Available at: https://digitalcommons.calpoly.edu/theses/2898
Date of Award
9-2024
Degree Name
MS in Agriculture - Animal Science
Department/Program
Animal Science
College
College of Agriculture, Food, and Environmental Sciences
Advisor
Fernando Campos-Chillón
Advisor Department
Animal Science
Advisor College
College of Agriculture, Food, and Environmental Sciences
Abstract
The production of embryos has been described as a revolutionary process with the ability to make cattle systems more successful. However, despite constant research done in the field of embryology, there remains a discrepancy between the quality of in vitro produced (IVP) and in vivo derived (IVD) embryos. This difference is potentially associated with the lack of synchronization between nuclear and cytoplasmic maturation events within the oocyte, which is carefully mediated in the ovarian environment and the cumulus oocyte complex (COC). The purpose of this thesis was to utilize a pre-maturation culture system to keep oocytes in an arrested germinal vesicle (GV) state before subjecting them to maturation. In the first half of the experiment, oocytes were pre-matured in C-type natriuretic peptide (CNP) supplemented medium for 12 hours. Following pre-maturation, oocytes were transferred to amphiregulin (AREG) for another 12 hours to develop. This procedure is known as CAPA-AREG. After fertilization and a 7- day culture, embryos were assessed for cleavage rate and blastocyst rate. Embryos were also subjected to staining in order to evaluate lipid content and mitochondrial activity via confocal microscopy and ImageJ software. Hurdles in acquiring data also encouraged an assessment on the IVF laboratory and how procedures can be optimized. Overall, embryology lab procedures must be strictly followed, and the laboratory environment must be maintained to the best of the staff’s ability to increase success rates. Due to mishaps in the laboratory, the effectiveness of CNP and AREG on improving bovine oocyte maturation and embryo development is still inconclusive. Further research is required to determine if CNP and AREG can be utilized in future bovine IVF procedures.