In vitro evaluation of frozen thawed kangayam bull semen enriched with antioxidants

The aim of this study was to assess the in vitro penetration rate of antioxidant enriched frozen thawed Kangayam bull semen. For the current investigation, 5-7-year-old Kangayam bulls were used. The semen was collected twice per week and two ejaculates were collected each time. They were subsequently transported to the laboratory for processing of semen and maintained in a water bath at 34°C. On the day of semen collection, three groups of semen were prepared with Tris-egg-yolk Glycerol Extender (TEYG) (group I), TEGY extenders with hyaluronan (group II), and TEGY extenders with metformin (group III) and stored in a water bath at 34°C. According to the group, the semen sample was first diluted at a ratio of 1:1 with the appropriate extender (TEYG, hyaluronan enriched or metformin enriched) and kept in laminar air flow at 22°C for seven minutes. Each semen sample was then extended using the appropriate semen extender in accordance with the dilution rate. After filling, sealing and printing, the final diluted semen sample was subjected to equilibration. Freezing was done as per the standard protocol. Oocytes were collected from cyclical animals on days 1, 5, 9 after estrus using the ultrasound guided transvaginal ovum pick-up method after ablation of the day 0 pre-ovulatory follicle. After oocyte and sperm maturation, the co-incubation of oocyte and sperm was done and the in vitro penetration rate was recorded. The overall in vitro penetration rate recorded in Kangayam cows was 46.66 per cent. Maximum in vitro penetration rate was observed in group II (52 per cent) followed by group III (46 per cent) and in group I (42 per cent). Based on the above findings, it was concluded that hyaluronan enriched semen may be used as a pragmatic approach for cryopreservation of Kangayam bull semen in order to augment the in vitro penetration rate in Kangayam.