|
This study was carried out to investigate the changes in ovary in repeatedly superovulated rabbits. A total of 57 New Zealand White and Californian, 25 mature virgin and 32 immature does were used in this study. For induction of repeated superovulation, PMSG and HCG were injected at 17-day and 30-day intervals for mature does and 17-day intervals for immature ones. The repeatedly superovulated does at 17-day intervals were induced luteolysis of pseudopregnant corpus luteum with PGF2${\alpha}$ on Day 8 to 9 p.c. The effect of repeated superovulation on reproductive organs was investigated on Day 3 p.c. in mature does and on Day 3 and 6 p.c. in immature ones, respectively. 1. In mature virgin does, the number of ovulation points in the 2nd and 3rd superovulation period averaged 7.0 and 5.0 at 17-day intervals and 13.4 and 6.0 at 30-day intervals, respectively. These numbers were statistically similar to 9.5 ovulation points in the control. However, there were less (p<0.05) ovulation points in those periods compared with 22.1 ovulation points in the 1st superovulation period. 2. In immature does, the number of ovulation points in the 2nd and 3rd superovulation period averaged 5.3 and 2.3, respectively. These numbers were significantly (p<0.05) decreased than 17.1 ovulation points in the 1st periods. The number of ovulation points in the 2nd superovulation period was similar to that in the control, but there was a significant (p<0.05) decrease in the number of ovulation points in the 3rd period as compared to the control. 3. In mature virgin does, the number of visible normal and hemorrhagic follicles (>1.0mm diameter) on day 3 p.c. averaged 19.1 and 8.9 in the 1st superovulation period, respectively. In the 2nd 3rd superovulation period, the number of normal follicles averaged 8.3 and 15.5 at 17-day intervals and 17.8 and 14.5 at 30-day intervals. The number of hemorrhagic follicles in the 2nd and 3rd superovulation period averaged 6.3 and 2.0 at 17-day intervals and 5.2 and 7.8 at 30-day intervals, respectively. There was a slight decrease, although not significant, in the number of normal and hemorrhagic follicles in the 2nd and 3rd period at 17-day intervals compared to that in the 1st period. 4. In immature does, the number of visible normal follicles on day 3 and day 6 p.c. in the 1st superovulation period averaged 27:3 and 26.1, respectively. The follicles on day 3 p.c. tended to increase slightly more than that in the cortrol, but the average number of normal follicles on day 6 p.c. did not differ from that in the control. The number of visible hemorrhagic follicles on day 3 and day 6 p.c. in the 1st of follicles in the 1st superovulation period average 10.2 and 9.9, respectively. There was a slight increase in the number of follicles in the 1st period compared to that in the control. In the 2nd and 3rd superovulation period, the number of normal follicles revealed a slight decrease in the 3rd period, but the number of hemorrhagic follicles was not different between periods. 5. The number of growing follicles with incipient intral formation on day 3 p.c. in mature does of the 1st superovulaton period average 29.7 and the average number of growing follicles in the 3rd period was 26.7 at 17-day intervals and 31.0 at 30-day intervals, respectively. These numbers did not differ from that in the control. In immature does, the number of growing follicles averaged 57.7, 45.0 and 59.3 in the 1st, 2nd and 3rd superovulation period, respectively. There was a slight but not significant decrease in the number of growing follicles in the 3rd period compared to that in the control.
|