Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1995. / Vita. Abstract. Includes bibliographical references (leaves 64-68). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 54-59). Also available via the Internet.

Introduction: Numerous past reports have mentioned or have been totally concerned with the significance of spermatozoan agglutination following treatment with blood sera, female genital fluids and other biological and synthetic media. Since semen is a colloid (undissolved particles suspended in a suitable medium such as gas, liquid, solid), spermatozoan agglutination should be at least partially definable by physical chemical measurements and should thereby be predicted and controlled... / Ph. D.

Swelling of the apical ridge and anterior acrosome of motile bovine sperm was observed using differential interference contrast optics. Transmission electron microscopy indicated that the acrosomal matrix was extended into complex folds and/or projections. Outer acrosomal and plasma membrane integrity was retained. Anterior acrosomal swelling (AS) was first observed after neat-semen had been slowly cooled to 4°C and stored for 1 day. With subsequent dilution (25 X 10⁶ sperm/ml) and incubation of sperm in a Tris fructose medium at 37°C, a majority of the motile sperm had AS. Of these unique conditions, storing sperm (1500 X 10⁶ /ml) in seminal plasma (SP) at 4°C was very conducive to AS. Replacing SP with egg yolk-citrate (EYC) inhibited AS. Using a Tris buffer with 54 mM fructose as an incubation medium eliminated the necessity of storing sperm in SP provided storage in EYC at 4°C was ≥3 days. AS occurred after storage at 37 or 4°C but not at 21°C. Storing cauda epididymal sperm at 4°C with and without 30.8 mM fructose or glucose in EYC or egg yolk-Tris (EYT) media demonstrated that AS formation required the presence of either sugar. Storing cauda sperm in EYT at 4°C with 0, 3.9, 7.7, 15.4, 30.8, and 61.7 mM fructose indicated that a minimum of 7.7 mM fructose was necessary for a strong AS response. Storage media pH was measured at the end of storage. Media pH was 6.7 with 0 mM fructose and had decreased during storage to 5.7-6.0 in media giving a strong AS response. Further experimentation with cauda sperm demonstrated that storage at reduced media pH would induce AS with or without the presence of fructose. Conversely, storage at normal pH's (6.6-6.8) inhibited AS even with fructose in the media. The proportion of motile sperm with AS was estimated from wet smears initially. Evaluation of acrosomal morphology from dry smears of vitally stained sperm was developed as a means of quantifying the proportion of viable sperm with AS. This technique also allowed closer scrutiny of the acrosomal morphology of viable sperm. The physiological importance of AS is unclear. It may be a unique form of sperm deterioration or a prelude to the true acrosome reaction since AS occurs without loss of sperm viability. / Doctor of Philosophy

No description available.

MSCAGR / Department of Animal Science / Preservation of semen is an important process to ensure that semen quality is sufficient for use in assisted reproductive technologies. This study evaluated the effectiveness of three different extenders to preserve bull semen stored under different conditions, as an alternative to frozen-thawed semen straws used for artificial insemination. Semen samples were collected from two Nguni bulls using an electro-ejaculator and transported to the laboratory at 37 °C for evaluation. Pooled semen was first aliquoted into three extenders namely Triladyl, Ham’s F10 and M199 at a dilution ratio of 1:4 (semen:extender), and then stored at controlled room temperature 24 °C. Secondly pooled semen was aliquoted into four groups of Ham’s F10 extender and diluted at a ratio of 1:4, then stored at 24 °C, 17 °C, 12 °C and 5 °C respectively. Sperm motility rates were analysed after 0, 24, 48 and 72 hours. Morphology, viability and sperm DNA fragmentation were analysed after 72 hours. The study was replicated four times and data was analysed by ANOVA. Triladyl had higher sperm viability rate and total motility rate for 72 hours (P<0.01). However, Ham’s F10 had higher progressive motility rate as compared to the other extenders. There was no significant difference (P<0.01), in the viability rate between Ham’s F10 and M199. No significant difference was also observed in total sperm abnormalities (absent tails, coiled tails and bent tails), except for reacted acrosomes (P>0.05), between the two Nguni bulls. Lower temperatures than 24 °C influenced sperm motility and viability in Ham’s F10. There was no significant difference in sperm DNA fragmentation rates (P<0.01), between all the four storage temperatures which indicated that temperature did not have an influence on sperm DNA fragmentation. In conclusion, bull semen can be preserved in Triladyl or Ham’s F10 and M199 culture media stored at 24 °C and stay alive for 72 hours. Triladyl proved to be the best suitable extender showing higher sperm viability and total motility rates as compared to Ham’s F10 and M199. Lower temperatures than 24 °C noticeably decreased sperm motility and viability in Ham’s F10 culture medium.