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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]

Understanding the anatomy of endocrine glands in fish allows for the formulation of a strategy for their reproduction. The current investigation aimed to investigate the immunohistochemical identification of hormonal-secreting cells in Mugil cephalus pituitary gland. Antisera against both piscine and mammalian hormones were used to complete the immunohistochemistry of the cell types in M. cephalus pituitary gland. The adenohypophysis and the neurohypophysis made up the two main sections of M. cephalus's hypophysis. Moreover, the adenohypophysis obtained exhibited three subdivisions: rostral pars distalis (RPD), proximal pars distalis (PPD), and pars intermedia (PI). In the glandular portion, seven cell types were identified according to their distribution, immunoreactivity, and grouping. The cells of prolactin (PRL) were acidophilic and occupied most of the RPD. They responded positively and specifically to antiserum against salmon PRL. Positive immunoreactivity was observed by antiserum of human adrenocorticotrophic (ACTH), within the lead hematoxylinpositive (PbH+) cells that surrounded the RPD neurohypophysis. Salmon growth hormone (GH) antiserum produced a specific and intense immunoreactivity in the PPD's acidophilic cells. Furthermore, basophilic cells, exhibiting a strong and distinct immunoreactivity to antisera against the subunits Iβ and IIβ of salmon gonadotropin (GTH), were localized in PPD's central area. The cells thought to secrete thyrotropin (TSH) were located between the PPD and RPD in the neurohypophysis. They underwent an adverse immunoreactivity when reacted to rat thyrotropin (rBetaTSH) antiserum. Within the PI, two cell types were identified: PbH+ cells that immunoreacted with alpha-melanin-stimulating hormone (α-MSH) antiserum and cells that displayed a positive immunoreaction to anti-salmon somatolactin (SL) and were classified as Periodic Acid-Schiffpositive (PAS+). Current pituitary gland immunohistochemistry of M. cephalus may help to explain hormonal alterations that take place during reproduction in the nature, in captivity, or when this fish is receiving hormonal treatments. [ABSTRACT FROM AUTHOR]

The aim of the present research was to improve Oreochromis niloticus reproduction by treating females exogenously with L-thyroxin (T4), which will stimulate the producing of inhibin and activin A during the growth of larvae, with an influence on the growth and survival of larvae. The immunohistochemical examination was carried out on developing larvae from O. niloticus spawners administered T4 and control, examining the allocation of activin/inhibin subunits A and B, as well as the inhibin subunit α, from 1-28 days post-hatching. The injection of the females with T4 hormone had a notable impact on the reproductive activity, leading to an enhancement in the quality of their eggs, as demonstrated by the significantly normal larvae upon hatching. Findings from the immunohistochemical investigation showed that only inhibin/activin βA were obtained in the differentiate kidney, heart, brain, digestive system, and gills. Strong immunoreactivities of inhibin/activin βA were located in all examined tissues and ages, indicating that injections of thyroxin (1 or 5μg T4/g BW) into O. niloticus female significantly improved the yield of them in the growing tissues of larvae. Inhibin/activin βA could control the differentiation and growth of various organs in O. niloticus larvae. Consequently, T4, inhibin, and activin A through direct or indirect means aided in the growth of O. niloticus larvae, as evidenced by the notable increases in larvae weight and length that obtained through the entire experiment. In addition, in comparison to the control, the treated females' larvae had a noticeably greater rate of survival. We could conclude that tilapia females' reproduction is enhanced by external T4 in the blood of females, which then transfers through the eggs to larvae. The thyroid hormone that was transferred seems to influence the production of inhibin/activin A, which could provide a unique growth advantage for the progeny of O. niloticus. [ABSTRACT FROM AUTHOR]

Steroid hormones; androgen and estrogen are thought to be the primary drivers of the tilapia sex differentiation (male and female). Cytochrome P450 aromatase is a steroidogenic enzyme, which changes androgens into estrogens and mediates the biosynthesis of estrogens. The current study investigated the aromatase immunoreactivity in the Nile tilapia's (Oreochromis niloticus) gonads larvae under temperature-induced and sex differentiation that occurs naturally. When the tilapia larvae were subjected to 35°C of high temperatures, the majority of them produced significantly more males (84%) than the controls (38%) at 25°C. The immunoreactivity of the enzyme aromatase was higher during normal ovarian differentiation than during testicular differentiation. This was observed in gonads subsequent to the commencement of ovarian differentiation, which involves the increase in both stromal and germ cells. In all temperature-exposed cases, there was a decline in aromatase immunoreactivity. Temperature caused females to become more masculine to varying degrees in their offspring. Additionally, the aromatase immunoreactivity decreased in males at 35°C. This shows that, for the purpose of drive differentiation toward testis development, aromatase repression within the gonad is necessary. Aromatase immunoreactivity was detected in the cytoplasm of germ cells and, to a lesser degree, in adjacent Leydig cells, following the start of differentiation in testis. This observation suggests that the aromatase immunoreactivity could be involved in the paracrine regulation of spermatogenesis. In conclusion, the temperature endocrine control for the tilapia sex differentiation shown in this research should help produce all-male populations of this fish in a way that is environmentally friendly, safe, easy to understand, and acceptable. [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]

Ancient roles of CRF and ACTH in immune-endocrine interactions were obtained early in the development process of fish alimentary canal. The immunolocalization of corticotrophin releasing factor (CRF) and adrenocorticotropic hormone (ACTH) was inspected in the developing gut of Oreochromis niloticus larvae. The aim was to investigate a possible involvement of these molecules early in the integration of immunological and endocrine systems. Immediately after hatching, the gut of O. niloticus is observed as a straight undifferentiated tube, and with the rapid development, it differentiates into four segments: buccopharinx, esophagus, presumptive stomach and intestine. The immunohistochemical investigation showed the immunolocalization of CRF in the growing digestive tract at all stages (from hatching to 42 days post-hatching). Immunoreaction of CRF was detected in the mucosal epithelium of both the undifferentiated gut and the developing esophagus, stomach, and intestine. Furthermore, CRF immunoreactivity was found in the gastric glands of the stomach. The number of CRF-immunoreactive (ir) cells and the strength of immunoreaction gradually increased as the larvae developed, particularly after the exogenous feeding began; 21 days after hatching. Only the goblet cells of the developing intestine exhibited an ACTH immunoreactivity, which increased at 7dph during the yolk sac resorbtion period. A dramatic decrease was recoded in the number and size of ACTH-ir cells associated with the beginning of the exogenous feeding, and at 28 days post hatching, a very weak immunoreaction was produced. The widespread anatomic distribution and early onset of CRF and ACTH activities, in the developing gut, indicate that these molecules play a functional role in food intake, growth, immunological response, and osmoregulation during O. niloticus development, particularly with the start of the exogenous feeding. [ABSTRACT FROM AUTHOR]

The physiological state of mature brood fish is a determining factor for achieving and stimulating a successful spawning process in captivity. In this 2- year investigation, the physiology of mature Liza ramada females was examined throughout the day at various times (24 hours) to ascertain the most suitable time for obtaining mature females raised in both saline water and fresh water in addition to handling them during the spawning season. In addition, blood concentrations of hormones involved in growth, acclimatization, and response to stress, as well as the levels of glucose, total protein, albumin, and the albumin: globulin ratio of L. ramada mature females were all investigated with respect to the factor of time during a period of 24hours. The highest levels of growth hormone, thyroxine, triiodothyronine, prolactin, cortisol, total protein and albumin were recorded at 12 midday and 6 in the morning for mature L. ramada females raised in both saline water and fresh water, respectively. These recorded levels were suitable for attaining a successful spawning and concurrently stimulating the process for L. ramada raised in captivity. Average levels of glucose were recorded for these fish at the aforementioned times. Low levels of the mentioned hormones, total protein, and albumin were observed at 6PM in fish raised in both saline and fresh waters. These hormones play a significant role in growth, acclimatization, stress response during handling, and stimulating spawning of L. ramada. In conclusion, it was proved that the optimal times for obtaining and handling mature L. ramada females during spawning induction are at 12PM for fish raised in saline water and 6AM for fish raised in fresh water. [ABSTRACT FROM AUTHOR]

Introduction: The localization and characterization of the hypophyseal cell types in L. ramada is so far lacking. Aim of the Work: The present study aimed to describe and determine the hypophyseal cells in L. ramada. Material and Methods: Immunohistochemical localization of the hormone-secreting cells in the hypophysis of L. ramada was completed by antisera against both mammalian and piscine hormones. Results: The hypophysis of L. ramada was comprised two main parts, the glandular part (adenohypophysis) and the nervous part (neurohypophysis). The adenohypophysis was divided into three subdivisions; rostral pars distalis (RPD), proximal pars distalis (PPD) and pars intermedia (PI). Seven of hormone-secreting cells were distinguished in the glandular part according to their grouping, distribution, and immunoreactivity. The acidophilic prolactin (PRL) cells occupied the bulk of the RPD and showed positive and specific immunoreaction with salmon PRL antiserum. Lead hematoxylin-positive (PbH+) cells, which were bordered the neurohypophysis in the RPD, gave positive immunoreactivity with human adrenocorticotrophic (ACTH) antiserum. The acidophilic cells of the PPD immunoreacted positively and strongly with antiserum against salmon growth hormone (GH). In addition, the central region of PPD comprised basophilic cells which were showed specific and strong immunoreaction with antisera against salmon gonadotropin (GTH) subunits; Iβ and IIβ. The presumptive thyrotropin (TSH) secreting cells were distinguished in the neurohypophysis between the RPD and the PPD, and they were negative immunoreacted with antiserum against rat thyrotropin (rBetaTSH). Two cell types were found in the PI; the Periodic Acid-Schiff-positive (PAS+) cells which had positive immunoreaction with anti-salmon somatolactin (SL) and the Lead hematoxylin-positive (PbH+) cells which immunostained with anti-alphamelanin-stimulating hormone (α-MSH). Conclusion: The localization of hypophyseal cells of L. ramada, consider as basis for understanding and tracking hormonal changes during its reproductive cycle in captivity. [ABSTRACT FROM AUTHOR]

Hypophyseal homogenate of common carp is considered one of the different hormonal sources for spawning induction in the teleosts. The present work aimed to measure the hormonal concentration of the hypophysis in different carp species, which can be used as a source of hormones for spawning induction in teleosts. The hypophysis of different mature carp species (both males and females); namely, common carp (Cyprinus carpio), grass carp (Ctenopharyngodon idella) and silver carp (Hypophthalmichthys molitrix) were evaluated biochemically to discuss their hormonal source. Five hormones in the pituitary gland, including: adrenocorticotropin hormone (ACTH), prolactin hormone (PRL), growth hormone (GH), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were analyzed using electrochemiluminescence immunoassay (ECLIA). Compared to female carps, the hypophysis homogenate of male carps recorded lower levels of the measured hormones. The biochemical results showed that the hypophysis homogenate of H. molitrix showed higher levels of 426±13, 118±6, 2355±47, and 1005±35 ng/mg for PRL, GH, LH, and FSH, respectively. Whereas, lower level of ACTH (5±0.5 ng/mg) was recorded compared to those obtained in C. carpio and C. idella. However, the concentrations of those hormones recorded the lowest values in male carpfish, while the concentration of ACTH hormone was higher in male common carp, recording 13±1.2 ng/mg. The present biochemical observations revealed the suitability and effectiveness of the cheap silver carp hypophysis as a spawning inducer in fishes. [ABSTRACT FROM AUTHOR]

The present study aimed to compare between gill rakers of some marine fishes with different feeding habits. A total of 78 specimens in 13 species belonged to 6 fish families: Sparidae (Sparus aurata, Diplodus noct, Rhapdosargus haffara and Boops boops); Family: Mugilidae (Mugil cephalus, Mugil capito and Liza aurata); Family: Siganidae (Siganus rivulatus and Siganus luridus); Family: Synodontidae (Saurida undosquamis and Synodus saurus); Family: Clupeidae (Herklotsichthys quadrimaculatus) and Family: Carangidae (Caranx sexfasciatus) were collected by irregular visits from land fish market in different localities of Egyptian Mediterranean Sea and Suez Gulf; during the period from March, 2014 to November, 2014. Results showed that, the first gill arch formed of one piece, consisting of two limbs (upper and lower limbs). The gill arch carried two rows of gill rakers on its concave border and two rows of gill filaments on its convex one. The gill rakers in the anterior row (oral row) are longer, more in number and more developed than that of the posterior row (aboral row). The gill arch in family Sparidae is bow-like shape. The anterior gill rakers on the first gill arch of most sparid species are short, conical in shape adapted to carnivorous feeding. The gill arch of fish species in Mugilidae is mostly crescent-shaped and rarely bow-shaped. The anterior gill rakers on the first gill arch are long and great in number adapted to detritus feeding. The gill arch in family Synodontidae is V shaped. The anterior gill rakers on the first gill arch appeared as clusters of small tooth patches adapted to piscivores feeding. The gill arch in family Siganidae is hook-like shape. The anterior gill rakers on the first gill arch were needle spine in shape with secondary projections adapted to herbivorous feeding. The gill arch in fish species of Clupeidae is V like shape. Gill rakers are well developed and arranged in only one row. They are numerous and elongated adapted to seizing food items in the plankton feeding. The gill arch in fish species of Carangidae is bow-like shape. Gill rakers are moderate in length and number adapted to carnivorous feeding. According to the different feeding habits, the results showed that, the highest average length of the first gill arch (mm) is recorded in carnivore and piscivore fish. The maximum averages number and the length of the anterior gill rakers are recorded in detritivore fish and plankitivore fish. The highest percentages of the anterior gill raker length /gill arch length ratio (%) are recorded in plankitivore fish and detritivore fish. Results showed that, the maximum inter raker space (μm) and the inter raker space/gill arch length (%) is recorded in carnivore fish. The maximum breadth at the raker base (μm) in the anterior row of rakers is recorded in piscivore fish. The highest breadth at the raker base/gill arch length (%) in the anterior row of rakers is recorded in carnivore, piscivore and planktivore fish. The highest posterior gill raker length (μm) and the posterior gill raker length /gill arch length ratio (%) are recorded in detritivore fish. In conclusion: The morphological characters of the gill rakers in the first gill arch were differ in species studied according to different feeding habits. So that, can be used in determine the fish family and feeding habits. [ABSTRACT FROM AUTHOR]