Removing seminal plasma improves bovine sperm sex‐sorting

Abstract

Bull ejaculates with sperm concentrations of less than 1 billion sperm sort poorly for sex chromosomes, but whether this is because of the sperm concentration or the concomitant seminal plasma content has not been elucidated. Experiments were conducted to determine why ejaculates with lower sperm concentrations sort poorly and develop a protocol to increase sorting efficiency. In Experiment I, spermatozoa at 160 or 240 × 10 sperm/mL were stained at 49, 65 or 81 μm Hoechst 33342 with 0 or 10% seminal plasma and then sex-sorted. In Experiment II, seminal plasma was adjusted to create samples with sperm concentrations of 0.7, 1.4 and 2.1 × 10 sperm/mL, prior to sex-sorting. In Experiment III, spermatozoa were diluted to 0.7, 1.4 and 2.1 × 10 sperm/mL using TALP containing 0 or 10% seminal plasma prior to sex-sorting and cryopreservation. In Experiment I, the optimal staining combination was 160 × 10 sperm/mL stained with 65 μm Hoechst 33342 and no seminal plasma. In Experiment II, the percentages of membrane-impaired sperm were lower for sample concentrations of 2.1 × 10 sperm/mL (15%) than for samples at 1.4 × 10 (17%) or 0.7 × 10 sperm/mL (18%; p < 0.01). The X sort rate was slower for samples stored at 0.7 × 10 sperm/mL (3.45 × 10 sperm/sec) than for samples stored at 1.4 × 10 and 2.1 × 10 sperm/mL (3.85 and 3.94 × 10 sperm/sec, respectively; p < 0.05). In Experiment III, samples containing 0% seminal plasma had higher percentages of live-oriented cells (54 vs. 50%; p < 0.05), fewer dead sperm (19 vs. 22%; p < 0.01) and higher post-thaw motility (41 vs. 35%; p < 0.05) than samples containing 10% seminal plasma. Ejaculates with high sperm concentrations result in superior sorting because these samples have less seminal plasma during staining than ejaculates with lower initial sperm concentrations as all samples are diluted to 160 × 10 sperm/mL for staining. Therefore, sorting efficiency appears to be affected by seminal plasma concentration, not by the original sperm concentration.

Reproductive performance of sexed versus conventional semen in Holstein heifers in various semiarid regions of Iran

“…However, it has been declared that high concentration of the bull seminal plasma may decrease the semen sorting efficiency (Steinhauser et al 2016) which can subsequently result in lower conception rate of this kind of semen. Semen sexing showed a significant effect on the number of services per conception (SpC).…”

Bovine sperm-oviduct interactions are characterized by specific sperm behaviour, ultrastructure and tubal reactions which are impacted by sex sorting

“…Supplementation of sex-sorted spermatozoa with seminal plasma from different, highly reproductive quality bulls might support sperm binding capacity after sex-sorting. To apply seminal plasma after sex-sorting might be important as it is known that removal of seminal plasma before the sex-sorting process improves sorting rate, increases sperm motility and reduces damage to sperm DNA and the sperm plasma membrane 69 . Further to that, supplementation of BSP proteins might hold promise to improve sperm binding capacity, as has been documented in capacitated sperm.…”

Effect of the pH in the enrichment of X or Y sex chromosome-bearing sperm in bovine

“…To get the offspring of our desire, people are interested in separating X- and Y-bearing sperm for further usage in artificial insemination and thereby meeting the need of humankind. Though with the continuous improvement [31,32] and advancement like use of optimized microfluidic system, better results in the human motile sperms before in vitro fertilization process [33] is achieved but still an alternative technique to enrich X and Y chromosome bearing sperm cells which would employ simpler and less expensive equipment is the need of the hour. Earlier study in mammals shows non-significant and contradictory results for impact of altering the pH on the migration of X- and Y-bearing sperm [34].…”