Comparison of Harvesting Techniques and Corpus Luteum Bearing on Recovery and Quality of Sheep Oocytes

Document Type : Original Article

Authors

1 Department of Animal Production, Faculty of agriculture, Kafrelsheikh University

2 Animal Production Department, Faculty of Agriculture, Kafrelsheikh University, Kafrelsheikh, 33516, Egypt.

3 High Institute for Agricultural Co-operation, Shoubra, Egypt.

Abstract

The aim of this study was to assess the effects of the slicing and puncture process and CL-bearing on the recovery and efficiency of oocytes from sheep ovaries. In the present study, 100 ovaries with corpus luteum (CL+) and without corpus luteum (CL-) were used. Ovaries weight, length, width, and thickness were measured.  Using the slicing and puncture methods, the follicles were counted. The follicles were grouped in small follicles (< 2 mm), medium follicles (2-5 mm), and large follicles (> 5 mm). Oocytes have been categorized as compact cumulus / oocyte complexes (COCs), expanded (EXO), partially denuded (PDO), denuded (DO), and degenerated (DEG) oocytes according to their morphology. Our results revealed that the average weight of sheep ovaries CL+ (0.868 g) were significantly (P>0.05) greater than ovaries CL- 0.727 g, but there were no significant differences in length or width. The average number of total and compact oocytes/ovary when slicing was significantly (P>0.05) higher than puncture techniques were used (6.87 vs. 5.70) and (3.39 vs. 2.46), respectively. CL+ ovaries showed insignificantly (P<0.05) lower oocyte recovery rate in total, compact (COCs) and denuded oocytes, while the opposite of this trend in partial denuded and degenerated oocytes as compared to CL- ovaries. In conclusion, the cumulus-oocyte complexes obtained from sheep ovaries without CL and from the slicing rather than puncture method can be used for in vitro embryo production of sheep.

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