Journal of Cell and Animal Biology Vol. 1(2), pp.029-033, September 2007          
© 2007 Academic Journals

Full Length Research Paper

Effects of season on the quality and in vitro maturation rate of Egyptian buffalo (Bubalus bubalis) oocytes

Khairy M. A. Zoheir¹*, Abdoon A. S. ¹, Mahrous K. F. ¹ ,Amer M. A. ¹, Zaher M. M. ³ Li-Guo Yang⁴ and El- Nahass E. M. ¹

¹National Research Center- Cell biology department- Dokki- Cairo- Egypt.
²National Research Center- Animal Physiology and AI department- Dokki- Cairo- Egypt.
³Cairo University- Faculty of Science- Cairo- Egypt.
⁴College of Animal Science and Technology- Huazhong Agricultural University- Wuhan- PR China.

*Corresponding author. E-mail: khma25@yahoo.com

Accepted 22 August, 2007

Recent advances in in vitro maturation, fertilization and culture technology allowed progress in an increasing the number of off springs produced from genetically superior females but this progress still has important factors affect the yielding and quality of the oocytes. It was referred that, there is a distinct similarity in season profile between an in vitro and in vivo reproductive traits. The influence of season on oocyte quality has been largely considered, as a factor of high impact.  The purpose of this paper was to study the effects of season on the quality of oocytes and its relationship with cumulus cells expansion, maturation and developmental rates of in vitro maturation of Egyptian buffalo oocytes. The main goal of our investigation was shown to evaluate the role of change in the temperature during the year on the buffalo and consequently affecting the quality of their oocytes. The results showed significant differences between the four seasons. In spring and winter, the percentage of good quality oocytes was (71 and 74.6%), denuded oocytes was (12.8 and 9.1%) and the fair type of oocytes was (16.3 and 16.3%) respectively. Consequently the maturation rate was 85.5 and 92.5% respectively. While in summer and autumn, the percentage of good quality oocytes was (50 and 56.9%) instead of denuded oocytes was (25.5 and 18.5%) and the fair type of oocytes was (24.4 and 21.5%) respectively. Consequently the maturation rate was 59.6 and 74.5% respectively. The results revealed that, when the percentage of good oocytes increased, cumulus expansion and the maturation rate had increased. The higher degeneration of oocytes in the hot period reflects their lower developmental competence of oocytes compared with recovered in the cool environmental conditions.

Key words: Oocytes, season, maturation, buffaloes.