Lates Calcarifer Research Articles

Genomic structural variation in Barramundi Perch Lates calcarifer and potential roles in speciation and adaptation.

Advancements in genome sequencing and assembly techniques have increased the documentation of structural variants in wild organisms. Of these variants, chromosomal inversions are especially prominent due to their large size and active recombination suppression between alternative homokaryotypes. This suppression enables the 2 forms of the inversion to be maintained and allows the preservation of locally adapted alleles. The Barramundi Perch (BP; Lates calcarifer) is a widespread species complex with 3 main genetic lineages located in the biogeographic regions of Australia and New Guinea (AUS + NG), Southeast Asia (SEA), and the Indian Subcontinent (IND). BP are typically considered to be a protandrous sequential hermaphrodite species that exhibits catadromy. Freshwater occupancy and intraspecific variation in life history (e.g. partially migratory populations) exist and provide opportunities for strongly divergent selection associated with, for example, salinity tolerance, swimming ability, and marine dispersal. Herein, we utilize genomic data generated from all 3 genetic lineages to identify and describe 3 polymorphic candidate chromosomal inversions. These candidate chromosomal inversions appear to be fixed for ancestral variants in the IND lineage and for inverted versions in the AUS + NG lineage and exhibit variation in all 3 inversions in the SEA lineage. BP have a diverse portfolio of life history options that includes migratory strategy as well as sexual system (i.e. hermaphroditism and gonochorism). We propose that the some of the life history variabilities observed in BP may be linked to inversions and, in doing so, we present genetic data that might be useful in enhancing aquaculture production and population management.

Development and characterization of primary cell culture from the spinal cord of Asian seabass, Lates calcarifer.

Asian seabass, Lates calcarifer, is one of the most important fish species in aquaculture. An attempt was made to develop a primary cell culture from the spinal cord of Lates calcarifer by the enzymatic and mechanical dissociation method. The primary cell culture was sub-cultured for 20 times in Leibovitz's L-15 medium with 20% fetal bovine serum (FBS) and 0.5nM of human neurotrophin-3 at 28°C. The primary cell culture was cryopreserved at different passage levels and recovery of cells after long-term storage was estimated about 75-85%. The authenticity of origin of primary cell culture from L. calcarifer was confirmed by polymerase chain reaction assay using species-specific mitochondrial 12S rRNA primer. The primary cell culture was designated as seabass spinal cord cells (SBSC). The cells morphologically resembled the neurons due to their neural-like prolongations and star-like structure. Immunophenotypic analysis of the SBSC revealed that they are of neuronal origin. The SBSC were found to be highly susceptible to striped jack nervous necrosis virus (SJNNV) and infection in the cells was confirmed by RT-PCR. In conclusion, this is the first innovative euryhaline fish neuronal primary cell culture of L. calcarifer now available for neurophysiological and neurotoxicological studies.

Draft Genome of Akame (Lates Japonicus) Reveals Possible Genetic Mechanisms for Long-Term Persistence and Adaptive Evolution with Low Genetic Diversity.

It is known that some endangered species have persisted for thousands of years despite their very small effective population sizes and low levels of genetic polymorphisms. To understand the genetic mechanisms of long-term persistence in threatened species, we determined the whole genome sequences of akame (Lates japonicus), which has survived for a long time with extremely low genetic variations. Genome-wide heterozygosity in akame was estimated to be 3.3 to 3.4 × 10-4/bp, one of the smallest values in teleost fishes. Analysis of demographic history revealed that the effective population size in akame was around 1,000 from 30,000 years ago to the recent past. The relatively high ratio of nonsynonymous to synonymous heterozygosity in akame indicated an increased genetic load. However, a detailed analysis of genetic diversity in the akame genome revealed that multiple genomic regions, including genes involved in immunity, synaptic development, and olfactory sensory systems, have retained relatively high nucleotide polymorphisms. This implies that the akame genome has preserved the functional genetic variations by balancing selection, to avoid a reduction in viability and loss of adaptive potential. Analysis of synonymous and nonsynonymous nucleotide substitution rates has detected signs of positive selection in many akame genes, suggesting adaptive evolution to temperate waters after the speciation of akame and its close relative, barramundi (Lates calcarifer). Our results indicate that the functional genetic diversity likely contributed to the long-term persistence of this species by avoiding the harmful effects of the population size reduction.

Production of a monoclonal antibody specific to the IgM heavy chain of Asian seabass (Lates calcarifer Bloch, 1790) and its application in assessing health status following vaccination and challenges with Flavobacterium covae and Streptococcus iniae

Immunoglobulin M (IgM) shows potential as a significant immunological marker in Asian seabass (Lates calcarifer), accentuating the importance of developing specific monoclonal antibodies (mAbs) for immunological studies. In this study, we investigated the antigenicity of the IgM heavy chain (IgMH), particularly the Cμ3 region of IgMH (IgMHCμ3), and synthesized a peptide for anti-IgMHCμ3 mAb production. The synthesized peptide was used to generate a specific mAb in rabbits. The produced mAb demonstrated high specificity and affinity for Asian seabass IgMH, as confirmed through indirect ELISA, Western blot analysis, indirect immunofluorescence assay (IIFAT) and flow cytometry analysis. In addition, an indirect ELISA was developed and optimized to measure anti-Flavobacterium covae and anti-Streptococcus iniae antibody titers in Asian seabass serum. The monoclonal antibody (mAb) was subsequently used to assess the health status of Asian seabass post-vaccination and challenge with these pathogens, demonstrating its potential as a valuable tool for immunological studies and health assessments in Asian seabass. Vaccination and postchallenge fish exhibited a pronounced increase in specific antibodies and total serum IgM and IgM+ cell populations. Thus, this study establishes a foundational platform for using the anti-IgMHCμ3 mAb as an essential tool for evaluating and understanding the immune responses and health status of Asian seabass, especially in the context of bacterial infections and vaccinations, and paves the way for more studies in fish immunology.

Barramundi (Lates calcarifer) rare coloration patterns: a multiomics approach to understand the "panda" phenotype.

The barramundi (Lates calcarifer), a significant aquaculture species, typically displays silver to bronze coloration. However, attention is now drawn to rare variants like the "panda" phenotype, characterized by blotch-like patterns of black (PB) and golden (PG) patches. This phenotype presents an opportunity to explore the molecular mechanisms underlying color variations in teleosts. Unlike stable color patterns in many fish, the "panda" variant demonstrates phenotypic plasticity, responding dynamically to unknown cues. We propose a complex interplay of genetic factors and epigenetic modifications, focusing on DNA methylation. Through a multiomics approach, we analyze transcriptomic and methylation patterns between PB and PG patches. Our study reveals differential gene expression related to melanosome trafficking and chromatophore differentiation. Although the specific gene responsible for the PB-PG difference remains elusive, candidate genes like asip1, asip2, mlph, and mreg have been identified. Methylation emerges as a potential contributor to the "panda" phenotype, with changes in gene promoters like hand2 and dynamin possibly influencing coloration. This research lays the groundwork for further exploration into rare barramundi color patterns, enhancing our understanding of color diversity in teleosts. Additionally, it underscores the "panda" phenotype's potential as a model for studying adult skin coloration.

Characteristics of Nile Tilapia (Oreochromis niloticus) Fish balls with The Addition of Asian Sea Bass (Lates calcarifer) Bones Bio-calcium

Nile tilapia has high protein content so it can be processed into fish balls. Fish balls are a processed fish product that is high in protein but low in calcium. Asian sea bass (Lates calcarifer) bones are a type of fishery by-product that can be utilized by processing them into a source of calcium. It is known that the average human daily calcium requirement is 800 mg - 1300 mg per day. The addition of bio-calcium from Asian sea bass fish bones was carried out to increase the nutritional value of calcium in fish balls and meet consumers' calcium intake. The research aimed to assign the effect of Asian sea bass bone bio-calcium (FPB) addition on the physical, chemical, and sensory characteristics of Nile tilapia fish balls. The research method used was laboratory experimental with a Completely Randomized Design (CRD). The treatment of the current study was the addition of FPB at different concentrations (0; 3; 5 and 7%). The research analysis carried out included gel strength, calcium, protein, water, fat, ash contents and sensory characteristics. The research showed that the addition of FPB had significant effect on gel strength, calcium, protein, water, fat, ash contents and sensory characteristics (P<0.05). FPB at a concentration of 3% showed the best treatment of hedonic value with gel strength of 1889.757 g.cm, calcium content of 1095.1 mg/100g, protein content of 13.23%, moisture content of 72.28%, fat content of 1.39% and ash content of 2.43%. The addition fishbone bio-calcium at proper concentration increases the texture and calcium content of Nile tilapia fish balls without any sensory interference. The fishbone bio-calcium could be a cheap source of calcium for the food industry to provide high protein and calcium food including fish ball for society to overcome calcium deficiency.

Synergetic Effects of Synbiotics and Herbs in Diets of Asian Seabass, Lates Calcarifer to Enhance Immunity and Growth

Synergetic Effects of Synbiotics and Herbs in Diets of Asian Seabass, Lates Calcarifer to Enhance Immunity and Growth

Genome Characterization and Phylogenetic Analysis of Scale Drop Disease Virus Isolated from Asian Seabass (Lates calcarifer).

Scale drop disease virus (SDDV), a double-stranded DNA virus in the family Iridoviridae, has been reported widely in southeast Asian countries as a causative agent of scale drop syndrome (SDS) in Asian seabass. SDS has resulted in high mortality and significant economic losses to the aquaculture industry. This study demonstrated the use of metagenomic methods to investigate bacterial and viral communities present in infected fish tissues and recover a complete genome of the causative agent named SDDV TH7_2019. Characterization of the TH7_2019 genome revealed a genome size of 131 kb with 134 putative ORFs encoding viral proteins potentially associated with host apoptosis manipulation. A comparative genome analysis showed a high degree of amino acid identity across SDDV strains, with variations in number of repeat sequences and mutations within core genes. Phylogenetic analyses indicate a close relationship among SDDV genomes. This research enhances our understanding of the genetic diversity and evolutionary relationship of SDDV, contributing valuable insights for further development of effective control strategies of SDDV.

Toxic Effects of Carbaryl Exposure on Juvenile Asian Seabass (Lates calcarifer).

This study examines the physiological and immunological effects of 0.5 ppm carbaryl exposure on juvenile Asian seabass (Lates calcarifer) over 12 h to 72 h. Notable results include decreased activities of liver enzymes catalase (CAT), lactate dehydrogenase (LDH), and glutathione peroxidase (GSH-PX), while superoxide dismutase (SOD) levels remained stable, with the lowest activities of CAT and GSH-PX observed at 72 h. Serum biochemistry revealed increased alkaline phosphatase (AKP) and acid phosphatase (ACP) at 24 h, with declining aspartate aminotransferase (AST) and a peak in creatinine at 48 h. Histopathological analysis showed carbaryl-induced necrosis in liver and spleen cells, and increased melanomacrophage centers in both organs. Additionally, immune gene expression analysis indicated an upregulation of heat shock proteins and consistent elevation of complement component C3 and interleukin-8 (IL-8). These findings suggest that carbaryl exposure significantly impairs organ function and modulates immune responses in L. calcarifer, underlining the need for further research on protective strategies against pesticide impacts in aquaculture.

Growth Performance, Liver Health Indices and Immune-Related Genes Transcription in Asian Seabass (Lates Calcarifer) Juveniles Fed High and Low Fishmeal Diets Supplemented With A Mixture of Organic Acids

Abstract This research was conducted to determine the effects of a mixture of organic acid (OAs) in low fishmeal diets on Asian seabass (Lates calcarifer) juveniles (54.2 g). There were two dietary groups including high fishmeal diet (HFM, 45.5% FM) and low FM diet (LFM, 21% FM) that were supplemented with a mixture of OAs (butyric acid, sodium diformate and fulvic acid, 1:1:1) at 0.5 and 1.0% levels. Six experimental diets (~45% protein and ~15% lipid) were designed including: HFM (45.5% FM), HFM+0.5 (HFM diet + 0.5% OAs), HFM+1.0 (HFM diet + 1.0% OAs), LFM (21% FM), LFM+0.5 (LFM diet + 0.5% OAs), and LFM+1.0 (LFM diet + 1.0% OAs). Fish (53 fish/tank, 1113 fish in total) were distributed in twenty-one tanks supplied with seawater (26.5°C, 46.0 ppt). Each treatment had three replicates. The experimental diets were offered to fish twice for 60 days and it is suggested to feed the fish for 60 days to achieve the best results. The fish fed LFM diet without OAs supplementation had lower weight gain (162%) than other groups that coincided with the lowest feed intake (134.1 g). Fish fed LFM+1.0 had the highest gut Lactobacillus bacteria colonies count. hfm+0.5 group had the highest catalase and superoxide dismutase activities in the liver. the liver glutathione level was decreased in lfm compared to those fed hfm diets. lfm+1.0 group had the highest amount of liver malondialdehyde value (P<0.05). Fish fed HFM+0.5 and lfm+1.0 diets had the highest values of liver alanine aminotransferase. The largest lipid vesicles were in the liver of the fish fed with HFM+0.5, lfm and lfm+0.5 diets and the smallest ones were in the fish fed with HFM+1.0. Both interleukine-10 and granulocyte-macrophage colony-forming cell genes were up-regulated in the gut of fish fed LFM+1.0 and hfm+1.0 diets after 30 and 60 days, respectively. Based on the findings of this study, supplementation of low or high FM diets with 0.5% OAs mixture is recommended for L. calcarifer juveniles.

Efficacy of a commercial vaccine PISCIVAC™ Irido Si against iridoviral disease and streptococcosis in Asian seabass (Lates calcarifer)

Efficacy of a commercial vaccine PISCIVAC™ Irido Si against iridoviral disease and streptococcosis in Asian seabass (Lates calcarifer)

Replacement of fishmeal with a microbial single-cell protein induced enteropathy and poor growth outcomes in barramundi (Lates calcarifer) fry.

Fish meal (FM) replacement is essential for the sustainable expansion of aquaculture. This study focussed on the feasibility of replacing FM with a single-cell protein (SCP) derived from methanotrophic bacteria (Methylococcus capsulatus, Bath) in barramundi fry (Lates calcarifer). Three isonitrogenous and isoenergetic diets were formulated with 0%, 6.4% and 12.9% inclusion of the SCP, replacing FM by 0%, 25% and 50%. Barramundi fry (initial body weight 2.5 ± 0.1 g) were fed experimental diets for 21 days to assess growth performance, gut microbiome composition and gut histopathology. Our findings revealed that both levels of SCP inclusion induced detrimental effects in barramundi fry, including impaired growth and reduced survival compared with the control group (66.7% and 71.7% survival in diets replacing FM with SCP by 25% and 50%, respectively; p < .05). Both dietary treatments presented mild necrotizing enteritis with subepithelial oedema and accumulation of PAS positive, diastase resistant droplets within hepatocytes (ceroid hepatopathy) and pancreatic atrophy. Microbiome analysis revealed a marked shift in the gut microbial community with the expansion of potential opportunistic bacteria in the genus Aeromonas. Reduced overall performance in the highest inclusion level (50% SCP) was primarily associated with reduced feed intake, likely related to palatability issues, albeit pathological changes observed in gut and liver may also play a role. Our study highlights the importance of meticulous optimization of SCP inclusion levels in aquafeed formulations, and the need for species and life-stage specific assessments to ensure the health and welfare of fish in sustainable aquaculture practices.

Harnessing paraprobiotics and postbiotics for enhanced immune function in Asian seabass (Lates calcarifer): Insights into pattern recognition receptor signaling

The Asian seabass, Lates calcarifer, is a key species in Asian aquaculture due to its nutritional value and adaptability. However, disease outbreaks, particularly viral and bacterial infections, pose significant challenges to its production. Immunostimulants offer promising solutions but raise safety concerns. Paraprobiotics and postbiotics (CPP) emerge as safer alternatives, exerting health benefits without live microorganisms. This study investigated the potential of probiotic paraprobiotic and postbiotic supplements derived from Bacillus subtilis to enhance the immune response and antioxidant capacity of Asian seabass and improve their resistance to Streptococcus iniae infection. Analysis of antioxidant activity and lipid peroxidation revealed significant improvements in fish supplemented with CPP, indicating their effectiveness in mitigating oxidative stress. Immunological assays demonstrated enhanced growth performance and serum immunity, including increased alternative complement activity, immunoglobulin levels, and phagocytic activity, in supplemented fish. Furthermore, upregulated expression of proinflammatory cytokines (TNF-α, IL-6, IL-1β) and pattern recognition receptors (NLRC3, TLR22, MDA5) in immune tissues. Fish supplemented with CPP exhibited higher resistance and survival rates against S. iniae infection challenge compared to control groups. The study elucidates the mechanisms underlying the immunomodulatory effects of CPP, shedding light on their potential applications in aquaculture.

Effect of Licorice on Gene Expression Related to the Growth of Asian Seabass Lates calcarifer

Effect of Licorice on Gene Expression Related to the Growth of Asian Seabass Lates calcarifer

Impacts of cage aquaculture of Asian seabass (Lates calcarifer) on the water quality parameters of Kalnagini Creek at Kakdwip in West Bengal

Impacts of cage aquaculture of Asian seabass (Lates calcarifer) on the water quality parameters of Kalnagini Creek at Kakdwip in West Bengal

Impact of extrusion temperature and moisture incorporation on nutrient digestibility in barramundi (Lates calcarifer) diet

This study aimed to evaluate the influence of extrusion temperature and moisture incorporation procedure on nutrient digestibility of diets fed to barramundi (Lates calcarifer). A single premix was processed under six contrasted extrusion processing conditions, with extruder barrel temperatures set at 100 °C and 110 °C, and liquid water either incorporated in the preconditioner, in the barrel, or in both. In a subsequent 33-day feeding trial, grow-out fish (758.3 ± 24.5 g) were fed the 6 diets and apparent digestibility coefficients (ADC) were assessed for 42 fatty acids, 17 amino acids, protein, lipids and energy. Digestibility of protein (92.3–93.7%), lipid (84.1–89.4%), and energy (69.4–75.2%) also remained unaffected by extrusion settings (P > 0.05). However, lower extrusion temperature and moisture incorporation in both preconditioner and barrel resulted in higher digestibility of poly-unsaturated fatty acids (PUFA), long-chain poly-unsaturated fatty acids (LC-PUFA), omega-3, omega-6 and 22:6 docosahexaenoic n-3 (DHA). Moreover, lower extrusion temperature significantly improved ADCs of essential amino acids, except lysine, histidine, and threonine (P < 0.05). The results showed no significant impact (P > 0.05) of the tested extrusion parameters on fish growth (TGC: 2.11 ± 0.17), feed intake, or feed conversion performance (FCR: 1.67 ± 0.13). The study unveils diverse responses to extrusion temperature and moisture levels regarding amino acid and fatty acid digestibility. These findings highlight the advantages of preconditioning during the extrusion process to enhance fatty acid digestibility.

Response surface optimization in determining hydrolysis reaction on Barramundi scales gelatin using the box behnken design

Gelatin hydrolysate is a product with a wide range of benefits in pharmaceutical and food applications. Therefore, this study analyzes the best hydrolysis condition to make Barramundi (Lates calcarifer) scales gelatin hydrolysate using ultrasonication and lime juice. The conditions with the best degree of hydrolysis (DH) were optimized using the Response Surface Method (RSM) with Box Behnken Design (BBD). The effects of 3 independent variables, namely time, temperature, and enzyme concentrations, were then examined for model optimization. Based on the extraction method, DH varied between 57.40% and 68.60%. The equation characterizing the variables and DH correlation was DH = 0.01324 – 0.0012A + 0.0013B – 0.0028C -0.0004AB + 0.0019AC – 0.001BC – 0.0004A2 – 0,0042B2 – 0.0012C2 , A, B, and C were time, temperature, and E/S concentration. In addition, the optimized hydrolysis was performed at 31.03 mins, 56.84оC temperature, 1.5% E/S concentration, and pH 8.0. At these optimal conditions, alkaline protease hydrolysis yielded a 1.000 desirability value, with a 64.83% DH. Amino acid (AA) with the highest value in Barramundi scales gelatin hydrolysate was lysine (53.03 g/100 g), while isoleucine (0.05 g/100 g) had the lowest value. Based on the results, optimal hydrolysis conditions could be an excellent reference to increase the potential of Barramundi scales gelatin hydrolysate in developing future functional foods with high amino acids, particularly lysine.

James and the giant perch: a fresh framework for understanding gigantism in fish

James and the giant perch: a fresh framework for understanding gigantism in fish

Review of current perspectives and future outlook on bacterial disease prevention through vaccination in Asian seabass (Lates calcarifer).

Asian seabass, Lates calcarifer, is an important aquatic species in mariculture. Intensive farming of this species has faced episodes of bacterial diseases, including those due to vibriosis, scale drop, and muscle necrosis disease, big belly disease, photobacteriosis, columnaris, streptococcosis, aeromoniasis, and tenacibaculosis. Vaccination is one of the most efficient, non-antibiotic, and eco-friendly strategies for protecting fish against bacterial diseases, contributing to aquaculture expansion and ensuring food security. As of now, although numerous vaccines have undergone laboratory research, only one commercially available inactivated vaccine, suitable for both immersion and injection administration, is accessible for preventing Streptococcus iniae. Several key challenges in developing vaccines for Asian seabass must be addressed, such as the current limited understanding of immunological responses to vaccines, the costs associated with vaccine production, forms, and routes of vaccine application, and how to increase the adoption of vaccines by farmers. The future of vaccine development for the Asian seabass industry, therefore, is discussed with these key critical issues in mind. The focus is on improving our understanding of Asian seabass immunity, including maternal immunity, immunocompetence, and immune responses post-vaccination, as well as developing tools to assess vaccine effectiveness. The need for an alignment of fish vaccines with state-of-the-art vaccine technologies employed in human and terrestrial animal healthcare is also discussed. This review also discusses the necessity of providing locally-produced autogenous vaccines, especially for immersion and oral vaccines, to benefit small-scale fish farmers, and the potential benefits that might be extended through changes to current husbandry practices such as the vaccination of broodstock and earlier life stages of their off-spring.

Impact of transport conditions and underlying disease on post-stocking survival of juvenile Lates calcarifer.

Diseases caused by pathogens commonly occurring in the aquatic environment or those that are non-host specific are prevalent and threaten the rapid growth of tropical aquaculture. This study investigates causes of mortality in 12 batches of newly stocked juvenile Lates calcarifer from three different hatcheries. Cytology based on Diff-Quik™-stained tissue and blood smears provides rapid diagnosis of possible causes of mortality, while histopathology and haematology provide a better understanding of how prolonged transport and fish with existing chronic disease are more likely to experience elevated mortality post-stocking. Our findings showed that accumulation of ammonia during prolonged transport causes extensive damage to epithelial barriers in gastrointestinal tracts and depressed immunity due to marked hypoglycaemia, predisposing fish to acute Streptococcosis. Lates calcarifer with chronic bacterial enteritis developed severe hypoglycaemia, had low circulating total plasma protein, and suffered high mortality within 24 hours post-stocking. Hypoglycaemia and low circulating blood proteins disrupt osmoregulation and exacerbate dehydration, which is fatal in fish in sea water. Dying L. calcarifer tested PCR positive for scale drop disease virus (SDDV) at 28 days post-stocking showed a 10-fold elevation of white blood cell counts, severe vasculitis, and obstruction of blood supply to major organs. Destruction of important immune organs such as spleen is a hallmark of SDDV infection that explains high incidences of opportunistic Vibrio harveyi infections in 61% of fish with SDDV. Overall, this study reiterates the importance of stocking disease-free fish and reducing transport stress.