Relationship between Mineral Composition of Seminal Plasma and Semen Quality in Various Ram Breeds

Background: Seminal plasma of mammals is a complex fluid, which serves as a carrier for the spermatozoa on their journey from the male testes to their target, the oocyte. Seminal plasma contains a variety of biochemical components, some of which are relatively specific for the regulation of sperm function. The objective of this study was to investigate enzyme activities aspartate-amino-transferase (AST), alkaline phosphatase (ALP), lactate-dehydrogenase (LDH) and concentrations of macroelements[ sodium (Na) and potassium (K) and calcium (Ca) ] in seminal plasma. Moreover the present study was performed to investigate proteins in ram seminal plasma and the correlation between specific proteins and semen characteristics in cross breed ram. Materials, Methods & Results: Sixteen crossbred fertile rams (four Baluchi × Moghani, four Ghezel × Baluchi, four Ghezel × Merino, and four Merino × Moghani) were used in this study. Three ejaculates of each animal were collected during the breeding season and examined spermatozoa with light microscopy for motility, concentration, for dead sperm and morphology. Seminal plasma was harvested by centrifugation and then subjected to analysis enzyme, mineral composition and SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Total protein, AST, ALP, LDH, Na, K and calcium Ca were measured. Spearman’s correlation coefficient test was applied to examine the correlation between seminal plasma protein fractions with all the parameters of the semen. Differences were considered to be statistically significant at P < 0.05. The highest seminal plasma concentration of Na, K and Ca was recorded in Ghezel ×Merinos rams. The result showed that there was a significant negative correlation between Na and K but small correlation was recorded between Na and Ca. The highest plasma concentration of ALP was recorded in Baluchi × Moghani ram and the lowest was recorded in Merino × Moghani ram (8 ± 1.25 and 3.33 ± 0.01 U/mL, respectively). The highest plasma concentration of LDH and AST was recorded in Ghezel × Baluchi ram (4.68 ± 0.19 U/mL, 19 ± 4 U/mL respectively). Significant correlations were found between LDH levels and sperm viability. The results obtained indicate that ram seminal plasma protein profile is characterized by many protein bands with molecular weights, ranging from 8.81 to 95.82 kDa. Five proteins in this study had quantitative difference between seminal plasma from crossbred rams. Discussion: The results showed that the relative content of protein bands wasn’t significantly different by semen characteristics. Thus this study indicates that the relative content of seminal plasma proteins could not be an essential index to evaluate ram semen quality. Also increase in the percentage of live and normal sperm corresponded to an increase in LDH activity in the seminal fluid. It has been stated that LDH plays an important metabolic role in sperm capacitation and fertilization. This study suggest that the cations Na and K generally establish the osmotic balance, and seminal plasma osmolality ultimately plays an important role in the activation sperm cell also potassium ions (K) are also intracellular cations, and the concentrations in the seminal fluid may be an indication of sperm plasma membrane integrity. Thus some enzyme and mineral composition could be an essential index to evaluate cross breed ram semen quality.