Gonad Somatic Index Research Articles

Differences in Growth Performance and Meat Quality between Male and Female Juvenile Nile Tilapia (Oreochromis niloticus) during Separate Rearing.

This study compared the growth and flesh quality of juvenile male and female Nile tilapia grown in separate RAS tanks. The Genetic Sex Determination method yielded 40 males and 40 females. Males grew longer and heavier than females, and the results showed significant variation between the sexes in terms of weight gain rate (WGR), specific growth rate (SGR), and final body length and weight. In terms of the feed conversion ratio (FCR), Gonad Somatic Index (GSI), and Viscera Somatic Index (VSI), females presented better results than males. Male and female Hepatosomatic Index (HSI) values did not differ significantly-no difference in blood serum values. The meat's moisture and crude protein composition did not alter significantly from male to female; however, the crude fat and ash levels did differ significantly. Male and female animals were given the same seventeen distinct types of amino acids, and there was no distinct variation in the profiles of total amino acids (TAAs) and essential amino acids (EAAs) between the sexes. However, in the non-essential amino acid (NEAA) category, there were marginally significant differences, wherein females performed better than males. Males and females differed considerably in crude fat and ash levels but not in the moisture content or crude protein composition of the meat. Regarding fatty acids, males outperformed females in terms of total fatty acids (TFAs), polyunsaturated fatty acids (PUFAs), and saturated fatty acids (SFAs). However, no significant difference in the amount of monounsaturated fatty acids (MUFAs) in muscle was found between males and females.

Unveiling the mechanisms of reproductive toxicity induced by full life-cycle exposure to environmentally relevant concentrations of tris(2-chloroethyl) phosphate in male zebrafish

Tris (2-chloroethyl) phosphate (TCEP), a commonly used organophosphate flame retardant, has garnered considerable concern owing to its pervasive presence in the environment and its toxic effects on living organisms. The perpetuation of populations and species hinges on successful reproduction, yet research into the mechanisms underlying reproductive toxicity remains scant, particularly in aquatic species. In this work, zebrafish embryos were exposed to TCEP (0, 0.8, 4, 20, and 100 µg/L) for 120 days until sexual maturation, and multiple reproductive endpoints were investigated in male zebrafish. Our results showed that the body weight, body length, and gonadal-somatic index (GSI) were remarkably decreased in all TCEP treatment groups (except GSI in the 0.8 µg/L TCEP-treated group). Long-term exposure to TCEP led to reduced reproductive capacity of male zebrafish, as evidenced by decreased fertilization. Histological observation gave an indication of delayed testicular development and inhibited spermatogenesis under TCEP stress. The content of testosterone (T) was significantly elevated in all TCEP treatment group, whereas 17 β-estradiol (E2) levels remained stable. Transcriptome analysis revealed a lot of downregulated genes involved in steroid hormone biosynthesis, energy metabolism, and sperm motility, which might account for the imbalance of steroid hormone levels, retarded spermatogenesis and declined fertilization success. Overall, these findings offered a thorough understanding of the mechanisms underlying the male reproductive toxicity caused by TCEP, highlight the risk of TCEP on reproductive health of fish.

Sex-Linked Changes in Biotransformation of Phenol in Brook Trout (Salvelinus fontinalis) over an Annual Reproductive Cycle

The microsomal metabolism of phenol (11 °C) over an annual reproductive cycle from June to December was studied using fall spawning adult brook trout (Salvelinus fontinalis). Hepatic microsomes were isolated from three male and three female fish each month. Incubations were optimized for time, cofactor concentration, pH, and microsomal protein concentration. The formation of phase I ring-hydroxylation metabolites, i.e., hydroquinone (HQ) and catechol (CAT), was quantified by HPLC with dual-channel electrochemical detection. Sample preparation and chromatographic conditions were optimized to achieve the separation and sensitivity required for the analysis of these labile products. Biotransformation of phenol over a range of substrate concentrations (1 to 150 mM) was quantified for the calculation of Michaelis–Menten constants (Km and Vmax) for each month. Results indicate a nearly equal production of HQ and CAT among males and females in late June. At the peak of maturity in October, there was an approximate ten-fold greater production of ring-hydroxylation metabolites noted in females in comparison with males on a total liver basis. In vitro phase II biotransformation of phenol glucuronidation was assessed by determining the Michaelis–Menten constants (Km, Vmax) using brook trout hepatic microsomes over a range of substrate concentrations (1 to 60 mM). Initially, there were no significant differences in the glucuronide rate of formation (pmol/min/mg protein) or total capacity (nmol/min/liver) between females and males. At the peak of maturation, the maximum rate of glucuronide formation was 4-fold less in females; however, the total capacity was 2-fold less in females due to the increased liver size in the females. The alterations in biotransformation coincided with increases in the hepatic and gonadal somatic indices and with changes in plasma hormone concentrations. These experiments provide insight into the metabolic deactivation of xenobiotics and to provide data for the prediction of altered hepatic biotransformation rates and pathways during the reproductive cycle.

Elucidating the reproductive toxicity mechanisms in female zebrafish: A transcriptomic study of lifetime tris(2-chloroethyl) phosphate exposure

Tris(2-chloroethyl) phosphate (TCEP), emerging as a predominant substitute for brominated flame retardants (BFRs), is now increasingly recognized as a prevalent contaminant in aquatic ecosystems. The extent of its reproductive toxicity in aquatic species, particularly in zebrafish (Danio rerio), remains insufficiently characterized. This study subjected zebrafish embryos to various concentrations of TCEP (0, 0.8, 4, 20, and 100 μg/L) over a period of 120 days, extending through sexual maturation, to assess its impact on female reproductive health. Notable reductions in body weight (0.59- and 0.76-fold) and length (0.71- and 0.77-fold) were observed at concentrations of 20 and 100 μg/L, with a concomitant decrease by 0.21- to 0.61-fold in the gonadal somatic index across all treatment groups. The reproductive output, as evidenced by egg production and hatchability, was adversely affected. Histopathological analysis suggested that TCEP exposure impedes ovarian development. Endocrine alterations were also evident, with testosterone and 11-ketotestosterone levels significantly diminished by 0.38- and 0.08-fold at the highest concentration tested, while 17β-estradiol was elevated by 0.09- to 0.14-fold in all exposed groups. Transcriptomic profiling illuminated numerous differentially expressed genes (DEGs) integral to reproductive processes, including hormone regulation, neuroactive ligand-receptor interactions, oocyte meiosis, and progesterone-mediated maturation pathways. Collectively, these findings indicate that lifelong exposure to TCEP disrupts ovarian development and maturation in female zebrafish, alters gene expression within the hypothalamic-pituitary-gonadal axis, and perturbs sex hormone synthesis, culminating in pronounced reproductive toxicity.

The reproductive pattern of the white barrel jellyfish Rhizostoma pulmo (Cnidaria, Scyphozoa) in the gulf of Taranto (Ionian Sea)

Understanding the mechanisms that lead to the proliferation of large jellyfish populations over time is crucial to prevent andmitigate any possible negative impacts on human activities and ecosystem functioning. Rhizostoma pulmo (Macri, 1778) is an outbreak forming species of the Mediterranean Sea that has been observed in anthropized areas including the Gulf of Taranto. To describe seasonal changes in the reproductive patterns of R. pulmo from May to December 2016, we measured jellyfish diameter, the number and diameter of oocytes using histological and biochemical analyses (lipids, carbohydrates, proteins, and organic matter), as well as the gonadal somatic index (GSI). Jellyfish size did not fluctuate considerably during the collection period, with specimens measuring between 19.5 and 38.2 cm in diameter. Our findings revealed a strong gonadal activity over the summer and a spawning event between September and October. Male and female gonad morphology was similar to other previously reported Rhizostomeae. Oocytes were categorized into three developmental classes, recognizable by their diameter and shape: <15 μm for pre-vitellogenesis, 15-30 μm for vitellogenesis, and >30 μm mature oocytes. The number of mature oocytes peaked in August, with smaller eggs recorded in May and October and larger eggs recorded near the end of the summer. The GSI fluctuated greatly between sampling dates, peaking in August. Lipid levels varied significantly throughout the sampling period, with the greatest value in May (277.26±98 μg lipid mg AFDW-1) and the lowest in September (70.36±41.5 μg lipid mg AFDW-1). Carbohydrates, proteins, and organic matter (62 ± 6 %) remained stable during the sampling period. The biochemical analyses of jellyfish sexual reproduction we report on here can be used as a tool for identifying jellyfish spawning periods and better understanding the reproductive process that control jellyfish population dynamics.

Effects of thyroxin and luteinizing hormone releasing hormone on reproductive physiology of Rohu (Labeo rohita): Insights into spawning performance, oocyte maturation, steroidogenesis, and follicular development genes

As the global aquaculture industry grows, attention is increasingly turning towards assisted reproductive technologies. In this study, we examined the impact of D-Ala6, Pro9-Net-mGnRH (LHRHa: 0.4 mL/kg) and two doses (1 and 10 μg/kg fish) of thyroxin (T4) administered through a single injection on oocyte maturation, spawning performance, sex steroid hormone levels, as well as the expression of genes related to steroidogenesis and follicle development (ZP2, Cyp19a1a and SF-1) in Rohu (Labeo rohita). The study found that untreated female Rohu did not spawn, while those treated with LHRHa and thyroxin ovulated and spawned across a hormonal gradient. The highest spawning success was observed with a thyroxin dosage of 10 µg/kg (no significant change with a dose of 1 μg/kg), and female latency period decreased with increasing dosage. Additionally, females treated with thyroxin exhibited significantly higher fecundity than other experimental groups. Treatment with LHRHa and two doses of thyroxin significantly increased the gonadal somatic index compared to the control and sham groups. Hormonal treatment also led to increased fertilization success, hatching rate, and larval survival. At 12 h post-injection, females treated with thyroxin exhibited a significant decline in estradiol levels and expression of Zp2, Cyp19a1a, and SF-1 compared to other experimental groups. Levels of DHP significantly increased across the hormonal gradient. Histological analyses supported a steroidogenic shift, where oocyte maturation was accelerated by hormone administration, particularly with both doses of thyroxin. In conclusion, the findings suggest that thyroxin is a recommended treatment for assisted reproduction of Rohu due to its ability to induce spawning, increase fecundity and improve larval survival.

Environmentally relevant estrogens impaired spermatogenesis and sexual behaviors in male and female zebrafish

Environmental estrogens (EEs) are found extensively in natural waters and negatively affect fish reproduction. Research on the reproductive toxicity of EEs mixtures in fish at environmentally relevant concentrations is scarce. In this study, adult male zebrafish were exposed for 60 days to EES (a mixture of EEs), EE2-low (5.55 ng/L, with an estrogenic potency equal to EES), and EE2-high (11.1 ng/L). After exposure, the expression levels of vtg1, vtg3, and esr1 in the livers in EES-treated fish remained unaltered, whereas they were significantly increased in EE2-treated fish. Both EE2-high and EES exposures notably reduced the gonad somatic index and sperm count. A disrupted spermatogenesis was also observed in the testes of EE2-high- and EES-exposed fish, along with an alteration in the expression of genes associated with spermatogonial proliferation (pcna, nanog), cell cycle transition (cyclinb1, cyclind1), and meiosis (aldh1a2, cyp26a1, sycp3). Both EE2 and EES significantly lowered plasma 11-ketotestosterone levels in males, likely by inhibiting the expression level of genes for its synthesis (scc, cyp17a1 and cyp11b2), and increased 17β-estradiol (E2) levels, possibly through upregulating the expression of cyp19a1a. A significant increase in tnfrsf1a expression and the tnfrsf1a/tnfrsf1b ratio in EE2-high and EES-treated males also suggests increased apoptosis via the extrinsic pathway. Further investigation showed that both EE2-high and EES diminished the sexual behavior of male fish, accompanied with reduced E2 levels in the brain and the expression of genes in the kisspeptin/gonadotropin-releasing hormone system. Interestingly, the sexual behavior of unexposed females paired with treated males was also reduced, indicating a synergistic effect. This study suggests that EES have a more severe impact on reproduction than EE2-low, and EEs could interfere not only with spermatogenesis in fish, but also with the sexual behaviors of both exposed males and their female partners, thereby leading to a more significant disruption in fish reproduction.

Endocrine and Transcriptome Changes Associated with Testicular Growth and Differentiation in Atlantic Salmon (Salmo salar L.).

Sexual maturation of Atlantic salmon males is marked by dramatic endocrine changes and rapid growth of the testes, resulting in an increase in the gonad somatic index (GSI). We examined the association of gonadal growth with serum sex steroids, as well as pituitary and testicular gene expression levels, which were assessed with a DNA oligonucleotide microarray. The testes transcriptome was stable in males with a GSI < 0.08% despite the large difference between the smallest and the largest gonads. Fish with a GSI ≥ 0.23% had 7-17 times higher serum levels of five male steroids and a 2-fold increase in progesterone, without a change in cortisol and related steroids. The pituitary transcriptome showed an upregulation of the hormone-coding genes that control reproduction and behavior, and structural rearrangement was indicated by the genes involved in synaptic transmission and the differentiation of neurons. The observed changes in the abundance of testicular transcripts were caused by the regulation of transcription and/or disproportional growth, with a greater increase in the germinative compartment. As these factors could not be separated, the transcriptome results are presented as higher or lower specific activities (HSA and LSA). LSA was observed in 4268 genes, including many genes involved in various immune responses and developmental processes. LSA also included genes with roles in female reproduction, germinal cell maintenance and gonad development, responses to endocrine and neural regulation, and the biosynthesis of sex steroids. Two functional groups prevailed among HSA: structure and activity of the cilia (95 genes) and meiosis (34 genes). The puberty of A. salmon testis is marked by the predominance of spermatogenesis, which displaces other processes; masculinization; and the weakening of external regulation. Results confirmed the known roles of many genes involved in reproduction and pointed to uncharacterized genes that deserve attention as possible regulators of sexual maturation.

The reproduction performance of catching Planiliza subviridis (Teleostei: Mugilidae) in different moon periods from Jepara Coast, Central Java, Indonesia

Abstract. Yudiati E, Yuniarti T, Trianto A, Arifin Z, Ruliaty L, Soleh M, Naryaningsih A, Suryati. 2024. The reproduction performance of catching Planiliza subviridis (Teleostei: Mugilidae) in different moon periods from Jepara Coast, Central Java, Indonesia. Biodiversitas 25: 1823-1830. Mullets (Planiliza subviridis Valenciennes 1836) are highly promising species for aquaculture development. Information on the reproductive performance of wild-caught fish is crucial for enhancing mullet production. This study aimed to assess the gonadal maturity level of female mullets captured during full and new moon phases. Sampling using lift nets was conducted from June to July 2023, comprising 104 individuals, 51 during the new moon and 53 during a full moon. Fish caught during different moon phases were measured for gonad maturation level (GML) and morphometric parameters (body weight, total length, head length, body width, and head width), assessed for gonad somatic index (GSI), fecundity, and egg diameter. Over 50% of individuals were at GML III during dark moon phases, while during bright moon phases, only 10-15% were at GML III; GSI ranged from 0.6-15%. The fecundity of GML I and II females was higher during the full moon (220,212-395,000 eggs per individual) compared to the new moon, while GML III females during dark moon phases ranged from 225,000-250,000 eggs. Mullets exhibit increased reproductive output during the new moon phase and engage in synchronous spawning during moonlight cycles. Therefore, prospects for mullet culture appear promising, with cultivation and domestication suggested during new moon periods.

Revealing the reproductive biology and growth dynamics of Arius maculatus (Thunberg, 1792) in the Mekong Delta estuary, Vietnam

Referring to the Mekong River, it is the largest river in Southeast Asia's Indo-Burma biodiversity hotspot, and it sustains a diverse range of fish species. In order to manage the river's fisheries in a sustainable way, it is important to have a comprehensive understanding of population dynamics. This study focuses on the spotted catfish, Arius maculatus (Thunberg, 1792), which is commercially valuable and found in the estuarine areas of the Mekong Delta, Vietnam. Monthly samplings were conducted at Tran De and Dinh An estuaries from July 2017 to May 2019, revealing distinct patterns in the gonad-somatic index (GSI) and hepato-somatic index (HSI). The spotted catfish were found to breed throughout the year, with peak breeding periods in March and August. The length at first maturity (Lm) was determined to be 12.80 cm for males and 11.79 cm for females. The fecundity, although relatively low, was measured at 16 ± 3 yolks per female and 144 ± 60 hyalines. The Von Bertalanffy growth parameters were calculated as L∞ (the asymptotic length) = 20.6 cm, K (growth coefficient) = 0.5 year−1, and t0 (theoretical age at zero length) = − 0.603 year−1. The length at first capture (Lc) was found to be 8.93 cm. Evaluation of the mortality rates revealed that the spotted catfish population is being overexploited, as indicated by an exploitation rate (E) of 0.695, which exceeds the optimum level of 0.50. It is crucial to implement effective management strategies to ensure the sustainable fisheries of Arius maculatus in the Mekong Delta estuary in Vietnam.

Gonadal Maturation and Spawning of Barred Loach (Nemacheilus fasciatus) Induced by Topical Gill Hormone Application

Barred loach Nemacheilus fasciatus are unable to reproduce naturally in captivity due to the lack of environmental cues and gonadal maturation occurs slower than in the wild. To optimize breeding procedures for this fish species, we determined whether hormone application via the gills was an effective process and assessed hormone dosage treatments. Oodev™ was used to induce gonadal maturation and Ovaprim™ was used to induce spawning via a topical gill approach. Multiple maturation parameters such as gonadal-somatic index (GSI) and hepatosomatic index (HSI), fecundity, and egg diameter; and spawning parameters such as latency period, egg produce, fertilization rate (FR), hatching rate (HR), survival rate (SR) were recorded and compared between the hormone dosage treatments and control treatment. Both the Oodev™ gonadal maturation induction and Ovaprim™ spawning induction were effectively applied to barred loach via topical gill application. Gonadal maturation parameters were positively correlated with dosage and all were significantly different. Fry survival rate was not different between doses. The optimal dose of Oodev™ (0.75 µL/g fish) resulted in male GSI of 5.334 ± 0.320%, female GSI of 15.501 ± 0.675%, male HSI of 0.416 ± 0.023%, female HSI of 1.670 ± 0.104%, egg fecundity 4584.20 ± 493.216 eggs, egg diameter 0.964 ± 0.0151 mm. Ovaprim™ optimal dosage (3.00 µL/g female and 1.50 µL/g male) was resulted latency period 11.05 ± 0.52 hours, egg produced 3504.83 ± 358.57, FR 96.77 ± 0.88%, HR 83.62 ± 3.78%, and SR 91.44 ± 2.53%.

Bitter Melon (Momordica charantia L) Fruit Extract Affects The Gonad Development and Ovulation of Female Tilapia (Oreochromis niloticus); Study of Gonadal Morphology and Histopathology

One of the problems in the cultivation of tilapia (Oreochromis niloticus) is the ability to reproduce early and quickly mature gonads so that the fish kept are difficult to reach the size of market demand. This study aims to determine the effect of various doses of bitter melon fruit extract on the development of female gonads and to study the histopathological changes in the structure of the gonad. This research was carried out in July-September 2021. There were 600 juveniles of tilapia used in this study. Tilapia rearing was carried out in 12 containers (each 200 L volume of water) for 60 days. The experimental design was carried out with 4 treatments of bitter melon extract (BME) consisting of 0 g, 0.1 g, 0.2 g, and 0.3 g for 1 kg of feed and 3 replicates. Parameters observed were gonad morphology, gonad somatic index, and histopathology of the gonad. The gonadal maturity index for all treatment has not significant (P&gt;0.05) but the morphology of the gonad showed differences in size and color. Based on histopathology analysis shows structural changes in the form of oocyte cells undergoing necrosis and increased oocyte atresia in BME treatment.

Age, growth, reproduction and mortality of Xenocypris argentea (Günther,1868) in the lower reaches of the Tangwang River, China.

To investigate various population biological parameters of Xenocypris argentea in the lower reaches of the Tangwang River (China), a comprehensive study was conducted for the first time. A total of 1,003 samples were collected from April to November 2022. The collected samples revealed that female X. argentea had total lengths ranging from 12.4 cm to 25.7 cm (weighing 15.86 g to 159.55 g), and male X. argentea had total lengths ranging from 10.8 cm to 23.9 cm (weighing 9.27 g to 121.06 g). The age of the samples was determined using otolith analysis, indicating that the ages ranged from 1 to 5 years old in both females and males. The length-weight relationships were further analyzed, uncovering the allometric growth index (b) was 3.1296 for females, indicating a positive allometric growth pattern. Differently, males exhibited a b value of 3.0274, suggesting an isometric growth pattern. Furthermore, the von Bertalanffy growth formula provided insights into the growth characteristics of X. argentea, revealing an asymptotic total length (L∞) of 36.096 cm and a growth coefficient (K) of 0.121. The analysis of the gonadal somatic index (GSI) and ovarian development period indicated that the spawning period occurred from April to July, with peak spawning in June. The study also explored fecundity-related traits, finding that individual absolute fecundity (FA) ranged from 11,364 eggs to 56,377 eggs, while eviscerated body weight relative fecundity (FW) ranged from 209 eggs/g to 823 eggs/g. The exploitation rate (E) for X. argentea was calculated as 0.574, suggesting that the population of X. argentea has been overexploited. By revealing previously unknown data on the key life history traits of X. argentea, this study has provided valuable insights that are crucial for the development of conservation strategies and policies.

A biological perspective for the fishery management of a small urban lake in Indonesia: a case study on the reproductive stage of the red devil (Amphilopus citrinellus) in Situ Cilodong, West Java, Indonesia

The presence and establishment of invasive alien fish species is one of the biggest threats to aquatic biodiversity. The red devil, Amphilopus citrinellus, is one of the emerging invasive species and its occurrence is massively detected in common water bodies in tropical areas such as Indonesia. However, the topic remains under-reported from the small urban lakes. This study aims to present the reproductive characteristics of the fish in Situ Cilodong, a small urban lake in the country, that can be used as a principal reference for population control. The sampling was conducted in June 2021 and May 2022 using a mix of seven mesh-sized gillnets. The results of the length-weight relationship reveal that both the female and male fish perform isometric growth type. The calculated Gonad Somatic Index (GSI) and the histological analysis confirmed that the fish is a multi-spawner species. The results imply that sustainable population control efforts must include intensive catch and engage a participatory approach between the legal authority and the local fishers.

Feeding Lycium barbarum polysaccharides (LBP) alleviates apoptotic, inflammatory hepatopancreas atrophy and injury in Chinese mitten crab (Eriocheir sinensis) poisoned by T-2 toxin

Chinese herbs and their purified components in aquafeeds have been proved effective to combat stress in aquatic animals to combat toxic environmental stress. Lycium barbarum poly-saccharides (LBP) is an active antioxidant, anti-inflammatory and antitoxic purified herbal agent. The objective of this paper was to evaluate the effect of 0.1–2.0% LBP on the hepatopancreas of Chinese mitten crab (Eriocheir sinensis) challenged with 2 mg/kg T-2 toxin orally for 5 weeks. The results showed that feeding LBP significantly restored the hepatopancreas index (HI), gonadsomatic index (GSI) reduced by T-2 toxin. Moreover, H&E sections indicated that LBP dose-dependently restored the disrupted microstructure of the hepatopancreas. In antioxidative capacity, significant increases in malondialdehyde (MDA) reduction and elevated glutathione (GSH) content, gluta-thione reductase (GPx) activity were seen in the 0.5% LBP group. In addition, reactive oxygen species (ROS) and apoptosis rate of hepatopancreas showed the anti-apoptotic effect of LBP doses, plus qPCR assay of 10 apoptosis-related genes to support them. The mRNA abundance of three pro-inflammatory genes was significantly reduced by LBP, corroborating its anti-inflammatory efficacy. In brief, feed supplementation with LBP alleviated the oxidative stress-apoptosis-inflammation induced by co-feeding T-2 toxin in E. sinensis, maintained the structural and functional integrity of the hepatopancreas, prevented degenerative atrophy.

Effect of Foeniculum vulgare Mingled Diet upon Growth, Reproduction and Spawning Performance of Guppy Fish

Naturally breeding fish cannot meet the demand of humans. So induced breeding is essential to fulfill this demand. Induced breeding ensures a timely supply of fish seeds having desired characteristics and different techniques can be used for this purpose. In this perspective synthetic hormones, extracts of pituitary hormones, Gonadotropin-releasing hormones, and sometimes Human chronic gonadotropin are used as a spawning inducer for fishes. Plant extracts can also be used as it is a new technique which could be used in aquaculture. The basic aim of our study was to enhance the growth as well as to check the effect of the traditional herb Foeniculum vulgare on the reproductive performance of Poecilia reticulata.&#x0D; Methodology: Samples were collected from a local fish shop in Sargodha. Ethanolic extract of Foeniculum vulgare seeds was prepared and mixed with different commercial feed. This feed was given to fish for 90 days to test the effect of Foeniculum vulgare seed extract on growth and reproduction performance. Water quality parameters were also maintained and recorded daily. Fecundity and Gonad somatic index were measured after dissection by removing the ovaries. Fecundity was calculated by counting the number of larvae and eggs seen with the naked eye. The hatching rate was measured by counting the number of hatching in each spawning.&#x0D; Results: According to the growth results, different levels of fennel seed extract has a significant effect on weight gain, length gain and survival rates of the fish in different groups. Statistical analysis cleared that T2 showed the highest weight and length gain. The feed Conversion Ratio decreased significantly. Results of reproduction parameters showed that the highest absolute fecundity (9.4 ± 0.19), GSI (8.69 ± 0.2) and spawning have increased in T2 followed by T1, T3, and control respectively. The observation of present research shows that Foeniculum vulgare seed extract can act as an estrogenic compound and growth promoter in commercial aquaculture.

Reproductive aspects of European hake, (Merluccius merluccius, Linnaeus, 1758) based on histological depiction of both sexes in the Eastern Mediterranean (Aegean Sea)

Despite European hake’s (Merluccius merluccius) economic and ecological significance, there are still significant gaps in our knowledge. The present study updates some aspects of European hake’s reproductive biology and for the first time microscopically showcases all reproductive stages for both sexes from the Aegean Sea (Eastern Mediterranean), which were sampled using commercial bottom trawls between May 2021 and October of 2022. The reproductive cycle of 861 individuals (413 males and 448 females) was assessed, with gonad-somatic index (GSI) exhibiting a seasonal cycle peaking in late spring (May) and attaining lowest values in late summer (August). A highly significant seasonal and sex effect and their interaction on the GSI was further exhibited. The oocyte diameter frequency distribution of the different maturity stages exhibited significant size differences between the juvenile virgin stages (I and II) and adult immature and maturing stages (III, IV and V), due to the presence of cortical alveolar oocytes. Male to female ratio for the entire population was not significantly in favor of females (0.92:1), however sex ratio exhibited a significant male prevalence in smaller sizes (less than 30 cm in total length) and a female prevalence in larger sizes. Females reached the onset of sexual maturity (L50) at higher sizes (38.93 cm) compared to males (29.44 cm) with onset of sexual maturity for both sexes reached at significantly higher length compared to other published Mediterranean studies.

Morphology, Histology, and Transcriptome Analysis of Gonadal Development in Octopus minor (Sasaki, 1920).

Octopus minor is an economically important species, but little is known about the histological pattern and regulatory mechanisms during gonadal development. In this study, we investigated the annual changes in total body weight (TW), gonad somatic index (GSI), gonadal histological features, and transcriptome of O. minor. The results indicated that both females and males showed a similar TW trend. The GSI peaked in June in females, while it remained constant at around 3% in males. Nine and four histological stages were observed in ovaries and testes, respectively. Our field sampling results implied that O. minor might have overwintering periods for both eggs and larvae. Transcriptome analysis revealed that a total of 1095 and 2468 genes were significantly expressed during ovarian and testicular development, separately. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis displayed that 126 GO terms and 5 KEGG pathways were significantly enriched in the ovarian group of advanced vitellogenic oocytes vs vitellogenic oocytes (AVO vs VO). The pathways "Ribosomal", "Cell cycle", and "Progesterone-mediated oocyte maturation" were predicted to promote yolk deposition. Additionally, the testicular comparison group of spent vs mature (Spent vs Mature) showed significant enrichment in 674 GO terms and 13 KEGG pathways, suggesting that energy metabolism and cell repair pathways may be involved in the spermatogenesis process. This work revealed the development process of the gonads and shed light on the potential regulatory pathways of O. minor, providing novel insights and laying a molecular basis for artificial breeding.

Waterborne exposure to microcystin-leucine arginine induces endocrine disruption and gonadal dysplasia of Pelophylax nigromaculatus tadpoles via the hypothalamic-pituitary-gonadal-liver axis

The impact of microcystins on the gonad development and reproduction endocrine in the tadpole stage on amphibians remains unclear. In this study, the tadpoles (Pelophylax nigromaculatus) were exposed to 0, 1, and 10 μg/L of microcystin-leucine arginine (MC-LR) for 60 days to explore the impacts of environmental realistic concentration MC-LR on gonad development and reproduction endocrine, respectively. After MC-LR exposure, the germ cell structure has changed, especially in oocytes. The 10 μg/L MC-LR exposure group showed a significantly diminished gonad somatic index (GSI) in females. However, the sex ratio of tadpoles did not differ significantly. Moreover, gene transcription (figla and nobox) related to ovarian development and genes (sox9 and dmrt1) associated with testicular development were down-regulated after MC-LR exposure. After MC-LR exposure, the gene transcripts encoding gonadotropin-releasing hormone (gnrh1 and gnrh2) were down-regulated in the hypothalamus, while gonadotropins (FSH and LH) levels increased in serum. The transcripts of testosterone synthesis-related genes (star, cyp11a1, 3β-hsd, cyp17a1, and 17β-hsd) were up-regulated in the gonads, and the testosterone (T) concentration increased in serum. However, key gene transcript (cyp19a1) involved in estradiol synthesis was down-regulated and the estradiol (E2) concentration decreased in serum, resulting in the absence of a compensatory mechanism for positive feedback regulation of the hypothalamic-pituitary-gonadal (HPG) axis to maintain E2 levels. The vitellogenin gene (vtg1) transcription level was significantly down-regulated. The E2/T content ratio decreased in MC-LR concentration-dependent manner. Consequently, MC-LR exposure interfered with the hypothalamic-pituitary-gonadal-liver (HPGL) axis in tadpoles, which in turn affects gonadal development, especially the ovaries. Overall, this study provides the initial evidence that MC-LR exerts significant effects on reproductive endocrinology and gonadal development in amphibian tadpoles, highlighting the susceptibility of the tadpole reproductive system to the environmental risks of MC-LR.

Determining the Effect of Different Ecological Conditions on the Maturation of Rabbitfish (Siganus guttatus)

A study aimed at the rabbitfish Siganus guttatus (Bloch, 1787), the reproductive ability of one economically important marine and brackish fish in Giang lagoon systems and marine Asia. The future expectations of mariculture development were decided in Vietnam. The region had enough fingerlings for intensive culture and polyculture to contribute to environmental conservation and sustainability. There were 3 experiments in 3 different ecosystems for fish culture and maturity by feeding a commercial feed and finding suitable areas for the maturing period. The results showed that the growing fish kept in cages on the lagoon had the best growth and rate maturity, much higher than fish in cages of shrimp ponds and plastic bottom ponds, as showed a much bigger size of body, 610 g/head for females and 542 g/head for males, while other culture more 500/head, especially after 3 months of feeding, more than 20% matured for females, they reached more 50% at 6 months feeding. The length at first sexual maturity was 28.87 to 31.20 cm and 27.47 to 29.20 cm for females and males, respectively. The potential ova diameter is from 405 to 483 µm, P &lt; 0.05; the benefit for spawning, gonads maturity stages, with GSI (gonadal-somatic index), 3.03 to 4.53 were opportunities for the spawning season, ova diameter and fecundity and the gonadal-somatic index were differed significantly (P &lt; 0.05) males and females. This result showed the maximum (peak), and all fish can mature and get to spawning. In conclusion, different ecosystems impacted maturity and spawning during the moon season.