Cellular and molecular characterization of the impact of laboratory setup on bovine in vitro embryo production

One of the main objectives related to performing comparative analysis of embryonic transcriptomes is to share information with other reproductive biologists or commercial service providers. Biological extracts influence performance of in vitro production systems and affect the reproducibility of results between production sites; these sources of variation could impede the potential for knowledge transfer. The objective of the present study was to assess the impact of the production site when sharing a common in vitro embryo production protocol. Biological extracts and semen were shared between production sites and thus removed as potential sources of variation. To remove the impact of blastocyst staging, all comparisons used expanded blastocysts. Although blastocyst yields and the number of Tunel positive cells per embryo differed between production sites, blastocysts were morphologically very similar in regards to cell number, their allocation to either the trophoblast or inner cell mass, or their gender ratio. These observations were also confirmed at the gene expression level, as indicated by highly similar transcript abundances. Only 36 genes out of the 16,121 expressed during bovine prehatching development were statistically differentially expressed, of which a large proportion were associated with the apoptotic process. These results highlighted the impact of laboratory set up, including personnel experience, when replicating an in vitro production system. Although inherent differences may arise, given the similarity of results between production sites, we concluded that embryo production protocols have the potential to be transferred and shared.