Presence of mitotic cells: A parameter of embryo quality

• Published in: Animal reproduction science Vol. 35; no. 3; pp. 173 - 182
• Main Authors: Wurth, Y.A., van der Zee-Kotting, W.I., Dieleman, S.J., Bevers, M.M., Kruip, Th.A.M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.1994
• Subjects: ANIMAL EMBRYOS; CALIDAD; COWS; EMBRIONES ANIMALES; EMBRYON ANIMAL; MITOSE; MITOSIS; OVULACION; OVULATION; QUALITE; QUALITY; SUPEROVULACION; SUPEROVULATION; VACA; VACHE
• ISSN: 0378-4320; 1873-2232
• DOI: 10.1016/0378-4320(94)90033-7

The aim of this study was to identify objective parameters for measuring embryo quality instead of those based on morphological appearance. We have investigated the relationship between embryo quality as assessed by morphological appearance and the number of blastomeres in bovine embryos at 5–7 days as well as the relation between embryo quality and presence of mitotic and pycnotic nuclei. Superovulated cows were slaughtered from 5 to 7 days after ovulation and embryos were flushed from the excised uteri. They were fixed in acetic acid-ethanol, and stained with orcein, following qualification according to their morphological appearance by microscopy. Blastomere numbers were determined for each day and quality. Some of the Day-6 embryos were classified according to the presence of mitotic and/or pycnotic cells. The number of blastomeres per embryo increased with increasing quality and with age except for poor embryos, where the number of blastomeres remained low. Classification of the Day-6 embryos according to the status of their cells, showed that 72% of the excellent and good embryos were categorized as having mitotic cells. Of the embryos that were classified as fair or poor, 53.5% had no visible mitotic activity. Mitotic activity is indicative of embryo quality. It is correlated with high numbers of blastomeres and might be responsible for embryo viability.