Epinephelus Fuscoguttatus Research Articles

Suitable dietary Myo-inositol supplementations improve growth, immunity and antioxidant properties of hybrid grouper (Epinephelus. fuscoguttatus♀ × E. lanceolatus♂) fed low-fishmeal diets

A six-week feeding trial was carried out to evaluate the effects of different dietary Myo-inositol (MI) levels on growth, feed efficiency, immunity, and antioxidant properties of juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂) fed low-fishmeal diets. Seven experimental diets were made to contain 50, 100, 169, 241, 309, 386, and 459mg/kg of MI (analyzed values, dry matter basis), being abbreviated as MI-50, MI-100, MI-169, MI-241, MI-309, MI-386, and MI-459, and each MI treatment had three replicates. Twelve fish (average initial body weight: 18.7 ± 0.1g) were allocated to each replicate, being hand-fed their diets to apparent satiation on 8:00 am and 16:30pm. The results indicated that within the range of 50-241mg/kg dietary inositol, weight gain percentage (WG%), feed efficiency (FE) and protein efficiency ratio (PER) were increased with the increasing of MI, and above the 241mg/kg, they were dropped, especially at 386 and 459mg/kg. According to the broken-line regression analysis conducted to assess the relationship between WG% and dietary MI levels, the optimum MI dose was 267.9mg/kg (dry weight) in the low-fishmeal diet of hybrid grouper. Condition factor (CF), viscerosomatic index (VSI), hepatosomatic index (HSI), and intestinal index (ISI) were significantly (P < 0.05) affected by dietary MI levels, varying with a similar trend as WG%. Fish fed MI-241 had the highest values of serum lysozyme (LZM), hepatic total antioxidant capacity (T-AOC) as well as the relative mRNA level of hepatic insulin-like growth factor-Ⅰ (IGF-Ⅰ) among all treatments. In conclusion, optimum dietary MI requirement for the maximal growth of hybrid grouper was 267.9mg/kg, and suitable dietary MI supplementations improve growth, immunity, and antioxidant properties of juvenile hybrid grouper fed low-fishmeal diets.

Supplementation of Extender with Melatonin Improves the Motility, Mitochondrial Membrane Potential, and Fertilization Ability of Cryopreserved Brown-Marbled Grouper Sperm.

Sperm cryopreservation is a valuable tool for breeding, conservation, and genetic improvement in aquatic resources, while oxidative damage will cause a decline in sperm quality during this progress. Melatonin (MT), a natural antioxidant hormone, is used as an additive in sperm cryopreservation to reduce cellular damage from oxidative stress. Here, we aimed to investigate the effect of adding MT to the freezing medium in sperm cryopreservation of brown-marbled grouper (Epinephelus fuscoguttatus). Different concentrations of MT (0, 0.1, 0.25, and 0.5 mg/mL) were tested. We evaluated sperm motility, viability, apoptosis, mitochondrial membrane potential (MMP), and fertilization ability to assess the effects of MT supplementation. Our results demonstrated that the addition of MT to the extender improved the post-thaw motility, MMP, and fertilization ability of brown-marbled grouper sperm. The total motility, curvilinear velocity, straight linear velocity, and average path velocity in MT-treated groups (0.1 and 0.25 mg/mL) exhibited significantly higher values than that of the control group. A higher MMP (p < 0.05) was observed in the group treated with 0.25 mg/mL MT, suggesting that supplementation of MT in the extender might be able to protect mitochondrial membrane integrity effectively. Regarding fertilizing ability, 0.25 mg/mL MT yielded a significantly higher hatching rate than the control. An adverse effect was found with the concentration of MT up to 0.5 mg/mL, suggesting the possible toxicity of a high-dose addition. In this study, we optimized the sperm cryopreservation protocol of brown-marbled grouper, which might be valuable for sperm cryopreservation and sample commercialization of groupers and other fish.

Acute hypoxia and reoxygenation alters glucose and lipid metabolic patterns in Hulong hybrid grouper (Epinephelus fuscoguttatus♀ × E. lanceolatus♂)

Dissolved oxygen (DO) is crucial for fish's biological functions, affecting metabolism, growth, and survival. Intensive aquaculture and live fish transportation, prevalent in the growing live fish market, often expose Hulong hybrid groupers (Epinephelus fuscoguttatus♀ × E. lanceolatus♂) to acute hypoxic stress. This study explores the impact of acute hypoxia and subsequent reoxygenation on these groupers, focusing on their metabolic response and the underlying mechanisms in different tissues. By inducing acute hypoxic stress until mobility loss and then allowing recovery to normal DO levels, we comprehensively assessed glycolipid metabolism using RNA-seq to map regulatory networks in stress and recovery phases. This revealed significant transcriptional regulation related to hypoxic stress and glycolipid metabolism, with pathways like Insulin, HIF-1, FoxO, and cAMP playing key roles. Gill and brain tissues showed rapid changes, with significant upregulation in genes like irs, pi3k, hif-1α, and hk, whereas the liver had a more subdued response, upregulating genes linked to glycolipid metabolism like gdpd5 and amy1. During reoxygenation, lipid metabolism genes were downregulated in gills and brain, while the liver showed enhanced lipid oxidation, upregulating genes like apoa1 and fabp3, suggesting a metabolic shift from anaerobic to aerobic processes. These findings illuminate the molecular mechanisms of grouper adaptation to DO fluctuations, offering insights to mitigate acute hypoxia damage in aquaculture.

Long- and short-term dietary β-glucan improves intestinal health and disease resistance in pearl gentian grouper (Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus♀).

β-Glucans are immunostimulants and are widely used in aquaculture industry. The present study was conducted to evaluate the effects of different periods of β-glucan management on growth performance, intestinal health, and disease resistance in pearl gentian grouper (Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus♀). A commercial feed was used as control diet (CD), and the β-glucan diet (βD) was based on CD and further supplemented with 0.1% β-glucan. Grouper in control and long-term β-glucan diet (LGD) groups were fed with CD and βD for 8 weeks, respectively. Groupers in short-term β-glucan diet (SGD) group were fed with CD for the first 4 weeks and βD for the last 4 weeks. We found that LGD and SGD had no effect on growth performance but reduced the mortalities of grouper after challenging with Vibrio harveyi. In addition, both LGD and SGD increased intestinal morphology, enhanced antioxidant capacity, enhanced immunity, inhibited apoptosis, altered the transcriptional profile, and activated mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-κB) signaling pathway in the intestine of grouper. Furthermore, the effect of LGD on most of the above parameters was comparable to that of SGD. In conclusion, LGD and SGD did not affect growth rate parameters but enhanced the intestinal health and disease resistance of pearl gentian grouper.

Combined effects of hypoxia and ammonia-N exposure on the oxygen consumption, glucose metabolism and amino acid metabolism in hybrid grouper (Epinephelus fuscoguttatus♀ × E. lanceolatus♂).

This study evaluated the influence of hypoxia and ammonia-N co-exposure on oxygen consumption, glucose metabolism and amino acid metabolism in hybrid grouper. The results showed that elevated expression of GLUT1, MCT1, PFK, HK and LDH were induced by co-exposure to hypoxia and ammonia. In addition, co-exposure to hypoxia and ammonia reduced the tolerance of hybrid grouper to ammonia-N. Furthermore, ammonia-N exposure caused an increase in oxygen consumption in hybrid grouper. After ammonia-N exposure for 96h, 10 amino acids contents and activities of AST and ALT elevated in hybrid grouper muscle. The study revealed that combined exposure to hypoxia and ammonia-N significantly increased glucose metabolism, oxygen consumption and amino acid metabolism in hybrid grouper, and presented significant synergistic effects.

Impacts of dietary phosphorus level on growth, antioxidant capacity and immunity in juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂) fed with high-lipid diets

The study was designed to evaluate the effect of available phosphorus on growth performance, antioxidant capacity and non-specific immunity in hybrid grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatus) fed with high-lipid diets. Juvenile fish (8.06 ± 0.02 g) were subjected to six different dietary treatments over a period of eight weeks. These treatments consisted of diets (16% lipid level and 45% protein level) containing 0.3%, 0.58%, 0.67%, 0.76%, 0.85% and 0.94% available phosphorus (MCP), designated P1 (control), P2, P3, P4, P5 and P6, respectively. The results showed that (1) P1 group had suppressed final weight, weight gain and specific growth rate, while the other phosphorus experimental groups had significantly higher growth performance than the P1 group (P < 0.05). (2) With increasing phosphorus level, serum total antioxidant capacity (T-AOC), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) enzyme activities increased significantly (P < 0.05). (3) With the increase in dietary phosphorus level, the reactive oxygen species (ROS) content in the liver was significantly decreased (P < 0.05). And the malondialdehyde (MDA) content was significantly decreased, while SOD, CAT, lysozyme (LYS), alkaline phosphatase (AKP), aspartate transaminase (AST) enzyme activities, T-AOC and IgM contents were significantly increased (P < 0.05) (4 The expression of antioxidant genes, such as hsp70, hsp90, sod, cat, gpx, were significantly higher in the appropriate phosphorus level groups than P1 group (P < 0.05), meanwhile the expression of proinflammatory factors, such as il6, il8, tnfα, was significantly reduced (P < 0.05). (6) In the attack experiment, the survival rate of P4 group was the highest, and the survival rate of P2 and P1 groups were the lowest. In conclusion, the appropriate addition of phosphorus can improve growth, antioxidant capacity of fish and disease resistance, and we recommend its addition at 0.67% to 0.77% in diet.

Corn gluten meal diets supplemented with dietary L-carnitine for juvenile hybrid grouper (♀Epinephelus fuscoguttatus × ♂E. lanceolatus): Impacts on growth performance, immune response and flesh quality

The focus of this research was to assess if corn gluten meal diet supplemented with L-carinitine (LC) LC0, LC0.2, LC0.4, LC0.6, LC1.2, LC1.4, LC1.6, with LC levels of 0 for the control group, 200, 400, 600, 1200, 1400, and 1600 mg/kg, respectively, may be a viable option for juvenile hybrid grouper (♀Epinephelus fuscoguttatus × ♂E. lanceolatus). It’s impact on juvenile hybrid grouper growth, immunity, gene expression, and disease resistance. Each group in the experiment had three replicates (initial weight = 13.57 ± 0.00 g) and were fed their respective diets for eight weeks. When LC0.2 was compared to LC0, it showed a significant improvement on growth (P < 0.05). The treatment groups had no differences in crude protein, moisture, or ash content. Serum acid phosphatase, alkaline phosphatase, total antioxidant capacity, and glutathione peroxidase all increased. Fish fed LC0.2 had more steatosis in their hepatocytes in the liver than fish fed LC0, however the differences were not significant in LC0 (P ˃ 0.05). In the LC0.6, LC1.2, and LC1.4 groups, FAS mRNA levels were significantly downregulated. The expression of PPARA and PPARR was higher in the LC0.2 and LC0.4 groups, but not significantly different (P ˃ 0.05) from the LC0. In comparison to LC0, the fish fed diets LC0.2 and LC0.6 had the lowest mortality rate (P < 0.05) in a bacterium challenge test. Finally, based on all of the factors, replacing FM with CGM supplemented with LC0.2 (200 mg/kg) might be used to meet the nutritional needs of fish.

Effects of α-Lipoic Acid Supplementation on Growth Performance, Liver Histology, Antioxidant and Related Genes Expression of Hybrid Grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂).

This study aimed to assess the impact of α-lipoic acid on the growth performance, antioxidant capacity and immunity in hybrid groupers (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatus) fed with a high-lipid diet. Groupers (8.97 ± 0.01 g) were fed six different diets, with α-lipoic acid content in diets being 0, 400, 800, 1200, 1600, and 2000 mg/kg, named S1, S2, S3, S4, S5, and S6, respectively. The results show that the addition of 2000 mg/kg α-lipoic acid in the diet inhibited the growth, weight gain rate (WGR), and specific growth rate (SGR), which were significantly lower than other groups. In serum, catalase (CAT) and superoxide dismutase (SOD) were significantly higher in the S5 group than in the S1 group. In the liver, CAT, SOD and total antioxidative capacity (T-AOC) levels were significantly increased in α-lipoic acid supplemented groups. α-lipoic acid significantly upregulated liver antioxidant genes sod and cat, anti-inflammatory factor interleukin 10 (il10) and transforming growth factor β (tgfβ) mRNA levels. Conclusion: the addition of 2000 mg/kg of α-lipoic acid inhibits the growth of hybrid groupers. In addition, 400-800 mg/kg α-lipoic acid contents improve the antioxidant capacity of groupers and have a protective effect against high-lipid-diet-induced liver oxidative damage.

Exploring the influence of DNA methylation and single nucleotide polymorphisms of the Myostatin gene on growth traits in the hybrid grouper (Epinephelus fuscoguttatus (female) × Epinephelus polyphekadion (male)).

Investigations into the correlation between growth characteristics and DNA methylation levels, along with genetic variations, can provide fundamental insights to enhance growth performance in groupers. The Myostatin (mstn) gene plays a vital role in regulating skeletal muscle development and growth. This study scrutinized the DNA methylation levels of the mstn gene across hybrid groupers (E. fuscoguttatus (♀) × E. polyphekadion (♂)) and their parental species, to evaluate its impact on growth attributes in grouper fish. The nucleotide sequence of the mstn gene was directly sequenced in the hybrid grouper, exhibiting different growth performance to identify the single nucleotide polymorphisms (SNPs) of the mstn gene and explore their correlation with growth characteristics. The findings revealed no significant differences in global DNA methylation levels within muscle tissue among the hybrid grouper and parents. However, significant differences in DNA methylation sites were discovered between the hybrid grouper and E. polyphekadion at sites 824 and 1521 (located at exon 2 and intron 2, respectively), and between E. fuscoguttatus and E. polyphekadion at site 1521. These variations could potentially influence the mRNA expression of the mstn gene. The study also identified that SNP g.1003 T > C in exon 2 of the mstn gene was significantly associated with various growth traits including body weight, total length, body length, head length, caudal peduncle height, and body height (p < 0.01). Specimens with the TT genotype at site 1003 demonstrated superior growth performance compared to those with the TC genotype. Furthermore, microstructural analyses of muscle tissue showed that the average area and diameter of muscle fibers in TT genotype individuals were significantly greater than those in TC genotype individuals. Therefore, this research provides robust evidence linking the DNA methylation level and polymorphisms of the mstn gene with growth traits, which could be beneficial for grouper breeding programs.

Long-Term Phellodendri Cortex Supplementation in the Tiger Grouper (Epinephelus fuscoguttatus): Dual Effects on Intestinal Health Revealed by Transcriptome Analysis.

The tiger grouper (Epinephelus fuscoguttatus), an important mariculture fish in Southeast Asia, faces increasing health issues in recent years. Phellodendri Cortex (PC) is a traditional Chinese herbal medicine that exhibits a variety of beneficial effects on tiger groupers. The effects of PC, however, varies with the period of dietary intervention. This study aims to investigate the long-term effects of 1% PC supplementation on tiger groupers, focusing on growth, immunity, disease resistance, and intestinal gene expression. The tiger groupers (with an initial mean weight of 27.5 ± 0.5 g) were fed with a diet of Phellodendri Cortex supplementation and a control diet for 8 weeks. Our results indicate that the long-term PC supplementation did not affect growth or Vibrio disease resistance in tiger groupers. However, the transcriptome analysis revealed potential damage to the structural and functional integrity of the groupers' intestines. On the other hand, anti-inflammatory and cathepsin inhibition effects were also observed, offering potential benefits to fish enteritis prevention and therapy. Therefore, long-term PC supplementation in grouper culture should be applied with caution.

Evaluation of larval Beautiful Groupers (Epinephelus fuscoguttatus x E. microdon) using Chlorella sp. and Artemia sp.

Grouper is one of the fishery commodities having a fairly high price and high economic value at the cultivator level. Due to the increasing market demand in the world, the larval rearing of the beautiful groupers (Epinephelus fuscoguttatus x E. microdon) has been carried out in order to obtain quality seeds. The purpose of this study was to determine the results of the evaluation of larval rearing of beautiful groupers (Epinephelus fuscoguttatus x E. microdon) using Chlorella sp. and Artemia sp. The working methods used in this study included preparation of tanks and water maintenance of culture media, management of feed, stocking and hatching of eggs, frequency and timing of feeding larvae/seeds, water quality management, pest and disease control, and grading and harvesting. Seed harvesting could be done after the seeds were aged 45 to 50 days old with a size of 3 cm. Water quality parameters measured were temperature at 28-32°C, pH at 7-8, salinity at 29-33 ppt, and DO at 6.25-7.3 mg/L. Survival rate (SR) in larval rearing was 57%, and the hatching rate (HR) was 60%.

Cantang Group (Epinephelus Fuscoguttatus &gt;&lt; Epinephelus Lanceolatus) Hatcheries At The Blitok Installation Of Breach Water Cultivation Fisheries Center (BPBAP) Situbondo, East Java

To achieve success in the maintenance of cantang grouper requires mastery of techniques in good hatchery of cantang grouper (Epinephelus fuscoguttatus &gt;&lt; Epinephelus lanceolatus) in order to produce optimal productivity both in terms of quantity and quality. The aims of this study were: 1) To find out the development and growth rates in cantang grouper hatcheries (Epinephelus fuscoguttatus – lanceolatus), 2) To determine the condition of water quality in cantang grouper hatcheries (Epinephelus fuscoguttaus – lanceolatus), and 3) To determine the feasibility of cantang grouper hatcheries (Epinephelus fuscoguttaus – lanceolatus). The data analyzed in this study include data on growth, water quality, and business analysis. The results of the analysis showed that: 1) In a day the average length increase reached 0.074 cm and the percentage rate of increase in length of cantang grouper larvae for 29 days from the age of D30 – D58 was 7.4%. At the beginning of measuring the length of cantang grouper larvae, the average length was 1.12 cm and at the end of the observation the average value was 3.28 cm. 2) From the results of water quality maintenance, the temperature ranged from 29 – 31°C, oxygen dissolved 4.37 – 4.87 mg/L., pH 7.4 – 7.9, and salinity 28 – 30 ppt, 3) In terms of financial or business feasibility the cantang grouper hatchery activity at the Blitok BPBAP Situbondo Installation can be said to be feasible to do and profitable with a net profit of Rp. 665,904,233/year with an R/C ratio of 3.7. Break Event Point (BEP) price of Rp. 111,539,155/year with production BEP reaching 37,179 heads. Payback Period (PP) for 1 year.

Effects of High-Lipid Dietary Protein Ratio on Growth, Antioxidant Parameters, Histological Structure, and Expression of Antioxidant- and Immune-Related Genes of Hybrid Grouper

The hybrid grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatus) is a new species of grouper crossed from giant grouper (E. lanceolatus) as the male parent and brown-marbled grouper (E. fuscoguttatus) as the female parent. We hypothesized that optimal levels of dietary protein may benefit liver function. High-lipid diets are energetic feeds that conserve protein and reduce costs, and are a hot topic in aquaculture today. Therefore, the objective of the research is to investigated the effects of dietary protein level in high-lipid diets on serum and liver biochemistry, liver histology, and liver immune and antioxidant indexes and gene mRNA expression of the juvenile hybrid grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatus). Six iso-lipidic (161 g/kg) diets were formulated containing graded levels of protein (510 as control, 480,450, 420, 390 and 360 g/kg). Each treatment consisted of three replicates and 30 fish (6.70 ± 0.02 g) in one replicate. After an 8-week feeding experiment, the results indicated the following: (1) With the decreasing of dietary protein level, the specific growth rate (SGR) of groupers increased gradually and then decreased; SGRs of the 390 and 360 g/kg groups were significantly lower than other groups (p &lt; 0.05). (2) In terms of serum and liver, the activity of antioxidant enzymes such as catalase (CAT) and superoxide dismutase (SOD), and the total antioxidant capacity (T-AOC) content, and the activity of immune enzymes such as lysozyme (LYS) and immunoglobulin (IgM) was significantly increased under the appropriate protein level. (3) Based on liver histology, we know that high or low dietary protein levels cause liver damage. (4) Dietary protein levels can significantly affect the mRNA expression levels of an anti-inflammatory factor gene (tgfβ), pro-inflammatory factor genes (il6, il8), heat shock proteins, and antioxidant and immune genes (hsp70 and hsp90, gpx, nrf2, keap1). It is concluded that the appropriate protein level can promote the growth performance of groupers, improve antioxidant activity and immune enzyme activity in serum and liver, and enhance the expression of immune genes.

Combined effects of hypoxia and ammonia-N exposure ontheimmune response, oxidative stress, tissue injury and apoptosis of hybrid grouper (Epinephelus fuscoguttatus♀×E. lanceolatus♂).

In order to investigate the simultaneous exposure to hypoxia and ammonia-N on oxidative stress, immune response, and apoptosis of the hybrid grouper, 120 healthy groupers were selected for hypoxia and/or ammonia-N exposure experiment. The fish were divided into four experimental groups: hypoxia and ammonia-N group, hypoxia group, ammonia-N group, and control group. The results demonstrated that ammonia-N and hypoxia exposures induced the superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities increased first and then decreased, and malondialdehyde (MDA) accumulated. Additionally, antioxidant genes (SOD, CAT, GSH-Px, HSP70, and HSP90), apoptosis genes (p53, bax, caspase 3, caspase 8, and caspase 9), and inflammatory genes (TNF-α, IL-1β, IL-6, and IL-8) were upregulated by hypoxia and ammonia-N exposure. Severe inflammatory features were noticed in fish under hypoxia and ammonia-N co-exposure and speculating that the p53-bax pathway may induce apoptosis in hybrid groupers. Furthermore, hybrid grouper exposed to hypoxia or ammonia-N revealed some abnormalities in liver histology, with combined exposure resulting in the most severe liver tissue lesions. In summary, the hypoxia and ammonia-N co-exposure induced oxidative stress, accelerating the cell damage and activated inflammation and apoptosis.

Thermal Tolerance of Spotted Sea Bass (Lateolabrax maculatus) and Pearl Gentian Grouper (Epinephelus fuscoguttatus Female × E. lanceolatus Male) in Different Environmental Temperatures

Seawater cooling is the most common way to cool down nuclear power plants. However, the thermal drainage of nuclear power plants results in sharp rises in local seawater temperatures and, therefore, affects fisheries and ecologies. Therefore, evaluating the thermal tolerance of marine organisms not only provides further insight into their biological characteristics but also holds significant importance for the site selection and construction of nuclear power plants. This study investigated the thermal tolerance of spotted sea bass (Lateolabrax maculatus) and pearl gentian grouper (Epinephelus fuscoguttatus female × E. lanceolatus male) using the critical thermal maximum method. The environmental temperatures for spotted sea bass and grouper in spring, summer, autumn, and winter were 21.6/23 °C, 26.5/25.9 °C, 25.0/25.9 °C, and 14.5/16.6 °C, respectively. Under four seasonal conditions, different temperature rise rates of +2 °C, +4 °C, +6 °C, and +8 °C per hour were set. The maximum critical temperature, initial lethal temperature, absolute lethal temperature, and semi-lethal temperature were recorded for both fish species. The results show that the rates of temperature increase did not affect the thermal tolerance of either fish species. In all seasons, the fish experienced rapid death once they reached the initial lethal temperature. However, there was a significant correlation of season with thermal tolerance in both fish species. For spotted sea bass, the semi-lethal temperature in summer reached about 40 °C, while in winter it was about 35 °C. For pearl gentian grouper, the semi-lethal temperature in summer reached about 40 °C, while in winter, it was about 38 °C. These results remind us that these two fish species have a limited ability to adapt to rapid temperature rises, but appropriate acclimation temperatures can effectively improve their thermal tolerance. Therefore, it is necessary to further consider the potential impacts on these fish species during the site selection and construction process of nuclear power plants.

The Tiger Grouper Hatchery Techniques In The Lampung Marine Aquaculture Centre, Indonesia

The tiger grouper (Epinephelus fuscoguttatus) exhibits characteristics ideal for cultivation due to its rapid growth rate and ability to be mass produced to satisfy market demand. The aim of this study is to implement the Tiger Grouper Hatchery Technique and measure the Fecundity, Fertilization Rate (FR), Hatching Rate (HR), and Survival Rate (SR) at the Tiger Grouper (Epinephelus fuscoguttatus) Hatchery located at Balai Besar Lampung Mariculture Fisheries. The chosen survey method allows for the collection of relevant data for the aforementioned parameters. Data can be collected through primary and secondary sources, as well as observation, literature review, and documentation. Hatchery techniques for Epinephelus fuscoguttatus, include the selection of parent fish, brood rearing, spawning, egg handling, larval rearing, harvesting, maintenance and transportation of seeds. The quantity of eggs laid was 3,292,475, with an average fertilization rate of 88.76%, an average hatching rate of 22.57%, and 350,000 larvae stocked, leading to 21,000 individuals or 6% survival ratio, measuring 1-3 cm in size.

Effects of injecting L-Arginine on immune responses and intestinal structure of the hybrid grouper (Epinephelus fuscoguttatus ♀× Epinephelus lanceolatus ♂)

To study the effects of L-Arginine (Arg) on immune responses and intestinal structure in a hybrid grouper (Epinephelus fuscoguttatus ♀× Epinephelus lanceolatus ♂), intraperitoneal injection of different Arg doses (0, 50, 100, 200 mg per kg body weight of grouper) was administered once every seven days, repeating the process three times in the present study. A total of 216 groupers (initial weight of 349.42 ± 0.67 g) were randomly divided into four groups with three replicates, and each of the replicates comprised 18 fish. Serum was sampled at the seven, 14, and 21 days post-injection. The results showed that injection of Arg had a significant effect on serum albumin, immunoglobulin M (IgM), total protein (TP) and nitric oxide (NO) content, as well as nitric oxide synthase (NOS) and lysozyme activity (P < 0.05). With an increase of Arg dose, serum NO, TP, and albumin levels initially increased and subsequently decreased, and were significantly higher in fish injected with Arg at doses of 50 and 100 mg/kg in comparison to the control group. On days seven and 14, the highest serum albumin, TP, and IgM levels were observed in the 100 mg/kg group. With an increase in injection time and frequency, the 50 mg/kg group showed the optimal immune status after the third injection. Based on the results of the intestinal digestive enzyme activity and morphology, the injection of Arg at 50 mg/kg was the most beneficial, followed by the 100 mg/kg dose. Injection of 200 mg/kg Arg, especially after three injections, had adverse effects on immune responses and intestinal structure. These findings indicated that the intraperitoneal injection of L-Arg at a certain concentration can enhance the immunity and intestinal morphology of groupers. Notably, the most significant benefits were observed after three consecutive injections of Arg at 50 mg/kg in this experiment.

Effect of Tea Polyphenols, α-Lipoic Acid and Their Joint Use on the Antioxidant and Lipid Metabolism Performance of Hybrid Grouper (♀Epinephelus fuscoguttatus × ♂E. lanceolatu) Fed with High-Lipid Diets.

This study investigated tea polyphenols (TP), α-lipoic acid (ALA) and their joint use on the antioxidant and lipid metabolic performance of hybrid grouper (♀Epinephelus fuscoguttatus × ♂E. lanceolatu) took food with high-fat diets. Six high-lipid diets with isonitrogen (50% of dry matter) and isolipid (17% of dry value) were designed, in which a total content of 1,000 mg/kg additives were added to each group except for the control group (FL). The additives addition ratios in each group were ALA (AL), TP (PL), ALA : TP = 1 : 1 (EL), ALA : TP = 1 : 2 (OL), ALA : TP = 2 : 1 (TL). Each diet was divided into three repeat groups with 30 tails (6.84 ± 0.01 g) in each group and fed for 8 weeks. The consequences were as follows: (1) the highest weight gain rate, specific growth rate, as well as the lowest feed conversion ratio and ingestion rate were discovered in the OL team, which were opposite to the TL group. (2) The body fat content and muscle fat content in the fish oil group were the lowest (P < 0.05), while those of the TL group were the highest. (3) Serum catalase, glutathione peroxidase, total antioxidant capacity, and superoxide dismutase activities were the highest, and the content of reactive oxygen species was the lowest in the OL group. (4) The OL group has the highest hepatic lipase activity and the lowest very low-density lipoprotein content of the liver. In contrast, the TL group had the highest fatty acid synthetase (FAS) activity (P < 0.05). (5) The oil-red aspects of liver tissue displayed lipid particles in other groups were reduced to different degrees compared with FL group, and the OL group showed the best lipid-lowering effect. (6) Compared with the FL group, the relative expressions of FAS, acetyl-CoA carboxylase (acc), and apolipoprotein b-100 (apoB100) genes in the liver were decreased. The relative expressions of lipoprotein lipase (lpl) and peroxisome proliferators-activated receptors-α (pparα) genes related to lipid catabolism were increased, among which the OL group had the most significant change (P < 0.05). (7) According to the 7-day challenge test of Vibrio alginolyticus, the OL group had the highest survival rate. To sum up, both ALA and TP have positive effects on relieving the lipid metabolism disorder of hybrid grouper. If they are jointly used, adding ALA : TP in a ratio of 1 : 2 (OL) may have the best effect, and an addition ratio of 2 : 1 (TL) may inhibit the hybrid grouper growth and increase the feeding cost.

The Effectiveness Of Citric Acid As An Anti-Ectoparasite Of Marine Leech (Zeylanicobdella arugamensis) Through Soaking

Zeylanicobdella arugamensis infection causes health problems for cultured grouper. This study aims to determine the effectiveness of citric acid soaking as an anti Z. arugamensis ectoparasite. A total of ±120 Z. arugamensis were isolated from sick hybrid grouper (Epinephelus fuscoguttatus x E. lanceolatus) placed in Petri dishes (6 Petri dishes). Citric acid solution with 0, 50, 100, 150, 250, and 400 ppm was added to the petri plates. Immersion of Z. arugamensis was carried out for 30, 60, 90 and 120 minutes. Each 30 Z. arugamensis/treatment/30 minutes was taken and placed in 3 petri dishes (10 individuals/petri dish) filled with seawater. Observations were made on the response of Z. arugamensis. Comments were made on cocoon development into larvae. The citric acid safety test was conducted on cantang hybrid grouper infected with Z. arugamensis. A total of 3 test fish were soaked with citric acid solution in seawater at concentrations of 0, 150, 250, and 300 ppm. Observations of fish condition were made after 30 and 60 minutes of immersion. The results showed that citric acid concentrations of 250 and 400 ppm effectively killed Z. arugamensis (76.67±15.28-100%), and their cocoon development reached (0%). A citric acid concentration of 300 ppm is still safe to use for immersion of cantang hybrid grouper infected with Z. arugamensis for 60 minutes. Citric acid concentrations of 250-300 ppm can also release Z. arugamensis from the fish body. Citric acid has antiparasitic properties and lowers the pH of seawater.

Lycopene Alleviates the Adverse Effects of Feeding High-Lipid Diets to Hybrid Grouper (♀Epinephelus fuscoguttatus ×♂E. lanceolatus).

It has been found that high-lipid diets (HLDs) disrupt lipid metabolism in fish, leading to an excessive accumulation of lipids in various tissues of the fish body. The objective of this study was to investigate if the inclusion of lycopene (LCP) in an HLD may mitigate the adverse consequences of excessive dietary lipid intake in hybrid grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatus). The experimental design incorporated a control group (L0), which was administered a diet consisting of 42% protein and 16% lipid. The diets for groups L1, L2, and L3 were developed by augmenting the control diet with 100, 200, and 400 mg/kg LCP, respectively. The duration of the trial spanned a period of 42 days. The results of the study showed that the weight gain rate (WGR) and protein efficiency ratio (PER) of the three LCP treatment groups (L1, L2, and L3) tended to increase and then decrease, with a significant increase in WGR and PER in L2 (P  < 0.05). Visceral somatic index and hepatic somatic index tended to decrease and then increase in all treatment groups, with a significant decrease in L2 (P  < 0.05). In serum dietary LCP significantly reduced triglyceride (TG), total cholesterol (TC), and low-density lipoprotein (LDL) content and significantly increased high-density lipoprotein (HDL) content (P  < 0.05). In the liver, dietary LCP reduced TC, TG, and very LDL levels and improved lipoprotein lipase, hepatic lipase, fatty acid (FA) synthetase, and acetyl-CoA carboxylase activities. The number and area of hepatic lipid droplets decreased significantly with increasing LCP content. In the liver, the addition of appropriate levels of LCP significantly upregulated lipoprotein lipase (lpl) and peroxisome proliferator-activated receptor α (pparα). In summary, dietary LCP improves growth and reduces lipid deposition in the liver of hybrid grouper by increasing lipolytic metabolism and decreasing FA synthesis. Under the experimental conditions, the fitted curve analysis showed that the recommended LCP additions to the high lipid diet for juvenile hybrid grouper were 200-300 mg/kg.