TITLE:
Buck Semen Does Not Easily Succumb to Oxidative Stress
AUTHORS:
Cyril Mpho Pilane, Malebogo Audrey Bopape, Bovula Ntombizodwa, Mohleko Helen Mapeka
KEYWORDS:
South African Indigenous Bucks, Oxidative Stress, Motility, Semen
JOURNAL NAME:
Open Journal of Animal Sciences,
Vol.9 No.1,
January
4,
2019
ABSTRACT: Semen processing and
manipulation generally result in loss of sperm motility and sperm velocity due
in part to oxidative stress. In this study we investigated
the vulnerability of South African indigenous
unimproved buck semen to oxidative stress induced by an oxidative stress
inducing agent, namely, hydrogen peroxide (H2O2). Semen
ejaculates were collected from four superior South African
indigenous unimproved bucks in a total of ten collections and then each duplicate was treated with different concentrations
of H2O2 in presence or absence of Dithiothreitol (DTT). Sperm motility and velocities were determined using the computer aided
sperm class analyser (CASA). SYBR-14 and propidium iodide (PI) Live/Dead assay
kit was used to determine cell viability and Yo-Pro-1 plus PI Apoptosis kit was
used to determine apoptosis. Statistical analysis was performed on the data using
SPSS version 17.0 for Windows (SPSS Inc., Chicago, IL). South African indigenous unimproved buck raw semen
motility was between 97% with 98% viability and 0% apoptotic cells. Comparisons of the untreated controls at 0 and 3 hrs incubations revealed
that after 3 hrs there was overall a decrease in the number viable cells with
the majority of remaining cells exhibiting circular movements accompanied by
high progressive (PM) and rapid (RAP) motilities. In
treated South African indigenous unimproved buck semen, H2O2 marginally increased total motility (TM) with few apoptotic sperm cells while
retaining high viability. Also, H2O2 increased straight line distances travelled of more than 4
fold as compared to untreated controls with no circularly moving cells.
Moreover, inclusion of DTT, an antioxidant, had minimal effects on TM, RAP, curvilinear velocity (VCL), straight line velocity (VSL), linearity (LIN) and wobble (WOB) but positively affected PM, average path
velocities (VAP), apoptosis and viability. Our Pearson’s correlation data
revealed that only straightness (STR) was highly positively affected by H2O2.
Overall, the South African indigenous unimproved buck semen resisted
deterioration in TM, RAP, VCL, VAP, VSL, LIN, WOB, viability and apoptosis
under oxidative stress conditions. These data suggest that the South African
indigenous unimproved buck semen does not easily succumb to
oxidative stress.