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

Abstract

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