Relationship between post-ovulation time and fertilization rate of eggs in artificial insemination of tiger puffer, Takifugu rubripes

This study was conducted to examine the relationship between post-ovulation time and fertilization rates of artificially inseminated eggs of tiger puffer Takifugu rubripes. After hormonal treatment using cholesterol pellet incorporating LHRH-a (400 μg/kg), four-hour interval palpation was performed to check expansion and hardening of the abdomen due to hydration of oocyte which indicates the completion of final oocyte maturation. Ovulation occurred between 18 and 36 hours after confirming hydration. The fertilization rate of the eggs collected from ten fish decreased as the time increased, showing 70.5% (peak), 7.7% and finally 0% within 4, 24 and 36 hours after ovulation, respectively. These results suggest that artificial fertilization of tiger puffer must be carried out immediately after ovulation in order to obtain good quality eggs.