Effect of maturation periods and leukaemia inhibitory factor on in vitro bovine embryo development

The period of in vitro maturation,~20 vs 24 hours) with of without supplementation of :,~uk_ni;ia inhib toryy factor (LIF) (0, 500, 1000 or 2000 U/ml) was studied on bovine embryo development in vitro in a 2 x 4 factotial experiment w id oestgnoo i, a randomized block design . A total of 870 bovine oocytes were used . Besides embryo development, cell numbers of blastocysts v. : ;re also co , mted in order to study the quality of the embryos . Oocytes were matured in a modified TCM199 medium containing 10 ug/nil of FS-14 and LP., I 1~ t1L rstradiol, fertilized in TALP and cultured in SOF/AABSA medium. There was no interaction between maturation periods and LIF doses on embryo development (P0 .05). Maturation periods, however, affected (P0.05) blastocyst rates but did not for cleavage o, oocytes and the percentage of oocytes that developed into blastocysts . LIF doses during in vitro maturation did not affect embryo development (P0 .05) . Cell numbers of blastocysts were also not affected by maturation periods and LIF doses (P0 .05), however 20 h in vitro maturation and supplementation of LIF doses tended to increase the cell numbers. This study suggests that 20 h maturation increases blastocyst rates and that supplementation with LIF during maturation does not affect the quality of embryos produced in vitro