Spermatozoa motility in the ship sturgeon (Acipenser nudiventris Lovetzky, 1828): Effects of pH, dilution ratio, ions and osmolality

In this study effects of extenders on motility of spermatozoa (pooled semens from 3 male) of the ship sturgeon (Acipenser nudiventris) were investigated. Optimum ionic content (Na+, K+, Ca2+ and Mg2+), pH and buffer content (tris, tris-hcl, hepes) of activation solution as well as the optimum dilution rate and osmolality were determined. The results show optimum motility characteristics of spermatozoa in buffered solutions tris-hcl 30 mML-1 containing 12.5, 1, 7 and 15 mML-1 Na+, K+, Ca2+ and Mg2+, respectively, at dilution rate 1:100 and pH 8.5. At osmolalities of 68-94 mOsmol Kg-1 the spermatozoa motility was partly inhibited but the motility of A. nudiventris spermatozoa is inhibited by high osmotic pressure (133 mOsmol Kg-1 or more). The results of the present study demonstrated that various parameters such as ion concentration (Na+, K+, Ca2+ and Mg2+), osmotic pressure, pH, buffer content and dilution rate. affect the motility duration of ship sturgeon spermatozoa. K+ concentration in combination with osmotic pressure controlled spermatozoa motility in ship sturgeon. In conclusion Na+, Ca2+ and Mg2+ counter the inhibitory action of K+ and bivalent cations (Ca2+ and Mg2+) are more effective than Na+.