| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1985: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
Prepubertal gilts are regarded to be inexpensive sources of oocytes and embryos for reseach purpose. In the present study, the optimum dose of PMSG for inducing superovulation in non-cyclic gilts was first invesigated. Although seasonal and individual variations in response to PMSG existed, the treatment with 1250 iu PMSG followed 72 h later with 500 iu hCG appeared to be optimum for follicular development and ovulation; mature oocytes were collected from these follicles about 40 h after hCG. By inseminating once at 30 h after hCG, embryos were successfully recovered from oviduct (3 days after hCG) and uterus (5 days). When the mature oocytes were inseminated in vitro (in vitro fertilization; IVF), satisfactory result was obtained; fertilization rate was 82% at 3 h after insemination. Sixty one % of the IVF eggs developed to 2-4 cell stage. After transfer of these IVF eggs (1-2 cell) to 4 recipients, one became pregnant and farrowed 4 normal piglets (17 eggs were transfered into oviduct in this case). On the other hand, oocytes matured in vitro gave unsatisfactory results in IVF despite these oocytes were apparently normal at light microscopic level. Therefore, the ultrastructure of these oocytes were next investigated. As a result, no visible difference was observed between oocytes matured in vivo and in vitro. However, some abnomalities of mitochondria appeared to be involved in vitro matured oocytes.
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