Addition of Ficoll and Disaccharides to Vitrification Solutions Improve in vitro Viability of Vitrified Equine Embryos

The aim of the present study was to evaluate the in vitro viability of equine embryos vitrified in three different solutions. Day 6 and 6.5 embryos were measured and morphologically evaluated. Only grade 1 or 2 morulae and early blastocysts were vitrified. Eighteen embryos were distributed in Group 1: 40% ethylene glycol in PBS, Group: 2 and 3: 40% ethylene glycol, 18% ficoll, 0.3M sucrose or 0.3M trehalose in PBS, respectively. The vitrified embryos were loaded individually into 0.25 ml straws, which were cooled and immersed in liquid nitrogen. After warming at 20°C for 20s, the embryos were expelled out into 0.5M sucrose in PBS and transferred to PBS solution. The embryonic diameter was measured again and morphology and viability were evaluated with Propidium iodide and Hoechst 33258 dyes. Embryos vitrified with sucrose (19.2%) and trehalose (26.7%) showed the highest percentage of viable cells and morphological quality.