Effect of protein supplementation and presence of an antioxidant on the development of bovine zygotes in synthetic oviduct fluid medium under high or low oxygen tension.

The aim of this study was to investigate the effect of protein supplementation of culture medium and the presence of a putative antioxidant on bovine zygote development under 5% (low) and 20% (high) O2. In Experiment 1, presumptive zygotes (n=992) were cultured in synthetic oviduct fluid (SOF) alone or supplemented with 3 mg/mL PVP, 3 mg/mL BSA (SOFB), and/or 10% FCS (SOFBF) in 5% CO2, 5% O2, 90% N2. In Experiment 2, zygotes (n=1916) were cultured in SOF, SOFB or SOFBF with or without taurine under high and low O2. In Experiment 1, presence of BSA or BSA plus FCS significantly increased the speed of development compared to SOF or SOF+PVP. Blastocyst quality was also improved, as evidenced by increased hatching rate and cell numbers. In Experiments 2, taurine had no effect on development irrespective of oxygen concentration or protein supplementation. In conclusion, the presence of protein in the culture medium and culture under reduced O2 significantly improved embryo development. Taurine had no effect on development.