Effects of type and state of co-culture cells on in-vitro development of porcine oocytes matured and fertilized in vitro.

PURPOSE: The present study was to investigate the impact of type and state of co-culture cells on developmental competence of porcine oocytes matured and fertilized in vitro. METHODS: Porcine zygotes were co-cultured with granulosa cells (GCs) (Group 1) or porcine oviductal epithelial cells (pOECs) at follicular stage (Group 2), ovulation stage (Group 3) or corpus luteum (CL) stage (Group 4) or cultured in a medium without co-culture cells (control group). RESULTS: The proportion of oocytes developed to 2-cell stage embryos in Group 2 was similar to that in control group, but significantly (p < 0.05) lower than that in Groups 1, 3 and 4. The proportions of oocytes developed to > or = 4-cell stage embryos in Groups 3 and 4 were significantly (p < 0.05) higher than that in Groups 1 and 2. At 144 h after insemination, 12.0, 14.8 and 20.0% of oocytes developed to blastocysts in Groups 1, 3 and 4, respectively. However, no embryos in control group developed beyond 4-cell stage and no embryos in Group 2 developed to blastocyst stage. CONCLUSION: As compared with GCs and pOECs at follicular stage, the pOECs at ovulation and CL stages had a better competence to support porcine embryo development under in vitro conditions.