الفهرس 
المقدمةيوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
This study was carried out at Physiology and Biotechnology Laboratory, Animal Production Department, Faculty of Agriculture, Mansoura University during the period from October 2013 to February 2014 to evaluate the effect of supplementing maturation medium with some natural antioxidants (Vitamins) or their combination. Two experiments were conducted; addition of retinol (RET, 10 µmol), ascorbic acid (ASA, 100 µmol) or α-tocopherol (TOC, 100 µmol) was evaluated in the 1st experiment, while their combination (RET + ASA, RET + TOC, ASA + TOC and RET + ASA + TOC) at the same levels of 1st experiment), were evaluated in the 2nd experiment, on cumulus cell expansion and in vitro nuclear maturation of buffalo oocytes. Oocytes were collected from slaughterhouses ovaries. Only compact oocytes were used for in vitro maturation using TCM-199 medium supplemented with different vitamin levels for 22 h in CO2 incubator at 38.5 °C, 5% CO2 and 95% humidity. Maturation rate was determined in terms of degree of cumulus cell expansion and percentage of oocytes reached metaphase-II stage (nuclear maturation).
The obtained results could be summarized as the following:
1. Average number of follicles and oocytes were 4.53 and 2.73 per ovary, respectively.
2. Oocyte recovery rate by aspiration was 60.21%.
3. Percentage of acceptable oocytes was 85.2%, being 50% for compact and 35.2% for less compact oocytes.
4. Average number of acceptable oocytes was 2.32 per ovary, being 1.36 and 0.96 for compact and less compact oocytes, respectively.
1st experiment:
1. All vitamin supplements yielded higher percentages of oocytes showing full expansion of cumulus cells (77.2, 69.4 and 69.2% for TOC, ASA and RET, respectively) as compared to control medium (60.2%), but the differences were not significant.
2- Maturation rate in term of percentage of oocytes reached to telophase-I and metaphase-II was significantly (P<0.05) higher for media supplemented with RET, TOC and ASA, being 83.5, 82.2 and 81.94% as compared to 68.54% in control medium, respectively.
2nd experiment:
1- All vitamin combination yielded higher percentages of oocytes showing full expansion of cumulus cells and lower percentage of non-expanded oocytes than the control medium.
2- Maturation rate in term of percentage of oocytes reached to telophase-I and metaphase-II was significantly (P<0.05) higher for media supplemented with all combinations than the control medium.
Conclusively, the present results indicated that the supplementation of maturation medium (TCM-199) with retinol, ascorbic acid and α-tocopherol or their alternative combinations as a non enzymatic antioxidants had a beneficial effect on the cumulus cell expansion and nuclear maturation of buffalo oocytes. Supplementation of retinol alone or in combination with ascorbic acid reflected the best results.