Man-Hye Han

130 PREDICTION OF PARTHENOGENETIC DEVELOPMENTAL POTENTIAL BY POLAR BODY EXTRUSION AND FIRST CLEAVAGE ON IN VITRO MATURATION AND DEVELOPMENT OF PORCINE FOLLICULAR OOCYTES

The objective of this study was to examine the selection effects of in vitro matured porcine follicular oocytes with polar body extrusion and early cleavage as a non-invasive marker to know the developmental competence in advance. Porcine oocytes matured for 48 h and then examined for polar body extrusion. The examined oocytes were matured for an additional 16–18 h, activated with 7% ethanol, and cultured in 5 µg mL–1 cytochalasin B for 5 h for diploid formation. The treated oocytes were examined for cleavage after 48 h and continued culturing for 5 days. Each treatment was replicated by 3–4 times. Oocytes of 21.9% (70/320) were discarded in morphological selection, and 32.1% (167/520) oocytes were discarded by failure of first polar body extrusion. The selected oocytes were matured and activated, and after 48 h, the cleavage rate was examined. In morphologically selected oocytes, 15.8% (30/190) were not cleaved, 52.6% (100/190) were normally cleaved (consisted of 2–7 cells), and 31.6% (60/190) were hyper-cleaved (consisted of 8 cells or more) at 48 h after activation. However, in the first polar body extruded oocytes, 7.1% (18/253) were not cleaved, 73.1% (185/253) were normally cleaved, and 19.8% (50/253) were hyper-cleaved. From the morphologically selected oocytes, 16.7% (10/60) were developed up to blastocyst stage from those in which cleavage selection was not performed and 31.7% (19/60) from those in which cleavage selection was performed. From the polar body extruded oocytes, 39.0% (39/100) were developed up to blastocyst stage from those in which cleavage selection was not performed and 49.0% (49/100) from those in which cleavage selection was performed. Cleavage was examined within 12 h interval after activation (0 = time of activation) up to 48 h. At 0–12, 12–24, 24–36, and 36–48 h intervals, 4.1% (9/220), 68.6% (151/220), 19.1% (42/220), and 2.3% (5/220) oocytes were cleaved, respectively, and 5.9% (13/220) oocytes were not cleaved at 48 h after activation. The cleaved embryos in each interval were cultured and developed up to blastocyst with 0 (0/9), 39.1 (59/151), 9.5 (4/42), and 0% (0/5), respectively. This result suggests that the polar body extruded and cleaved at 12–36 h embryo has higher developmental potential than the others.

158 EFFECTS OF APOTRANSFERRIN ON IN VITRO MATURATION OF CUMULUS–OOCYTES COMPLEXES (COCs) IN HANWOO, KOREAN NATIVE COWS

For in vitro production of embryos, animal sera have been used as energy sources, maturation promoters, vitamins, growth factors, and antioxidative compounds. However, the sera had risk of virus and mycoplasma infections which could result in too big offspring and cause dystocia in ovine and bovine. Apotransferrin (apo-Tf) is a component of mammalian sera and has played a role as an antioxidant in media. A study was conducted to investigate the effects of apo-Tf on in vitro maturation of cumulus-oocytes complexes (COCs) in Hanwoo, Korean native cows. Ovaries were collected from a slaughterhouse and COCs were taken from 2-6-mm antral follicles. The collected COCs were washed three times with 0.1M polyvinyl alcohol (PVA)-TCM199 and matured in 0, 1, 10, or 100 ¼g/mL apo-Tf with TCM-199 at 39°C, 5% CO2, 95% air for 6, 12, or 24 h. Mature COCs were fertilized with frozen-thawed Korean native cattle semen treated with BO medium (Brackett and Oliphants 1975 Biol. Reprod. 12, 260-274) containing 5 mM caffeine and 1 ¼g/mL heparin for 8 h and developed to the blastocyst stage in 5% FBS and 0.3% BSA in TCM199-IVMD (IFP, Japan). To evaluate the morphology of nuclear types, the matured COCs were fixed in 1:3 acetic acid-ethanol for 30 s and stained with 3% basic Fuchsin. IVM and IVF were replicated three times. All of the results were analyzed by ANOVA using the STATVIEW program. The maturation rates of control were 34.2%, 37.3%, and 45.8% for 6, 12, and 24 h, respectively. There were no differences among the concentrations of apo-Tf, and nuclear types at 78.3-87.0% GVBD for 6 h, 82.8-91.3% MI for 12 h, and 88.9-100.0% MII for 24 h, with 1, 10, and 100 ¼g/mL apo-Tf, respectively. Conversely, there was significant difference between 1 µg/mL and 10 ¼g/mL in terms of cleavage rates, although the others did not vary significantly (P < 0.05). There were significant differences among the concentrations of apo-Tf for blastocyst formation (P < 0.05). Blastocysts matured with 1, 10, and 100 ¼g/mL apo-TF and developed in 5% FBS and 0.3% BSA in TCM199-IVMD showed rates of 8.8-21.6%, 9.4-35.3%, and 9.1-19.1%, respectively. The control groups developed to the blastocyst stage showed rates of 8.6%, 10.8%, and 10.5% in 5% FBS and 0.3% BSA in TCM199-IVMD, respectively. These results suggest that apo-Tf is an important factor for the in vitro maturation and in vitro development of bovine COCs.