뱀장어(Anguilla japonica) 성성숙 유도 기법 향상 연구

Abstract

The eel (Anguilla japonica) is a commercially important species. Over the past decades, it has experienced a drastic reduction in its natural stocks. Thus, the development of technologies for artificial seed production is considered essential, nowadays, to guarantee the eel aquaculture and to reduce pressure on natural populations. Exogenous hormones must be administered to eels because sexual maturity cannot be induced in artificial breeding environments. Generally, Salmon pituitary extract (SPE) induces sexual maturity in female eels (human chorionic gonadotropin, hCG for male eels), and MIH (17α-Hydroxyprogesterone, OHP and 17α,20β-dihy droxy-4-pregnen-3-one, DHP) are used to ovulation. In other words, the eel has been sexually matured through weekly heterologous hormone injections, which cause stress to the fish. The quality of eggs obtained from maturation-induced eel is unstable such as oocytes mostly becoming over-ripe, low hatching rate, and high motality rate. In this study, to improve methods for maturation induction, 1) research on the advancement of MIH treatment technology, 2) method of inducing sexual maturity using an osmotic pump, 3) Effect of recombinant gonadotropins (rec-GTHs) on induction of sexual maturity was investigated. Based on the results, I suggest that the optimum stages for SPE priming, MIH (OHP+DHP mixture) injection, and ovulation are stages 4 to 5, 5 to 6, and 6 to 7, respectively. As a result of sexual maturity induction using an osmotic pump, the sexual maturity induction rate was lower than the traditional SPE administration method, but the mortality rate was low and egg quality was improved. As a result of examining the effect on sexual maturation of rec-GTHs produced using insect cells (Silkworm) and animal cells (CHO-cell) as a bioreactor, it is suggested that rec-GTHs may have a positive effect on in vitro sexual maturation in female eels. Based on the results of this study, it is believed that the optimal MIH treatment method and sexual maturity induction method using an osmotic pump will be practically applied to harvesting high-quality eggs.