Analysis Of Sperm Storage Ability Related Traits Of Chicken And The Preliminary Mechanism Study Based On Transcriptome Sequencing

The sperm storage tubules in the uterovaginal junction is the basis for the continuous production of fertile eggs in a prolonged period after artificial insemination.The duration of fertility of hens had a significant effect on the artificial insemination interval and fertilization rate.The present firstly compared the duration of fertility in White Leghorn,Columbia Rock,Barred Rock,and Rhode Island Red and the variation among hens of the same breed.Sperm storage tubules characteristics,and the expression levels of related hormones and receptor genes in high and low duration of fertility White Leghorn.RNAseq technology was used to construct transcriptome profiles of sperm storage tubules tissues of individuals with different duration of fertility.The key genes related to the sperm storage ability of hens were screened,which laid a foundation for the establishment of molecular breeding technology to improve the sperm storage ability of hens.The main results are as follows:The daily fertility rate decreased with days,but to different extents in four breeds.There were significant difference in egg number,fertilized eggs number in week 1~4,average fertility rate in week 1~4,maximum days of fertilization,maximum number of consecutive fertilized eggs,fertilized eggs in week 1,2,and 2~3 among individuals within the breed(P < 0.05).The related traits of the Rhode Island Red were the highest.These mentioned traits also had variation in the varieties,and the variation of Barred Rock and Columbia Rock was larger,the variation of Rhode Island Red was smaller.There was no difference in sperm storage tubules numbers between high and low sperm storage ability groups(P > 0.05).The average cross section area of sperm storage tubules of high sperm storage ability group was higher than that of the low group(P <0.05).There was significant difference in progesterone hormone concentration between groups(P < 0.05).A total of 322 differentially expressed genes were identified in the sperm storage gland of hens with high and low sperm storage capacity,including 82 up-regulated genes and 240 down-regulated genes.They were enriched in biological processes including ovarian steroidogenesis,the metabolism of linoleic acid and ether lipids metabolism,arachidonic acid metabolism.Important genes such as translocated protein gene(TSPO),cyclic adenosine phosphate binding protein gene(CREB3L1),calcineurin regulatingprotein gene(RCAN1),keratin gene(KRT15),and mitogen-activated protein kinase gene(MAPK13)were screened and found to be mainly concentrated in the metabolism of estrogen signaling pathways,oxytocin metabolic pathway.In summary,this study reveals that there are large variations in hens' duration of fertility between and within breeds,which is the basis for genetic improvement.Transcriptome sequencing results further prove that fat synthesis and metabolism pathways in the sperm storage tubules may affect this trait,which needs further study.This study lays the foundation for finding new methods to increase the fertility rate of hens and to carry out molecular methods for breeding for fertility.