The effects of oviductal cell co-culture and different gas mixtures on the development of bovine embryos in vitro

Abstract

The objective of the current study was to investigate the effects of the addition of oviduct co-culture to synthetic oviduct fluid (SOF) and Menezo B2 media used in an in vitro study of cows, and the effects of different gas atmospheres (5% CO2 or 5% CO2, 5% O-2, and 90% N-2) on in vitro cultures. Oocytes obtained through aspiration from the ovaries of slaughtered Holstein cows were washed and cultured within a TCM-199 maturation medium at 38.8 degrees C for 23 h. Then the matured oocytes and thawed semen, prepared in accordance with the swim-up method, were incubated for fertilization within in vitro fertilization (IVF)-Tyrode's albumin lactate pyruvate (TALP) medium with an atmosphere including the combination of 5% CO2, 5% O-2, and 90% N-2 gas, at 38.8 degrees C for 18-24 h. Fertilized oocytes were distributed into 3 main groups: Group I: B2 (5% CO2), Group II: B2 medium (5% CO2, 5% O-2, and 90% N-2), and Group III: SOF (5% CO2, 5% O-2, and 90% N-2), and each group was divided into 2 subgroups, with and without oviduct co-culture cells, and were cultured for 9 days. The percentage of embryos that reached the blastocyst stage was 34.0%, 20.0%, and 32.3% in the co-culture group and 26.7% and 23.3% in the without co-culture group, respectively. Group III showed the highest development of expanded blastocyst stage (P < 0.01). In conclusion, the addition of co-culture to B2 (5% CO2 atmosphere) and SOF (5% CO2, 5% O-2, and 90% N-2 atmosphere) media increased the rate of transferable embryos.