Histocytological changes in the corpuscles of stannius in relation to ovarian development of freshwater featherback Notopterus notopterus (Pallas) during growth, maturation and spawning phases (original) (raw)
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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.
The histological status of adrenocortical tissues and the correlated seasonal changes in ovarian activities in Mystus vittatus was performed. The tubules and nests of interrenal and chromaffin cells were located in cephalic kidney around the main branches of posterior cardinal vein. Various female germ line cells were identified in the ovary based on size, distinctive features and histoarchitechture of the cells. However, on the basis of relative abundance and size of the different oocytes, the event of oogenesis has been found to occur in four distinct phases, including growth, maturation, spawning and post-spawning. The cytoplasmic features and the architecture of the interrenal and chromaffin cells varied during different phases of the reproductive cycle. During growth and maturation phases, the amount of cytoplasmic granules of interrenal cells increased than chromaffin cells that was in coincidence with the increase of early and late perinucleolar oocytes followed by highest frequency percentage of oocyte at stages IV and V. The cytoplasmic mass of interrenal cells was gradually elevated along with hypertrophied nuclei from the end of maturation and spawning phases also correlated with the increased frequency of mature oocytes. Therefore, gradual accumulation of cytoplasmic granules in the interrenal cells was noticed during post-spawning phase. The cytological variations in the interrenal and chromaffin cells harmonized with constitution of different ovarian cells during different reproductive phase in M. vittatus.
Micron, 2014
With the intent to provide additional information on the reproductive biology of the ostariophysian fish, the oocyte development in Serrasalmus maculatus is here described under light and electron microscopy by using some cytochemical methods. Our results are discussed considering the cellular processes that drive the oocyte development and comparing to the available information on other groups of fish. Despite the oocyte development to be in general a conserved process, some characteristics of the oocytes of this species come to light. Possibly related to the reproductive strategy of S. maculatus are the absence of oil droplets and the presence of well-developed cortical alveoli. Besides this finding, our results suggest the presence of high content of basic residues in yolk proteins, the presence of acidic polysaccharides in the zona pellucida and a possible involvement of the follicular cells in the steroidogenesis process.
2014
Studies were conducted on the changes occurring in the ovaries of adult female Kutum, (Rutilus frisii kutum Kamenskii, 1901) in Bandar-e Kiashahr in Southwestern of Caspian Sea during a yearly cycle (between two spawning period) from October 2007 to April 2008. No abnormalities or pathological changes in the ovarian or body of the investigated fish were detected. The aims of this study were confirm to timing, frequency and duration of the spawning period, monitor changes in the gonado-somatic index (GSI), relate (GSI) to the histological characteristics of the ovaries and describe the stages of Kutum oocyte and ovarian development. Gonadal samples were taken monthly from the females stained with HandE stain and Samples were studied by light microscope. Different stages of oocyte development (nucleus changes, oocyte diameter and forming of yolk vesicle, yolk granules and lipid droplets) were surveyed. Six maturity stages were observed during our study that included: Virgin stage (I), Maturing virgin (II), Developing (III), Gravid (IV), Spawning (V) and Spent (VI). This study has shown that gonadosomatic index (GSI) began to increase in March and reached the highest value (29.47±4.2) in April and then decreased sharply in early may. According to the results gonad development of Kutum was synchronous group.
Ovarian development of a river catfish Hemibagrus nemurus (Valenciennes, 1840) in captivity
Hemibagrus nemurus is a riverine catfish with high economic and nutritive values. Investigations on ovarian development of this fish were carried out to determine the mode of ovarian development and describe the oocyte developmental stages. Histological studies were done on ovaries using Light Microscopy and Scanning Electron Microscopy. Fish were sampled monthly for a period of six months (August 2009 to January 2010). The mean oocyte diameter (OD) ranged from 871 ± 161.41μm to 1167 ± 26.77μm and the highest oocyte diameter was in November. Oocyte size - frequency distribution showed a polymodal distribution. The mean gonadosomatic index (GSI) ranged from 1.14 ± 0.87% to 7.06 ± 1.40% and highest GSI was in November. The ovaries exhibited three phases of oocyte growth, which were primary growth, secondary growth and maturation phases. Based on histological criteria, the oocyte developmental stages were divided into seven stages as chromatin nucleolar, early perinucleolar, late perinucleolar, cortical alveolar, vitellogenesis, mature oocyte and germinal vesicle migration stages. All the seven stages of oocyte development were observed in the ovaries. Oogonia were always present throughout the developmental stages. The ovaries had more than two stages of oocyte development. This is the first report on the mode of ovarian development of H. nemurus. These findings indicated that H. nemurus has asynchronous mode of ovarian development and is capable of spawning several times in a year under favourable conditions.
Journal of Fish Biology, 1996
To clarify the dynamics and regulation of oogenesis in single-and multiple-spawning cyprinid fish with group-synchronous oocyte development, a multidisciplinary approach to their reproduction was undertaken using three species from the River Meuse (Belgium): the roach Rutilus rutilus as a single spawner, and the bleak Alburnus alburnus and the white bream Blicca bjoerkna as multiple spawners. The gonadosomatic index (GSI) and histomorphometric changes (distribution of oocyte size, relative proportion of the various oocyte stages) in the ovary are compared. Different patterns of GSI and oocyte growth were observed both between the single-and multiple-spawner fish and between the two multiple spawners. Maximum GSIs were higher in roach (21%) than in bleak and white bream (17·7 and 14·5%, respectively), and compared to the rapid decline of GSI in the roach population, the GSI of multiple spawners decreased progressively during the spawning season. In roach, a short gonadal quiescent period and an early onset of vitellogenesis was recorded from late summer onwards whereas, in bleak and white bream, exogenous vitellogenesis was not systematically observed before winter. A protracted spawning season and/or a low water temperature in autumn are hypothesized to explain this long period of gonadal quiescence. In bleak, during the spawning season, the oocytes recruited arose from the stock of endogenous vitellogenesis and attained the final maturation stage very rapidly. This recruitment occurred during the whole spawning season. In white bream, the differentiation of vitellogenic oocytes from smaller oocytes was completed before the onset of the spawning season. During the spawning period, the proportion of vitellogenic oocytes decreased progressively whereas the percentage of oocytes in the final maturation stage remained approximately constant. 1996 The Fisheries Society of the British Isles
Neotropical Ichthyology, 2010
Based on new knowledge coming from marine perciform species, the origin of oocytes and their development in the Ostariophysi, Gymnotus sylvius is described. In both Gymnotus sylvius and marine perciform fish, oogonia are found in the germinal epithelium that forms the surface of the ovarian lamellae. At the commencement of folliculogenesis, proliferation of oogonia and their entrance into meiosis gives rise to germ cell nests that extend into the stroma from the germinal epithelium. Both cell nests and the germinal epithelium are supported by the same basement membrane that separates them from the stroma. At the time of meiotic arrest, oocytes in a cell nest become separated one from the other as processes of prefollicle cells, these being derived from epithelial cells in the germinal epithelium, gradually encompass and individualize them while also synthesizing a basement membrane around themselves during folliculogenesis. The oocyte enters primary growth while still within the cell nest. At the completion of folliculogenesis, the oocyte and follicle cells, composing the follicle, are encompassed by a basement membrane. The follicle remains connected to the germinal epithelium as the both share a portion of common basement membrane. Cells originating from the stroma encompass the ovarian follicle, except where there is a shared basement membrane, to form the theca. The follicle, basement membrane and theca form the follicular complex. Oocyte development occurs inside the follicular complex. Development is divided into the stages primary and secondary growth, oocyte maturation and ovulation. Cortical alveoli appear in the ooplasm just prior to the beginning of secondary growth, the vitellogenic stage that begins with yolk deposition and proceeds until the oocyte is full-grown and the ooplasm is filled with yolk globules. Maturation is characterized by the germinal vesicle or nuclear migration, germinal vesicle breakdown or nuclear envelop fragmentation and the resumption of meiosis. At the ovulation the egg is released from the follicular complex into the ovarian lumen. When compared to marine Perciformes that lay pelagic eggs, oocyte development in Gymnotus sylvius has fewer steps within the stages of development, the two most remarkable being the absence of oil droplet formation during primary and secondary growth, (and the consequent absence of the oil droplets fusion during maturation), and the hydrolysis of yolf preceding ovulation. . ovo é liberado do complexo folicular para o lúmen ovariano. Em comparação com os Perciformes marinhos com ovos pelágicos, o desenvolvimento oocitário em Gymnotus sylvius tem menos etapas dentro dos estágios de desenvolvimento, sendo as duas mais notáveis delas as ausências da formação das gotas de lipídio durante os crescimentos primário e secundário (e a consequente fusão das gotas para formar um único glóbulo de lipídio durante a maturação) e, a hidrólise do vitelo antecedendo a ovulação.
A Standardized Terminology for Describing Reproductive Development in Fishes
Marine and Coastal Fisheries: Dynamics, Management, and Ecosystem Science, 2011
Proceedings of the 4th Workshop on today to classify a female into the right maturity stage or phase (sub-stage). Here the males are ignored, as often done, but there does also exist reliable histological classification schemes for this gender, although demanding a higher level of expertise. Oocyte recruitment Studies on oocyte recruitment are very limited in the fish literature, primarily because of the high complexity in enumerating these small cells. The most natural route to take is by using sophisticated stereology (see Hagstrøm Bucholtz et al. this WS), but the procedure is extremely laborious and is complicated by shrinkage/distortion problems along the so-called z-axis. Thus, we advocate also the use of advanced packing density formulae (Kurita and Kjesbu 2009) in combination with Delesse principle (see Korta et al. this WS). The concept of natural down-regulation (Kurita et al. 2003) has opened up a completely new understanding of oocyte number regulation and thereby quantification and standardization. However, to understand the underlying processes, histology is clearly required to address atresia formation and fate. Atresia Studies on atresia have been ongoing for many years but only now one can say if it is being correctly quantified. The combination of image analyses (whole mount) using specific stains and validation by histology look very promising for further method development (Witthames et al. 2009).