الفهرس 
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Abstract
This study was carried out at the Laboratory of Physiology and Biotechnology, Animal Production Department, Faculty of Agriculture, Mansoura University, in cooperation with the International Livestock Management Training Center (ILMTC), Kafr El-Sheikh Governorate, belonging to the Animal Production Research Institute, Dokki, Giza, Egypt, during the period from February 2012 to October 2014.To assess the integrity of follicles after exposed, freezing and fresh, the follicular morphology was examined by histological staining. Vitrified, exposed and fresh ovaries were fixed in fixed in 10% buffered formaldehyde solution for at least 48 h, and were embedded in paraffin wax and serially sectioned at 6-μm-thickness, every 10th section of each ovary was mounted on glass slides, and stained with haematoxylin and eosin.The aim of this experiment was to evaluate the effect of two antioxidants Vitamin E (α-Tocopherol, 200µM) and (GSH, reduced, 200µM) on in vitro maturation of NZW rabbit oocytes recovery from ovaries exposure to vitrification solution or vitrification as compared as fresh ovaries.Results showed that weight; length and width showed slight increase after exposure or vitrification of ovaries, but the differences were not significant. Granulosa cell layers within the follicles were observed, being more compact in fresh than in exposed and vitrified ovaries respectively. Also, theca externa layer was more condensed in fresh than in exposed ovaries only.Results revealed that number of normal follicles/ovary at different developmental stages was significantly (P<0.05) the highest for fresh ovaries, moderate for exposed ovaries, while vitrified ovaries showed significantly the lowest number of follicles. Results showed that number of follicles (normal and abnormal) at different developmental stages was nearly similar on the right and left side.The total number of oocytes/ovary was significantly (P<0.05) greater when they were recovered from fresh ovaries than those from exposed or vitrified ovaries while number of abnormal oocytes/ovary was significantly lower in fresh than in exposed and vitrified ovaries.Results showed that total number of oocytes, and number and percentage of normal and abnormal oocytes was nearly similar on the right and left side (12).Results showed that average number of compact oocytes was significantly (P<0.05) the highest, while number of degenerated oocytes was significantly (P<0.05) lower when they were recovered from fresh ovaries.Recovery rate of expanded oocytes was significantly (P<0.05) higher from vitrified than from fresh and exposed ovaries. However, recovery rate of denuded oocytes was not affected significantly by preservation method (Table 18).The percentage of matured oocytes was significantly (51.34%) higher for oocytes matured by GSH than VE (43.62%) versus the lowest percentage of control oocytes at MII stage (31.80%).Cleavage rate was significantly (P<0.05) the highest for fresh, moderate for exposed, while the lowest for vitrified ovaries.Oocytes recovered from ovaries exposed to vitrification solution or vitrified showed lower maturation rate than those recovered from fresh ovaries. Although oocytes are adversely affected by low temperatures, freezing, and cryoprotective substances, they do not completely lose their capacity to develop oocytes from the germinal vesicle to MII stage. Supplementation of maturation medium with antioxidant, in particular GSH slightly improved the maturation rate oocytes recovered from cryopreserved ovaries, but still at lower level than that occur for fresh oocytes. Based on the poor results of preservation of oocytes recovered from ovarian tissues, the current study may conclude cryo-preservation of oocytes after recovery from fresh ovaries rather than those from cryo-preserved ovarian tissues. In addition, the current study suggests further studies on an appropriate freezing and thawing processes of the ovaries to avoid factors which lead to accelerate apoptosis.