78 EFFECT OF EXTENDER AND STORAGE PERIOD ON THE SOUTH AFRICAN INDIGENOUS KOLBROEK BOAR SPERM CELL MOTILITY RATES FOLLOWING ANALYSIS BY COMPUTER-ASSISTED SPERM ANALYSIS

Abstract

The choice of the short-term extender is important to preserve the quality of the diluted South African indigenous Kolbroek boar semen during short-term storage prior to artificial insemination. The aim of this study was to identify the suitable extender for short-term storage of Kolbroek boar semen at 17°C. Five ejaculates were collected separately from five Kolbroek boars using the gloved-hand technique in a 300-mL glass beaker. The filtered sperm fraction were sealed with a gauze filter inside a prewarmed (39°C) insulated thermos flask. Following semen collection, the semen was evaluated for macroscopic characteristics; semen volume, pH, and concentration. Sperm cells morphology was evaluated using eosin-nigrosin staining solution using fluorescent microscope system. Only ejaculates with >75% motile sperm and <15 abnormalities were used. The semen was pooled and diluted with five different short-term extenders, namely: Beltsville Thawing Solution (BTS), Kobidil⁺, Hungarian Standard, Citrate, and Tris-based extenders at a ratio of 1:1 (v/v). Sperm cells motility parameters were evaluated using a sperm class analyzer (SCA) at 0, 3, 24, and 48 h intervals. The data were analysed by SPSS. The results demonstrated that sperm cell motility rate did not differ when stored at 0 (88.9 ± 8.3) and 3 (93.8 ± 4.4) h irrespective of extender. However, semen that was diluted with Hungarian extender and Tris-based extender maintained higher proportion of sperm cells motility (90.0 ± 2.5 and 87.8 ± 4.8, respectively) for a longer period during storage for 24 h as compared with the other extenders. In conclusion, the study demonstrated that prolonged storage of boar sperm cells reduces motility rates. However; Hungarian Standard and Tris-based extenders preserved sperm motility rate better than the other extenders when stored up to 48 h at 17°C. Thus, this study suggests that Kolbroek sperm cells can be transported within 24 to 48 h in South African regions without adversely affecting motility rates when diluted with Hungarian Standard and Tris-based extender at 17°C without cryopreserving them.