234 NEW CULTURE MEDIA AFFECTS BLASTOCYST DEVELOPMENT AND GENE EXPRESSION LEVELS IN IN VITRO-PRODUCED BOVINE EMBRYOS

Abstract

The purpose was to examine effects of different media for bovine in vitro oocyte maturation (IVM) and in vitro embryo culture (IVC) on blastocyst rates, morpho-kinetics, and relative abundance of mRNA of 8 genes associated with critical processes and developmental competence in the embryo. Abattoir-derived cumulus-oocyte complexes (COC) were in vitro matured (IVM) in either TCM199 [+0.5% BSA and gonadotropins (Suigonan Vet 150 I.E. mL–1)] or in a novel commercially available media (Bo-IVM), and a total of 1196 presumptive zygotes, from 4 replicates, were submitted to in vitro culture (IVC) and cultured in either SOF (+0.5% BSA) or in a novel commercially available media (Bo-IVC). Blastocyst rates and morpho-kinetics were assessed on Day 8 after fertilization. The high-quality blastocysts from each group were analysed by RT-qPCR, on single blastocysts using earlier verified primers, for BAX, BCL2L1, DNMT3A, FASN, G6PD, HSPA1A, SLC2A1, and SLC2A3. Data on blastocyst rates were analysed for statistical differences using a linear regression model, using a binary reproach and general estimating equations. One-way ANOVA was used to detect differences in the relative abundance of mRNA between groups, whereas differences between maturation and culture media were analysed by a 2-way ANOVA. Blastocyst rates in the Bo-IVM/Bo-IVC (37%), TCM199/Bo-IVC (33%), Bo-IVM/SOF (26%), and TCM199/SOF (28%) groups were significantly different from each other (P < 0.0001). Specifically, the Bo-IVM/Bo-IVC group differed significantly from both SOF-cultured groups (P < 0.01). Subjectively, this group also had embryos of the highest quality and most advanced development. Significantly increased levels of mRNA transcripts were found for embryos cultured in Bo-IVC for all genes (P < 0.05) except BCL2L1. In conclusion, the developmental rates and gene expression of in vitro-produced bovine blastocysts were affected by the use of different culture media. Increased blastocyst rates, apparently superior embryo quality, and more abundant gene expression were achieved when blastocysts were cultured in Bo-IVC culture media compared with SOF.The project was supported by The Danish Council for Strategic Research.