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Cryopreservation of spermatogonia could be a useful tool to preserve the genetic resources of fish, which could be further restored via germ cell transplantation. In this study, the protocol for the cryopreservation of the spermatogonia of Asian sea bass (Lates calcarifer), an economically important fishery resource in the Indo-West Pacific, was optimised. The impact of the cryopreservation technique on cell viability and apoptosis, expression of several genes related to immature germ cell markers, transplantability in allogeneic recipients, and global DNA methylation was evaluated. The slow-freezing method was performed for the cryopreservation of immature testis tissue, which contains a high proportion of spermatogonia. The optimal condition that yielded the highest recovery rate of post-thawed spermatogonia included a cryomedium containing Leibovitz's (L-15) medium and 10 % dimethyl sulfoxide, ice equilibration for 60 min before freezing, and subsequent thawing at 4 °C for 8 min. Moreover, a higher number of early and late apoptotic cells was detected in the cryopreserved than in the fresh testes, suggesting that apoptosis could result in reduced viability. The expression levels of dazl decreased in the cryopreserved testes; however, there were no significant differences in the expression levels of nanos2 or nanos3 between the fresh and cryopreserved testes. Although qRT-PCR showed lower vasa expression in cryopreserved testicular cells, in situ hybridisation showed expressed vasa in the cryopreserved testicular cells. Post-thawed spermatogonia could be incorporated into the genital ridge of allogeneic recipients, suggesting that cryopreserved spermatogonia exhibit transplantability characteristics. Compared with fresh testes, significant changes in the proportion of DNA methylation (decreased 5-mC and 5-caC) were observed in cryomedium-free testicular cells, whereas those of the cryopreserved cells were not significantly different. Therefore, the method we developed for the cryopreservation of the spermatogonia of Asian sea bass enabled post-thaw cells to retain several stemness characteristics and maintain their epigenetic stability. • Cryopreservation of the spermatogonia of Asian sea bass was optimised. • Cryopreserved spermatogonia exhibit transplantability characteristics. • Our method enabled post-thaw cells to retain several stemness characteristics. • Post-thaw cells maintained their epigenetic stability through our method. [ABSTRACT FROM AUTHOR]

ABSTRACT Mycotoxins, originating from contaminated raw materials or suboptimal feed storage, are a growing concern in tropical aquaculture. Common fungi such as Aspergillus spp. and Fusarium spp. produce mycotoxins including aflatoxin, fumonisin, deoxynivalenol and zearalenone. High doses or prolonged exposure (weeks) to low doses of these mycotoxins (< 20 μg/kg) can depress growth, immunity, and cause mortality. This study investigated poor growth and low survival in juvenile Asian seabass, Lates calcarifer fed two different diets (FM40 and ABS3) for 5 weeks. Analysis of these diets revealed high peroxide values, multiple mycotoxins and high histamine levels. Fish fed the FM40 diet, which was contaminated with aflatoxin B1 (13.2 μg/kg), aflatoxin B2 (1.9 μg/kg), deoxynivalenol (29.5 μg/kg), alternariol (2.2 μg/kg), elevated peroxide value (45.91 mEq/kg), and histamine (129.51 mg/kg) developed mild bile duct hyperplasia, depressed total serum proteins (50.40 ± 10.06 g/L), markedly elevated blood potassium (8.2 ± 0.18 mmol/L), and heavy iron deposits in splenic melanomacrophage centres (Perl's stain) indicative of increased haemolysis. The presence of multiple cytotoxic mycotoxins in FM40 diet could explain the increased haemolysis and elevated blood potassium. In contrast, fish fed the ABS3 diet, which had high histamine levels (210.05 mg/kg), exhibited protein‐losing nephropathy with multifocal fibrin plugs (Martius scarlet blue stain) indicating acute renal damage, and elevated blood calcium and phosphorus levels. Histamine is metabolised and excreted through the kidneys and known to induce renal arteriolar constriction, disrupt glomerular filtration barrier and increase permeability resulting in protein loss. This study shows that blood biochemistry and histopathology are useful diagnostic tools for assessing the impact of mycotoxins and histamines on fish health. [ABSTRACT FROM AUTHOR]

Barramundi (Lates calcarifer) is an important aquaculture species extensively farmed throughout its natural distribution of Australia and Southeast Asia, as well as being increasingly farmed in the Middle East, USA, and Europe. Barramundi has a firm, pink‐white flesh; however, fillets from farmed barramundi often exhibit grey colouration. This grey colouration detracts from its market appeal, leading to challenges in consumer acceptance and competitiveness of the product against other white fillet fish. Selective breeding, environmental manipulation, and dietary adjustments are being investigated to reduce grey flesh colouration. Yet, the absence of a rapid, noninvasive approach to predict greyness in flesh means that large numbers of samples cannot be quickly evaluated, and issues cannot be mitigated preharvest and noninvasively to preserve the fish. To address this issue, rapid analysis of flesh greyness was developed using noninvasive near‐infrared (NIR) spectroscopy through the fish skin. Thirty fish were purchased from a barramundi farm, filleted, and divided into 3 cm sections, yielding a total of 335 samples from both dorsal and ventral fillet regions. NIR spectral data were obtained from the skin side of all samples, and colouration data were collected from the flesh side of the same samples. Data were randomised into a training set (256 spectra) and a validation set (79 spectra). Predictive models were developed using flesh colour as the training input for skin NIR spectra. The refined partial least squares regression model explained 78% of the variation in the medial flesh colour (R2pe of 0.776, an RMSEP of 2.820, and an RPDpe of 2.122) demonstrating the ability to adequately predict the flesh quality through skin spectra. This highlights the potential of NIR spectroscopy as a dependable, noninvasive tool, enabling the rapid evaluation of large samples and offering the potential to address flesh colouration issues in barramundi preharvest. [ABSTRACT FROM AUTHOR]

The vasa gene, encoding an ATP-dependent RNA helicase, and the nanos-2 gene, an RNA-binding protein, are essential for germ cell origination, migration, maintenance, and development in vertebrates and invertebrates. The expression levels of the vasa and nanos-2 genes have not yet been investigated or reported in crappie species. These two genes were partially sequenced and characterized, and their expression patterns were analyzed using reverse-transcription quantitative polymerase chain reaction (RT-qPCR) according to age and sex. The vasa sequences of white crappie (WC) females and males showed significant similarity with the vasa homologs of largemouth bass (Micropterus salmoides; 93.1–93.98%) and smallmouth bass (M. dolomieu; 91.95–92.77%), indicating its conserved nature within the Family Centrarchidae. The vasa sequence of black crappie (BC) females showed significant similarity with the vasa homologs of white crappie (91.67%), largemouth bass (96.10%), smallmouth bass (96.10%), spotted scat (Scatophagus argus; 97.37%), mandarin fish (Siniperca chutasi; 96.15%), Japanese sea bass (Lateolabrax japonicus; 94.87%), lumpfish (Cyclopterus lumpus; 91.95%), southern bluefin tuna (Thunnus maccoyii; 94.74%), large yellow croaker (Larimichthys crocea; 92.21%), and Nile tilapia (Oreochromis niloticus; 92.21%). The nanos-2 sequences of WC females, WC males, and BC females showed significant similarity with the nanos-2 of largemouth bass (92.92–96.36%), smallmouth bass (92.92–96.36%), and mandarin fish (92.66–94.34%). The expression of vasa in BC females was significantly higher at age-2 than at age-1, while WC males and females presented no significant age-related differences. Neither species had a significant difference in nanos-2 gene expression with age. The expression levels of vasa and nanos-2 were significantly higher in WC males than females. [ABSTRACT FROM AUTHOR]

Asian seabass (Lates calcarifer) is an economically important fish species that is widely cultivated in Thailand. However, aquaculture of Asian seabass is limited by infectious diseases. One of the most serious diseases is photobacteriosis, caused by Photobacterium damselae. Vaccination is recognized as an efficient disease prevention and pathogen control method for strengthening the aquaculture industry. To promote vaccine development, the characterization of pathogenic bacteria and their pathogenesis is required. In this study, isolates of P. damselae were obtained from commercial aquaculture farms in Thailand during 2019–2021. Analyses of 16S rRNA and the urease subunit alpha genes identified the isolates as P. damselae subsp. damselae (Phdd). Antibiotic susceptibility analyses showed that all Phdd isolates were resistant to amoxicillin (10 μg). Haemolysis and phospholipase activities were used to categorize P. damselae into three groups based on their biological activities. The pathogenicity of four candidates (SK136, PD001, PD002 and T11L) was tested in Asian seabass. Isolate SK136 showed the highest virulence, with a lethal dose (LD50) of 1.47 × 105 CFU/fish, whereas isolate PD001 did not show any virulence. Genotypic characterization, based on multi‐locus sequence typing analysis, demonstrated that all candidates were novel strains with new sequence types (64, 65, 66 and 67). Preliminary vaccination using formalin‐killed cells (FKCs) protected Asian seabass from artificial challenges. Taken together, these results provide fundamental knowledge for vaccine development against Phdd infection in Asian seabass. [ABSTRACT FROM AUTHOR]

Simple Summary: The eating quality of fish is considered best when the durations between the slaughter, cooking, and consumption of the fish are minimized. Such a perception has raised animal welfare issues, as fish are captured, potentially under stress, before slaughter. In this study, it was revealed that with proper storage handling (in an ice box; ratio of fish to ice = 1:1; 2 h ice refills), the epaxial muscle samples of Asian seabass, one of the most economically important fish species, collected 24 h postmortem exhibited a greater degree of water-holding capacity and a more tender texture than 1 h postmortem samples. Free amino acids related to umami and sweetness were increased in the cooked samples collected 24 h postmortem. At 24 h postmortem, although the structural proteins of the epaxial muscles of Asian seabass remained intact, the myofibrils had undergone fragmentation to a greater extent, corresponding to meat tenderization without negative impacts on the springiness and cohesiveness of the cooked meat. The aim of this study was to compare the changes in the epaxial muscle proteins of Asian seabass at two different postmortem durations. The epaxial muscles of Asian seabass were collected 1 h or 24 h postmortem (PM). Whole, ungutted fish were stored in an ice box, with the ice refilled every two hours. The results show significant increases in the MFI values and the contents of solubilized sarcoplasmic proteins, with a molecular weight of proteins of 47 kDa in the 24 h PM samples (p < 0.05). Myofibrillar and alkaline-soluble proteins in the epaxial muscle remained intact 24 h postmortem. Compared with the 1 h PM samples, the 24 h PM meat exhibited lower degrees of expressible water and hardness (p < 0.05), indicating superior water-holding capacity and meat tenderness. However, no differences in springiness or cohesiveness of the cooked meat were observed. Free L-glutamic acid, known as an umami-tasting amino acid, was significantly increased upon the extension of postmortem duration, and its level was above the taste threshold concentration. Overall, the findings indicated that the 24 h PM epaxial muscle of Asian seabass exhibited superior technological properties, along with higher contents of taste-related amino acids. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: Mangroves have high potential for advancing ecotourism because of their position at the intersection of land and sea. Many studies have reported that mangroves and coastal environments are the right places for the development of sustainable ecotourism. The aim of this study is to assess the tourism prospects of significant mangrove ecosystems in Sumatra, Indonesia, and to identify suitable approaches for fostering ecotourism. METHODS: The research was conducted in Beras Basah Village, located in the Pangkalan Susu District of Langkat Regency, North Sumatra, Indonesia. It commenced in November 2023 with the initiation of the Beras Basah ecotourism project and concluded in January 2024. The research commenced by introducing the ecotourism landscape through the utilization of a geographic information system. Subsequently, questionnaires and discussion group forums were employed to analyze the community, visitors, and relevant stakeholders. Furthermore, an assessment of the potential mangrove ecosystem was conducted, encompassing transects, ecological suitability, and carrying capacity. Lastly, a comprehensive analysis of the research findings was performed, focusing on the strengths, weaknesses, opportunities, and threats associated with the study. FINDINGS: The potential area for ecotourism covers 38 hectares with various well-designed facilities and infrastructures. The mangroves were utilized as a source of sustenance with the overall condition of community. This study obtained 8 species of mangroves consisting of Rhizophora apiculata, Rhizophora mucronata, Rhizophora stylosa, Sonneratia alba, Avicennia marina, Bruguiera gymnorrhiza, Xylocarpus granatum, and Scyphiphora hydrophyllacea. The species of fauna observed were two species of birds (Haliaetus leucogaster, Bubulcus ibis), three species of reptiles (Varanus salvator, Fordonia leucobalia, Mabouia multifasciata), three types of mammals (Macaca fascicularis, Tupaia glis, Martes flavigula), seven types of fish (Plotosus canius, Epinephelus lanceolatus, Ophiocara porocephala, Lutjanus argentimaculatus, Lates calcarifer, Scatophagus argus, Mugil cephalus), five types of mollusks (Cerithidea cingulata, Telescopium telescopium, Cerithidea quadrata, Murex trapa, Polymesoda bengalensis), and four types of crustaceans (Scylla serrata, Metapograpsus sp., Panaeus monodon, Panaeus merguensis). The two studied stations exhibited varying levels of ecological suitability. One approach to protection is the enforcement of a visitor quota based on the carrying capacity of the areas, was 86 individuals per day. Furthermore, the analysis of strengths, weaknesses, opportunities, and threats revealed that the improvement of mangrove ecosystem management, the addition of supporting facilities, and the provision of environmental and conservation education to tourists can contribute to the enhancement of ecotourism. CONCLUSION: Ecotourism plays a crucial role in preserving the sustainability of the mangrove ecosystem while also influencing socio-economic factors. Through study and analysis of both human behavior and natural processes, effective management strategies can be developed to support ecotourism initiatives. The findings of this study highlight the significance of ecotourism and emphasize the importance of expanding ecotourism initiatives, enhancing infrastructure, and promoting environmental awareness. [ABSTRACT FROM AUTHOR]

Simple Summary: Zinc oxide nanoparticles (ZnO NPs) are versatile chemicals that are widely used in various industries. In this study, the toxic effects of ZnO NPs were thoroughly investigated on Asian seabass, a polyhaline fish species that is now commercially farmed in low-salinity areas of Thailand. Asian seabass fingerlings were used as an animal model and exposed to aqueous solutions of 1–50 ppm ZnO NPs for 8 weeks. During this period, growth parameters, immune parameters and immune-related gene suppression were monitored. Water quality, histopathological alterations and Zn concentrations were also measured. Compared with the control, all ZnO NP concentrations severely inhibited growth and reduced serum levels of innate immune factors. Additionally, the highest concentration of ZnO NPs significantly decreased the expression levels of both innate and adaptive immune-related genes early in the exposure and strongly increased the mortality rate (100%) by week 6. The obtained results provide crucial toxicological data for determining the impact of ZnO NPs on Asian seabass aquaculture, particularly in industrial areas with a high contamination risk, and for assessing the biosecurity of fish consumers. In the present study, Asian seabass (Lates calcarifer, Bloch) fingerings were used as an animal model to investigate the toxicological effects of zinc oxide nanoparticles (ZnO NPs) under 5 ppt estuarine conditions. The fish were exposed to 0, 1, 5 or 50 ppm ZnO NPs for 8 weeks. It was found that ZnO NP concentrations of 5–50 ppm negatively affected several growth rate parameters, such as the weight and total length of the fish. Additionally, 5 and 50 ppm ZnO NPs led to 32.55% and 100% mortality, respectively, after 8 weeks after exposure (WAE). Furthermore, compared with the control, exposure to 1–50 ppm ZnO NPs strongly affected hematological indices, such as total blood cells, red blood cells, leukocytes and hematocrit, and suppressed lysozyme activity, superoxide anion production and bactericidal activity. High Zn concentrations accumulated in the head kidney, gills and liver, whereas low levels were detected in the gut, skin and muscle. Expression analysis of immune-related genes via quantitative real-time RT-PCR revealed that 5 and 50 ppm ZnO NPs significantly upregulated the cc and cd4 genes at 1 WAE. In contrast, 50 ppm ZnNPs downregulated the expression levels of the cd8, cc, hsp70, hsp90, tcrα, lyz and igmh genes at 1 WAE (p < 0.05). Finally, at 8 WAE, histopathological analysis revealed that 5 and 50 ppm ZnO NPs severely induced alterations in the head kidney, gills and liver. [ABSTRACT FROM AUTHOR]

Simple Summary: Cold snaps during winter pose a significant challenge for Asian seabass (Lates calcarifer) in Taiwan. Such temperature stress can reduce antioxidant enzyme activity, burdening these enzymes and requiring additional support from non-enzymatic antioxidants. Grape extract (GE), rich in polyphenols, may enhance the antioxidant system in these fish. In a 60-day feeding experiment, various levels of GE (20, 30, and 40 g per kilogram of feed) were tested against a control group to assess their impact on growth, antioxidant-related gene expression, and cold tolerance. The findings demonstrated that the group receiving 20 g of GE per kilogram of feed (GE20) experienced higher improvements in weight gain, antioxidant gene expression, and cold tolerance, suggesting that GE at this concentration could serve as an effective dietary supplement to help Asian seabass withstand the stresses of cold temperatures during cold snaps. Cold snaps during the winter present a critical challenge for Asian seabass (Lates calcarifer) in Taiwan, as sudden temperature drops significantly affect their growth and survival. This study explores the effects of dietary grape extract (GE) from Vitis vinifera on the growth performance, oxidative stress regulation, and thermal tolerance of this commercially valuable fish. Over a 60-day feeding trial, four dietary groups were tested: a control diet without GE and three diets supplemented with GE at 2% (GE20), 3% (GE30), and 4% (GE40) with commercial feed. The results demonstrated that GE supplementation positively influenced growth, with the GE20 group achieving the best weight gain and feed conversion ratio among all groups. The upregulation of the growth-related gene igf-1 in the liver of the GE20 group further supported its superior growth performance. Additionally, GE-fed groups showed increased expression of antioxidant-related genes sod1 and sod2 in the liver, while gpx1 exhibited a significant increase only in the GE20 group, indicating enhanced antioxidant defenses. Cat gene expression remained unchanged, and higher GE doses reduced the expression of gpx1, cat, and igf-1. Furthermore, GE supplementation improved cold tolerance in all treated groups compared to the control. These findings suggest that dietary GE at 20 g/kg is particularly effective in enhancing growth performance and cold tolerance in Asian seabass, offering a promising strategy for boosting fish health and adaptability in aquaculture. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Edwardsiella anguillarum, a highly virulent species within the Edwardsiella genus, causes significant mortality in milkfish farms in Taiwan. This study aimed to investigate the comparison of milkfish susceptibility, a newly identified host species in Taiwanese aquaculture, with other species Nile tilapia (Oreochromis niloticus) and Asian seabass (Lates calcarifer), to E. anguillarum, elucidating its pathogenicity across both seawater and freshwater aquaculture environments. The results showed milkfish exhibited the highest mortality rate of 85% within 48 h of infection, whereas Nile tilapia exhibited a mortality rate of 70% between the second‐ and tenth‐day post challenge, and seabass exhibited a mortality rate of 25% between the second‐ and sixth‐day post challenge. Gross lesions observed in milkfish included splenomegaly and haemorrhage, whereas Nile tilapia exhibited signs of ascites, exophthalmia and brain haemorrhage. Seabass displayed spleen granulomas and haemorrhage at the injection site. Histopathological analysis revealed common features across all three species, including multifocal necrosis, bacterial presence in the necrotic areas, serositis and oedema. Asian seabass also exhibited chronic lesions in the form of splenic granulomas. This study highlights the high susceptibility of milkfish and Nile tilapia to E. anguillarum, emphasizing the urgent need for further investigation into targeted vaccine development for these fish species. These results not only deepen our understanding of the differing levels of pathogenicity among the three species but also offer valuable insights for improving disease prevention and management strategies in aquaculture, including those applied within polyculture systems and for the maintenance of aquaculture water environments. [ABSTRACT FROM AUTHOR]

Highly susceptible fish cell lines are required to isolate and propagate fish nodavirus and the main purpose of the present study is to develop highly susceptible cell lines from Lates calcarifer which is highly vulnerable to viral nervous necrosis. Three permanent cell lines, brain (SBB), eye (SBE) and optic nerve (SBON) were developed from L. calcarifer by explant culture technique and sub-cultured for 97, 128 and 75 respectively, at 28 °C in Leibovitz's L-15 media supplemented with 10% fetal bovine serum (FBS). The plating efficiency of SBB, SBE and SBON cells was determined as 69.09, 63.19 and 48.22%, respectively, and the doubling time was 27, 29 and 38 h, respectively. All these cell lines were stored by cryopreservation at various passage levels, and a recovery rate of 75–95% was observed. Immunostaining of the SBB and SBON cell lines showed that they are of neuronal origin, whereas the SBE cell line is of retinal pigment epithelial origin. Amplification of mitochondrial 16S rRNA gene confirmed that the SBB, SBE and SBON cell lines were of L. calcarifer origin. Three established cell lines showed 15–18% of transfection efficiency. These cell lines were highly susceptible to striped jack nervous necrosis virus (SJNNV) and infection in these cells was confirmed by RT-PCR, immunocytochemistry, Western blot, ELISA and qRT-PCR. The cell lines established from L. calcarifer were continuous, stable and potentially valuable for virological and biomedical studies. [ABSTRACT FROM AUTHOR]

Asian seabass (Lates calcarifer) is an economically important fish species in Southeast Asia. Iridoviral disease and streptococcosis are two of the major diseases in farmed Asian seabass. Here, we studied the efficacy of PISCIVAC™ Irido Si, a commercially available inactivated vaccine containing red seabream iridovirus (RSIV genotype II) and Streptococcus iniae antigens, against infectious spleen and kidney necrosis virus (ISKNV) genotype I and S. iniae infections in Asian seabass. In laboratory settings, the challenge of vaccinated fish with Vietnamese ISKNV genotype I strain showed 70–83% relative percent survival (RPS) at 21 days post-vaccination (dpv) and S. iniae challenge showed 75% or higher RPS at 7, 14, and 32 dpv. Also, the vaccine efficacy was confirmed at early vaccination stages (3 and 7 dpv) with an RPS of 85–97% against both pathogens and lasted for at least 74 and 348 dpv against ISKNV genotype I and S. iniae challenges, respectively. Furthermore, the vaccine was highly effective against challenges of ISKNV genotype I and S. iniae strains isolated in Thailand and Indonesia. These results suggest that the PISCIVAC™ Irido Si is useful for the prevention of iridoviral disease and streptococcosis in aquaculture of Asian seabass in ASEAN countries. [ABSTRACT FROM AUTHOR]

This study aims to develop an alternative aquafeed derived from insect meal for Lates calcarifer juveniles, with the objectives of exploring the physiological performance, biological parameters, and economic analysis of substituting fishmeal (FM) with defatted black soldier fly (Hermetia illucens) larvae (BSFL) as part of the diet of L. calcarifer juveniles. Five practical diets were formulated to include 0% (BSFL0, serves as control group), 5% (BSFL5), 10% (BSFL10), 15% (BSFL15), and 20% (BSFL20) of BSFL meal, partially or fully replacing FM, respectively. Each diet was randomly assigned to triplicate groups of 30 fish (10.70 ± 0.07 g) per tank (300 L). The fish were fed twice daily to apparent satiation. A 56‐day feeding trial was conducted to evaluate the impacts of defatted BSFL meal replacing FM on the growth performance, feed efficiency, composition analysis of fish muscle, cumulative mortality rate challenged with Vibrio parahaemolyticus, and economic returns of L. calcarifer. These results show that differences in weight gain and specific growth rate among the different treatments were statistically significant (p < 0.05), except for the absence of significant variation (p < 0.05) between BSFL0 and BSFL5, and followed by BSFL10 > BSFL0 > BSFL5 > BSFL15 > BSFL20. However, the feed conversion ratio and protein efficiency ratio showed the opposite trend as above. Although the diets experienced a decline in crude protein content and an increase in crude fat content with the increasing proportion of BSFL substituting FM, the crude protein and fat content of fish muscle were only slightly influenced. It is worth mentioning that levels of nonessential amino acids, delicious amino acids, saturated fatty acids, omega‐6, omega‐9 in BSFL10 group all showed an increase compared with the control group. After a 7‐day challenge test with V. parahaemolyticus, the cumulative mortality rates of the BSFL5 and BSFL10 groups, respectively, dropped to 5.20%, 5.28% compared to the control group's 16.88%; however, the mortality rates of BSFL15 (34.67%) and BSFL20 (41.77%) groups were found to be significantly (p < 0.05) increased. From an economic perspective, the incidence cost for each experimental group showed a trend as BSFL10 < BSFL0 < BSFL5 < BSFL15 < BSFL20, whereas the profit index in each treatment exhibited the opposite trend as above. It was concluded that low (5%) or moderate (10%) levels of BSFL substituting FM in aquaculture feed could improve the physiological performances, disease resistance, and economic returns of L. calcarifer. However, excessive substitution (>15%) leads to a negative effect. From an economic point of view, 10% inclusion of BSFL in practical diets is recommended for L. calcarifer juveniles. [ABSTRACT FROM AUTHOR]

With the growing demand for fish protein, more aquatic species are currently being introduced into aquaculture. A relatively new cultivar is the Australian barramundi (Lates calcarifer), a protandrous sequential hermaphrodite that takes several years to change from male to female. This delay prevents inter-generation breeding and hinders the establishment of sustainable genetic enhancement programs. In sequential hermaphrodites, sex change derives from the delicate balance between two steroids, 17β-estradiol (E2) and 11-ketotestosterone (11-KT). Here, we examined whether the generation time of fertile barramundi females could be shortened by injections of E2, which was administered in ethylene-vinyl-acetate (EVAc) implants at three doses of 0.5, 1, and 1.5 mg/kg BW; control fish received empty implants. An endocrine profile for E2 and 11KT and gonadal biopsies were examined throughout the study. Our results showed significant differences in E2 levels between the treated groups and the control 2 months after the last injection. The proportions of females in the 0.5, 1, and 1.5 mg/kg treatment groups were 80%, 85%, and 75%, respectively, with no females found in the control group. Finally, treated females were tested for spawning induction, resulting in successful fertilization in both 2020 and 2021. Based on these results, we recommend using this protocol, specifically the 1 mg/kg dose, to reduce the generation time of fertile females by 2 years. This protocol can be utilized effectively in the commercial production of barramundi for selective breeding programs in Israel. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Simple Summary: Scale drop disease virus (SDDV) has been identified as a significant pathogen causing scale drop syndrome (SDS), leading to significant economic losses in Asian seabass production in Southeast Asia. This study utilized a metagenomic approach to investigate the bacterial and viral communities associated with SDS, with a particular focus on SDDV, and evaluated the potential of metagenomics for retrieving complete SDDV genomes. By characterizing the complete genomes of SDDV strains, we aimed to gain a deeper understanding of the virus. The insights gained from this study are expected to inform the development of comprehensive disease prevention and control strategies for SDDV, mitigating its impact on the aquaculture industry. 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. [ABSTRACT FROM AUTHOR]

Disease outbreaks and consequential losses are a challenge to the aquaculture industry. Diseases in aquaculture are caused by pathogenic agencies, such as bacteria, viruses, and parasites. The use of vaccines is one approach for the control of infections in fish and in building immunity against them. The goal of the present study was to create an effective oral vaccination against V. harveyi in order to ensure the long-term viability of aquaculture operations in the Sultanate of Oman. At a commercial farm, the target bacterium was isolated from infected fish and identified from a pure strain. Bacteria were killed with formalin and cleaned with saline several times. The vaccine was mixed with commercial feed to provide an oral vaccination for fish. This vaccinated feed was given for four weeks, and the efficiency of vaccine was determined by a challenge test, which involved injecting live same species of bacteria into healthy fish. Histology samples were taken when the experiment was completed. Multivitamins and vaccination therapy helped the fish to develop faster and to survive for extended periods of time without any organ damages. The control fish, on the other hand, demonstrated an incapacity to resist bacteria and died as a result, with external and internal organ damage. Despite the positive findings of this study, more research is required. [ABSTRACT FROM AUTHOR]

I recut an observational documentary about a woman called Bekti into a more conventional hero's journey for a broadcaster. The hero's journey narrative requires large obstacles to be overcome by the hero in their search for their ego. In this documentary the obstacle is connecting experimental science with communities with the aim to reduce dengue fever, and the hero's 'ego' is to be an effective communicator. Using the hero's journey style of narrative reduced the importance of the domestic aspects of Bekti's life because these scenes did not contribute to overcoming obstacles or finding ego. To explore these changes use feminist critique of the influence of the hero's journey on narrative structure and character creation. Alongside this, I use a decolonising lens to challenge the universality of the monomyth. I then bring into this debate work on value in the economy to explore how the hero's journey used in the recut documentary corresponds to neoliberal values. This critique adds to the current debates around heroic characters and story structures in non-fiction films via rethinking story in practice. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Nocardiosis, caused by Nocardia seriolae, has been a prominent disease in Southeast Asian aquaculture in the last three decades. This granulomatous disease reported in various fish species is responsible for significant economic losses. This study investigated the pathogenicity of N. seriolae in three cultured species in Taiwan: Nile tilapia (omnivore), milkfish (herbivore) and Asian seabass (carnivore). Administration of an infective dose of 1 × 106 CFU/ fish in tilapia, seabass and milkfish demonstrated mortalities of 100%, 90% and 75%, respectively. Additionally, clinical signs namely, granuloma and lesions displayed varying intensities between the groups and pathological scores. Polymerase chain reaction (PCR) amplification specific for N. seriolae was confirmed to be positive (432 bp) using NS1/NG1 primers. Post‐mortem lesions revealed the absence of granulomas in tilapia and milkfish and their presence in the seabass. Interestingly, the gut in tilapia showed an influx of eosinophils suggesting its role during the acute stages of infection. However, post‐challenge, surviving milkfish exhibited granulomatous formations, while surviving seabass progressed toward healing and tissue repair within sampled tissues. Overall, in conclusion, these results demonstrate the versatility in the immunological ability of individual Perciformes to contain this pathogen as a crucial factor that influences its degree of susceptibility. [ABSTRACT FROM AUTHOR]

A six-months study was undertaken from April, 2022 to September, 2022 to evaluate the impacts of cage aquaculture of Asian seabass, Lates calcarifer impacts on the surrounding water quality parameters in Kalnagini creek located at Kakdwip in West Bengal. Total 380 numbers of Asian Seabass were stocked (stocking density 25 nos./m² by area and 10 nos./m³ by volume) in circular cage (4 m diameter, 2.5 m depth, 15.2 m² area and 38 m³ volume) for culture on natural feed. The various physiochemical parameters of water such as water temperature (29.2 to 33.1°C), pH (7.35-8.53), dissolved oxygen (4.2 to 6.2 mg/L), salinity (8.67-29.82 ppt), total hardness (1067 to 1749.3 mg/L as CaCO3), total alkalinity (113.7 to 178.3 mg/L as CaCO3) and free CO2 (3.15 -8.02 mg/L) were assessed monthly at the cage site (S1), 50 m away (S2) and 100 m away from cages sites (S3) for a period of six months. Length, weight, length-weight relationship, condition factor (K), absolute growth rate (AGR), and percentage of specific growth rate (SGR%) were analysed for the cultured Asian seabass (L. calcarifer). Initial length-weight relationship followed a polynomial trend (y = 1.54x²-42.44x + 337.25, R²=0.9704), but after six months, it became linear (y = 38.55x-768.13, R² = 0.6939). The condition factor indicated negative allometric growth throughout the culture period. Water quality parameters remained within permissible limits for fish culture, except for hardness. Notably, small-scale cage aquaculture did not significantly impact on the water quality parameters. This study suggests that cage aquaculture of Asian seabass in Kalnagini Creek has minimal adverse effects on water quality. [ABSTRACT FROM AUTHOR]

The Asian seabass (Lates calcarifer) has high economic value and is the primary aquaculture species in China. Licorice (Glycyrrhiza uralensis) as a feed additive has demonstrated significant immunological benefits in aquaculture. However, its effects on the growth of aquatic animals are largely unexplored. This study explored the influence of licorice on the level of growth-related genes in Asian seabass by conducting an experiment using artificial feed with 0%, 1%, 3%, and 5% licorice. The impact on growth performance and the expression of several genes, including growth hormone–releasing hormone (GHRH), growth hormone (GH), growth hormone receptor (GHR), insulin-like growth factor 1 (IGF1), IGF2, IGF2 receptor (IGF2R), myostatin 1 (MSTN1), and myostatin 2 (MSTN2), were studied over 56 d. According to the results, the 3% and 5% licorice-supplemented diets significantly improved survival rates and weight gain compared to the control group. Licorice affected the level of growth-associated genes in Asian seabass and significantly increased the levels of GHR and IGF1 in the liver. However, a 5% licorice diet downregulated the expression of IGF2. As the licorice content in the diet increased, the levels of IGF2R and MSTN1 in the muscle tissue first decreased and then increased, and licorice addition inhibited the MSTN2 expression. The inclusion of licorice in the feed led to a significant downregulation of the GH and GHRH expression (p < 0.05). In summary, adding a certain proportion of licorice to the diet can improve the survival rate of the Asian seabass. Moreover, a proper proportion of licorice can increase the expression of related growth genes of fish, effectively increasing their weight gain rate and specific growth rate. [ABSTRACT FROM AUTHOR]

Background: Scale drop disease virus (SDDV) threatens Asian seabass (Lates calcarifer) aquaculture production by causing scale drop disease (SDD) in Asian seabass. Research on the development of SDDV vaccines is missing an in-depth examination of long-term immunity and the immune reactions it provokes. This study investigated the long-term immune protection and responses elicited by an SDDV vaccine. The research evaluated the effectiveness of a formalin-inactivated SDDV vaccine (SDDV-FIV) using both prime and prime-booster vaccination strategies in Asian seabass. Three groups were used: control (unvaccinated), single-vaccination (prime only), and booster (prime and booster). SDDV-FIV was administered via intraperitoneal route, with a booster dose given 28 days post-initial vaccination. Results: The immune responses in vaccinated fish (single and booster groups) showed that SDDV-FIV triggered both SDDV-specific IgM and total IgM production. SDDV-specific IgM levels were evident until 28 days post-vaccination (dpv) in the single vaccination group, while an elevated antibody response was maintained in the booster group until 70 dpv. The expression of immune-related genes (dcst, mhc2a1, cd4, ighm, cd8, il8, ifng, and mx) in the head kidney and peripheral blood lymphocytes (PBLs) of vaccinated and challenged fish were significantly upregulated within 1–3 dpv and post-SDDV challenge. Fish were challenged with SDDV at 42 dpv (challenge 1) and 70 dpv (challenge 2). In the first challenge, the group that received booster vaccinations demonstrated notably higher survival rates than the control group (60% versus 20%, P < 0.05). However, in the second challenge, while there was an observable trend towards improved survival rates for the booster group compared to controls (42% versus 25%), these differences did not reach statistical significance (P > 0.05). These findings suggest that the SDDV-FIV vaccine effectively stimulates both humoral and cellular immune responses against SDDV. Booster vaccination enhances this response and improves survival rates up to 42 dpv. Conclusions: This research provides valuable insights into the development of efficient SDDV vaccines and aids in advancing strategies for immune modulation to enhance disease management in the aquaculture of Asian seabass. [ABSTRACT FROM AUTHOR]

Simple Summary: This study presents an analysis of the gastrointestinal tract (GIT) of Malabar red snapper, comparing it with Asian seabass. It highlights slight differences in moisture content, crude protein, and ash between the two species, with Malabar red snapper showing higher essential fatty acid levels. Additionally, Malabar red snapper's GIT features protective mechanisms in the esophagus and distinct glandular densities in the stomach. The intestine also shows variations in goblet cell distribution and acid mucin secretion along its length. These findings offer valuable insights for the aquaculture sector, especially concerning Malabar red snapper. This study offers a comprehensive morpho-histological analysis of the gastrointestinal tract (GIT) of the Malabar red snapper. A comparison of its GIT morphology with that of the Asian seabass reveals similarities and differences between the two species. Additionally, the moisture content, crude protein, and ash in the fillets of Malabar red snapper and Asian seabass were slightly different, with Malabar red snapper exhibiting higher levels of essential fatty acids. Furthermore, higher levels of the polyunsaturated fatty acid (PUFA)/saturated fatty acid (SFA) ratio and docosahexaenoic acid (DHA)/eicosapentaenoic acid (EPA) ratio, and a lower omega-6/omega-3 ratio, were observed in Malabar red snapper compared to Asian seabass. The Malabar red snapper's esophagus featured protective mechanisms such as simple columnar epithelial cells, mucous-secreting glands, and goblet cells that were predominantly stained for acid and neutral mucosubstances. Furthermore, its stomach, with mucus cells that were weakly stained for acid mucosubstances, exhibited distinct regions with varying glandular densities, with the pyloric region featuring few glands. The pyloric caeca of the fish were composed of five finger-like structures and few goblet cells. Several goblet cells gradually increased from the anterior to the posterior region of the intestine. These findings provide useful insights for the aquaculture sector, focusing on Malabar red snapper. [ABSTRACT FROM AUTHOR]

This study was done to appraise the effects of the combination of dietary Gracilaria pulvinata and Sargassum ilicifolium on growth, immunity, and fatty acid profile in Asian seabass (Lates calcarifer). A total of 540 juveniles (36.06 ± 0.05 g) were stocked into eighteen 200 L tanks and divided into six experimental treatments, each in triplicate. Fish were fed diets containing 0 (control), 3% (SW3), 6% (SW6), 9% (SW9), 12% (SW12), and 15% (SW15) mixtures of both seaweeds powder in equal proportions (1 : 1) for 56 days. There was no improvement in weight gain parameters. Serum lysozyme and peroxidase activities in SW9 and SW12 treatments were significantly higher in compare to other treatments. The highest activities of skin mucus lysozyme, alkaline phosphatase, and total protease were observed in the SW12. Liver igf-1, il-1β, il-8, and lysozyme expression showed a rising trend up to SW9 and then decreased. Liver antioxidant enzymes activity and glutathione content showed a similar pattern of changes. Liver total antioxidant capacity was highest in the SW9 treatment, while the lowest value of liver malondialdehyde was observed in the 12% seaweed treatment. The amount of total n‐3 polyunsaturated fatty acids, especially docosahexaenoic acid, was higher in the SW12 and SW15 treatments in compare to others. Our findings suggest that adding 9%–12% of Gracilaria and Sargassum seaweed powder to the diet improves serum and mucosal immunity, antioxidant status, and fatty acid profile in L. calcarifer juveniles. [ABSTRACT FROM AUTHOR]

An experiment was conducted to assess the potential use of algal oil (AO) and vegetable (soya and palm oil; 1:1) oil (VO) mixtures as replacers for fish oil (FO) in Asian seabass (Lates calcarifer) diets. Six iso-nitrogenous (45% crude protein) and iso-lipidic (10% crude lipid) diets were formulated incorporating FO, VOs, and AO at 100:0:0 (T1), 0:0:100 (T2), 50:25:25 (T3), 25:50:25 (T4), 0:50:50 (T5), and 0:75:25 (T6), respectively. Each diet was given to five tanks (100 L with 10 fish in each) of juvenile fish (3.89±0.23 g initial weight) fed to satiation for 8 weeks. At termination, five replicate groups of fish were used for survival rate (SR), final weight, weight gain, consumed feed, feed conversion ratio (FCR), and specific growth rate (SGR) determination. Proximate composition, nutrient utilization, digestive enzyme activities of the pyloric caeca and intestine, and immune parameters were assessed using fish from three replications. A pooled sample consisting of three replicates was used for the determination of fatty acid profile and lipid quality indices. The liver samples from four replicate groups of fish were pooled into two samples and analyzed for Δ6-desaturase and Elovl5 gene expressions. The SR, growth performance, and feed conversion ratio were not significantly different (p>0.05) among treatments; however, feed consumption was significantly different (p<0.05) among treatments. The highest feed consumption (36.45±2.01 g/fish), final weight (32.41±2.78 g fish−1), and weight gain (28.53±2.78 g fish−1) were observed in T4 feeding group. Moreover, substituting FO with AO and VOs significantly affected (p<0.05) viscerosomatic index, intraperitoneal fat, carcass lipids, and lipid retention efficiency (LRE). The VSI (5.45±0.42) and IPF (1.53±0.03) were the lowest in the T4 feeding group (p<0.05). The 100% AO feeding group (T2) showed significantly lower carcass lipid and LRE (p<0.05). Specific lipase activity in pyloric caeca was significantly higher in T4 feeding group (p<0.05). Docosahexaenoic acid (22:6n-3) and eicosapentaenoic acid (20:5n-3) contents of fish carcasses were higher in the 100% AO-fed group. There was a significant (p<0.05) impact on the expression of Δ6-desaturase and Elovl5 genes in liver tissue. There were no significant differences (p>0.05) in innate immune parameters among the treatments. The findings of this study indicate that 75% of FO can be replaced by a combination of 25% AO and 50% VOs in Asian seabass (L. calcarifer) diets without impairing growth performance, nutrient utilization, and health status. These results can be used to develop more sustainable feeds that are less reliant on marine resources. [ABSTRACT FROM AUTHOR]

The document is an author index from the European Journal of Clinical Investigation, listing the names of various authors and their corresponding articles, presentations, or posters. It covers a wide range of topics and perspectives in clinical investigation, medical research, and scientific studies. [Extracted from the article]

Background: The bacteriocins, particularly derived from lactic acid bacteria, currently exhibit potential as a promising food preservative owing to their low toxicity and potent antimicrobial activity. This study aimed to evaluate the efficacy of lactocin 63, produced by Lactobacillus coryniformis, in inhibiting the deterioration of Lateolabrax japonicas during chilled storage, while also investigating its underlying inhibitory mechanism. The measurement of total viable count, biogenic amines, and volatile organic compounds were conducted, along with high‐throughput sequencing and sensory evaluation. Results: The findings demonstrated that treatment with lactocin 63 resulted in a notable retardation of bacterial growth in L. japonicas fish fillet during refrigerated storage compared with the water‐treated and nisin‐treated groups. Moreover, lactocin 63 effectively maintained the microbial flora balance in the fish fillet and inhibited the proliferation and metabolic activity of specific spoilage microorganisms, particularly Shewanella, Pseudomonas, and Acinetobacter. Furthermore, the production of unacceptable volatile organic compounds (e.g. 1‐octen‐3‐ol, hexanal, nonanal), as well as the biogenic amines derived from the bacterial metabolism, could be hindered, thus preventing the degradation in the quality of fish fillets and sustaining relatively high sensory quality. Conclusion: The results of this study provide valuable theoretical support for the development and application of lactocin 63, or other bacteriocins derived from lactic acid bacteria, as potential bio‐preservatives in aquatic food. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Members of the genus Erysipelothrix are emergent pathogens of cultured eels, as well as several characid and cyprinid species. Since 2013, E. rhusiopathiae has been reported from diseased barramundi (Lates calcarifer) cultured in North America; we recovered 8 E. rhusiopathiae isolates from diseased fish during different outbreaks from the same farm. The E. rhusiopathiae isolates from barramundi were compared phenotypically and genetically to E. piscisicarius isolates characterized from ornamental fish and E. rhusiopathiae recovered from aquatic and terrestrial animals. All barramundi isolates were PCR-positive for the surface protective antigen type B (spaB) gene, and shared ≥ 99.7% sequence similarity among concatenated multilocus sequence analysis gene sequences, indicating a high degree of genetic homogeneity. These isolates were > 99% similar to other spaB- positive isolates from marine invertebrates and marine mammals, consistent with findings for other spa types. The spaA and spaB isolates shared < 98% similarity, as well as < 90% similarity with spaC- positive E. piscisicarius. Similar clonality among the spaB isolates was observed using repetitive element palindromic PCR. In experimental intracoelomic injection challenges conducted to fulfill Koch postulates, 67% of exposed tiger barbs (Puntigrus tetrazona) died within 14 d of challenge. Our study supports previous work citing the genetic variability of Erysipelothrix spp. spa types and the emergence of members of the genus Erysipelothrix as nascent fish pathogens. [ABSTRACT FROM AUTHOR]

To evaluate the potential of Bifidobacterium animalis subsp. lactis BLa80 (BLa80) as a probiotic for Japanese seabass (Lateolabrax japonicus) aquaculture, we assessed the effects of BLa80 on the growth, immune response, antioxidant capacity, and intestinal microbiota of Japanese seabass. Fish fed normal feed (non-BLa80) or feed with 1×1010 CFU/g BLa80 were cultured for 15 (15d-BLa80) or 30 (30d-BLa80) days in a recycling seawater system indoor. The results showed that BLa80 supplementation improved survival, increased body mass index, and accelerated the growth of juvenile Japanese seabass. BLa80 treatment decreased the levels of oxidants (H2O2 and malondialdehyde) and increased the activities of antioxidants (catalase, glutathione peroxidase, glutathione S-transferase, serum superoxide dismutase, total antioxidant capacity, and glutathione). BLa80 reduced hindgut T-help 17 cell-related factors (IL-17, TNF-α, and RORγ) and increased regulatory T cell-related factors (IL-10 and Foxp3) comparing with control. BLa80 stimulated the hindgut anti-apoptotic gene Bcl-2 and downregulated the expression of pro-apoptotic genes (JNK, FoxO3a, PUMA, Bax, Apaf-1, Caspase-3, and Caspase-9). These results indicate that BLa80 supplementation significantly promotes the growth, enhances serum antioxidant capacity, reduces apoptosis of the hindgut and liver cells, improves innate immunity of the hindgut, and alters the structure of the hindgut microbiota of juvenile Japanese seabass. [ABSTRACT FROM AUTHOR]

A sudden disease outbreak was reported in Asian seabass (Lates calcarifer) cultured in open brackish water cages along the west coast of Kerala, India. Moribund samples with typical characteristic blister-like clusters of excessively hypertrophied cells were collected from the skin and fins. These tissues (white and pink nodule like growth) were excised, analyzed, and subjected to DNA extraction using the phenol chloroform isoamyl alcohol method. PCR targeting the universal conserved region of the major capsid protein (MCP) gene of lymphocystiviruses confirmed that the causative agent belongs to the genus Lymphocystivirus within the family Iridoviridae and hence called as Lymphocystis disease virus (LCDV). Phylogenetic analysis of the obtained isolate based on the MCP gene revealed maximum nucleotide similarity (91.68%) to LCDV strain, LCDV-PGF (GV genotype) found in painted glass fish (Chanda baculis/Parambassis baculis) isolated from Japan. To the best of our knowledge, this is the first PCR detection and phylogenetic analysis report of the major capsid protein gene of LCDV from Asian seabass cultured in India. [ABSTRACT FROM AUTHOR]

The article analyzes the practices of the pulp industry and its by-products in the far north of Espírito Santo, between the municipalities of Conceição da Barra and São Mateus, over the last 60 years. To do so, it presents the entry process of the pulp industry in this territory, known as Sapê do Norte, where more than 30 quilombola communities live. We will discuss the logic and form of eucalyptus plantations, their effects and, more recently, the ontological conflicts arising from the criticism coming from quilombolas and partner activists regarding the management methods of the place by the pulp company. In this way, we analyze the processes and practices of world construction of the colonizers - extractivism corporations, large landowners and the State - as colonial ontological designs. We conclude that it is possible to observe the updating of the colonial technologies of the pulp industry, from strictly coercive violence with the use of the State's military apparatus, to the era of conflict and criticism management, remaining as a fundamental part of the process of maintaining non-humans. and of humans as colonized subjects within a colonial world construction. [ABSTRACT FROM AUTHOR]

Coccidiosis is an important disease in juvenile fish because of severe intestinal injury during infection. We first reported the mixed infection of intestinal coccidia and its association with health status and pathological findings in juvenile Asian seabass (Lates calcarifer) cultured in Thailand. Two groups of Asian seabass, 60‐day fish and 90‐day fish, were sampled to investigate prevalence and coccidian infection intensity using morphological characterization and PCR. Phylogenetic analysis of 18S rRNA gene amplified from the intestines revealed Eimeria sp. and Cryptosporidium sp. infection. The prevalence of Eimeria sp. and Cryptosporidium sp. in sampled fish was 100%. Clinical outcomes assessed, using health assessment index (HAI) scoring and semi‐quantitative grading of intestinal lesions and inflammation, demonstrated that all fish developed variety of pathology and clinical illness; however, infection intensity in 60‐day fish was significantly higher (p <.05) than 90‐day fish. The HAI score of 60‐day fish was poorer than 90‐day fish, which correlated to a high infection intensity (r =.397), analysed by Pearson correlation coefficient. Overproduction of intestinal oxidants contributing to mucosal injury was examined by nitrotyrosine expression. The high production of reactive nitrogen species indicated severe inflammatory response, and intestinal injuries occurred mainly in the 60‐day fish. [ABSTRACT FROM AUTHOR]

BACKGROUND: Cold plasma exhibits broad applicability in the realm of fish sterilization and preservation. The combination process of plasma-activated water and dielectric barrier discharge (PAW-DBD) was optimized, and its disinfection effects on bass fillets were studied. RESULTS: The best conditions for disinfection of PAW-DBD were as follows. Bass fillets were soaked in PAW for 150 s, and then treated by DBD system at 160 kV for 180 s. The total viable count (TVC) reduced by 1.68 log CFU g-1. On the 15th day of refrigerated storage, TVC of PAW-DBD group was 7.01 log CFU g-1, while the PAW and DBD group exhibited a TVC of 7.02 and 7.01 log CFU g-1 on day 12; the TVC of the control group was 7.13 log CFU g-1 on day 6. The sensory score, water-holding capacity, and 2-thiobarbituric acid reactive substance values of the PAW-DBD group were significantly higher than those of PAW and DBD group (P < 0.05), whereas the TVC, Pseudomonas spp. count, and pH of the group were significantly lower (P < 0.05) during refrigerated storage. CONCLUSION: PAW-DBD treatment can enhance the disinfection effect, maintain good quality, and extend the storage period of bass fillets. [ABSTRACT FROM AUTHOR]

Black soldier fly larvae meal (BSFM) from Hermetia illucens has emerged as a dependable protein source in aquaculture. This study aimed to assess BSFM's digestibility in barramundi juveniles and compare it to soy protein concentrate meal (SPCM). Four diets (control, 30% BSFM; 30% SPCM; and commercial feed control) were tested on 1,800 barramundi juveniles (weight: 71.1 g) over 51 days in a recirculating aquaculture system (RAS). The final body weight (FBW) of fish fed with BSFM reached 222.2 (± 8.7), with a thermal-unit growth coefficient (TGC) of 4.33 (± 0.15) and a feed conversion ratio (FCR) of 1.04 (± 0.01). While BSFM and SPCM inclusion did not significantly impact FBW, body weight gain (BWG), TGC, or survival rates (P > 0.05), FCR increased. BSFM significantly raised total feed intake (P < 0.05) but did not affect daily feed intake (P > 0.05). Importantly, BSFM and SPCM inclusion did not alter diet apparent digestibility coefficient (ADC) for any nutrient groups (P > 0.05), with BSFM showing high ADC for dry matter (76.8%), crude protein (93.2%), and gross energy (83.9%). No significant difference (P > 0.05) was observed in these ADCs between BSFM and SPCM. The high digestibility of BSFM in warm seawater RAS (29.4°C) under high stocking density (33.7 kg m−3) supports its efficacy in contemporary barramundi farming. [ABSTRACT FROM AUTHOR]

Background: In this study, the protective immunity and immunogenicity of the monovalent and bivalent Streptococcus iniae and Vibrio harveyi vaccine were evaluated in Asian seabass. To analyze immune responses, 1200 Asian seabass with an average weight of 132.6 ± 25.4 g were divided into eight treatments in triplicates (50 fish per tank) as follows: S. iniae immunized by injection (SI), V. harveyi immunized by injection (VI), bivalent S. iniae and V. harveyi (SVI) immunized by injection, S. iniae immunized by immersion (SIM), V. harveyi (VIM) immunized by immersion, bivalent S. iniae and V. harvei (SVIM) immunized by immersion, phosphate-buffered saline (PBS) by injection (PBSI) and control group without vaccine administration (CTRL). Blood and serum samples were taken at the end of the 30th and 60th days. Then the vaccinated groups were challenged with two bacteria (S. iniae) and (V. harveyi) separately and mortality was recorded for 14 days. Results: This study reveals that there is no significant difference in the hematological parameters on the 30th and 60th days of the experiment in the vaccine-immunized groups compared to the CTRL group (P > 0.05). Meanwhile, there was no significant difference in the amount of serum albumin level, respiratory burst activity, and serum bactericidal activity in the vaccine-immunized groups compared to the CTRL group on the 30th and 60th days of the experiment (P > 0.05). Total protein on the 60th day (in the VI and SVI groups), globulin on the 30th day (in the VI and SVI groups) and the 60th day (in the VI group) compared to the CTRL and PBSI groups had a significant increase (P < 0.05). Complement activity (in the VI and SVI groups) and lysozyme (in the SI and SVI groups) increased significantly compared to the control group (P < 0.05). Serum antibody titer against S. iniae had a significant increase in the SI, VI, SVI and SVIM groups compared to the CTRL and PBSI groups (P < 0.05). Serum antibody titer against V. harveyi had a significant increase in the groups immunized with the vaccine compared to the CTRL and PBSI groups (P < 0.05). A significant increase in the relative percentage survival (RPS) following challenge with S. iniae in the SVI (86.6%), SI (83.3%,) and VI (73.3%) groups were observed compared to the CTRL (43.3%) and PBSI (40%) groups (P < 0.05). Also, a significant increase in the RPS after challenge with V. harveyi in the SVI group, VI 86.6%, SVI 83.3%, VIM 80% and SVIM 76.6% were observed compared to the CTRL (46.6%) and PBSI (50%) groups (P < 0.05). Conclusion: Overall, the results demonstrated that the bivalent vaccine of S. iniae and V. harveywas able to produce significant immunogenicity and RPS in Asian seabass [ABSTRACT FROM AUTHOR]

Feed additives are gaining popularity as dietary supplements with the potential to support growth, immune competence, and the general health of aquaculture species. This study aimed to evaluate growth performance and feed utilization in juvenile Asian seabass, Lates calcarifer, fed experimental diets containing enzymes derived from the solid-state fermentation (SSF) of Aspergillus niger and mannan oligosaccharides (MOS), both individually and in combination. Fish were fed six experimental diets: control (no additives), SSF (0.025% & 0.05%), MOS (0.1% & 0.2%), and combined SSF (0.025%) + MOS (0.05%). The feeding trial was conducted for ten weeks in triplicate for each experimental diet consisting of 51 fish in 120 L tanks. Following the collection of growth performance metrics, proximate analysis of muscle and feces samples was performed, and all datasets were statistically analyzed with One-way ANOVA. The results showed that the highest specific growth rate (SGR = 1.29%) and lowest feed conversion rate (FCR = 1.0) were obtained by fish fed the diet supplemented with SSF (0.025%) + MOS (0.05%). The synergistic effects of SSF as an exogenous enzyme source and MOS in supporting gut health likely facilitated enhanced nutrient digestibility and absorption, which supported the growth of juvenile Asian seabass. [ABSTRACT FROM AUTHOR]

Aquaculture has been one of the fastest-growing sectors in agriculture and plays an important role in supplying high quality proteins for humans. Genetic improvement for important traits is essential for increasing aquaculture production. The aquaculture of Asian seabass (Lates calcarifer) has become important in Southeast Asia and Australia and has expanded to other countries. In Singapore, a breeding program was initiated in 2004, aimed at improving growth rates, high omega-3 content, and disease resistance within Asian seabass populations. Many genomic resources have been developed to achieve these goals. The breeding program was established with a broodstock of 549 broodfish collected from the wilds of Indonesia, Thailand, Malaysia, and Singapore. Through four generations of family-based selection, utilizing a combination of conventional selective breeding, molecular parentage analysis, marker-assisted selection, and genomic selection techniques, three distinct elite lines of Asian seabass were successfully established. Each line consisted of approximately 200 broodfish. These lines were selected for growth, higher omega-3 content, and disease resistance, respectively. These traits have been improved without dramatically reducing genetic variation. This review provides a comprehensive overview of the methodologies adopted and status of the genetic improvement of the above-mentioned traits. Concurrently, certain gaps in the existing body of research have been identified. In the future, additional traits related to the ability to use feeds with reduced fishmeal, as well as adaptation to climate change and resistance against emerging diseases should be included in the breeding program. [ABSTRACT FROM AUTHOR]

Asian seabass, Lates calcarifer is among the most cultured aquaculture species in the Southeast Asian region due to its remarkable tolerance for a diverse environmental fluctuation. In aquaculture, salinity has a direct influence on many biological, physiological and market value of any cultured fish. This study investigated the impacts of different salinities (0, 15, & 30 ppt) on Asian seabass growth, body indices, feeding performance, organoleptic qualities, and production cost for 85 days. Ninety fish were reared in 700-liter tanks equipped with recirculation system with 10 fish each tank. They were fed with commercial marine feed. The findings revealed Asian seabass in 15 ppt attained significantly higher (p>0.05) body weight (470.40 ± 41.16 g), total length (31.51 ± 0.81 cm), total feed intake (309.28 ± 35.66 g/fish) and daily feed intake (3.64 ± 0.42 g/fish/day) compared to 30 ppt but remained insignificant with 0 ppt. Meanwhile, there was no significant difference (p<0.05) in terms of body weight gain, specific growth rate, body indices, and feed conversion ratio of Asian seabass when reared in different salinities. The organoleptic qualities showed that rearing Asian seabass in different salinities has no significant effect (p<0.05) on odour, appearance, texture, and flavour score. However, the overall acceptance score of Asian seabass reared in 30 ppt (3.53 ± 0.22) was significantly higher (p>0.05) compared to 15 ppt but remained insignificant with 0 ppt. Economically, Asian seabass cultured in 15 ppt yielded the most optimal conditions for profitable production. The findings conclude 15 ppt can promotes enhanced growth performance and profitability, while 0 ppt and 30 ppt can promote consumer acceptance positively. [ABSTRACT FROM AUTHOR]

In 2015 and 2016, two Barramundi (Lates calcarifer) farms in Singapore reported a disease outbreak characterized by lethargic behavior, pronounced inappetence, generalized skin lesions, erosions of the fins and tail, and ultimately high mortality in their fish. Next-generation sequencing and PCR confirmed presence of a novel virus belonging to the Alloherpesviridae family, Lates calcarifer herpesvirus (LCHV), which was subsequently isolated and cultured. We characterize, for the first time, the complete genome of two cultured LCHV isolates. The genome contains a long unique region of approximately 105,000 bp flanked by terminal repeats of approximately 24,800 bp, of which the first 8.2 kb do not show any similarity to described genomes in the Alloherpesviridae family. The two cultured isolates share 89% nucleotide identity, and their closest relatives are the viruses belonging to the genus Ictalurivirus. Experimental infections using one of the cultured LCHV isolates resulted in identical clinical signs as originally described in the index farm, both in intraperitoneal-injection infected fish and cohabitant fish, with mortality in both groups. Histopathological analysis showed pronounced abnormalities in the gills. Virus culture and PCR analysis confirmed the replication of LCHV in the infected fish, and thus Koch's postulates were fulfilled. [ABSTRACT FROM AUTHOR]

Purpose: To study the morphology of all the life stages and the life cycle of the parasitic isopod Cymothoa indica Schioedte and Meinert, 1884, and its prevalence in different commercial fishes in the Chilika Lagoon, India. Methods: From April 2021 to December 2022, different life stages of the said parasites were collected from five different fish species from four localities of the Chilika Lagoon. The parasites were carefully removed from the host with a pair of forceps and then identified following standard literature and description. The morphology of all life stages, life cycle, and prevalence of the isopod C. indica were carried out as per the standard protocol. Results: A total of 1252 host fishes were analysed. The total prevalence was 44.5%. The host with the highest prevalence of C. indica was Glossogobius giuris, with 58.79% of the hosts parasitized by at least one parasite individual. Followed by the host Datnoides polota (50.98%), Johnius dussumieri (46.25%), Etroplus suratensis (28.45%) and the least prevalence was in Lates calcarifer (14.70%). The description of the life stages is based on the observation of 523 females, 116 males, 46 Juveniles, and 50 embryonic stages of the said parasites. Conclusion: The description of all the life stages and life cycles certainly helps to identify this species with clarity and ease in understanding the species' biology. In future, this study may be helpful in the effective management towards the improvement of aquaculture productivity. [ABSTRACT FROM AUTHOR]

The article presents the discussion on Palmer projectile point, named after Palmer Mountain near the Hardaway site in North Carolina, dating back to the Early Archaic period around 9,500 to 8,000 BP. Topics include identified Palmer points as predecessors to Kirk Corner Notch points, noting their distribution across the North Carolina Piedmont and neighboring region; and characteristics, distribution, and evolutionary relationship of Palmer points.