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|Title: ||The Development of Ovarian Tissue and Female Germ Cells in the Protandrous Black Porgy Fish|
|Authors: ||Mong-Fong Lee|
|Keywords: ||Oocyte development|
|Issue Date: ||2016-08-25T02:23:48Z
|Publisher: ||Zoological studies|
|Abstract: ||Abstract: The morphology of developing bisexual gonads and female germ cells in the
protandrous black porgy, Acanthopagrus schlegeli (Sparidae), is described using light and electron microscopy.
The central (ovarian) cavity and sex differentiation were observed in the differentiating gonad at 5 mo of age.
Testicular tissue was the main tissue in the gonad with a small portion of ovarian tissue limited to the area
around the central cavity and main blood vessel. Oogonia which were grouped as cell nests in the germinal
epithelium and oocytes appeared during the period from the differentiated gonad to the 1st spawning period.
Ovarian lamellae, containing oogonia and primary oocytes, developed towards the central cavity after the
1st spawning season. The testicular tissue regressed but ovarian tissue developed during the non-spawning
period in 1+- and 2+-yr-old fish. Female germ cells were classified into oogonia, chromatin-nucleolus oocytes,
perinucleolar oocytes, cortical alveolar oocytes, vitellogenic oocytes, and maturing oocytes. Only primary
oocytes, the most advanced type of oocyte, could be found in the bisexual ovary before the occurrence of the
sex change. Testicular tissue regressed together with the development of vitellogenic oocytes during the sex
change in some 3-yr-old fish. A blood vessel reached each oocyte. There were light and dark electron-dense
areas in the germinal epithelium connected by cell junctions. Oogonia and oocytes had many mitochondria
and highly electron-dense structures such as cement and nuage. Granulosa and theca cells surrounded the
oocytes. Organelles such as mitochondria, endoplasmic reticula, and Golgi bodies were found in the highly
electron-dense area of granulosa cells at the vitellogenic oocyte stage. Microvilli extended from oocytes through
the zona radiata to granulosa cells. The developmental profile of ovarian lamellae in ovarian tissue and changes
in the testicular/ovarian tissue in the bisexual gonad were further summarized. These histological data provide
important information for further studies on the molecular mechanism of sex differentiation and sex change in
the protandrous black porgy.
|Appears in Collections:||[水產養殖學系] 期刊論文|
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