Lateolabrax Japonicus Research Articles

Autochthonous probiotic bacteria improve intestinal pathology and histomorphology, expression of immune and growth-related genes and resistance against Vibrio alginolyticus in Asian seabass (Lates calcarifer).

The study isolated two strains of intestinal autochthonous bacteria Lactiplantibacillus plantarum1 (MH155966.1) (L1) and Lactiplantibacillus plantarum2 (MH105076.1) (L2) from the Choobdeh Abadan region. The aim of this study was to investigate the effects of different strains of probiotic bacteria on the growth performance, digestive enzyme activity, histopathologic and histomorphometric characterization of the intestine, expression of immune and growth related genes, and evaluate Lates calcarifer resistance against Vibrio alginolyticus. To achieve this, for each treatment 60 L. calcarifer juveniles (75 ± 12g) were randomly distributed in three fiberglass tanks (300L) and fed for 45 days. The treatments were established as Diet 1 (control diet); L1 (diet with Lb. plantarum isolated 1); L2 (diet with Lb. plantarum isolated 2) with a bacterial concentration of 1 × 109 CFU/g. Nine fish from each treatment were sampled and examined, after euthanasia. The fish were placed 2cm from the beginning of the intestine for microscopic sampling of villi height, villi width and thickness of the epithelium, with 3 treatments: The result showed differences in the mean values of total weight were found at the end of the experiment. After 45 days of culture, the fish fed with L1 had higher (P < 0.05) growth performance than the other treatment groups. But at the end of the trial, in L2, the digestive enzyme activities were higher (P < 0.05) than the other treatment groups. The fishes fed diets supplemented with the L2 group, like the digestive enzyme activities test, presented an increase in the thickness of the epithelium of the intestine, and villus height, and villus width were greatest in L2. Fish feeding with L1 and L2 probiotics induced higher transcription levels of interleukin-10 (IL-10), granulocyte-macrophage colony-forming cells (GMCFC), epidermal growth factor (EGF), and Transforming Growth Factor Beta (TGF-β) genes in the gut, which may correlate with better immune and hematological parameters in these groups. The results of the challenge test revealed that the percentage of survival was significantly higher in L1 (76.2%) and L2 (80.95%) treatments than in the control (P < 0.05). These results indicate that host-derived probiotics (Lb. plantarum) have significant potential as important probiotics to enhance nutrient utilization, Digestive enzymes, and metabolism by increasing the gut surface area of Lates calcarifer juveniles at 45 days of culture.

River-sea migration patterns of juvenile Japanese seabass influence migrations in subsequent stages

The Japanese seabass Lateolabrax japonicus, an important commercial fishery species, exhibits partial migration, where some individuals migrate upstream into rivers, and others inhabit estuarine and coastal areas within the same population. Although this migratory behavior has been documented in juvenile seabass, the prevalence of river use and the ecological significance of partial migration in subsequent developmental stages remain unclear. To understand the river use of subadult and adult Japanese seabass, we estimated the river use history using otolith Sr/Ca ratios from individuals captured in both marine and riverine environments. Based on hierarchical clustering with Dynamic Time Warping, Sr/Ca ratios at age 0 were clustered into three habitat use patterns: coastal resident, estuarine resident, and river migrant. Groups that used coastal and riverine habitats at age 0 tended to use coastal and riverine habitats, respectively, from spring to fall of age 1 and above, with overlapping distributions during winter. Subadult and adult river use patterns were linked to juvenile river use, indicating a carryover effect. Additionally, seasonal migration between the sea and rivers became less active with age, and the high growth sustained by river use also declined with age, suggesting that the benefits of river use are less for older (subadult and adult) seabass. This study highlights that juvenile habitat use experience drives subadult and adult partial migration of Japanese seabass, with individuals seeking environments adapted from past experiences. Our findings indicate that the seabass population consists of individuals adapted to various environments, from the sea to the rivers, maximizing the use of biological productivity.

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.

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.

Effect of dietary supplementation of selenium-L-methionine on growth, antioxidant capacity and resistance to nitrite stress of spotted seabass (Lateolabrax maculatus) under two rearing water temperatures

A 10-week feeding trial, followed by 24-h nitrite stress, was performed to evaluate the effects of dietary selenium-L-methionine (Se-Met) on growth, Se accumulation, antioxidant capacity, transcripts of selenoproteins and histological changes of muscle as well as resistance to nitrite stress in spotted seabass (Lateolabrax maculatus) reared at optimal (27 °C) and high (33 °C) temperatures. Five experimental diets were formulated to contain 0, 0.9, 1.8, 3.5, and 7.0 mg Se-Met/kg. Each diet was fed to fish (2.60 ± 0.2 g) in two parallel treatments at 27 or 33 °C. The results showed that elevated temperature (33 °C) induced thermal stress in fish, and fish under thermal stress exhibited lower weight gain (WG) and hepatosomatic index (HSI) but a higher condition factor (CF) compared to those reared at 27 °C. However, the growth and feed utilisation were promoted in L. maculatus with 0.9 to 3.5 mg/kg Se-Met treatments. The protein and lipid content in the muscle increased with the dietary Se-Met level, and the total Se level in the whole body and muscle showed a linear increase with dietary Se-Met supplementation. Thermal stress changed the histology of the muscle, leading to raised levels of malondialdehyde (MDA), reduced antioxidant parameters in the serum and liver, and a decrease in the transcripts of selenoprotein genes in the muscle. Meanwhile, increased antioxidant capacity of serum and liver and up-regulated transcripts of selenoprotein of muscle were observed in L. maculatus reaching a maximum with 3.5 mg Se-Met/kg treatment. After 24 h of nitrite stress, thermal stress exacerbated oxidative damage caused by nitrite stress in L. maculatus. In contrast, dietary Se-Met enhanced the resistance to nitrite stress of L. maculatus fed with Se-Met enriched diets containing 0.9 to 1.8 mg Se-Met/kg. Based on the effects of dietary Se-Met on the growth, antioxidant capacity and resistance to nitrite stress of L. maculatus, this study suggests that the optimal range of Se-Met supplementation in L. maculatus diets is 1.80 to 2.39 mg Se-Met/kg of diet at 27 °C and 1.80 to 4.46 mg Se-Met/kg of diet at 33 °C.

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&lt;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.

Tenderization of giant squid (Dosidicus gigas) meat pretreated with pulsed electric field and Asian seabass trypsin with the aid of vacuum impregnation

Giant squid (Dosidicus gigas) meat (GSM) generally has a tough texture, significantly lowering its acceptability by consumers. To enhance tenderness, GSM was pretreated with pulsed electric field (PEF) at 250 V for 5 min (PEF-GSM). Thereafter, PEF-GSM was soaked in partially purified trypsin (PPT) from pyloric caeca of Asian seabass obtained from ammonium sulfate precipitation (40%–60% saturation). The soaking was done at various concentrations of PPT (0, 5, 10 and 20 units/mL) with the aid of vacuum impregnation (VI) (2 cycles). Subsequently, PPT-soaked GSM samples were incubated at 60 °C for 5 and 10 min, followed by cooking at 100 °C for 2 min. For quality assessment, untreated cooked GSM (CON-GSM) was also prepared. Lightness of PEF-GSM samples increased (p < 0.05), compared to that of CON-GSM. After hydrolysis with PPT, myofibrillar proteins were degraded with coincidental upsurge in AAGC (α-amino group content). Protein degradation and AAGC became more pronounced with increasing PPT concentration and incubation time. PEF-GSM treated with PPT at 20 units/mL (PEF-GSM-20) and incubated for 10 min had the decreased firmness and toughness values, however its cooking loss slightly increased. Degradation of myofibrillar proteins was reconfirmed by FTIR spectra and microstructure alteration. PEF-GSM-20 with incubation at 60 °C for 10 min showed higher overall likeness score (p < 0.05), indicating a significant improvement in acceptability of consumers. Thus, combined application of PEF, PPT (20 units/mL) and VI before incubation at 60 °C for 10 min significantly enhanced the eating quality of GSM, making it more preferable for consumers.

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.

Characterization of Myxovirus resistance (Mx) gene from Chinese seabass Lateolabrax maculatus: Insights into the evolution and function of Mx genes

Chinese seabass (Lateolabrax maculatus) stands out as one of the most sought-after and economically significant species in aquaculture within China. Diseases of L. maculatus occur frequently due to the degradation of the germplasm, the aggravation of environmental pollution of water, and the reproduction of pathogenic microorganisms, inflicting considerable economic losses on the Chinese seabass industry. The Myxovirus resistance (Mx) gene plays pivotal roles in the antiviral immune response ranging from mammals to fish. However, the function of the Mx gene in L. maculatus is still unknown. Firstly, the origin and evolutionary history of Mx proteins was elucidated in this study. Subsequently, an Mx gene from L. maculatus (designed as LmMxA gene) was identified, and its functions in combating antiviral and antibacterial threats were investigated. Remarkably, our findings suggested that while Mx group genes were present in chordates, DYN group genes were present in everything from single-celled animals to humans. Furthermore, our investigation revealed that the LmMxA mRNA level increased in the kidney, spleen and liver subsequent to Vibrio anguillarum and poly(I:C) challenged. Immunofluorescence analysis indicated that LmMxA is predominantly localization in the nucleus and the cytoplasm. Notably, the expression of MAVS, IFN1 and Mx1 increased when LmMxA was overexpression within the EPC cells. Moreover, through assessment via cytopathic effect (CPE), virus titer, and antibacterial activity, it becomes evident that LmMxA exerts a dual role in bolstering both antiviral and antibacterial immune responses. These compelling findings laid the foundation for further exploring the mechanism of LmMxA in response to innate immunity of L. maculatus.

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&lt;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.

VmmScore: An umami peptide prediction and receptor matching program based on a deep learning approach

Peptides, with recognized physiological and medical implications, such as the ability to lower blood pressure and lipid levels, are central to our research on umami taste perception. This study introduces a computational strategy to tackle the challenge of identifying optimal umami receptors for these peptides. Our VmmScore algorithm includes two integral components: Mlp4Umami, a predictive module that evaluates the umami taste potential of peptides, and mm-Score, which enhances the receptor matching process through a machine learning-optimized molecular docking and scoring system. This system encompasses the optimization of docking structures, clustering of umami peptides, and a comparative analysis of docking energies across peptide clusters, streamlining the receptor identification process. Employing machine learning, our method offers a strategic approach to the intricate task of umami receptor determination. We undertook virtual screening of peptides derived from Lateolabrax japonicus, experimentally verifying the umami taste of three identified peptides and determining their corresponding receptors. This work not only advances our understanding of the mechanisms behind umami taste perception but also provides a rapid and cost-effective method for peptide screening. The source code is publicly accessible at https://github.com/heyigacu/mlp4umami/, encouraging further scientific exploration and collaborative efforts within the research community.

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)

Integrated assessment of trace elements in a marine ranching area based on multi-species and multi-level biomarkers: a case study in China’s national-level marine ranching demonstration area

The goal of this study was to evaluate the trace element pollution in a marine ranching area in China based on molecular responses (expression of metallothionein and antioxidant enzyme genes), and biochemical biomarkers (metallothionein content, antioxidant enzyme activities, and malonaldehyde level) in four indicator species. We collected samples of two fish (Lateolabrax maculatus and Sebastes schlegelii), one crustacean (Charybdis japonica), and one gastropod (Rapana venosa) from the western Furong Island marine ranching area and from an adjacent area in March 2022 and measured the trace element content in these indicator species as well as in the seawater and sediment. We found that the bioaccumulation characteristics of trace elements and the response patterns of biomarkers were species specific. Moreover, not every biomarker was significantly correlated with environmental trace element content. We then established two biomarker combinations indicative of trace element pollution in seawater and sediment, respectively, based on the correlation between biomarkers and trace element contents. The selected biomarkers were integrated using integrated biomarker response version 2 (IBRv2). IBRv2 values in the studied marine ranching area were lower than those in the adjacent area. Additionally, these values were consistent with the bioaccumulation of trace elements in the indicator species, the integrated trace element pollution index for seawater, and the potential risk index for sediment. These results show that this multi-biomarker and multi-species IBRv2 approach provided a comprehensive diagnosis of trace element pollution in the marine ranching area. Therefore, its application may be beneficial for marine environmental monitoring and management in view of the ecotoxicological impact of pollutants on organisms.

Comparison of nutritional compositions and heavy metals analysis between wild and farmed Tilapia (Oreochromis sp.) and Asian Seabass (Lates sp.) in Sabah, Malaysia

In Sabah, Malaysia, Tilapia and Asian seabass are culturally and economically important seafood choices. Understanding their nutritional content and contaminants, both wild-caught and farmed, is crucial as demand increases. This study aimed to analyze the proximate composition and heavy metals concentrations in Tilapia and Asian Seabass fish flesh, and compare the wild-caught and farmed samples. The results revealed significant nutritional variations between the two groups. Wild-caught Tilapia exhibited higher protein content (16.90 ± 0.50 %), carbohydrate levels (0.7 ± 0.10 %), moisture (80.25 ± 0.58 %), and ash content (9.22 ± 1.27 %) while farmed Tilapia displayed elevated fat content (3.55 ± 0.05 %) and energy values (94.5 kcal per 100 g). Iron concentrations in both wild and farmed Tilapia remained within safe limits for human consumption and Zinc was detected in wild Tilapia only. Meanwhile, the farmed Asian Seabass demonstrated higher protein (18.45 ± 0.25 %), fat (0.9 ± 0.10 %), carbohydrate (0.8 ± 0.20 %), ash content (21.04 ± 2.1 %), and energy values (85.5 kcal per 100 g) compared to the wild. Further study can be conducted to study the benefits of these fish species to human health upon consumption.

Effects of oxidized fish oil diet supplemented with tea polyphenols on intestinal health and liver metabolism of spotted sea bass (Lateolabrax maculatus)

In this study, the effects of oxidized fish oil diet supplemented with tea polyphenols (TP) on the intestinal health and liver metabolism of spotted sea bass (Lateolabrax maculatus) were investigated. Five kinds of diets were designed. They were the negative control (NC) group without antioxidants and TP, the positive control (PC) group with antioxidants, three experimental groups were supplemented with 0.05 %, 0.10 %, and 0.15 % TP (TP1, TP2, and TP3). The fish with a mean body weight of 11.43±0.02 g was fed on five diets for 56 days. The results showed that TP1 improved lipase (LPS) activity. The intestinal superoxide dismutase (SOD) activity of TP1 was significantly higher than that of the NC group and was not different from that of the PC group. Histological observation of the intestine showed that the height of the intestinal villus was significantly increased and the width of the intestinal villus was significantly decreased in TP1, while the muscular thickness layer did not change significantly. Furthermore, inflammatory symptoms were present in the intestines of all groups, with improvements observed in TP1 and TP3. By intestinal microbial analysis, the results showed that the ACE and Chao1 indexes of TP1 were significantly higher than those of the NC and PC groups, and the Shannon and Simpson indexes were significantly lower than those of the NC and PC groups. Regarding the structure of the microbiome community, there were a lot more Fusobacteriota in TP2 and TP3 at the phylum level, and there were a lot more Cetobacterium at the genus level. The metabolomic analysis of TP1's liver showed that it controls the metabolism of amino acids, nucleotides, cofactors, vitamins, energy, and carbohydrates. The results showed that adding TP to the oxidized fish oil diet enhanced the intestinal health and liver metabolism of spotted sea bass.

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.

Comparative analysis of the structural and compositional change of spotted sea bass (Lateolabrax maculatus) gut microflora following Aeromonas veronii infection and the effects of Lactobacillus plantarum on these changes

Growing evidence suggests a close relationship between gut microbiota and infectious diseases. However, the specific role of gut microbiota in host-pathogen interactions during aquaculture-related infections remains poorly understood. This study investigated the diversity and composition of gut microbiota communities in Aeromonas veronii-infected Lateolabrax maculatus using high-throughput sequencing. The results revealed significant changes in the structure and composition of L. maculatus gut microbiota after A. veronii infection. Over time, Bacteroidetes and Firmicutes decreased significantly, while Proteobacteria increased significantly after A. veronii infection. Most intestinal bacteria showed a decline in abundance over time, with probiotics (such as Lactobacillus) experiencing a significant decrease and pathogens (such as Aeromonas) showing a significant increase. Conversely, no differences were observed in the structure and composition of gut microbiota between healthy L. maculatus and those infected with A. veronii after treatment with Lactobacillus plantarum; no changes in relative abundances of other bacterial phyla or genera except for Aeromonas. Furthermore, intestinal flora’s structural diversity and composition differed significantly from untreated L. maculatus infected with A. veronii. These findings suggest alterations in the structure and composition of gut microbiota following A. veronii infection. L. plantarum can maintain a dynamic balance within the intestinal flora, reducing the potential risk of pathogen infections.

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