EFFECTS OF GONADOTROPIN TREATMENT ON OVARIAN FOLLICLE - GROWTH, OOCYTE QUALITY AND IN-VITRO FERTILIZATION OF OOCYTES IN PREPUBERTAL GILTS

This study was undertaken to compare the effects of FSH-pituitary (FSH -P), eCG, and a combination of gonadotropins containing 400 IU eCG and 200 IU hCG (PG 600) on the growth of large follicles, oocyte quality and in vitro fertilization (IVF) rate of in vitro matured (IVM) oocyte s in prepubertal gilts. The ovaries were removed via midventral laparo tomy 48 h (Experiment 1) or 72 h (Experiment 2) after the first inject ion. In Experiment 1, 30 gilts received 1 of 5 treatments: 1) saline ( 3 ml im, once, n=6); 2) FSH-P8 (8 mg im, twice, with a 24-h interval, n=6); 3) FSH-P16 (16 mg im, twice, with a 24-h interval, n=6; 4) eCG ( 1000 IU im, once, n=6); or 5) PG 600 (5 ml im, once, n=6). Compared wi th saline, treatment with PG 600 or eCG induced significant (P<0.05) g rowth of large follicles (greater than or equal to 6 mm). In Experimen t 2, 16 gilts received 1 of 5 treatments: 1) saline (n=4); 2) FSH-P8 ( n=4); 3) FSH-P16 (n=4); 4) eCG (n = 4), or 5) PG 600 (n=4). The same i njection protocol as in Experiment 1 was used. Compared with treatment with FSH-P8 or FSH-P16, eCG increased (P<0.05) the number of large fo llicles. The proportion of good oocytes was increased (P<0.05) with FS H-P8 or FSH-P16 compared with treatment with eCG or PG 600. Moreover, oocytes from eCG-treated gilts had a greater (P<0.05) rate of male and female pronuclei than FSH-P or saline-treated gilts. In conclusion, t reatment with FSH-P resulted in a higher proportion of oocytes with mu ltilayer cumulus cells, whereas treatment with eCG resulted in higher pronuclear rates following in vitro fertilization in prepubertal gilts .