Available at: https://digitalcommons.calpoly.edu/theses/3327
Date of Award
6-2026
Degree Name
MS in Agriculture - Animal Science
Department/Program
Animal Science
College
College of Agriculture, Food, and Environmental Sciences
Advisor
Fernando Campos-Chillon
Advisor Department
Animal Science
Advisor College
College of Agriculture, Food, and Environmental Sciences
Abstract
Bovine in vitro embryo production is limited by the fact that gametes and embryos develop outside the reproductive tract, where they normally receive a complex set of biological signals that support fertilization and early development. This study examined whether supplementing bovine in vitro fertilization media with seminal plasma extracellular vesicles (SEVs) from bulls of known fertility could improve embryo development and post-cryopreservation survival. The study was motivated by the idea that SEVs may help restore biologically important signals that are lost during standard semen preparation and IVF procedures. A three by two factorial design was used across seven replicates and 1,171 oocytes to evaluate the effects of bull fertility status and SEV treatment on developmental outcomes. Semen from high and low fertility bulls was combined with one of three treatments conditions: no SEV (control), low fertility SEVs, or high fertility SEVs. Outcomes were assessed using cleavage rate, blastocyst rate, and blastocyst re-expansion following a series of vitrification and warming. Although SEV supplementation did not produce statistically significant differences in cleavage or blastocyst rates, a consistent numerical trend was observed across developmental stages. Post-warming survival of vitrified blastocysts remained high and was not significantly affected by SEV supplementation. Survival was 95.8% at the second warming and 92.5% at the third overall, with no significant differences between warming stages or SEV groups. These findings suggest that SEV supplementation did not harm embryo cryotolerance under the conditions tested. Overall, the results indicate that high fertility SEVs may offer a biologically meaningful advantage in bovine IVF by supporting embryo development in a more physiological environment. However, the lack of statistical significance and the relatively high variability, especially for the blastocyst rate, show that any benefit was limited under this experimental setup. SEVs appear promising as a component of assisted reproduction research, but their effects likely depend on culture conditions, dosage, and timing of exposure.