Vol. 39 No. 2, 2000
Morphological Changes and Competence of Maturing Oocytes in the Protandrous Black Porgy, Acanthopagrus schlegeli
Wen-Shiun Yueh and Ching-Fong Chang*
Department of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan 202
Wen-Shiun Yueh and Ching-Fong Chang (2000) The
study objectives aimed to investigate the morphological changes of
oocytes during final oocyte maturation and ovulation, and the
maturational competence of oocytes to respond to maturation-inducing
steroids in the protandrous black porgy, Acanthopagrus schlegeli.
Females were injected with 2 successive doses of LHRH analog (10 and 50
µg per fish) on days 0 and 1. The oocytes were obtained at 6- or 3-h
intervals from the genital pore after treatments. Morphological changes
during oocyte maturation and ovulation were observed, and oocyte
diameters in in vitro culture (with or without hormones) were measured.
Oocyte maturation and ovulation occurred at 20-28 h and 36- 60 h after
the 2nd LHRH-A injection, respectively. It took 4-8 h to complete the
process of oocyte maturation (in vivo) and 40 min for ovulation (in vitro).
17,20β,21-trihydroxy-4-pregnen-3-one, and HCG) could significantly
induce oocyte maturation in oocytes collected at 9 and 6 h prior to the
occurrence of germinal vesicle breakdown (GVBD). Oocyte maturation
spontaneously occurred in oocytes collected at 3 h prior to GVBD. HCG
showed no synergistic effects with steroids in the induction of oocyte
Key words: Black porgy, Maturation-inducing steroid, Oocyte culture, Oocyte growth, Oocyte maturation.
*Correspondence: Tel: 886-2-24622192 ext. 5209. Fax: 886-2-24621579. E-mail: email@example.com