Reproduction Abstracts

In pigs, the quality of In vitro-produced embryos is much lower than that of in vivo-derived embryos. The poor quality of In vitro-produced porcine embryos has been attributed to the apparently sub-optimal embryo culture media that is commonly created in-house. Few studies have examined the capacity of commercially available media, typically used to culture human embryos, to support the development of porcine embryos. The aim of the present study was to determine the effectiveness of in-house and commercially available single-step and sequential media systems in supporting the development of in-vitro produced porcine embryos. Embryos were generated using standard In vitro-production protocols and cultured for 7 days prior to vitrification. In experiment 1 (single-step media), embryos were randomly allocated to 2 groups (in-house porcine zygote medium-3 (PZM3): n=503; Origio™: n=464). In experiment 2 (sequential media), embryos were randomly allocated to 3 groups (in-house modified PZM3: n=239; Origio™: n=222; Vitrolife™: n=241). Each experiment was replicated three times. In experiment 1, embryos cultured in the single step PZM3 formed blastocysts at a greater rate than those cultured in the single step Origio™ medium (33% vs 21%; P<0.05). While blastocysts of the Origio™ group tended to display a greater post-thaw survival rate than those of the PZM3 group (72% vs 54%; P=0.09). In experiment 2, embryos cultured in the three sequential media systems, modified PZM3, Origio™ and Vitrolife™, cleaved (76%, 80 and 82%, respectively) and formed blastocysts (32%, 29% and 30%, respectively) at similar rates. Furthermore the post-thaw survival rates (67% to 69%) did not differ significantly. The results indicate that the in-house media was more effective than commercial single-step medium in supporting the development of In vitro-produced porcine embryos to the blastocyst stage, but there were no significant differences in embryo development or post-thaw survival rates between the in-house and commercial sequential media systems. Key words: porcine embryo, single step medium, sequential media, vitrification