng Zhang¹Zhanbing Han¹Runzhi Wang²Qiang Li¹Dingding Zhang¹Mingjun Yang³Pengkun Yang^1*

• ¹College of Animal Science and Technology, Henan University of Animal Husbandry and Economy, Zhengzhou, China
• ²Nanjing Institute of Animal Husbandry and Poultry Science, nan jing, China
• ³Henan Tiancheng Pigeon Industry Co., Ltd, ping ding shan, China

The long interval between successive egg-laying cycles in pigeons results in low egg production. The hypothalamus-pituitary-ovary (HPO) axis is of crucial importance in the regulation of egg laying in poultry. Phenotypic differences in egg-laying intervals between the two breeds of pigeons were found in the breeding phenotypic data: European meat pigeons showed a significantly shorter egg-laying interval (32.76±3.25 days) compared to Shiqi pigeons (33.11±3.86 days, P=0.024). Transcriptome sequencing was carried out on the hypothalamus, pituitary, and ovary tissues of European meat pigeons and Shiqi pigeons. Specific numbers of differentially expressed genes (DEGs) were accurately identified in each tissue. Gene Ontology (GO) enrichment analysis revealed that the DEGs in the hypothalamus and pituitary were involved in multiple biological processes such as thyroid hormone transport. In the ovary tissue, most of the DEGs were related to various embryonic developments and steroid synthesis. In the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, the hypothalamus and pituitary had enrichments in pathways such as glycosphingolipid biosynthesis, with the thyroid hormone signaling pathway being significantly enriched. In the ovary, the differential genes were mainly enriched in steroid hormone production, cAMP signaling pathway, cortisol synthesis, and other pathways. Finally, several key genes related to steroidogenesis and embryonic and tissue development were also discovered in the ovary, such as StAR, EYA1, HAND2, HOXB8 and NRN1. This study is conducive to a deep understanding of the regulatory role of the HPO axis during the egg-laying interval in pigeons and provides a data foundation for shortening the interval.