Initial sperm motility parameters and promoter methylation levels of the six selected adult bulls.

Note: Bulls 1, 2, and 3 belonged to the high-motility group, whereas bulls 4, 5, and 6 belonged to the low-motility group. We amplified a 175 bp fragment (-233 bp to -59 bp) with 17 CpG sites in the core promoter region of each bull. Each fragment was cloned into pEASY-T3 vector and transformed into E. coli DH5α cells for clone sequencing. Sixty selected clones (10 clones per bull) and 1,020 CpG sites were analyzed. No significant difference in the frequency of DNA methylation of the HIBADH promoter between the high-performing (5.88%, n = 30 clones) and low-performing bulls (6.66%, n = 30 clones) (P > 0.05) was found, and all clones were hypomethylated (<50% of CpG sites on a given methylated strand). The 7th CpG site showed higher methylation level in the high-motility group (73.33%, 22/30) than in the low-motility group (23.33%, 7/30) (P < 0.01).
Initial sperm motility parameters and promoter methylation levels of the six selected adult bulls.