Selected heavy metals versus antioxidant parameters in bull seminal plasma - a comparative study

To investigate the effects of lead (Pb) and cadmium (Cd) content on basic motility characteristics (motility, progressive motility) and selected antioxidant parameters (total antioxidant status - TAS, superoxide dismutase - SOD, albumin - ALB) in the bovine seminal plasma semen samples were collected from breeding bulls and used in the study. Motility analysis was carried out using the Computer Assisted Sperm Analysis (CASA) system. Subsequently, the samples were centrifuged and fractions of seminal plasma were collected. Pb and Cd concentrations were determined by the voltametric method (ASV), antioxidant parameters were analyzed by UV/VIS spectrophotometry using commercial kits. The analysis showed that the average concentrations of the trace elements were 0.57 ± 0.01 μg/mL for Pb and 0.11 ± 0.01 μg/mL for Cd. The correlation analysis revealed that both heavy metals were negatively correlated with motility (r = -0.777; P < 0.001 for Pb and r = -0.786; P < 0.001 for Cd), progressive motility (r = -0.763; P < 0.001 for Pb and r = -0.792; P < 0.001 for Cd), TAS (r = -0.375; p > 0.05 and r = -0.334; P > 0.05, respectively), SOD (r = -0.746; P < 0.001 and r = -0.537; P < 0.05, respectively) as well as with ALB (r = -0.609; P < 0.01 and r = -0.699; P < 0.001, respectively). Moreover the samples were categorized in three quality groups (Excellent, Good, Medium) according to their motility values. The lowest Pb and Cd concentrations but the best antioxidant characteristics were found in samples of excellent quality, medium quality samples were described by the highest Pb and Cd concentration and the worst antioxidant power. This study demonstrates that Pb and Cd are serious toxic elements, which are able to increase the risk of oxidative stress development and a subsequent decrease of semen quality.