In the present study, we investigated the effect of porcine follicular fluid (PFF) concentration (10% vs. 1%) and protein-free media (PFF 0%) on maturation of porcine oocytes in vitro and analysed difference in gene expression in resulting blastocysts following parthenogenetic activation. Three groups were tested; 1) 10% PFF: Tissue culture medium (TCM) 199+10% PFF; 2) 1% PFF: TCM 199+1% PFF; and 3) 0.1% PVA: TCM 199+0.1 PVA. Cumulus-oocyte-complexes were cultured in the respective media containing gonadotrophin (1 ug/ml), epidermal growth factor (10 ng/ml), cystein (0.57 mM), sodium pyruvate (0.91 mM), insulin (5 ug/ml), 9-cis retinoic acid (5 nM) for 20～22 h and then without hormonal supplements for an additional 20-22 h. Data was analyzed using statistical analysis system(SAS) program. There was no significant difference in oocyte maturation rate. However, significantly higher (p<0.05) proportions of embryos developed to the blastocyst stage when oocytes were matured in 10% PFF group (45%) than in the 1% PFF group (31.1%). The total cell numbers were not significantly different among groups (52 ± 1.3 vs. 54.6±3.1 vs. 54.4±2.5, respectively). The relative abundance (ratio to beta-actin mRNA) of gene transcripts related to apoptosis in blastocysts was measured by real- time PCR. The expression of anti-apoptotic gene (BclxL) was up-regulated and the expression of pro-apoptotic gene (Bax) was down-regulated in 10% PFF group than in the other groups. Therefore, it can be concluded that supplementation of 10% PFF during in vitro maturation improves embryo development by reduction of apoptosis. * This study was supported by IPET (#311011-05-1-SB010), RNL Bio (#550-20120006), MKE (#10033839-2011-13), Institute for Veterinary Science, the BK21 program and TS Corporation.

• Jung Eun Park(Department of Theriogenology and Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, 151-744, Korea)
• Hyun Ju Oh(Department of Theriogenology and Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, 151-744, Korea)
• Min Jung Kim(Department of Theriogenology and Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, 151-744, Korea)
• Geon A Kim(Department of Theriogenology and Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, 151-744, Korea)
• Eun Jung Park(Department of Theriogenology and Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, 151-744, Korea)
• Jin Choi(Department of Theriogenology and Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, 151-744, Korea)
• Joon Ho Moon(Department of Theriogenology and Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, 151-744, Korea)
• Byeong Chun Lee(Department of Theriogenology and Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, 151-744, Korea) Corresponding author