TIEMPO A PRIMERA DIVISIÓN EMBRIONARIA IN VITRO PUEDE PREDECIR LA CAPACIDAD DE DESARROLLO A BLASTOCISTO EN BOVINOS

Bovine embryos that rapidly reach the two-cell stage have higher probabilities of becoming viable blastocysts. Our objective was to evaluate the effect of time of the first embryonic division on the development rate of bovine blastocysts produced in vitro and also to determine embryo viability by differential staining of living and dead blastomeres. In vitro embryos divided at 36h (early) and 48h (late) post fertilization were separated and in vitro cultured for the remaining time (up to 7 days). Blastocyst rates from the groups of embryos divided in two-cells at 36h and 48h, corresponding to three repetitions, were 38.7% and 23.2%, respectively, showing statistically significant differences (p=0.0168). However, the proportion of living cells assessed by differential staining of the 36h and 48h groups were 93.7% and 88.2%, respectively, showing no significant differences. Although the results indicate that an early embryo splitting favors a high rate of blastocysts, separation management of the embryos causes stress reducing the total number of blastocysts compared to our control group without separation of embryos two-cell.