Passive Immunoneutralization of Endogenous Inhibin Increases Ovulation Rate in Miniature Shiba Goats

摘要

We reported previously that passive immunization against inhibin enhances follicular growth and increases the ovulation rate However, the ovulation rate was not comparable to the number of follicles, Therefore, the aim of this study was to attempt toincrease the ovulation rate by increasing the interval between inhibin immunization and PGF2a injection, Five miniature Shiba goats were treated with 10 ml inhibin antiserum (inhibin-AS) developed against [Tyro~(30)]-inhibin α (1-30) A control group (n=5) was treated with normal goat serum, All animals were injected intramuscularly with 125 μg PGF_(2α) 72 h after treatment to induce estrus and ovulation, Blood samples were collected for hormonal assay and the ovulation rate was determined by laparotomy. In contrast to the control group, there was a significant increase in plasma concentrations of FSH in the immunized group. After luteolysis, plasma concentrations of estradiol-17β increased markedly to a preovulatory peak about 2 folds higher (P<0.01) than that of controls. In addition, the ovulation rate was greater in the immunized group (14,4 ± 2.2) than in the control group (2,2 ± 0.6), and the mean number of follicles ≥ 4 mm in diameter was 10,0 ± 0.8 in the inhibin-AS group compared with2,4 ± 0.3 in control group. The present results demonstrate that immunoneutralization of endogenous inhibin increased FSH secretions in miniature shiba goats. The increased FSH secretion enhanced follicular growth and increased the ovulation rate. Additionally, increasing the interval between inhibin-AS and PGF_(2α) injections (to 72 h) resulted in a greater ovulation rate compared with the previous protocol (48 h). Therefore, inhibin-AS treatment proved to be an effective alternative to exogenous gonadotropin methods for induction of superovulation in goats.