Induction of superovulation and recovery of fertilized oocytes in prepubertal miniature pigs after treatment with PG600

The purpose of this study was to examine whether superovulation can be indu ced by hormonal treatment with PG600(R) (400 IU eCG and 200 IU hCG) at the prepubertal stage in miniature pigs. In Experiment 1, 14 prepubertal miniat ure pigs received 1, 1/2 or 1/4 vial of PG600, im on Day 0 (the first day o f treatment). Presentation of estrus was monitored thereafter. On Days 10 t o 13 (i.e., 6 to 8 d after estrus), the number of corpora lutea (CL) and re sidual follicles was counted by an exploratory laparotomy. Injection of 1/2 vial of PG600 effectively induced estrus and ovulation in the pigs. In Exp eriment 2, 15 prepubertal miniature pigs that received 1/2 vial of PG600 we re artificially inseminated into the uterus by an exploratory laparotomy at 100 to 104 h after PG600 injection. Oocytes were recovered from the oviduc ts at 121 to 145 h after PG600 administration. The oocyte recovery rate was 66% (15 oocytes/pig, average), and 84% of these were at the 1-cell stage. In Experiment 3, 15 prepubertal miniature pigs that received 1/2 vial of PG 600, followed by 100 IU hCG 70 h later, were artificially inseminated into the uterus. Oocytes were recovered synchronously at 120 to 122 h after PG60 0 treatment. The recovery rate was 80% (17 oocytes/pig, average) and 90% of the oocytes recovered were at the 1-cell stage. These results suggest that superovulation of prepubertal miniature pigs can be induced by 1/2 vial of PG600 injection, and by the combined treatment with PG600 and hCG injectio n, the fertilized ova can be synchronously recovered at around 120 h after PG600 injection. This procedure may provide a useful system for biomedical research using the miniature pigs, especially for producing transgenic anim als for use in human disease models. (C) 2000 by Elsevier Science Inc.