Effect of transportation on development of fresh or vitrified-warmed bovine embryos

The aim of this study was to evaluate the viability of ill vitro produced bovine embryos. fresh or warmed, after submitted to different periods of transportation (6h-12h). Oocytes obtained from ovaries collected from slaughterhouse were matured, fertilized and Cultured in vitro. After seven days, grades I and II blastocysts (according to IETS manual) were selected and vitrified after exposition to PBS solution with 5% fetal calf serum (HM), added with 10% ethylene glycol (EG) and 10% of dymetil sulfoxide (DMSO), for one minute, followed by HM Solution with 20% EG and 20% DMSO, for 20 seconds. Embryos were loaded into open pulled straws (OPS) and plunged into liquid nitrogen. Warming was performed at 39 degrees C by embryo exposure to decreasing concentration of sucrose (0.25 and 0.15M), for five minutes in each step. The warmed embryos were distributed in three groups: V0: ill vitro cultured after warmed; V6: embryos loaded into straws and kept for 6 hours at 35 degrees C, before ill vitro culture; and V12: embryos loaded into straws and kept for 12 hours at 35 degrees C, before in vitro culture. Each group was evaluated by control groups of fresh embryos (CO, C6 and C12, respectively). The embryos were co-cultured with cumulus cells in TCM-199 micro droplets added with SFB. Re-expansion and hatching rates after 48 hours in culture were evaluated and results were compared by the Chi-square test. Re-expanded rates among groups V0, V6 and V12 as well as hatching rates among vitrified groups and among control groups did not differ. However, hatching rates were different between vitrified groups and their respective controls. The satisfactory rates of hatching suggest that it is possible to transport warmed and fresh ill vitro produced embryos for periods up to 12 hours.