Glass wool column filtration for stallion sperm selection. A comparative analysis with the single layer colloid centrifugation.

Glass wool column filtration (GWCF) selects human, bull, boar, dog, and buffalo spermatozoa, but reports in the horse are scarce. Single layer colloid centrifugation with Androcoll-E is currently the standard procedure to select good quality equine sperm. This study was designed to assess GWCF (50 and 75 mg columns; GWCF-50 and GWCF-75 respectively) efficacy to select good quality sperm from fresh and frozen-thawed equine semen, and to compare its performance with Androcoll-E colloid centrifugation. Percentage total motile (TM), progressively motile (PM), morphologically normal (MN), osmotically competent (HOS+), and acrosome-intact/osmotically competent (AI/HOS+) sperm were determined. In studies done with fresh semen samples (n=17), suspensions subjected to GWCF-50 showed an improvement (P<0.05) in PM and HOS+ sperm after selection. With GWCF-75, an increase (P<0.05) in PM, MN and HOS+ sperm was observed. Results with GWCF were comparable or better than with Androcoll-E selection. Sperm recovery was similar between procedures for all semen parameters. Total Sperm Count recovery was lower after GWCF-75 (GWCF-50=60.0; GWCF-75=51.0; Androcoll-E =76.0 million sperm; median; P=0.013), but results on Total Progressive Sperm Count were similar (GWCF-50=23.0; GWCF-75=27.0; Androcoll-E =24.0 million sperm; median; P=0.3850). Using frozen-thawed semen samples (n=16), an improvement (P<0.05) in TM, PM, NM, HOS+ and AI/HOS+ sperm was observed in GWCF-75 filtrates. Results were comparable to Androcoll-E centrifugation, except HOS+ that increased (P<0.05) only after GWCF-75. Recovery was comparable for all parameters in frozen samples. GWCF is a simple and low-cost procedure that selects equine sperm with a quality comparable to colloid centrifugation with Androcoll-E .