Seminal plasma contains TGF-β and CXCL10 but sperm washing before cryopreservation is beneficial for post-thawing sperm motility in Black Bengal goats (Capra hircus)

Abstract

Problem: Artificial insemination, which requires cryopreservation of semen, is not completely optimized in goats because bucks discharge a small volume of ejaculate and seminal plasma (SP) contains specific proteins that are detrimental to spermatozoa at cryopreservation. However, it is not known the effects of sperm washing (removal of SP) before cryopreservation on the post-thawing frozen spermatozoa of Black Bengal bucks. Moreover, it is completely unknown whether SP of goats contains TGF-β and CXCL10 that have been proven essential for fertility in other mammals.

Methods: Thirty-five ejaculates were collected from six mature Black Bengal bucks at one-week intervals and were subjected to microscopic evaluation for semen characteristics at pre- and post-freezing condition. The concentrations of TGF-β and CXCL10 in the SP using ELISA were determined. SP was harvested with centrifugation of fresh semen at 1500 g for 15 minutes twice at room temperature.

Results: Semen characteristics were significantly varied between bucks. Seminal plasma of all ejaculates contained TGF-β and CXCL10 while significant variation of concentrations between bucks was observed in case of CXCL10. Cryopreservation of semen reduced total motility and progressive motility, while sperm washing before cryopreservation was beneficial to the total motility and progressive motility of post-thawing spermatozoa.

Conclusion: Black Bengal buck seminal plasma was affluent of TGF-β and CXCL10 and washing of spermatozoa before cryopreservation was beneficial to the post-thawing sperm motility. The results of the current investigation will be helpful for future research on the roles of SP in female reproductive tract and pregnancy in Black Bengal goats.

Keywords: Black Bengal goats; CXCL10; TGF-β; seminal plasma; spermatozoa.