Demi-embryos were successfully produced by bisection of ICR mouse embryos at preimplantation stages. They were microsurgically bisected using a microsurgical blade attached to a micromanipulator after pretreatment with 0.5 % pronase in PBS for two minutes or not. Embryos with softened zona pellucida were more easily bisected and less damaged than intact embryos. The highest success rate in bisection has been achieved by selecting blastocysts (94.1 % in success rate with intact blastocysts and 100 % in success rate with zona softened blastocysts). Demi-embryos without zona pellucida were cultured in D-PBS or M-16 medium at 37deg C, 5 % CO2 in air for 72 hours for 2-cell stage embryos, 48 hours for 4-to 8-cell stage embryos, 24 hours for morula stage embryos and 6-12 hours for blastocyst stage embryos. For the in vitro culture of 2-cell stage embryos, 100 micro M 2Na-EDTA was added to the media. M-16 medium was better for the in vitro development of mouse embryos than PBS, and PBS is not considered to be suitable for long-term culture of embryos, especially at early stage of cleavage. In M-16 medium, developing rate of demi-embryos of which pair underwent development to form eublastocysts was 15.8 % at 2-cell stage, 16.8 % at 4-cell stage, 38 % at 8-cell stage, 89.6 % at morula stage and 94.4 % at blastocyst stage, respectively. The more rapid and efficient production of demi-embryos and higher viability after bisection can be expected by softening zona pellucida with pronase and by selecting morulae or blastocysts rather than embryos at early stage of cleavage.

Methods of increasing the efficiency of semen fertilizing capacity in vitro with application of hormonal and biophysical methods of influence, as well as the determination of metabolic criterion of spermium viability were studied in the conditions of the republic of Belarus. Research object was frozen-deiced sperm of cattle. Research results showed that entering of 50 mkg/ml of prostaglandin into capacitation media increased the breaking level on 2,3-3,1%, but at the same time there was the decreasing of embryo output at the pre-implantation stages. Increasing of estrophan concentration in media for capacitation up to 100 mkg/ml, and its addition into media for fertilization made it possible to increase the embryo output at the stage of morula-blastocyte up to 1,6-18,5%. Application of 8mg/ml of caffeine as a capacitation agent for the preparation of cattle sperm for fertilization in vitro made it possible to obtain embryo output of 16,7% with breaking level of 25,9%. Influence of directed polarized light on semen after its maturation was more efficient in comparison with the influence on it just after swim-up procedure; the output of pre-implantation embryos was 16,7% against 12,9%. Application of laser radiation made it possible to get 14,7 % of morula-blastocytes. Intensity of sperm breath (0,41-0,63 tg), intensity of lipid peroxidation (0,88-0,97 conditional units /10E6 cells), intracellular content of adenosine triphosphate (0,97-1,60 Nm/10E6 cells) and membrane potential (33-35 uV) in the conditions of matured in vitro oocyte made it possible to get 16,4-17,3% of pre-implantation embryos with the breaking level of 39,8-42,3%