Evaluation of the lipid content in bovine oocytes and embryos with nile red: a practical approach

In this study, the fluorescent lipid dye Nile Red, was used to demonstrate that the lipid content of immature bovine oocytes is correlated with the morphological appearance of the ooplasm. Oocytes with a uniform dark cytoplasm contained significantly more intracellular lipids in lipid droplets compared with oocytes with a granulated or pale cytoplasm (p < 0.05). Furthermore, this lipid-analysing technique was applied for the first time on single bovine in vitro embryos, showing a significant increase of the lipid content in lipid droplets after culture in the presence of serum (p < 0.05).