Homologous seminal plasma efficiently activates epididymal tail sperm compared to traditional Tris buffer and Sperm-TALP in sheep

Abstract We hypothesized that ram epididymal tail sperm may be efficiently activated in homologous seminal plasma compared to tris and sperm-TALP. Eighty ejaculates were collected from five healthy fertile rams by artificial vagina for harvesting of seminal plasma by two-phase centrifugation. Spermatozoa were activated in three activation fluids- homologous seminal plasma (SP), sperm-TALP (TP) and tris buffer (TR) and were preserved at 4°C for 72 hours. Sperm motility was higher (p<0.05) for SP (64.33±4.80-48 hr; 52.50±2.14-72 hr) compared to both TP (51.66±2.10-48 hr; 40.83±3.00-72 hr) and TR groups (52.50±4.03-48 hr; 41.66±3.33-72 hr) at 48 and 72 hr of cold storage. CFDA (Carboxy fluorescein diacetate) positive sperm (Viable) percentage was also higher (p<0.05) for SP than TP and TR at 48 (72.39±0.62-SP, 67.13±1.29-TP, 66.89±1.65-TR) and 72 hours (63.37±2.19-SP, 56.13±1.60-TP, 58.18±1.49-TR) of cold storage. HOST reacted sperm percentage was also higher (p<0.05) for SP at 48 (65.10±1.55-SP, 59.95±0.24-TP, 61.50±1.11-TR) and 72 hours (55.09±1.17-SP, 46.53±0.78-TP, 50.16±0.16-TR) of cold storage compared to TP and TR groups. FITC-PNA (Fluorescein isothiocyanate conjugated to peanut agglutinin) negative sperm (Intact acrosomes) percentage was also higher (p<0.05) for SP than TR at 0 (91.66±0.90-SP, 88.13±1.02-TR), compared to TP at 48 (75.54±0.70-SP, 74.49±1.07-TP) and compared to TP and TR at 72 hours of cold storage (68.27±1.15-SP, 61.97±1.35-TP, 62.91±1.53-TR). In conclusion, homologous seminal plasma efficiently activated and preserved epididymal tail sperm compared to tris buffer and sperm-TALP. This study opened a new window of research to further explore the role of homologous seminal plasma in cryoprotection of epididymal tail sperm.