Investigation of Oocyte Retrieval Methods and Maturation Media on in vitro Development of Porcine Embryos

Abstract

The objectives of the study were to: Compare oocyte retrieval methods (aspiration and slicing) from pig ovaries on oocyte quality and quantity; compare in vitro maturation (IVM) media (North Carolina State University -NCSU 37; Tissue Culture Medium-TCM 199; and porcine follicular fluid-mpFF) on oocytes polar body extrusion; compare the effect of Electrical Stimulation (ES) and frozen-thawed semen on cleavage rates and compare the effect of culture media, cNCSU 37 and cpFF, on cleavage rates. Follicular fluid collected from the retrieval methods were assessed for the presence of oocytes and categorized as either Grades A, B or C. Grades A and B oocytes were randomly allocated per treatment groups, matured for 44 h and checked for polar body extrusion. Matured oocytes were randomly allocated to either ES or traditional in vitro fertilization (IVF-frozen-thawed semen). The ES and IVF took place in conjuncture with in vitro Culture (IVC) media. Zygotes were checked for cleavage and recorded. The treatment means were compared using the Fisher’s protected t-test least significant difference. Slicing had significantly higher amounts of Grade A (58.7%) and B (50.8%) oocytes than the aspiration method. Oocytes polar body extrusion were 25.3, 84.2 and 73.8% for NCSU 37, TCM 199 and mpFF, respectively. Zygotes cleavage was 48.1% for traditional IVF and 56.8% for ES; 66.6% for cNCSU 37 and 45.7% for cpFF. Slicing proved to be better than aspiration method for the total amount of Grades A and B oocytes retrieved. The TCM 199 and mpFF media had a higher percentage of oocytes with polar body extrusion than NCSU 37. Cleavage rate of zygotes were higher on ES and cNCSU 37.