Call number: LD2668 .T4 1986 S675 / Master of Science / Animal Sciences and Industry

In vitro embryo production has vastly improved over the past decade through the study of the in vivo environment and the metabolic requirements of embryos. In contrast, in vitro oocyte maturation ( IVM ) culture conditions have remained relatively unchanged and are suboptimal. The aim of this thesis was to create improved systems for bovine IVM by studying the metabolic profiles and requirements of intact cumulus oocyte complexes ( COCs ) during IVM and determining the ion and energy substrate composition of bovine follicular fluid ( FF ). Glucose, pyruvate and oxygen consumption of bovine COCs increased 2 - fold over the 24 h IVM period, with glucose being the preferred energy substrate. While initially the majority of glucose consumed by COCs is metabolised via glycolysis ( Llactate production ), a considerable proportion of glucose is used as a substrate for extracellular matrix ( ECM ) synthesis towards the end of IVM. Glucosamine ( an intermediate substrate of hyaluronic acid ) supplementation of IVM media lead to decreased glucose consumption and incorporation into ECM during FSH - stimulated expansion. Biochemical analyses of bovine FF demonstrated that the concentration of some ions and energy substrates varied with follicle size. Although follicular glucose concentrations increased with follicle size, levels were ~ 2 - fold lower than that found in Tissue Culture Medium ( TCM199 ), the most commonly employed medium for bovine IVM. Synthetic Follicular Fluid Medium ( SFFM ) was created, based on the FF data and also contained glucosamine. Two different glucose concentrations were examined, 2.3 mM glucose to represent physiological concentrations and 5.6 mM glucose, the same concentration as is in TCM199. Culturing COCs in different glucose concentrations manipulated the completion of nuclear maturation and this was dependant on concentration, gonadotrophin supplementation and the timing of media changes, demonstrating the importance of this substrate to meiotic competence. Although glucosamine had no effect on oocyte nuclear maturation, supplementation during IVM led to a dose - dependent decrease in blastocyst rates. The detrimental effects of glucosamine manifested during early cleavage and were associated with a 0.6 - fold decrease in protein synthesis levels within the oocyte compared to oocytes cultured in media with no glucosamine, suggesting a detrimental effect on developmental competence. Interestingly oocytes cultured in media containing glucosamine and EGF had significantly higher protein synthesis compared to the control group. The biochemical profiles of COCs during IVM and FF were determined and used to create new media that allowed manipulation of oocyte nuclear maturation but compromised cytoplasmic maturation. Further research is required to optimise SFFM and to investigate the detrimental effects of glucosamine on developmental competence. / Thesis (Ph.D.)--Medical School, 2004.

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Background: Intrauterine Insemination (IUI)is one of the common first-line assisted reproductive technologies (ART) for couples suffering infertility. Controlled ovarian stimulation (COH) with clomiphene citrate (CC) or aromatase inhibitor (like Letrozole) is often used in adjunct to IUI to increase the pregnancy outcome. Both CC and letrozole can be given alone as a single ovulation induction agent or they can be combined with injectable gonadotropin for purpose of superovulation. Study objectives: To systematically review the efficacy and adverse outcomes of letrozole and CC for supervulation in infertility patients undergoing IUI. Method: Systematic review of pertinent randomised controlled trials (RCT) using the bibliographic databases EMBASE, PubMed, Cochrane, Medline (OVID), Academic Search Premier and CINAHL. References of selected articles identified were hand-searched for additional relevant citations. RCTs that have compared the pharmacological performance of CC and letrozole as a single agent or combination with equal dose of gonadotropins were included. Results: Ten published randomized controlled trials were included in this review. The mean age, infertility diagnosis and duration of infertility of the recruited participants were comparable. Pregnancy rate was found to be comparable in clomiphene citrate (CC) group and letrozole (L) group. Higher peak estrogen concentration and greater number of dominant follicles were reported in CC group. Endometrial thickness was found significantly greater in L group. Adverse outcomes of rate of miscarriage, multiple pregnancies, ectopic pregnancies, OHSS and fetal anomalies were not significantly different between the two intervention groups. Conclusion: Letrozole and CC, considered equally patient-friendly agent due to oral route administration. Both agents achieved similar pregnancy rates without any increased risk of adverse events in either group. Letrozole can be used as alternative first-line OI agent to CC in reproductive treatments. Drug selection for patients should be done according to the cost effectiveness, duration of therapy, characteristics and compliance of patients. / published_or_final_version / Public Health / Master / Master of Public Health

Thesis (MTech. degree in Agriculture.)--Tshwane University of Technology, 2011. / There is limited information on semen characterisation and fertility rate of unimproved indigenous goat following cryopreservation. The aim of the study was to characterise semen, evaluate raw and frozen-thawed semen and test the fertility rate of frozen-thawed semen.

No description available.

Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Sciences, 1991. / Includes bibliographical references (leaves 274-316).

Thesis (doctoral)--Universität, Mannheim, 2007. / Description based on print version record. Includes bibliographical references (p. [231]-249).

No description available.

No description available.