Maintenance of Bovine Oocytes: RESULTS(2)

On prolonged culture of intact antral follicles, the percentages of the oocytes that remained at the GV stage after 24, 48, 96, and 168 hours were 96.8%, 89.1%, 28.5%, and 30.9%, respectively (Fig. 4). This gave a significant cubic decline with time (x2i = 8.53, p < 0.01). Oocytes that resumed meiosis within the antral follicle during culture were found at different stages of maturation up to and including second metaphase and also showed clear signs of degeneration (Fig. 5; Table 2).

Oocyte Maturation after Antral Follicle Culture

The percentages of oocytes recovered from each follicle culture period after maturation that developed to the MII stage were 80.0% (24 h), 68.8% (48 h), 22.8% (96 h), and 24.0% (168 h), respectively (Fig. 4). The number of oocytes able to resume meiosis and develop to MII decreased with the increasing period of antral follicle culture in an approximately linear response (x21 = 36.2, p < 0.001). The cell cycle stage of oocytes after follicle culture and subsequent maturation is shown in Figure 5. levitra super active plus
Fig4Maintenance of Bovine
FIG. 4. Maintenance of meiotic arrest in oocytes cultured within antral follicles for increasing time periods, and subsequent maturation to metaphase of the second meiotic division.

Fig5Maintenance of Bovine
FIG. 5. Graph showing the distribution of cell cycle phases in oocytes cultured within antral follicle. GV, intact germinal vesicle; Int, Intermediate, i.e., between GV and MII; M, arrested at MII.

TABLE 2. Cell-cycle stage of oocytes derived from different periods of follicle culture before and after maturation.

Im mature (%) Mature (%)
Days na GV Intb MII na GV Intb MII
2 37 33 2 2 45 8 6 31
4 49 14 25 10 14 13 8
7 46 14 26 6 50 10 28 12

a 5 Replicates. b Int, Intermediate stage.

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