| Project/Area Number |
59480075
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
畜産学(含草地学)
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
SHIMIZU Hiroshi FACULTY OF AGRICULTURE, HOKKAIDO UNIVERSITY Associate Prof., 農学部, 助教授 (90001453)
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| Co-Investigator(Kenkyū-buntansha) |
UEDA Junji FACULTY OF AGRICULTURE, HOKKAIDO UNIVERSITY Instructor, 農学部, 助手 (50002374)
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| Project Period (FY) |
1984 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 1986: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1985: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1984: ¥4,600,000 (Direct Cost: ¥4,600,000)
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| Keywords | body weight selection / ovulation rate / implantation rate / embryo loss / viability / 産子数 |
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| Research Abstract |
It was shown that there were apparent differences in litter size among three selected strains for juvenile body weight in mice, that was, M-strain was selected for male only, F-strain was selected for female only, and MF-strain was selected for both sexes. MF-strain was most increased in body weight and followed by F- and M-strains. However, the strain which most increased in litter size, was F-strain and, followed by M-strain. The litter size of MF-strain was not significantly different from C-strain (unselected strain). Objects of this project were to investigate some factors affecting a litter size and genetic relationships between body weight and reproductive traits. The following results were obtained.
1. F-strain showed the most increase in ovulation rate and the least loss of eggs before implantation and of embryos after implantation, while MF-strain ovulated as much as F-strain but lost much eggs and embryos before parturition. M-strain showed the increased ovulation rate following to F- and MF-strain, and the loss before implantation as less as F-strain but much loss in embryos.
2. Maternal effect on the loss of embryos was examined by transfering embryos from C-strain to M-, F- and C-strains. The results showed that the maternal effect was more important for survival of embryos than the effect of embryo itself and uterine condition of F-strain was superior to other strains for survival of embryos.
3. Factors and mechanism which caused the difference in reproductive traits between F- and M- strains could not be interpretated.
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