Determination of selected components in seminal plasma of donkey stallions and their correlation to semen quality parameters

Evaluation of selected components of seminal plasma as markers of ejaculate quality may be of interest when assessing the quality of semen. The aim of the study was to evaluate some biochemical parameters of seminal plasma in donkeys and compare them with the volume, concentration and motility of the ejaculate. A total of 11 ejaculates were collected from five donkey stallions (between one and three from each animal). Each ejaculate was assessed for volume, concentration and motility, and the seminal plasma biochemically examined after centrifugation. Total protein, creatinine, urea, alkaline phosphatase (ALP), alanine-aminotransferase (ALT), aspartate-amino-transferase, creatine kinase, gamma-glutamyl-transferase, lactate-dehydrogenase (LDH), sodium, potassium (K+), calcium, phosphate, chloride, copper (Cu), cholesterol, vitamin E (Vit E), magnesium (Mg2+), seminal plasma selenium (Se SP) and seminal plasma zinc (Zn SP) were identified. Biochemical analysis of the seminal plasma was then statistically evaluated using the Spearman coefficient of correlation. A significant positive correlation between ALP, ALT, LDH, Cu, Se SP and Zn SP and sperm concentration was found. Also there was a significant positive correlation between Vit E and sperm motility. Finally, there was a significant positive correlation between urea, K+, Mg2+ and the ejaculate volume. This is the first report about selected biochemical components of donkey's seminal plasma that we know of. However, further research using a larger number of individuals is necessary to confirm that these components of seminal plasma are useful as markers of ejaculate quality in donkey stallions.