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.