Differences in sperm functionality and intracellular metabolites in Norwegian Red bulls of contrasting fertility

Sperm chromatin integrity and DNA methylation in Norwegian Red bulls of contrasting fertility

“…Sperm quality parameters related to chromatin integrity for the two fertility groups are presented in Table 2. As previously reported in Narud et al (2020), higher percentages of DFI ( p < 0.001) and HDS ( p < 0.01) were observed in sperm cells from LF bulls compared to HF bulls. The mean levels of free thiols, total thiols, disulfide bonds, and protamine deficiency were not different ( p > 0.05) for LF bulls compared with HF bulls.…”

“…The chromatin integrity parameters were further subjected to Pearson correlation analysis to identify possible relationships with NR56 and among parameters. As presented in Narud et al (2020), DFI and HDS correlated negatively with NR56. Furthermore, the results presented in Table 3 shows that DFI and HDS correlated positively with each other and with protamine deficiency.…”

“…Sires were selected based on their field fertility performance, measured as NR56, as previously described by Narud et al (2020). In brief, data on AIs were collected from the Norwegian Dairy Herd Recording System (NDHRS).…”

“…A wide range of intrinsic and extrinsic factors may cause sperm DNA fragmentation, including oxidative stress, abortive apoptosis, deficiencies in recombination, age, semen handling, thermal stress, vaccinations, and bacterial infections (González‐Marín et al, 2012; Kumaresan et al, 2020). Studies have shown that the degree of sperm DNA fragmentation is negatively correlated with bovine field fertility (Gliozzi et al, 2017; Narud et al, 2020; Waterhouse et al, 2006) and the outcome of in vitro fertilization (IVF) (Fatehi et al, 2006; Simões et al, 2013). Further, the histone to protamine ratio in sperm cells affects male fertility, where infertile men possess sperm cells with higher proportions of retained histones compared to fertile men (X. Zhang et al, 2006).…”

“…Recently, we showed that the chromatin integrity parameters DNA fragmentation index (DFI) and high DNA stainability (HDS) in sperm cells from Norwegian Red bulls were significantly negatively associated with field fertility, expressed as 56‐day non‐return rate (NR56) (Narud et al, 2020). The aim of the present study was to evaluate several parameters related to sperm chromatin integrity in Norwegian Red bulls of contrasting NR56.…”