Identification of key genes affecting sperm motility in chicken based on whole- transcriptome sequencing

Sperm motility is an important index for the evaluation of semen quality. Improving sperm motil-ity is important to improve reproductive performance, promote breeding process, and reduce production cost. However, the molecular mechanisms regulating sperm motility in chickens remain unclear. In this study, histo-logical observation and whole-transcriptome analysis were performed on testicular tissue of chickens with high and low sperm motility. Histological observations showed that roosters with high sperm motility exhibited better semen quality than those with low sperm motility. In addition, the germinal epithelial cells of roosters with low sperm motility were loosely arranged and contained many vacuoles. RNA-seq results revealed the expression of 23,033 mRNAs, 2,893 lncRNAs, and 515 miRNAs in chicken testes. Among them, there were 417 differentially expressed mRNAs (DEmRNAs), 106 differentially expressed lncRNAs (DElncRNAs), and 15 differentially expressed miRNAs (DEmiRNAs) between high and low sperm motility testes. These dif-ferentially expressed genes were involved in the G pro-tein-coupled receptor signaling pathway, cilia structure, Wnt signaling, MAPK signaling, GnRH signaling, and mTOR signaling. By integrating the competitive relationships between DEmRNAs, DElncRNAs, and DEmi-RNAs, we identified the regulatory pathway of MSTRG.3077.3/MSTRG.9085.1-gga-miR-138-5p-CADM1 and MSTRG.2290.1-gga-miR-142-3p-GNAQ/ PPP3CA as crucial in the modulation of chicken sperm motility. This study provides new insights into the function and mechanism of ceRNAs in regulating sperm motility in chicken testes.