Fig. 1.

In vitro development of bovine day 2 embryos covered with washed light mineral oil (A, C, E and G) or sterile filtered light paraffin oil (B, D, F and H). Four- to eight-cell embryos (A and B) developed similarly until day 4 (8–16 cells; C and D) and then showed gradual differences in developmental capacity from day 6 (morula-blastocyst, E and F) to day 8 (G and H) according to oil variation. Sterile filtered paraffin oil supports increased and improved embryo production in vitro. Scale bars: 200 μm.