The objective of this study was to determine the optimum condition for porcine oocyte preparation for in vitro fertilization. A total of 1,130 immature oocytes collected from superficial follicles, 3-6 mm in diameter were allocated to 3 experiments. In Experiment 1, the length of time for oocyte maturation were examined (n=469). Immature oocytes were cultivated in TCM199 NaHCO3 supplemented with 10 μg/ml of FSH/LH and 1 μg/ml of Estradiol-17ẞ for 24, 40 or 48 hrs. Approximately 20% of oocytes were fixed and stained with aceto orcein to observe the maturation rate and the remainder were fertilized in vitro by freshly ejaculated sperm. After 4 hrs, the sperm at the concentration of 1x106 spz/ml were introduced to IVF medium containing 20-30 matured oocytes and were incubated for 18 hrs. The oocytes were later cultivated in TCM199 NaHCO3 + 10% FCS for 5 days to observe their cleavage and development. In vitro maturation, fertilization and embryo culture were performed at 38.5°C in an atmosphere of 5% CO2 in air. Higher maturation rates and higher cleavage rates were found in the 40 and 48 hr culture groups (67.6%, 23/34; 45.5%, 55/121 and 70.6%, 24/34; 37.6%, 49/130) than in the 24 hr group (10.3%, 3/29; 5%, 6/121) respectively (P<0.01). In Experiment 2, the oocyte quality was examined (n=400). Oocytes were categorized into 3 groups at collection, CCO (complex cumulus oocyte), P (partial layered cumulus oocyte) and D (denuded oocyte). Cleavage rates in CCO (36.8%, 50/136) and P (31.6%, 48/152) groups were significantly (P<0.05), higher than in the D group (19.6%, 22/112). In Experiment 3, the source of oocytes from sow or gilt ovaries (n=261) were compared. The difference in the cleavage rates was found between the 2 groups (23.4%, 30/128) and (48.1%, 64/133) for sow and gilt ovaries (P<0.05), respectively. Results indicate that a maturation period of 40 to 48 hrs is required for pig oocytes and that cumulus oocytes complexes require at least layer of cumulus cells for maturation and fertilization.
Faculty of Veterinary Science, Chulalongkorn University
Techakumphu, Mongkol and Srianan, Wanpen
"The Effect of Oocyte Preparation on Embryo Cleavage Rate after In Vitro Fertilization in the Pig,"
The Thai Journal of Veterinary Medicine: Vol. 27:
1, Article 7.
Available at: https://digital.car.chula.ac.th/tjvm/vol27/iss1/7