Histological and histochemical study of female germ cell development in the dusky grouper Epinephelus marginatus (Lowe, 1834) (original) (raw)
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Indian Journal of Fisheries, 2013
Ultrastructural changes in the oocytes and hepatocytes in the female Epinephelus diacanthus were studied with the progress of maturation. Transmission electron microscopic (TEM) observations revealed cytological changes associated with ovarian development. Nucleolus number increased in the perinucleolus stage, which is an indirect indication of increase in protein synthesis with the onset of oogenesis. Zonation of yolk sphere and presence of microvilli in the zona radiata were observed in mature oocytes. In comparison to the immature phase, mature/ripe satge hepatocytes showed greater development of both endoplasmic reticulum and increased density of mitochondria in the cytoplasm which is an evidence of progress in vitellogenin synthesis.
Indian Journal of Fisheries, 2011
Changes in biological indices (gonadosomatic index GSI, hepatosomatic index HSI and condition factor) and biochemical composition of body tissues and serum, associated with ovarian development were examined in Epinephelus diacanthus sampled for two years. GSI, HSI and Condition factor values increased with the maturation of gonads. Mobilisation of biochemical constituents from somatic tissues to the gonadal tissues with the maturation of the ovary was noticed. Highest protein percentage was in stage III (24.81%) ovary. The total lipid percentage of the ovary showed a gradual increase from Stage I (6.56%) to Stage III (13.48%). Total cholesterol showed a steady declining trend and carotenoid levels of the ovary showed a positive relationship with ovarian maturation. Ash content of the ovary increased from stage I (0.82%) to stage III (1.20%).
Turkish Journal of Fisheries and Aquatic Sciences, 2012
In this study, gonadal changes of dusky grouper Epinephelus guaza L.1758 were investigated by histo-anatomically according to sexual maturity in Antalya Bay of Eastern Mediterranean in Turkey. The specimens (n=104) were captured monthly by spear-fishing from their natural sites. The gonads of them were dissected as soon as and fixed in 10 % neutral buffered formaldehyde and Bouin’s solution. They were embedded in paraffin blocks after several histo-chemical processes. Sectioned tissue samples at 5µm were stained by Haematoxylin-eosin and Mallory trichrome techniques. Mainly four different stages which were immature stage, mature female stages (from F1 to F6), transitional stages (from T1 to T3), and mature male stages (from M1 to M3) were observed according to gonadal development. However GSI (Gonadosomatik indeks) is the most common used to quantify spawning time in fish; the RGI (Relative gonadal index) was found more appropriate than GSI for the fish. Dusky groupers spawned in Ju...
African Journal of Biotechnology, 2010
Monthly analysis of the maturity stages distribution revealed that the gadidae fish Merluccius merluccius has a long spawning period extending from early January to early June. All the females over 34.4 cm in body length are mature. The peak value of gonadosomatic index (GSI) was attained in January and continued to May and thereafter decreased gradually from June to August. The analysis of ova diameter revealed that there are eight ova groups in each ripe and spawning ovary; the first four groups are small and transparent and the remaining four groups are yolky. Fecundity shows a wide range for a given length, the absolute fecundity has a linear relationship with length groups and gutted weight. Relative fecundity ranged from 743 to 1699 egg per 1 cm and varied from 92 to 148 eggs per 1 g. The general pattern of the histological development of the ovaries includes six periods: 1. Immaturation period characterized by "small spherical cells each with a large nucleus". 2. The maturation period characterized by "appearance of isolated follicular epithelial cells around the oocyte and the formation of yolk nuclei". 3. Vacuolization period characterized by appearance of "marginal vacuoles; the oocyte wall consists of zona radiata coated with a follicular epithelial layer". 4. The yolk deposition period characterized by "the presence of yolk granules in the cytoplasm". 5. Ripening period characterized by "migration of the nucleus to the animal pole". 6. Spawning-spent period characterized by presence of "empty follicles, different stages of cytoplasmic growth". The ultrastructure of the vacuolized and ripe oocyte wall showing the presence of five different layers, in which the outer most layers, is theca layer; the second layer is the follicular epithelial layer and then the third and fourth layers are zona radiata externa and zona radiata interna, respectively. The fifth layer is known as "cortical alveoli".
Histochemical characteristics of the vitellogenic oocytes of the bluefin tuna, Thunnus thynnus L
Ciencias Marinas, 2002
Very little information is available with respect to dynamic aspects of oocyte development and to yolk composition of tuna species. Since histological approaches can offer considerable information about the ovarian development of fish, and because different cytochemical/immunohistochemical tests are suitable tools for proving the presence of different macromolecules in several organs/tissues/cells, they can be good biomarkers of the reproductive mechanism in fish. The present study investigates the presence and distribution of carbohydrates, proteins, glycoconjugates, lipids, calcium, iron and vitellogenin in the bluefin tuna, Thunnus thynnus oocytes during the synthesis of yolk (globules and granules) in the vitellogenic phase. During the initial vitellogenic phase, oocytes (diameter: 249 ± 21.87 mm) contain oil globules (or vacuoles) which consist exclusively of neutral lipids. During this phase very small yolk granules appear around the cytoplasm. Glycolipids, phospholipids, gly...
Tools of histochemistry and digital image analysis were used to quantify changes in the coverage area of lipid droplets (lipid content) of oocytes of the penshell Atrina maura during oogenesis and to determine its relation to changes in water temperature and seston content. These data led to calculating a lipid index as a criterion of gamete development and quality. Gonads were collected monthly for 18 mo and prepared for histochemical processing with Sudan Black B for identification of lipids. Finished slides were digitized for determining stages of oogenesis and variations in the size of oocytes. Two periods of greatest reproductive activity occurred during the study, with a lower peak from November through January (;15°C; 26 mg/g) and a major peak from April through June (;20°C; 25-40 mg/g). Oocyte area significantly varied during the stages of active development (516-2,743 mm 2 ), ripeness (1,073-2,930 mm 2 ), spawning (145-2,939 mm 2 ), and atresia (331-2,001 mm 2 ). Lipid incorporation into oocyte cytoplasm followed a clear seasonal pattern, peaking again in winter and spring. Temporal variations in the lipid index and its relation to oocyte diameter were irregular, but also peaked in winter and spring. Histochemistry and digital image analysis resulted in reliable methods for estimating oocyte development and quality in this species, and can certainly be applied in studies of reproduction of other bivalve, invertebrate, and vertebrate species.
The corpuscles of Stannius (CS) of important food fish Notopterus notopterus were studied in relation to ovarian maturation. Cytological status of CS were correlated with the ovarian development during growth, maturation and spawning phases. The cytoarchitecture of CS in N. notopterus showed two principle types of secretory cells (Type I and Type II) arranged along the connective tissue septa. Different germ line cells were recognized on the basis of size and histoarchitectural morphology of cells. The Type-II cells varied according to the proliferation of different stages of oocytes in harmony with the various reproductive phases. It was found that at the end of growth phase and onset of maturation phase the diameter along with cytoplasmic granules of Type-I cells increased considerably than the Type-II cells, which was correlated with the occurrence of cortical alveolus and yolk granule stages in the ovary. During the end of maturation and spawning phases the diameter of Type I cells further increased along with chromophobic cytoplasm and hypertrophied nuclei were arranged in clusters encircling the blood vessels. No significant changes were noticed in the Type II cells. These momentous changes correlated with the dynamic cytological activities like vitellogenesis and occurrence of mature oocytes in the ovary. Thus the cytological changes of the CS during growth, maturation and spawning phases accomplished with the ovarian maturation in N. notopterus.
Ovary Differentiation and Activity in Teleostei Fish
Theriogenology
Teleostei fishes constitute a very large group among the vertebrates. They present several reproductive strategies, and many species are gonochoristics. During the gonadal differentiation, the gonadal primordium undergoes morphological changes giving rise to male or female gonads. Considering the lack of information about gonadal morphogenesis in Teleostei, especially in tangent aspects concerning the establishment of the germinal epithelium and its relation with the formation of the ovarian cavity, Tanichthys albonubes, Corydoras schwartzi, and Amatitlania nigrofasciata were taken as biological models to establish a comparative analysis of the female gonadal differentiation. In undifferentiated gonad, the epithelial cells associate with primordial germ cells and form germline cysts. These are distributed throughout the gonadal tissue; after the entrance of the oogonia into meiosis, the folliculogenesis occurs forming the first follicles, in a quite conserved process. However, the formation of the ovarian cavity is distinct. In T. albonubes and A. nigrofasciata, the lumen is formed by pleating and in C. schwartzi, it is formed by cavitation. The central lumen formed characterizes the cystovarian of Teleostei. Although there are differences in the chronology of the differentiation, the processes involved are quite similar and culminate in the formation of analogous structures.