Whole Genome RNA Sequencing in Holstein Bull Spermatozoa with Different Cryoresistance

Whole transcriptome sequencing was performed to compare the transcript profiles of spermatozoa from the bulls with different sperm production characteristics and freezability. Ejaculates from Holstein bulls classified as having high and low cryotolerance and high and low sperm quality (n = 3 bulls per group) were analyzed for post-thaw motility, mitochondrial membrane potential, as well as plasma membrane and acrosomal integrity. Total RNA was isolated from decryopreserved spermatozoa from bulls of the GSF and PSF groups and subjected to RNA-sequencing (Illumina NextSeq 500 platform), transcript arrays were assessed using DESeq2, DESeq software packages in spermatozoa of each bull. Several differentially expressed genes (DEGs) associated with inflammation (IRG1, MMP12), spermatogenesis (Col4A2), and unknown functions (LOC 781178, LOC618942) that were preferentially downregulated in ejaculates with poor cryotolerance, were identified.