Abstract

The total glucose concentration of a medium changes with the extent of serum supplementation, and this may have an effect on embryonic development in vitro. In this study, 1- and 2-cell sheep embryos (N+109) were cultured for approximately 120 hours at 39 C under humidified 5% CO2, 5%)2 and 90% N2 in Synthetic Oviduct Fluid medium (SOF) supplemented with 20% human serum and a total glucose concentration of either 1.5 mM (modified-SOF) or 2.3 mM (unmodified-SOF). A slight effect was observed on the proportion of embryos developing to at least the expanded blastocyst stage (63% and 48% for modified-SOF and unmodified-SOF, respectively, P<0.1). Twenty-eight blastocysts from each treatment were selected and transferred to 28 synchronised, mature ewes (2 blastocysts per ewe). Pregnancy and number of foetuses were determined by ultrasonography 54 days after transfer. All ewes were pregnant and survival of embryos was 82% and 71% for modified-SOF and SOF, respectively. However, a high post-natal mortality rate was observed (37%), which was mostly attributed to a relatively high birthweight of dead lambs (6.4

JC, McEwan, GH Davis, KG Dodds, PF Fennessy, JN Clarke, GD Bruce, and MG Hishon

Proceedings of the New Zealand Society of Animal Production, Volume 52, , 211-216, 1992