The Response of Cockerel Semen Kinematic Parameters LIN, STR, WOB, ALH and BCF to Induced Oxidative Stress

Abstract

Computer-assisted sperm class analyser (CASA) analysis of avian semen following cryopreservation indicates that their semen motility and viability parameters become compromised, due in part to oxidative stress. To mimic these observations we have treated cockerel semen with an oxidative stress inducing agent, namely hydrogen peroxide (H2O2) and monitored the motility, kinematic and viability parameters over time. Briefly, five healthy and fertile South African Venda cockerels were selected and their semen was collected using the abdominal massage technique. The semen was then treated with H2O2 at 0 µM, 5 µM, 50 µM and 200 µM concentrations for 0, 3, 16 and 24 hrs. The semen motility, kinematic and viability parameters were then determined using the CASA system while the viability was determined using the SYBR-14/PI staining. The Pearson’s correlation coefficient was determined to test the relationships between the levels of induced oxidative stress, period of exposure to oxidative stress inducing agent and the motility plus kinematic parameters. Our data revealed that in raw cockerel semen, there was high and positive correlations between total motility (TM), progressive motility (PM), rapid (RAP), curvilinear velocity (VCL), straight line velocity (VSL) and average path velocity (VAP) while the kinematic parameters LIN, STR, WOB, ALH and BCF had low or negative correlations with them. Furthermore, TM, PM, RAP, VCL and VSL remained highly and positively correlated with the induced oxidative stress and also, linearity (LIN), straightness (STR), wobble (WOB), amplitude of lateral head displacement (ALH) and beat cross frequency (BCF) remained negatively correlated with the induced oxidative stress, after 3 hrs. After 24 hrs, TM, PM, RAP, VCL, VSL, VAP and ALH, became negatively correlated with the induced oxidative stress while LIN, STR, WOB and BCF became positively correlated with the induced oxidative stress. Conversely, when the H2O2 concentration used was correlated with motility and kinematic parameters over time, TM, PM, RAP, VCL, VSL, VAP became negatively correlated with oxidative stress while LIN, STR, WOB, ALH and BCF show negative or low correlations with the induced oxidative stress. This data indicates that LIN, STR, WOB, BCF and to some extend ALH, reveal the least correlations with the induced oxidative stress under persistent oxidative stress conditions in cockerel semen. In conclusion, cockerel semen, like buck semen, does not easily succumb to oxidative stress since the raw semen correlations of CASA analysed parameters are comparable to these observed after 3 hrs of H2O2 treatment. In addition, the oxidative stress levels tolerated by cockerel semen should not 5 µM H2O2 oxidative stress levels. Lastly, lack of correlation between LIN, STR, WOB, BCF and ALH and induced oxidative stress can be used in cockerel semen to show intolerable cryopreservation conditions.