cadmium as an etiology of sperm dysfunction in holstein bulls

oxidative stress has been identified as a crucial factor leading to male infertility largely due to peroxidativedamage to the sperm cell membrane. cadmium (cd) is a widespread environmental pollutant and oneof the well-known reproductive toxicants. because of its long biological half-life (10–30 years), cdaccumulates in the biological systems. the present study was designed to assess the concentration-dependent in vitro effect of 20 to 700 μm of cd on the membrane integrity, motility, and acrosomal status of holstein bull spermatozoa. we recorded a significant elevation in the malondialdehyde (mda) level, increased lipid peroxidation (lpo) rate and a drastic decrease in the spermatocrit values, especially at the 700 μm concentration of cd, indicating deleterious effects of cd on the intactness of the sperm membrane. there was also a negative correlation between the lpo rate and both the percentage of motile spermatozoa (r = -0.89) and sperm viability (r = -0.86). performing the gelatin test indicated that cd altered the integrity of acrosomal membranes and showed an abnormal acrosome reaction. in this regard, a reverse correlation was found between the lpo rate and the percentage of halos (r = -0.96). in conclusion, cd was proved to be a potential toxicant in the category of environmental factors that induced membrane impairments, lowered motility and viability, and decreased rate of acrosome reactions leading to bull sperm dysfunction.