Ovary Development in Polypterus senegalus | ||
| Egyptian Journal of Aquatic Biology and Fisheries | ||
| Article 17, Volume 28, Issue 6, November 2024, Pages 287-299 PDF (1.34 M) | ||
| DOI: 10.21608/ejabf.2024.392228 | ||
| Authors | ||
| Mostafa Mousa; Rania Barakat | ||
| Abstract | ||
| Oogenesis, the mode of developing an egg, is identified by a series of modifications to the main components of the germ cells in fish female. The previtellogenic stages and the vitellogenic or trophic phases that end with ripe or mature oocytes have been the two primary categories of these variations. The ovaries of Polypterus senegalus were clearly recognized as a paired elongated structures joined by a thin sheath of connective tissue. During growth of the P. senegalus ovary, multiple oocytes clutches were observed to mature each year. The ovarian development was found in six phases: including one prior to yolk formation (ovary with primary oocytes), four yolky ovaries containing various kinds of oocytes and ripe oocytes. The yolk's formation is composed of four phases: the stage of cortical granules, which signifies the beginning of yolk deposition, and the stages of yolk formation; primary, secondary and tertiary. Depending on the histochemical methods, two primary yolk components were seen during its deposition in P. senegalus: the proteinic material, which appeared as cortex granules and globules of yolk, and carbohydrate substance, which was present as polysaccharide granules. First to be deposited were cortical granules, then yolk globules. Proteins made up majority of the cortical granules and yolk globules. Initially, polysaccharides were seen as tiny granules scattered across the rim of the initial yolk oocytes and in zona radiata. They are stained positively with periodic acid Schiff (PAS). As the oocyte developed the granules containing polysaccharides showing an increase in number and forming manifested layer under the wall of yolky oocytes. To sum up, the current findings are essential for understanding gonadogenesis of P. senegalus and for supplying the fundamental knowledge needed for its effective reproduction. | ||
| Keywords | ||
| Histology; Histochemistry; Oogenesis; Vitellogenesis; Polypterus senegalus (Polypteridae) | ||
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