The effects of cyanocobalamin supplementation during the thawing of frozen boar semen on spermatozoa, in vitro fertilization, and embryonic development

The objective of this study was to assess the in vitro fertilization (IVF) of pig oocytes using frozen-thawed boar sperm in media supplemented with cyanocobalamin. Frozen semen pellets were thawed and incubated for 1 h in fertilization media containing cyanocobalamin (0, 0.5, 1.0 or 2.0 mu m) and evaluated for forward progressive motility, viability, and embryo cleavage. Forward progressive motility of the 0.5 and 1.0 mu m cyanocobalamin supplements was higher (P < 0.05) than the 0 and 2.0 mu m cyanocobalamin supplements. Membrane viability of sperm supplemented with 0.5 mu m cyanocobalamin was higher (P < 0.05) than all other groups. Oocytes were matured and fertilized with frozen-thawed boar semen that was previously incubated for 1 h in fertilization media containing cyanocobalamin (0 or 0.5 mu m; 100 oocytes/treatment). Fertilization characteristics were evaluated 12 h after IVF of oocytes and embryo development was analyzed at 48 h and 144 h post-IVF. There were no significant differences between treatment groups when evaluating fertilization, polyspermic penetration or male pronucleus development. Embryos derived from oocytes fertilized with 0.5 mu m cyanocobalamin supplemented sperm had a higher percentage (P < 0.05) of cleaved embryos compared to those without cyanocobalamin supplementation at 48 h after IVF. There were no significant differences in the percentages of embryos reaching the blastocyst stage by 144 h after IVF between treatment groups. The results of this study suggest that there are positive effects of 0.5 mu m cyanocobalamin supplementation during the incubation of frozen-thawed boar semen on early development of IVF derived pig embryos.