Study on Keeping Quality and Cryopreservability of Buffalo Semen in Egg Yolk and Soybean Based Extenders

The study was aimed to compare efficacy of egg yolk based diluent (TFYG) with soybean based commercial diluents (Bioxcell® and Optixcell®, IMV, France) for refrigeration and cryopreservation (-196°C) of six Surti buffalo semen. Each qualified ejaculate (n=8/bull, >70% initial motility) was split diluted @ 100 ×106 sperm ml-1 at 34°C with 3 diluents. Part of each aliquot was filled in French mini straws and rest transferred to refrigerator for gradual cooling to 4-5°C. After 4 h of equilibration at 4-5°C in cold handling cabinet, the straws were frozen using programmable bio-freezer. The initial mean motility, acrosome integrity and hypo-osmotic reactive sperm per cent of fresh semen were 78.54±0.30, 94.40±0.20 and 79.35±0.42%, respectively. Sperm progressive motility at 24 hrs of refrigeration storage was 68.33±0.45, 66.25±0.46 and 70.31±0.46 %, and at 72 hrs of refrigeration storage 52.50±0.68, 48.54±0.84 and 53.85±0.75 % in TFYG, Bioxcell and Optixcell diluents, respectively. Acrosomal integrity and hypo-osmotic reactivity at 24 hrs of refrigeration storage were 88.15±0.18, 87.25±0.21, 89.27±0.20% and 66.04±0.50, 63.81±0.45, 68.10±0.46%, whereas at 72 hrs of refrigeration, the values were 81.67±0.23, 80.60±0.30, 82.83±0.27% and 51.35±0.60, 47.35±0.68, 53.40±0.68%, respectively, in above 3 diluents. The pre-freeze sperm progressive motility recorded in TFYG, Bioxcell and Optixcell diluents was 69.48±0.37, 68.02±0.49 and 70.94±0.38%, and post-thaw motility was 47.71±0.79, 44.38±0.85 and 49.90±0.90%, respectively. Per cent sperm acrosomal integrity and hypo-osmotic reactivity in TFYG, Bioxcell and Optixcell diluents were 89.54±0.18, 88.58±0.22, 90.52±0.21% and 67.96±0.32, 65.65±0.42, 70.23±0.37% at pre-freeze stage, whereas 76.83±0.23, 75.90 ±0.27, 78.50±0.25% and 45.02±0.84, 42.31±0.82, 47.81±0.90% at post-thaw stage, respectively. The post-thaw longevity after 60 minutes of incubation (37°C) was 35.52±0.79, 31.15±0.85, 37.19±0.81%, respectively, in above 3 diluents. Among the three semen diluent percent sperm progressive motility, acrosomal integrity and hypo-osmotic reactivity at particular stage were higher in Optixcell showing at par results in TFYG, whereas Bioxcell showed significantly (P<0.05) lower findings than other two diluents. Optixcell is a commercial product much costlier than TFYG, hence there is a need to develop local soybean based semen extender which can give comparable results with TFYG.