Interactions between type of culture medium and addition of serum on development and gene expression of bovine blastocysts produced in vitro

ABSTRACT: Serum is commonly added to culture medium used for producing bovine embryos in vitro. Here it was tested whether addition of bovine serum to embryo culture medium increases the percent of embryos becoming blastocysts and alters blastocyst gene expression in a manner that could affect competence to establish pregnancy or that could lead to dysregulated fetal development. A secondary objective was to test whether actions of serum depend upon the specific medium used for embryo culture. Media used were synthetic oviduct fluid medium bovine embryo 2 (SOF-BE2) and a commercial medium termed BO-IVC. Fetal bovine serum and adult bovine serum were added at a final concentration of 10% (v/v) at either day 1 or 5 of development. Overall, addition of serum to culture medium increased blastocyst production. Effects of fetal bovine serum added at day 5 of development caused moderate changes in gene expression in the resulting blastocysts, with differentially expressed genes being those with an adjusted p-value of < 0.01 and an absolute log2 fold change > |1|. Serum resulted in 114 differentially-expressed genes for embryos cultured in SOF-BE2 and 108 embryos cultured in BO-IVC. Only 15 genes were regulated by serum similarly for both media including transcription factors ASCL2 (downregulated) and ZSCAN4 (upregulated) and the phosphoserine aminotransferase PSAT1 that has been implicated in fetal growth in mice. Genes of the melanoma antigen gene family that regulate degradation of specific transcription factors were also upregulated by serum. Expression data on eight biomarker genes were also used to calculate an embryo competence index that has been shown to predict embryo ability for survival after embryo transfer. Serum lowered the embryo competence index for both media, suggesting serum could compromise embryonic survival. In conclusion, actions of serum on the preimplantation embryo include changes in gene expression indicative of reduced embryo competence. Some changes in gene expression could potentially lead to alterations in fetal development

ORGANISM(S): Bos taurus

PROVIDER: GSE276832 | GEO | 2025/10/11

REPOSITORIES: GEO