Effect of post-activation culture conditions on the development of parthenogenetic embryos in cattle

Abstract

Purpose: to conduct a comparative analysis of the effect of commercial media BO-IVC and СR1aa at the stage of the activation and subsequent culture of artificially activated oocytes on the formation and quality of parthenogenetic bovine embryos.Materials and methods. 3 groups of disemeters of 50 goals in each were formed. In the first experimental group, the disemeted was in a meticulous manner with a ram-industrialist (artificial kriproporchid), in the second experimental-with a penEexctomed ram-industrialist. In the third (control) group, a producer ram was used. In the first experimental group of a ram-industrialist (artificial kriproporchid) with attached taps were released into a group of sheep twice a day for 1.5-2 hours. In the second experimental group of a penEctomed ram, it was placed in the corral to the disemetery in the morning for 3 hours. In the third group, the lamb producer was constantly with the disemets for two weeks, then he was changed on a new ram i.e. Used the methodology used in the farm. During the experiment, they observed the behavior of animals of all groups. In the experimental groups, after the detection of disemeters in the hunt, their natural insemination of the manufacturer was carried out. Based on the results of the subsequent oster, the effectiveness of the reproduction of sheep was evaluated.Results. The cleavage rate did not differ between the experimental groups, varying from 73,0 to 76,5%. Also, there was not found a significant effect of the conditions for post-activation culture of oocytes on their development before late morula and late blastocyst stage, which was for the CR1aa/CR1aa, CR1aa/BO-IVC and BOIVC/ BO-IVC groups 28,9±1,7, 40,4±7,5 and 36,0±6.4%, respectively. Meanwhile, we found out the effect of tested culture conditions on the ability of parthenogenetic embryos to overcome the 8-16 cell block and their quality on the late stages of embryo development. The rate of embryos with less than 16 nuclei was the highest in the CR1aa/CR1aa group (56,8±2,1 %). The replacement of CR1aa medium to BO-IVC medium (BO-IVC/BO-IVC group) significantly reduced this level (p<0,05). The positive effect was enhanced when CR1aa medium was used at the stage of culture in the presence of 6-DMAP and cycloheximide, and subsequent embryo development was in BO-IVC medium (CR1aa/BO-IVC group) (p<0.001). Furthermore, when we used the mixed variant of culture, the total cell number in parthenogenetic morula and blastocyst stage embryos increased (p<0.05).Conclusion. Thus, the BO-IVC medium at the stages of post-activation and subsequent development of artificially activated bovine oocytes is comparable to the CR1aa medium in terms of the efficiency of obtaining parthenogenetic embryos at the blastocyst stage. Nevertheless, its replacement at the post-activation stage with CR1aa medium makes it possible to improve the quality of parthenogenetic embryos.