Gonadal Maturation Research Articles

PENGARUH PEMAPARAN LASERPUNKTUR PADA TINGKAT (KEBUNTINGAN) KETEBALAN PERUT DAN FERTILISASI IKAN TAWES (PUNTIUS JAVANICUS)

Tawes fish (Puntius javanicus) is a freshwater fish that is easy to cultivate but tawes fish can spawn naturally only during the rainy season. Meanwhile, the market demand for tawes is increasing and the availability of seeds is not enough to meet market demand. To overcome this problem, it is necessary to apply technological advances in the form of a biostimulator for the development of Tawes fish farming business. The biostimulator used is a laser. Several studies state that the application of the use of soft lasers can be used to accelerate gonadal maturation. The purpose of this study was to determine the level of fertility and fertilization of tawes fish (Puntius javanicus), as well as to determine the level of abdominal thickness after laserpuncture exposure to prospective female parents. The method used in this study was an experimental method with a completely randomized design. This study consisted of 5 treatments with 1 control with each treatment being repeated 3 times, laserpuncture exposure treatment in 2/6 parts of the body once a week for 1 month. Treatment duration of exposure to laserpuncture for 2 seconds, 4 seconds, 6 seconds, 8 seconds and control. The results showed that exposure to different laserpuncture beams gave highly significant different results on the fertility of tawes fish. The best treatment was exposure to laserpuncture for 6 seconds with a fertilization value of 95.20%. The water quality during the study was within normal limits for tawes life which included a temperature of 27.80C, dissolved oxygen (DO) of 7.58 mg/l and a pH of 7.65.

The cloning and expression of the two types of kisspeptin gene in hard-lipped barb (Osteochilus vittatus)

Abstract. Prayogo NA, Rahayu SC, Sugito PPA, Meyanadewi SB, Sukardi P, Rositas RE, Bessho Y. 2023. The cloning and expression of the two types of kisspeptin gene in hard-lipped barb (Osteochilus vittatus). Biodiversitas 24: 2797-2804. Hard-lipped barb (Osteochillus vittatus Valenciennes, 1842) is a native Indonesian species with many benefits for economic, aquaculture, and environmental sustainability. Several studies showed that the species had high reproductive potential, with kisspeptin gene playing a role in reproductive hormone production and GnRH secretion. Kisspetin gene is also important for gonad maturation in fish. Therefore, this study aimed to determine the structure of Kiss-1 and Kiss-2 genes, as well as the expression of the kisspeptin gene in the hypothalamus and gonads in each phase of female hard-lipped barb development.The study procedure involved several stages, including organ preparation, isolation, sequence identification, and measurement of cGnRH gene expression. The structure of Kiss-1 gene in hard-lipped barb was obtained, and the nucleotide sequence had a product length of 213, coding for 89 amino acids. Meanwhile, Kiss-2 consisted of 230 nucleotides, coding for 76 amino acids, and the sequences observed had 70-80% with other fish species. The results showed that the expression values of Kiss-1 and Kiss-2 genes in the hypothalamus were higher compared to the gonads, with the lowest in the adult phase and the highest in the Juvenile phase. This information will lead us to use the kisspeptin gene to increase hard-lipped barb reproduction.

Management of Broodstock Rearing of Vanname Shrimp (Litopenaeus vannamei) at PT Esaputlii Prakarsa Utama, Barru Regency, South Sulawesi

The purpose of writing this final project is to find out how to manage the maintenance of vannamei shrimp (Litopenaeus vannamei) properly. The types of data used in collecting the required data include primary and secondary data.The data analysis method used to determine the management of vannamei shrimp broodstock (Litopenaeus vannamei) is qualitative descriptive data analysis. Held from January to April 2022 at PT Esaputlii Prakarsa Utama (benur kita) Barru Regency, South Sulawesi. The result of this Final Project is the acceptance of broodstock consists of preparation of brood acclimatization maintenance room and preparation of acclimatization basin, brood selection, acclimatization, brood maintenance consists of tub preparation, brood maintenance basin water filling and ablation management, circulation in the brood rearing basin of vannamei shrimp (Litopenaeus vannamei), gonad maturity level, sampling of mated brood, feed management, egg management including egg hatching, The harvest of naupli is up to the counting of naupli

Erratum: Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs.

Erratum: Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs.

Seasonal Variation in the Reproduction of Anodonta woodiana in The Lahumbuti River, Konawe Regency, Southeast Sulawesi

Mussel mussels are invasive shellfish whose reproductive potential in the Lahumbuti River is unknown. This study aims to determine the seasonal variations in the reproduction of mussel shells in the Lahumbuti River, Southeast Sulawesi. This research was carried out in the Lahumbuti River Konawe, Southeast Sulawesi in 2 periods, namely: May-October 2021 and February-June 2022. The mussels were collected manually using a hand scoop. Furthermore, the shells are washed from dirt/soil attached to the shell. The length and weight of the mussels (total weight and meat weight) were measured using a caliper and a digital scale with an accuracy of 0.5 mm and 0.01 g, respectively. TKG was observed microscopically by using a gonad microscope. Fecundity was calculated by the number of type D spats in the mussel gill sieves. The results showed that male and female mussels were in developmental phases (TKG I, II and III), gonadal maturity (TKG IV) and spawning (TKG V) were found throughout the season. The actual IKG values ​​did not differ based on the time of observation, although there was a tendency for the IKG values ​​to be found to be higher in February-April. Fecundity of mussel mussels ranged from 16317-58429. The size at first maturity of male and female mussel mussels occurred at 3.9 cm and 4.7 cm, respectively.

Kuluçkahane Kökenli F5 ve F6 Nesil Karadeniz Somonu Anaçlarının (Salmo labrax PALLAS, 1811) Üreme Performansları

In this study, reproductive performances of F5 and F6 generation hatchery-originated female Black Sea salmon (Salmo labrax) were evaluated to determine the effects of the ongoing selective breeding program. The study was conducted in freshwater pools and marine cage systems between 2018 and 2021. For the study, 53 specimens from F5 generation females with an average length of 52.71±7.08 cm and weight of 1561.29±639.76 gr, and also 56 broodstıcks specimens from F6 generation females with an average length of 51.92±5.35 cm and weight of 1506.12±417.28 gr were used. Gonad maturity controls and spawning studies were carried out in the 2018-2019, 2019-2020 and 2020-2021 breeding periods along the entire season, lasting from November to January. The number of ovulating females, their fecundity, egg diameters and fertilisation rates of eggs were recorded. In all seasons, 36.17% of F5 females ovulated in November, and the remaining females (63.83%) ovulated in December. Ovulation time in F6 females also showed a similar pattern of 1/3 of females (37.40%) ovulating in November and the remaining majority (62.60%) ovulating in December. According to the results, total egg yields as 4439.31±1675.69 and 4112.08±1041.16 egg/broodstock, relative egg yields as 2313.44±278.48 and 2345.76±516.30 egg/kg, egg diameters as 5.08±0.19 and 5.21±0.17 mm, and fertilisation rates as 96.78±3.24% and 96.63±3.73% were determined for F5 and F6 generations, respectively. In both generations, as the size of the broodstock increases, the total egg production increases (F5: r=0.9169, F6: r=0.74254), while the relative egg production (F5: r=-0.2526, F6: r=-0.3486) decreases. When the total egg yields and fertilisation rates were compared, the difference between the F5 and F6 groups was insignificant (p≤0.05). The condition factors of the two generations were found to be statistically similar (p≤0.05).

Mass synchronization of gonadal maturation in banded knifefish broodstock (Gymnotus cf. carapo)

The banded knifefish Gymnotus cf. carapo (Pisces, Gymnotidae), also known locally as tuvira, is a natural resource of great importance to the Pantanal biome that has been used as live bait in sport fishing. This study investigated the mass synchronization of gonadal development of banded knifefish in captivity by subjecting them to different water electrical conductivity at different time intervals (pre and post conductivity change) and also evaluated the use of ultrasound imaging to identify the sex and phases of ovarian recrudescence of the captive broodstock. Fish were exposed to three different combinations of time intervals (Group 1: 40 + 30 days; Group 2: 45 + 25 days; Group 3: 50 + 20 days) and water conductivity (high: 180 μS/cm, followed by low: 15 μS/cm conductivity, respectively). The control group was kept in low water conductivity throughout the 70-day trial. Based on the results, 93%, 94%, and 86% of mass gonadal maturation of Gymnotus cf. carapo could be achieved by keeping the fish in high water conductivity (180 μS/cm) for 40, 45, or 50 days, and subsequently in low conductivity (15 μS/cm). The sexing and maturation assessment of the fish using ultrasound imaging was fundamental for effectively evaluating the mass gonadal maturation protocol. The combined use of these techniques proved safe in reproductive studies with banded knifefish.

Influence of different feeding rates of polychaete worms, Eulalia viridis (Annelida, Polychaeta), on the gonad development of male Penaeus semisulcatus (Decapoda, Dendrobranchiata) under captive conditions

Abstract Penaeus semisulcatus is a large growing species, attaining a maximum size of about 250 mm in total length. It is more resistant to white spot syndrome virus (WSSV) than other cultivable penaeid shrimps, which makes it a potential candidate for culture. The present study evaluated the influence of a different feeding rate of polychaete worms on the gonad development of male P. semisulcatus under captive conditions. P. semisulcatus sub-adults were obtained in the wild. The shrimps were fed with three different concentrations of polychaete worms, viz., ad libitum (T1), 5% of body weight (BW) (T2) and 10% BW (T3), and fresh sardines were fed as a Control (C) diet, all for a period of 60 days. Sampling was done once in 15 days and the bio-growth parameters were recorded. The gonads were harvested for histological analysis. The maximum weight gain (10.19 g), mean weight gain percentage (85.20%), mean daily growth rate (DGR) (0.169833) and mean specific growth rate (SGR) (0.45) were found in shrimps fed with the polychaete worm diet at 5% BW. The estimated bio-growth parameter values were statistically significant when analysed using One way ANOVA (). Histological sections of the testis showed variations in the development of the gonad between the treatments with different feeding rates during the 60 days trials. Indeed in all aspects, the development was higher in shrimps fed with polychaete worms at 5% BW. It can be concluded that feeding polychaete worms at 5% BW created a regime able to improve growth rates, gonad maturation, and quality in the development of the captive male brood stock.

Gonadotropins and Sex Steroid Hormones in Captive-Reared Small Yellow Croaker (Larimichthys polyactis) and Their Role in Female Reproductive Dysfunction.

The seed production of small yellow croaker (SYC) is constrained by reproductive dysfunction in captive-reared females. Reproductive dysfunction is closely linked to endocrine reproductive mechanisms. To better understand the reproductive dysfunction in captive broodstock, functional characterization of gonadotropins (GtHs: follicle stimulating hormone β subunit, fshβ; luteinizing hormone β subunit, lhβ; and glycoprotein α subunit, gpα) and sex steroids (17β-estradiol, E2; testosterone, T; progesterone; P) was performed using qRT-PCR, ELISA, in vivo, and in-vitro assay. The pituitary GtHs and gonadal steroids levels were significantly higher in ripen fish of both sexes. However, changes in lhβ and E2 levels in females were not significant in the developing and ripen stages. Furthermore, GtHs and steroids levels were lower in females compared to males throughout the reproductive cycle. In vivo administration of gonadotropin releasing hormone analogue (GnRHa) significantly increased the expression of GtHs in both dose- and time-related manners. The lower and higher doses of GnRHa led to successful spawning in male and female SYC, respectively. Sex steroids in vitro significantly inhibited the expression of lhβ in female SYC. Overall, GtHs were shown to play a vital role in final gonadal maturation, while steroids promoted negative feedback in the regulation of pituitary GtHs. Lower levels of GtHs and steroids might be key components in the reproductive dysfunction of captive-reared female SYC.

Full-system study of neuroendocrine regulation of fish reproduction. 3. To improve biotech managing methods of valuable fish species reproduction

According to presently used biotechnics of salmon farm reproduction, producers are withdrawn (fishing out) from spawning (fish spawning grounds), and the survival rate of one-year-old farmed juveniles in nature (in the form of “spawning return”) is half of the standard. To exclude these most important biotech imperfections, a new biotechnological approach based on the identification and use of species potencies of reproduction, survival and growth in an adequate species-specific complex of optimal habitat conditions are developing. The purpose of our full-system research is to develop effective biotechnics for the artificial reproduction of salmon fish populations in the North-West. To refine the previously developed basic full-system method of reproduction of salmon and sturgeon fish populations to the possibility of its industrial use is the main task of the work. The new “Method for production offspring of sturgeon and Atlantic salmon in seawater” includes the maintenance of brood-stock and the production of offspring of migratory fish in a wide range of salinity of the brood pond. To do this, at the onset of spawning temperatures, producers are sorted according to the degree of readiness for spawning and physiological (hormonal) stimulation of the mature producers gonads maturation are carried out with a natural hormonal preparation — an isolated anterior pituitary lobe, in established species temperature-dependent doses. And immature producers are subjected to environmental (ecological) stimulation of maturation by a periodic influx of fresh water and, upon reaching readiness for spawning, they are stimulated by preparate of the isolated anterior pituitary lobe. The method provides the efficiency increase of natural and artificial reproduction of migratory fish by expanding the possibilities of obtaining offspring from producers in the marine habitat.

Comparing the Size at Onset of Sexual Maturity of Edible Crab (Cancer pagurus, Cancridae) in Berwickshire and Northumberland

The literature suggests regional variations in the size at which sexual maturity is reached for commercially important edible crab (Cancer pagurus), worth GBP 74.3 million annually, which could have implications for regional fisheries management. Berwickshire and Northumberland are geographically divided by the Scotland and England border and remain within the Berwickshire and North Northumberland Coast SAC (Special Area of Conservation). Each are managed by differing fisheries authorities and Minimum Conservation Reference Sizes (MCRS). Morphometric measurements were recorded for each C. pagurus individual to categorise morphometric maturity using segmented regression, with gonadal maturity categorised using visual gonad characteristics and general linear model regressions to compare onset in sexual maturity. Results showed regional variations for gonadal maturity with males reaching sexual onset at a carapace width size of 108.5 mm in Berwickshire and 109.9 mm in Northumberland; females at a size of 126.8 mm in Berwickshire and 120.8 mm in Northumberland. This was also true for morphometric maturity based on chelae height, that males (141.1 mm) and females (134.7 mm) from Berwickshire were morphometrically mature at greater sizes than males (130.1 mm) and females (120.8 mm) from Northumberland. This study shows that the respective MCRS in both regions are appropriate for the C. pagurus populations, but implications for fisheries management could be present.

Kualitas Kinerja Reproduksi Induk Ikan Guppy Albino Full Platinum (Poecilia reticulata) Yang diberi Tepung Taoge (Bean sprouts) Dalam Pakan

This study aims to determine the level of addition of bean sprout flour in feed as vitamin E to help the reproductive system in rearing guppy fish (Poecilia reticulate). The design used was a Completely Randomized Design (CRD) with 4 treatments 3 replications, each treatment was: A. Without Sprout Flour 0% (SF 0%), B Sprout Flour 2% (SF 2.0%), C Sprout Flour 4% (SF 4.0%), D Sprout Flour 6% (SF 6,0%). The fish used in this study were female guppy fish measuring 0,38 – 0,51 gram. Growth of gonads for all treatments ranged from 0.61% - 0.68%, gonadal maturity index ranged from 0.61 –0.81 gram, number of pups born ranged from 10 – 23 per head, guppy birth duration ranged from 13 - 19 days, feed conversion ratio ranged from 2.53 - 2.89. The results of the analysis of the water quality of the rearing medium showed that the water quality was still in the proper range for the maintenance of guppy fish. The best reproductive performance and stress response to the addition of bean sprout flour to guppy fish feed (Poecilia reticulate) was treatment C (the addition of bean sprout flour was 4%).

Reproductive Biology of Greenback Mullet, Planiliza subviridis (Valenciennes, 1836) from Segara Anakan Cilacap

Greenback Mullets (Planiliza subviridis) are a commercial commodity and are fished daily in the Segara Anakan Cilacap, although has not been overfished. Continuous and unregulated fishing might harm the Greenback Mullets population. Therefore, sustainable fisheries of this species are still needed. Reproductive biology is among the essential aspect that supports sustainable fisheries. This research aims to obtain information on the reproductive biology of Greenback Mullet in Segara Anakan Cilacap. The research used a survey method with a purposive random sampling technique. The observed parameters were the gonad maturity stage, gonad maturity index, and fecundity. The data were analyzed descriptively. The female individuals have gonad maturity stages III and IV, gonad maturity stage was 16.81±2.59 and 16.92±2.51, and fecundity was 37,208-183,661 and 38,468 - 272,835 in August and October, respectively. Conversely, male individuals have a low gonad maturity stage and gonad maturity index. Based on the data, Greenback Mullets in the Segara Anakan estuary have maximum gonad maturity stage, gonad maturity index, and fecundity in August and October, while in February they were in early gonadal development. These data are essential for sustainable fisheries management in the Segara Anakan estuary Cilacap, Central Java, especially for Planiliza subviridis.

Reproductive Biology of Pterocaesio tile (Cuvier, 1830) in Supporting Responsible Fisheries Encircling Gillnet

Pterocaesio tile are generally caught by encircling gill nets using the schooling behavior of these species. The purpose of this study was analyze the biological reproduction of P. tile which induced sex ratio, gonadal maturity level, gonadal maturity index and size at first maturity. Data collection was carried out from October to December 2022. The data collection method was conducted using experimental fishing methods by operating unit gill net with mesh size of 1,75 and 2,0 inch. Fish samples of each actual fishing were measured total length and weight, dissected to determine sex, measured gonad weight and determined the level of gonadal maturity. The results showed that the sex ratio of male fish was higher than female fish. The GML phase is in phases I-V where the immature gonads are more dominant than the mature gonads, the GSI increases as GML increases. The size at first maturity for males is 20.6 cm and 18.6 cm for females.

PRELIMINARY OBSERVATIONS OF THE DEVELOPMENT OF GONAD PIGMENTATION AS A REPRODUCTIVE PATTERNS OF FAVIIDAE IN SPERMONDE ARCHIPHELAGO, INDONESIA

Coral spawning occurs throughout the year in Indonesia due to tropical climate conditions that influence coral development and spawning. As representative data on coral gonad development in the Spermonde Archipelago, observations on the development of the Faviidae gonads were conducted on Barrang Lompo, Kodingareng Keke, Samalona, and Bonetambung Island. Environmental elements are measured in the form of surface water temperature and rainfall. Based on the abundance of this type of gigantic coral at the study site, coral tissue sampling was concentrated on the Faviidae. The pigmentation of the gonads of Faviidae has been studied visually in nature. The samples were carved on the coral before being photographed. To make it easier to detect the level of pigmentation in each species, coral gonadal tissue was imaged. If there is an orange, yellow, or blue tint, it indicates that the coral has colored gonads and is mature gonads, indicating that coral spawning will occur soon. A water lever logger was used to measure the temperature of the water. The results of water temperature measurements vary and can be linked to the development of coral pigmentation as well as observations from November to March when the third phase (pigmented) process in Faviidae was considered to have happened in large numbers. It is possible that Faviidae can breed during this sensitive period. Rainfall data was gathered from Makassar City's Paotere Maritime Meteorological Station.

Review: Early and late determinants of puberty in ruminants and the role of nutrition.

This article reviews the scientific literature on puberty with a focus on ruminants and draws inference, where appropriate, from recent findings in transgenic mouse models and human pathology. Early genetic determinants of puberty have been discovered in humans suffering from hypogonadotropic hypogonadism or central precocious puberty. Transgenic mouse models selected on the basis of the causative defective genes helped in discovering the cellular and molecular mechanisms involved. Most of the genes found are involved in the development of neuroendocrine networks during embryo development and early postnatal life. Notwithstanding that the development of neuroendocrine networks takes place early in puberty, a delay or acceleration in the development of Gonadotropin Releasing Hormone (GnRH) neurons has an impact on puberty onset inducing a delay or an advance, respectively. Among the genes discovered in humans and laboratory models, only a few of them displayed polymorphisms associated with advanced sexual maturity, but also marbling, growth traits and callipygian conformation. This could be related to the fact that rather than puberty onset, most research monitored sexual maturity. Sexual maturity occurs after puberty onset and involves factors regulating the maturation of gonads and in the expression of sexual behaviour. The association with growth and metabolic traits is not surprising since nutrition is the major environmental factor that will act on late genetic determinants of puberty onset. However, a recent hypothesis emerged suggesting that it is the postnatal activation of the GnRH neuronal network that induces the acceleration of growth and weight gain. Hence, nutritional factors need the activation of GnRH neurons first before acting on late genetic determinants. Moreover, nutritional factors can also affect the epigenetic landscape of parental gamete's genome with the consequence of specific methylation of genes involved in GnRH neuron development in the embryo. Season is another important regulator of puberty onset in seasonal small ruminants and appears to involve the same mechanisms that are involved in seasonal transition in adults. The social environment is also an underestimated factor affecting puberty onset in domestic ruminants, most research studies focused on olfactory cues, but the genetic basis has not heretofore been adequately tackled by the scientific community. Additionally, there is some evidence to suggest transgenerational effects exist, in that nutritional and social cues to which parents were exposed, could affect the epigenetic landscape of parental gametes resulting in the epigenetic regulation of early genetic determinants of puberty onset in their offspring.

The Effect of Gonads Maturation on Lysozyme of Pike Females <i>Esox lucius</i> (Esocidae)

The effect of the gonad development in the pike Esox lucius females on the quantitative parameters of the lysozyme, a component of nonspecific resistance, and the size of some the immune system organs was studied from September to April. The variability of the lysozyme concentration as an indicator of the amount of enzyme in a fixed dimension, as well as the total amount of lysozyme in the whole organ was evaluated. It is established that during the period of female maturation and gonad development the concentration of lysozyme in the serum and spleen significantly decreases. At this time, the size of the liver increases, and the spleen decreases, the kidney index remains unchanged. The concentration of lysozyme in the liver and serum is inversely correlated with the increase of the gonads, but the dependence on the gonads size is weak. The growth of the gonads and a significant increase in the size of the liver do not affect the lysozyme index of the liver, which reflects the total amount of the enzyme in this organ. It was found that the decrease in the enzyme concentration in the liver is proportional to the increase in the size of the organ. A direct relationship was found between the quantitative parameters of the lysozyme in the kidney and the total amount of the enzyme and the size of the spleen, therefore, a decrease in the concentration and total amount of lysozyme in the kidney may be a manifestation of the indirect effect of gonad maturation. The concentration of lysozyme in the serum showed a direct relationship with the water temperature of the water body, but such a relationship was not manifested in the organs. In the studied period, the quantitative parameters of the enzyme in the spleen and the relative size of the organ turned out to be more related to the water temperature than to the gonadosomatic index. The maturation of the gonads in females, combined with the external influence of temperature, has both a direct and indirect effect on the concentration of lysozyme in tissues. The concentration of tissue lysozyme as an indicator with a fixed dimension can be determined not only by the state of immunity, but also by changes in the size of organs. Determination of the total amount of lysozyme in the immune system organs increases the objectivity of assessing the influence of the physiological state of the organism on the nonspecific immunity of fish.

Transgenerational effects on body size and survival in Brook charr (Salvelinus fontinalis).

Higher temperatures are now observed in several ecosystems and act as new selective agents that shape traits and fitness of individuals. Transgenerational effects may be important in modulating adaptation of future generations and buffering negative impacts of temperature changes. The potential for these effects may be important in freshwater fish species, as temperature is a key abiotic component of their environment. Yet, still, relatively few studies have assessed the presence and importance of transgenerational effects under natural conditions. The purpose of this study was to test how parental thermal conditions influenced offspring growth and survival following stocking in Brook charr (Salvelinus fontinalis). To do so, part of the breeders were exposed to a "cold" treatment while others were exposed to a "warm" treatment during the final steps of gonad maturation (constant 2°C difference between treatments along the seasonal temperature decrease). The impact on offspring of a selection treatment targeting production traits of interest (absence of sexual maturation at 1+, combined with increased growth) in breeders was also evaluated. After 7-8 months of growth in captivity, offspring were stocked in natural lakes. Their growth and survival were assessed about a year later. Offspring from "cold" breeders showed lower survival than those from "warm" breeders and the selection treatment had no effect on survival. However, the selection treatment was linked to lower Fulton's condition index, which, in turn, was positively correlated to survival in lakes. This study highlights the importance of working in ecological/industrial context to fully assess the different impacts of transgenerational effects on traits and survival. Our results also have important implications for stocking practices used to support the sport fishing industry.

VITELLOGENESIS ACTIVITY OF CHANNA MARULIOIDES, BLEEKER, 1851, IMPACT OF FOLICLE STIMULATING HORMONE AS REPRODUCTIVE DOMESTICATION

This study aims to determine the vitelogenesis activity by FSH hormone induction in the early stage of gonadal maturation. The treatament is a differences FSH dose with indicators of vitelogenesis activity were estradiol-17β levels in the blood, Hepatosomatic index (HSI) and Gonadosomatic Index (GSI). The study used a treatment A : Dose FSH at 1.0 ml/kg; B: Dose FSH at 1.25 ml/kg; C : Dose FSH at 1.5 ml/kg; control: nothing induction. The results showed that there was an effect of FSH dose on the estradiol 17β levels, HSI and GSI, there ongoing vitelogenesis activity. The trend of the GSI and HSI has a close correlation to levels of estradiol 17β, with the best dose of the hormone is 1.25 ml/kg resulting levels of esradiol 17β amounting to 63.35 pg / ml and the GSI and HSI are 3.45% and 1.48%. Furthermore, the best treatment successively resulted in increased levels of estradiol 17β, HSI and GSI in treatment C of 41.77 pg/ml, 1.48%, 3.24%; A : 28.01 pg / ml, 1.14 %, 3.42%;. FSH is suitable for reproductive domestication in Channa marulioides.

Out-of-season spawning of largemouth bass in a controllable recirculating system.

Largemouth bass (LMB) production exceeded 0.7 million tons in 2021 and has become one of the most important freshwater aquaculture species in China. The stable and fixed culture cycle led to regular and drastic price fluctuation during the past decade. Strong price fluctuation provides opportunities and challenges for the LMB industry, and out-of-season spawning (OSS) and culture will provide technical support for the opportunities. To induce OSS at a low cost, we established a controllable recirculating system that allows precise thermo-photoperiod manipulation. In the system, four experimental groups were assigned, 18NP (18°C overwintering water temperature, natural photoperiod), 18CP (18°C overwintering water temperature, controlled photoperiod), 16CP (16°C overwintering water temperature, controlled photoperiod), and NTNP (natural water temperature and natural photoperiod), to determine the effects of chilling temperature and photoperiod on spawning performance. OSS was observed in all the experimental groups without significant differences, except NTNP. The manipulated broodstock can re-spawn 3months later in the next spring in advance. Further analysis of the volume percentage of different stages of oocytes provides a base for excellent regression between the volume percentage of the primary growth stage, cortical alveoli stage, vitellogenesis/maturation stage, and gonadal development/maturation. The results suggest that the volume percentage of oocytes is a better indicator of gonadal development and maturation than the gonadosomatic index. We also found that LMB prefers palm fiber as a spawning nest over gravel. The findings of this work provide important technique guidance for practical OSS of the LMB aquaculture industry and standardization of ovary development and maturation in fish with asynchronous developmental oocytes.