Effect of arachidonic acid on pre- and post-hatching in vitro bovine embryo development

Abstract

Context: Arachidonic acid (AA) is the precursor of prostaglandins, which may play autocrine roles during early embryo development. Aims: To test the developmental effects of addition of AA to pre- and post-hatching culture media on in vitro-produced bovine embryos. Methods: Pre-hatching effects of AA were tested by culturing bovine zygotes in synthetic oviductal fluid (SOF) supplemented with 100 or 333 μM AA. Post-hatching effects of AA were tested by culturing Day 7 blastocysts in N2B27 supplemented with 5, 10, 20 or 100 μM AA up to Day 12. Key results: Pre-hatching development to blastocyst was completely abrogated at 333 μM AA, whereas blastocyst rates and cell numbers were not altered at 100 μM AA. Impaired post-hatching development was observed at 100 μM AA, whereas no effect on survival rates was noted at 5, 10 and 20 μM AA. However, a significant reduction in Day 12 embryo size was observed at 10 and 20 μM AA. Hypoblast migration, epiblast survival and formation of embryonic-disc-like structures were unaffected at 5-10 μM AA. AA exposure downregulated the genes PTGIS, PPARG, LDHA and SCD in Day 12 embryos. Conclusions: Pre-hatching embryos are mostly irresponsive to AA, whereas AA was observed to have negative effects during early post-hatching development. Implications: AA does not improve in vitro bovine embryo development and is not required up to early post-hatching stages.