DOI: 10.5958/0976–0555.2014.00458.0    | Article Id: B-201 | Page : 370-374
I.A.H. Barakat*, A.R. Al-Himaidi1 and O.H. Abd-Elkader2 ibarakat@ksu.edu.sa
Address : Zoology Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Kingdom of Saudi Arab


The aim of the present work was to study the differences among different categories of immature sheep oocytes. Oocytes were divided into three categories: excellent, good and fair oocytes. Results showed that cumulus cells were close to each other and zona pellucida in all the three oocytes categories. All oocytes categories with cumulus cells exhibited an irregular shape, mucous material inter-granular cells, low number of small droplets and minutes tapes on the cell surface. Good oocytes category was characterized by the presence of a belt surrounding the oocytes. Moreover, there are large numbers of small holes on the ZP surface in all categories. The good oocytes also contained a large number of big holes. In contrast, fair and excellent oocytes have low number of large holes in the ZP surface. In conclusion, there are several differences between oocytes categories in the morphology of oocytes and ZP characteristics.  This study recommends using excellent and good oocytes in the in vitro embryo production for quality of the outer surface and integrity of zona pellucida than fair oocytes.


Immature oocytes SEM Sheep Zona pellucida.


  1. Adirekthaworn, A., Tharasanit, T. and Chuesiri, P. (2008). P3 A Scanning Electron Microscopic Analysis of Zona Pellucida of Cryopreserved Porcine Oocytes. Proceedings 7th Chula. Univ. Vet. Sci. Ann. Con., 1 May. pp: 59.
  2. Blondin, P. and Sirard, M.A. (1995). Oocyte and follicular morphology as determining characteristics for developmental competence in bovine oocytes. Mol. Reprod. Dev., 41: 54-62.
  3. Dunbar, B.S., Avery, S., Lee, V., Prasad, S., Schwahn, D., Schoebel, E., Skinner, S. and Wilkins, B. (1994). The mammalian zona pellucida: its biochemistry, immunochemistry, molecular biology, and development expression. Reprod. Fertil. Dev., 6:331–347.
  4. Epifano, O. and Dean, J. (1994). Biology and structure of the zona pellucida: a target for immunocontraception. Reprod. Fertil. Dev., 6: 319–330.
  5. Familiari, G., Nottola, S.A. and Macchiarelli, G. (1992). Human zona pellucida during in vitro fertilization: An ultrastructural study using saponin, ruthenium red, and osmium-thiocarbohydrazide. Mol. Reprod. Dev., 32: 51–61.
  6. Geert, V., Hans, N., Ann Van, S., Marie-The´re‘se, Y., Gerard, C., Patrick, V. and Aart, K. (2000). Structural Aspects of the Zona Pellucida of In Vitro-Produced Bovine Embryos: A Scanning Electron and Confocal Laser Scanning Microscopic Study. Biol. Reprod., 62: 463–469.
  7. Gordon, I. (2003). Laboratory Production of Cattle Embryos. CABI, New York, NY, USA.
  8. Hiroyuki, S., Jyh-Cherng, J.U., John, E. and Xiangzhong, Y. (1998). Surface ultrastructural characteristics of bovine oocytes following heat shock. J. Reprod. Dev., 44: 345 – 351.
  9. Hyttel, P., Fair, T., Callesen, H. and Greve, T. (1997). Oocyte growth, capacitation and final maturation in cattle. Theriogenology, 47: 23–32.
  10. John, K. (2007). Electron Microscopy Methods and Protocols. Second Edition, [Edited by Humana] Press Inc. Totowa, New Jersey. 07512.
  11. Kafi, M., Mesbah, F., Nili, H. and Khalili, A. (2005). Chronological and ultrastructural changes in camel (Camelus dromedarius) oocytes during in vitro maturation. Theriogenology, 63: 2458–70.
  12. Mahammadpour, A.A. (2007). Comparative histomorphological study of ovary ad ovarian follicles in Iranian Lori-    Bakhtiari sheep and native goat. Pakistan J. Biol. Sci., 10: 673-675.
  13. Nikas, G., Paraschos, T., Psychoyos, A. and Handyside, A. (1994). The zona reaction in human oocytes as seen with scanning microscopy. Hum. Reprod., 9:2135–2138.
  14. Reyes, M. D., Hetz, J and Palomino, J (2009). Ultrastructural study of the canine zona pellucida surface during in vitro maturation. Reprod Dom Anim., 44 (Suppl. 2), 247–250.
  15. Riddell, K.P., Stringfellow, D.A., Gray, B.W., Riddell, M.G., Wright, J.C. and Galik, P.K. (1993). Structural and viral association comparisons of bovine zonae pellucidae from follicular oocytes, day-7 embryos and day-7 degenerated ova. Theriogenology, 40:1281–1291.
  16. Suzuki, H., Presicce, G.A. and Yang, X. (1996). Analysis of bovine oocytes matured in vitro vs in vivo by scanning electron microscopy. Theriogenology, Abstract 271.
  17. Suzuki, H., Yang, X. and Foote, R.H. (1994a).Surface characteristics and size changes of immature, in vitro matured and in vitro fertilized bovine oocytes. Theriogenology, 41: 307.
  18. Suzuki, H., Yang, X. and Foote, R.H. (1994b) Surface alterations of the bovine oocyte and its investments during and after maturation and fertilization in vitro. Mol. Reprod. Dev., 38:421–430.
  19. Zhu, S.E., Zeng, S.M., Yu, W.L., Li, S.J., Zhang, Z.C. and Chen, Y.F. (2001). Vitrification of in vivo and in vitro produced ovine blastocysts. Anim. Biotech., 12: 193-203.

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