Correlation between systemic oxidative stress markers and semen parameters by sperm class analyzer (SCA) in dogs

Artificial insemination is becoming more common in domestic dog breeding and in the ex-situ conservation programs for endangered wild canids. Sperm cells under aerobic conditions produce reactive oxygen species (ROS), mostly originated from normal metabolic activity. The aim of this study was to investigate the correlation between oxidative status in dogs and sperm quality assessed by Sperm Class Analyzer (SCA). Ten male dogs, 7 fertile and 3 ipofertile, aged 1 to 7 years old were included in this study. Each animal was submitted to clinical ex- amination and semen collection and evaluation. Oxidative status was evaluated by d-ROMs test and Oxy-Adsorbent test in blood samples and the ratio between ROMs and OXY (%) was calculated and used as index of plasma oxidative state (OSi).Comparison between fertile and infertile dogs performed by Kruskal-Wallis analysis of variance (p < 0.05) showed significant differences between the two groups for the following kinetic parameters: VAP, VSL, BCF, STR, LIN, MOT%, PROG, RAPID, MEDIUM, SLOW, STATIC, OSi. Correlations between each kinetics parameter and OSi were evaluated separately in each group by Spearman test (high correlation: ρ = 0.6–0.9, p < 0.05): in in- fertile group a high positive correlationwere demonstrated between OSi and VCL, SLOW, STATIC. A significant negative correlation was present between OSi and MOT and RAPID. In fertile group a signifi- cantpositive and negative correlation were evaluated between OSi and SLOW and between OSi and PROG respectively. This study re- ports, for the first time, a direct correlation between oxidative stress and the main parameters of the fertility test in both fertile and infertile dogs. These results open new diagnostic, prognostic and therapeutic insights for canine male infertility.