Factors Influencing Sephadex Separation of Bovine and Ovine Spermatozoa

Abstract Fewer spermatozoa passed through a Sephadex G-15 column (40 to 120 μ m) when bovine sperm were extended in homogenized whole milk than in Tris-stepwise or Tris-complete extender (22 vs. 51 or 52%). Fewer bovine spermatozoa were recovered when they were extended in skim milk rather than in TEST or egg yolk-citrate (18 vs. 66 or 70%). The percentage of immotile ovine sperm from the caput or corpus epididymidis passing through a Sephadex column (∼65%) was similar to that for motile sperm from the cauda epididymidis (66%). For bovine sperm, 50% of the immotile sperm from the proximal caput or 60% of the progressively motile sperm from the distal cauda epididymidis passed through a Sephadex column, but far fewer (21 to 43%) of the immotile sperm from the distal caput or corpus epididymidis passed through the column. Retention of bovine or ovine sperm within the filter also was independent of the percentage of sperm with an intact acrosome. Thus, passage of sperm through a Sephadex G-15 column does not separate motile from immotile sperm or those with a normal acrosome from other sperm. The separation of sperm probably is on the basis of complex and interacting properties of the spermatozoal plasma membrane, the medium suspending the sperm, and the Sephadex gel. The Sephadex filtration procedure was unsatisfactory for evaluating quality of sperm in skim and homogenized whole milk extenders.