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In the present study, we investigated the distribution and activities of corticotropin-releasing factor (CRF) and adrenocorticotropic hormone (ACTH) immunoreactive (ir) cells in the brain and pituitary of Liza ramada during ovarian maturation, seawater acclimation, and induction of spawning. Using immunohistochemistry, we detected that CRF-ir cell bodies exist in different brain regions: medulla oblongata (MO), midbrain tegmentum, habenula, nucleus preopticus (NPO), and in a ventral hypothalamic region corresponding to the nucleus lateralis tuberis (NLTP). In the pituitary gland, we detected some ACTH-producing cells in the rostral pars distalis (RPD) containing CRF immunoreactivity. The synthetic and secretory activity of CRF-ir cells in the NPO and MO as well as ACTH-ir cells in the pituitary were enhanced during ovarian maturation. During seawater acclimation, CRF-ir cells in the NPO and MO and ACTH-ir cells in the pituitary showed dramatic increases in their synthetic activity. These cells showed dramatic increase in their secretory activity during spawning induced by human chorionic gonadotropin (HCG) injection in L. ramada. Finally, hormonally induced ovulation was accompanied with elevation of plasma cortisol and depletion of CRF and ACTH immunoreactivity within the brain and the pituitary gland, respectively. Taken together, our findings suggest that mature breeders of L. ramada may respond to stress resulting from ovarian maturation, and seawater acclimation as well as induced spawning. Mechanisms include enhancement of the synthetic and/or secretory activity of CRF-ir cells in the NPO and MO as well as ACTH-ir cells in the pituitary gland along with a rise in plasma cortisol during ovulation, supporting the possible role of these hormones during stress and reproduction in L. ramada.

Salinity is a crucial environmental factor that influences the growth, reproduction, and physiological responses of fish species. Understanding how different salinities affect Liza ramada is essential for selecting optimal conditions for aquaculture. This study aimed to assess the effects of salinity on the growth, osmoregulation, stress response, and maturation of L. ramada in captivity. In this investigation, blood levels of hormones related to growth, adaptation, and stress response were measured, along with glucose levels in L. ramada broodstock raised in the waters of varying salinities. Results indicated that prolactin and growth hormone levels were higher in freshwater and lower in saline conditions. Additionally, these hormone levels increased during gonad maturation across all salinities. In contrast, thyroxine concentrations exhibited a pattern similar to cortisol, with significantly higher levels in saline water compared to freshwater. Mature fish also displayed elevated hormone levels. Glucose concentrations in the fish raised in different salinities followed a similar trend to cortisol levels. Furthermore, triiodothyronine hormone levels varied slightly during maturation and across different salinities. The L. ramada stock in freshwater demonstrated superior growth rates in both length and weight, alongside higher condition factor and survival rates. However, broodstock grown in freshwater had a lower food conversion ratio. In saline environments, L. ramada exhibited increased sexual activity, with a higher frequency of mature gonad stages and elevated values of the gonadosomatic index (GSI) and hepatosomatic index (HSI). In light of these findings, we conclude that freshwater is conducive to the growth of L. ramada, while saline water is essential for achieving sexual maturity. [ABSTRACT FROM AUTHOR]

Monitoring the maturation of fish gonads requires an understanding of the locations of reproductive hormone formation both under the influence of environmental factors and under normal conditions. A crucial role in the biosynthesis of active steroid hormones is played by 3β-hydroxysteroid dehydrogenase (3β-HSD). The male and female Oreochromis niloticus gonads at different stages of the annual sexual cycle were analyzed for 3β-HSD using histochemical techniques to pinpoint the locations of steroid synthesis. In females, a specific cell type in the thecal layer, interstitial cells, and ovarian wall epithelial cells exhibited 3β-HSD activity. In males, only Leydig cells (interstitial cells) and lobule boundary cells exhibited 3β-HSD activity. During the stages of sexual maturation and spawning, the Leydig cells' steroidogenic activity increased. Additionally, during the maturing and spawning stages, 3β-HSD exhibited a strong reaction that increased in intensity and the apparent quantity of cells exhibiting a reaction. However, after spawning, the reaction decreased. Furthermore, during the oogenesis process, which is the development of the previtellogenic oocytes to the ripe oocytes, 3β-HSD activity was elevated in the various phases of ovarian maturation. In conclusion, it can be stated that the cells producing steroid hormones in the male and female gonads of O. niloticus have been sufficiently identified, and their steroid hormoneproducing capacity has been demonstrated. Naturally, more research is necessary to apply this finding to the development of fish gonads during the reproduction in aquaculture settings or under situations where this teleost species is concerned to environmental treatments. [ABSTRACT FROM AUTHOR]

Like females of many commercially important fishes, Liza ramada fail to complete ovarian development and do not undergo final maturation (FOM), ovulation or spawning when reared in captivity. The aim of the present work was to investigate the histological and physiological changes during the reproductive cycle of Liza ramada reared in freshwater fish ponds and during induction of spawning in saline water. In the present study, the levels of total thyroxine (T4), triiodothyronine (T3) and cortisol in the plasma of Liza ramada in a complete reproductive cycle were measured in correlation with the seasonal histological changes in gonads. During the reproductive cycle of females, serum triiodothyronine (T3), thyroxine (T4) and cortisol decreased during ovarian early-vitellogenesis and increased during mid-vitellogenesis to reach a peak for both T4 and cortisol. Then, these hormones declined to low levels during late-vitellogenesis. At the prespawning stage, all mentioned hormones re-increased to high levels and finally declined during induction of spawning. There was a decrease in serum levels of thyroid and cortisol hormones coincided with an increase in testicular activity of the fish. T3 and T4 increased during testis ripening to reach a peak during spawning, while cortisol reached a peak during ripe stage and decreased to low levels during spawning. In conclusion, the seasonal changes in thyroid hormones and cortisol concomitant with gonadal maturation and spawning of Liza ramada support role for these hormones in reproduction and stress response of this fish. [ABSTRACT FROM AUTHOR]

The present study deals with demonstrate the reproductive cycle of the broomtail wrasse, Cheilinus lunulatus which monthly collected from coral reef in Abu Galawa lagoon, Hurghada, Red Sea, during the period from December 2011 to November 2012. Results showed that, the averages of male and female gonadosomatic indices (GSI) were gradually increased during spring and summer months. Irregular trend was recorded to the female hepatosomatic index during all months of the year. It may be due to partially spawning in this fish. Shape, weight, size, colour, texture and structure of gonads were changed with the change of maturity stages. The testicular activity can be classified into five stages: immature stage, stimulating spermatogenesis, rapid spermatogenesis, mature (ripe) testis and Spent testis. Seven stages were recognized during the ovarian activity (previtellogenesis, earlyvitellogenesis, mid-vitellogensis, late-vitellogenesis, pre-spawning, ripe and spent stages). The testicular and ovarian developments were initiated when the day length (photoperiod) and water temperature had begun to increase during March to April. During May to August, however, the gradual increase of both photoperiod and water temperature reached its maximum values, gonads had ensured completion of testicular and ovarian development. It was concluded that Cheilinus lunulatus in Abu-Galawa lagoon of Hurghada, partially spawned during a long spawning season, which extended from May to October. It synchronizes between both males and females with coordination to increasing of both photoperiod and water temperature. [ABSTRACT FROM AUTHOR]

Inhibin and activin, dimeric protein hormones originally isolated from mammalian gonads, are involved in the regulation of vertebrate reproduction. In the present study, we investigated the localization of inhibin and activin subunits (α, βA, and βB) immunoreactivity in the brain, pituitary, and ovary of female Liza ramada using immunohistochemistry. We demonstrate that activin βA subunit immunoreactivity is found in most of the brain regions: telencephalon (Tel), midbrain tegmentum (MT), and cerebellum (C). In the pituitary gland, activin βA subunit immunoreactivity is observed in nerve fibers that are in close contact with somatotrophs and gonadotrophs. Strong immunostaining of activin βB subunit is detected in melanotropin (MSH)-producing cells in pars intermedia (PI), which are in close contact with gonadotrophs.In the ovary, the cytoplasm as well as follicle cells of previtellogenic oocytes exhibited strong immunoreactivity of activin βA. However, the activin βA and βB immunoreactivity is decreased when the oocytes entered the vitellogenic stage (recrudescence). The progress in the accumulation of yolk within oocytoplasm is accompanied by a decrease in the activin βA and βB immunoreactivity and eventually the immunoreactivity disappears completely when the oocytes become fully mature. Interestingly, the vitellogenic oocytes of female L. ramada obtained from fresh water (captivity) contain only weak immunoreactivity of activin βA compared to that of saline water (natural habitat). Moreover, immunoreactivity of activin βB is observed in the phagocytic granulosa cells during resorption of oocytes (atresia) within the ovary of female reared in captivity. The immunostaining of inhibin α in the ovary is similar to that of activin βB but the reaction intensity is weaker. However, the mature oocytes show a positive reaction for inhibin α. These results provide evidence for the presence of inhibin and activin-like molecules within L. ramada and reveal the distribution of these molecules in L. ramada brain–hypophysial–gonadal system. Our observations add some new informations to our current understanding of activin system in fish and suggest that inhibin and activin may play an important role for L. ramada reproduction in the event of oocyte growth and maturation. [Copyright &y& Elsevier]