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Abstract: Hemocytes are a critical component of the mussel defense system and the present study aims at investigating their spreading and oxidative properties during phagocytosis under in vivo experimental stress conditions. The spreading ability was measured by an automated cell analyzer on the basis of the circularity, a parameter corresponding to the hemocyte roundness. The oxidative activity was investigated by micromethod assay, measuring the respiratory burst as expression of the fluorescence generated by the oxidation of specific probe. Following the application of high temperature and exposure to air, there was evidence of negative modulation of spreading and oxidative response, as revealed by a cell roundness increase and fluorescence generation decrease. Therefore, the fall of respiratory burst appeared as matched with the inhibition of hemocyte morphological activation, suggesting a potential depression of the phagocytosis process and confirming the application of the circularity parameter as potential stress marker, both in experimental and field studies. [Copyright &y& Elsevier]

The article discusses a study on Bonamia-like microcell parasites such as Bonamia (B.) ostreae and B. exitiosa that were detected in the flat oyster Ostrea (O.) edulis L. from the Adriatic Sea in Italy. The O. edulis specimens that were collected and used as study subjects totaled to 750. The procedure of the study consisted of several steps such as microscopical examination, molecular analysis, and sequence determination and comparison. The results indicated the presence of B. ostreae throughout the Manfredonia Gulf since 1990.

Introduction: The intricate habitats of aquatic organisms, coupled with the prevalence of pathogens, contribute to a high incidence of various diseases, particularly bacterial infections. Consequently, the formulation of sustainable and effective disease management strategies is crucial for the thriving aquaculture sector. Methods and results: In this investigation, a strain of Bdellovibrio bacteriovorus , designated B. bacteriovorus FWA , was isolated from a freshwater fish pond. Identification was achieved through microscopic examination of morphological characteristics, biochemical property assessment, and phylogenetic analysis. The lysogenic capability of B. bacteriovorus FWA was evaluated, revealing its effectiveness in lysing Escherichia coli , Aeromonas hydrophila , Vibrio alginolyticus , Vibrio parahaemolyticus , and Edwardsiella tarda. Physiological analysis indicated that the optimal ratio of B. bacteriovorus FWA to host bacteria was 1:10,000, with strict aerobic requirements. The optimal pH range for growth and reproduction was 7.0–8.0, the ideal temperature was found to be 30–35°C, with a preferred Na+ concentration of 0% and a Ca2+ concentration of 15–25 mM. Additionally, B. bacteriovorus FWA demonstrated enhanced lytic activity against bacteria in aquaculture effluent while effectively managing ammonia-nitrogen levels. Discussion: In summary, B. bacteriovorus FWA holds significant promise for development as a probiotic agent in aquaculture. [ABSTRACT FROM AUTHOR]

The top shell, Turbo sazae, occurs commonly in the shallow rocky subtidal area of Jeju Island off the south coast of Korea, and it is one of the most valuable gastropod resources supporting the local shellfish industry. T. sazae landings in Jeju have declined dramatically in recent years, although the factors involved in this decline are yet to be identified. Recent studies also have reported that T. sazae is expanding its distribution range to the east coast of Korea, possibly due to the increasing seawater temperature. In this study, we investigated the hemocyte responses of T. sazae to elevated seawater temperatures in order to gain a better understanding of its immunological response to higher water temperatures. In this experiment, we exposed top shells to a gradual increase in seawater temperature, ranging from 22 °C to 30 °C, over a span of 9 days. We employed flow cytometry to assess various cellular immune responses, including hemocyte viability, phagocytosis capacity, and the production of reactive oxygen species (ROS) in T. sazae. The results showed that top shells exposed to elevated seawater temperature exhibited a significant decrease in phagocytosis capacity and an increase in ROS production after 3 days of the experiment. These findings indicate that an elevated seawater temperature imposes a stressful condition on T. sazae, characterized by reduced phagocytosis capacity and increased oxidative stress. [ABSTRACT FROM AUTHOR]

The Pinna nobilis, a Mediterranean mollusc, has suffered population declines due to a massive mortality event associated with various factors including the parasite Haplosporidium pinnae. Some populations show resilience, possibly due to local environmental conditions. In this study, a molecular multiplex PCR method was developed using species‐specific primers targeting Internal Transcribed Spacer (ITS) regions of P. nobilis and P. rudis, allowing accurate species identification and hybrid detection. Samples from Mediterranean areas were analysed, including putative hybrids and individuals from five other bivalve species. DNA was isolated, ITS regions were amplified and sequenced, and phylogenetic analyses confirmed species differentiation and primer specificity. The multiplex‐PCR successfully identified P. nobilis, P. rudis, and their hybrids based on distinct amplicon patterns. This study highlights the value of molecular tools in species conservation, especially for monitoring and managing hybridization, supporting effective biodiversity conservation strategies. [ABSTRACT FROM AUTHOR]

Aquaculture has rapidly emerged as one of the fastest growing industries, expanding both on global and on national fronts. With the ever-increasing demand for proteins with a high biological value, the aquaculture industry has established itself as one of the most efficient forms of animal production, proving to be a vital component of global food production by supplying nearly half of aquatic food products intended for human consumption. As in classic animal production, the prevention of diseases constitutes an enduring challenge associated with severe economic and environmental repercussions. Nevertheless, remarkable strides in the development of aquaculture vaccines have been recently witnessed, offering sustainable solutions to persistent health-related issues challenging resilient aquaculture production. These advancements are characterized by breakthroughs in increased species-specific precision, improved vaccine-delivery systems, and innovations in vaccine development, following the recent advent of nanotechnology, biotechnology, and artificial intelligence in the -omics era. The objective of this paper was to assess recent developments and milestones revolving around aquaculture vaccinology and provide an updated overview of strengths, weaknesses, opportunities, and threats of the sector, by incorporating and comparatively discussing various diffuse advances that span across a wide range of topics, including emerging vaccine technologies, innovative delivery methods, insights on novel adjuvants, and parasite vaccine development for the aquaculture sector. [ABSTRACT FROM AUTHOR]

Bivalve mollusks may be affected by numerous infectious diseases, which cause high mortality rates and economic burdens for producers. Another challenge for bivalve aquaculture is the protection of farms from human contamination, such as sewage and stormwater discharges. Ilha Grande Bay (IGB), located in Rio de Janeiro state, is the largest Brazilian producer of scallops (Nodipecten nodosus). This region has recently suffered a mass mortality of mollusks, and several environmental contaminants have been reported in the area. To contribute to the elucidation of scallop collapse and better characterize the human impacts, this study assessed the circulation of mollusk (Ostreid herpesvirus-1 [OsHV-1]) and human (mastadenovirus [HAdV] and norovirus GII) viral pathogens in waters and animals produced at IGB. Neither water nor animals were positive for OsHV-1. However, of the 7 points analyzed, 5 points showed contamination by HAdV or norovirus. HAdV and norovirus were detected in 5.5 and 6.9% of the analyzed water samples, respectively, in concentrations ranging from 2.39 × 10 3 to 1 × 10 5 genome copies/L. One scallop sample was positive for norovirus (4.5%). These results demonstrate human contamination in the region, presenting a risk of consumer contamination, and a non-association between OsHV-1 and the mass mortality described in scallops., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Studying inflammatory responses induced by vaccination can contribute to a more detailed understanding of underlying immune mechanisms in lumpfish (Cyclopterus lumpus). Tissue samples from lumpfish intraperitoneally immunized with a divalent oil-adjuvanted vaccine (Aeromonas salmonicida and Vibrio salmonicida) at water temperatures of 5, 10, and 15°C were collected at 630 day degrees and 18 weeks post injection. The relative amount of secretory and membrane-bound immunoglobulin M (IgM) gene transcripts in the head kidney was determined by qPCR. Vaccine-induced inflammatory lesions were assessed on histological sections of abdominal pancreatic/intestinal tissue from vaccinated fish in all three temperature groups. Inflammatory cells forming dense aggregations in lesions showed proliferative activity, many of which were identified as eosinophilic-granulocyte-like cells. IgM+ cells were scattered in inflammatory tissue dominated by connective tissue, showing no difference in numbers between lesions from fish vaccinated at 5, 10, and 15°C. Relative gene expression analysis of secretory and membrane-bound IgM revealed low overall expression in the head kidney of vaccinated fish at both 630 day-degrees and 18 weeks post injection. The results of this study indicate that the vaccine stimulated prolonged local inflammatory responses at the injection site, which were not influenced by temperature., (© 2024 The Author(s). Journal of Fish Diseases published by John Wiley & Sons Ltd.)

This study examined the effects of dietary supplementation of queen scallop Aequipecten opercularis with an indigenous strain of lactic acid bacteria (LAB), Lactiplantibacillus plantarum I, previously isolated from its digestive tract, on gut microbial populations and growth rates during cultivation under simulated climate change conditions (pH 7.8, T = 16 ± 2 °C). After one month of feeding, the results showed a noticeable reduction in aquaculture diseases causing pathogens while maintaining sufficient viable Lpb. plantarum I cells. A higher pH and temperature resulted in higher growth rates, measured by the weight and length of scallops, compared to the control group. The results obtained shed light on the influence of the addition of lactic acid bacteria on the growth of bivalve mollusks under normal and climate change conditions, and provide control of pathogenic microorganisms. In the context of climate change, host-pathogen interactions need to be recognized and put under control by applying natural solutions to minimize the environmental footprint. [ABSTRACT FROM AUTHOR]

This review summarizes the current knowledge on immune defence activities of the European sea bass Dicentrarchus labrax by reporting the consistent amount of work done on this economically-important species. A draft genome sequence is available for this species, together with whole transcriptomes from lymphoid and nonlymphoid tissues. Available full-length coding sequences of many immunoregulatory and immune-related genes allow for targeted quantitative PCR analysis, nowadays needed for -omics data verification, ex vivo and in vitro. The first anti-T cells monoclonal antibody teleost-wise was obtained in sea bass, followed by several monoclonal and polyclonal markers of lymphocyte populations, namely T cells (pan-T, CD3e, TcR?, CD45), and B cells (IgM, IgT, IgD). The combined use of molecular and biochemical tools enabled investigations on innate and acquired immune responses of sea bass in unstimulated/stimulated fish, along the development and under variable environmental conditions and food regimes. An overview of sea bass viral and bacterial pathogens and available vaccines against these microorganisms is also provided. The knowledge accumulated in the past 25 years validates the European sea bass as a reference marine model in the field of fish immunology. [ABSTRACT FROM AUTHOR]

Replicated studies are advantageous for optimizing larval rearing of the Eastern oyster (Crassostrea virginica) and increasing the availability of high-quality seed for the continued expansion of the U.S. oyster aquaculture industry. Although small-scale systems using live algal feeds have been used successfully, rearing larvae on algae concentrate presents additional challenges. To determine the feasibility of rearing oyster larvae in small-scale systems using algae concentrate, oyster larvae were raised for 2 weeks in replicate control (1,000 L) and microcosm (17 L) tanks. Five aeration strategies were tested in the microcosms in two separate trials. Results of this study indicate similar survival in small systems compared to controls through the appearance of eyed larvae. Accumulated algae and pink biofilm formation in microcosms using polyvinyl chloride (PVC) airlifts suggest that this aeration strategy is undesirable. One- and 5-mL air injectors maintained higher overnight oxygen levels than controls. The recovery of more eyed larvae after 14 dpf in control systems may be the result of significant temperature fluctuations in microcosms. Overall, this study demonstrates that algae concentrate can be used to rear oyster larvae in small-scale systems, providing a live feed alternative that saves space and labor in replicated studies. [ABSTRACT FROM AUTHOR]

The efficacy of dietary β‐glucan supplementation in golden trevally (Gnathanodon speciosus) was evaluated. The fish were fed five different diets supplemented with 0%, 0.05%, 0.10%, 0.20%, and 0.40% β‐glucan for 56 days. After 56 days of culture, survival was the highest when the fish were fed a 0.10% β‐glucan diet. Growth rates were higher in fish fed diets supplemented with all β‐glucan levels. Lymphocytes increased when the fish were fed a diet supplemented with 0.05% β‐glucan, and thrombocytes increased when the fish were fed 0.2% and 0.4% β‐glucan‐supplemented diets. The total aerobic bacteria count in the gut of golden trevally was higher (p < 0.05) and the total Vibrio counts in the gut of golden trevally were lower (p < 0.05) when the fish were fed any level of β‐glucan. Flesh protein content was higher and flesh lipid content was lower when fish were fed β‐glucan‐supplemented diets at levels greater than 0.1%. When challenged with Streptococcus iniae, fish fed diets containing 0.10% or 0.20% β‐glucan exhibited the highest survival rates. The current results suggest that supplementation with 0.05 to 0.2% β‐glucan in the diet would be beneficial for the culture of the golden trevally. [ABSTRACT FROM AUTHOR]

Ocean-based industries like shipping, aquaculture, and wind energy are growing at an unprecedented rate resulting in challenges related to siting and environmental management. As marine aquaculture and other oceanbased industries continue to expand, robust marine spatial planning analyses that reconcile existing ocean uses and integrate pertinent environmental and planning data are critical for identifying compatible locations. In this study, a series of geospatial analyses were used for aquaculture siting within and around a heavily trafficked and highly utilized maritime port in the San Diego Bay area of California, USA. Using a centralized geodatabase representing key aquaculture planning spatial datasets, recommendations for specific areas for aquaculture were developed based on appropriate environmental conditions for candidate shellfish and algae aquaculture species culture systems. Areas that were known constraints were first identified to determine potentially usable areas for shellfish and macroalgae (i.e., seaweed) aquaculture using an exclusion analysis, a type of multi-criteria decision analysis, to eliminate all areas without compatibility. Within the remaining usable area, we further considered shellfish and macroalgae culture system-specific factors within a 'culture systems analysis' to determine where different culture systems have potential for success. This analysis provides a foundation of coastal intelligence for guiding the aquaculture industry and natural resource managers towards appropriate siting decisions. This study can serve as a replicable example of aquaculture spatial planning approaches for siting sustainable aquaculture and other blue economy industries. [ABSTRACT FROM AUTHOR]

Vibrio anguillarum (V. anguillarum) is a bacterium that seriously harms flounder and other aquaculture species. Vaccination is an effective means of preventing vibriosis and is mainly administered by intraperitoneal injection. Effective antigen processing at the initial stage of immunization is essential to elicit adaptive immune responses and improve vaccine efficacy. To understand the early immune response of flounder caused by inactivated V. anguillarum, we detected the transcriptome profiles of the cells in the peritoneal cavity (PoPerCs) after inactivated V. anguillarum immunization. More than 10 billion high-quality reads were obtained, of which about 89.33% were successfully mapped to the reference genome of flounder. A total of 1985, 3072, 4001, and 5476 differentially expressed genes were captured at 6, 12, 24, and 48 h post immunization, respectively. The hub module correlated with the immunization time was identified by WGCNA. GO and KEGG analysis showed that hub module genes were abundantly expressed in various immune-related aspects, including the response to stimuli, the immune system process, signal transducer activity, autophagy, the NOD-like receptor signaling pathway, the toll-like receptor signaling pathway, the T cell receptor signaling pathway, and Th17 cell differentiation. Additionally, genes related to Th cell differentiation are presented as heatmaps. These genes constitute a complex immune regulatory network, mainly involved in pathogen recognition, antigen processing and presentation, and Th cell differentiation. The results of this study provide the first transcriptome profile of PoPerCs associated with inactivated V. anguillarum immunity and lay a solid foundation for further studies on effective V. anguillarum vaccines. [ABSTRACT FROM AUTHOR]

Investigations of bacterial communities are on the rise both in human and veterinary medicine. Their role in health maintenance and pathogenic mechanisms is in the limelight of infectious, metabolic, and cancer research. Among the most considered, gut bacterial communities take the cake. Their part in animals was assessed mainly to improve animal production, public health, and pet management. In this regard, canaries deserve attention, being a popular pet and source of economic income for bird-keepers, for whom breeding represents a pivotal point. Thus, the present work aimed to follow gut bacterial communities' evolution along on whole reproductive cycle of 12 healthy female canaries. Feces were collected during parental care, molting, and resting phase, and submitted for 16S rRNA sequencing. Data were analyzed and a substantial presence of Lactobacillus aviarius along all the phases, and a relevant shift of microbiota during molting and rest due to an abrupt decrease of the Vermiphilaceae family were detected. Although the meaning of such change is not clear, future research may highlight unforeseen scenarios. Moreover, Lactobacillus aviarius may be deemed for normal bacteria flora restoration in debilitated birds, perhaps improving their health and productivity. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the influence of feeds with or without β-glucan-based immunomodulatory supplements (groups BF and UB or B and U, respectively; feeding period 14 and 28 days) on the welfare of brown trout. The diets tested did not influence the rearing indices. The type of feed and the feeding period were confirmed to have a significant influence on the white blood cell (WBC) count. WBC counts were lower than those in the initial sample particularly on day 14 of the experiment. Red blood cell (RBC) counts and hematocrit (HCT) were determined by feeding period, and the values of these parameters decreased the longer the tested feeds were applied. These changes were accompanied by increases in the values of mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC). Feed type determined levels of chloride ion (Cl-) and ammonia (NH3) and alkaline phosphatase (ALP) activity and feeding period affected sodium (Na+) and albumin (ALB) concentrations, while aspartate aminotransferase (AST) activity depended on both factors. Changes in leukograms were noted in all the groups, inter alia, significant increases in the share of lymphocytes, and after changing diets, decreases in the percentage of neutrophils, myeloperoxidase activity (AMPO) in phagocytes and cidal ability (CA). After day 28, AMPO and CA values increased and were significantly higher in groups BF and UB. [ABSTRACT FROM AUTHOR]

Edible bivalves constitute an important bioresource from an economic point of view, and studies on their immune responses to environmental pollutants are crucial for both the preservation of biodiversity and economic reasons. The worldwide diffusion of copper(I)-based antifouling paints has increased copper leaching into coastal environments and its potential impact on both target and nontarget organisms. In this study, immunotoxicity assays were carried out with short-term (60 min) cultures of hemocytes from the bivalves Mytilus galloprovincialis--a mussel dominant in the macrofouling community--and Ruditapes philippinarum--a clam dominant in the soft-sediment community--exposed to CuCl to compare the toxic effects on their immune responses. The LC50 values were similar, 40 μM (3.94 mg L-1) for the mussel and 44 μM (4.33 mg L-1) for the clam. In both species, apoptosis occurred after exposure to 1 µM (98.9 μg L-1) CuCl, the concentration able to significantly increase the intracellular Ca2+ content. Biomarkers of cell morphology and motility revealed microfilament disruption, a significant decrease in yeast phagocytosis and lysosome hydrolase (β-glucuronidase) inhibition beginning from 0.5 µM (49.5 μg L-1) CuCl in both the mussel and clam. The same concentration of CuCl affected biomarkers of oxidative stress, as a significant decrease in reduced glutathione content in the cytoplasm and inhibition of mitochondrial cytochrome-c oxidase (COX) were detected in both species. Comparison of the biomarkers showed that clam is more sensitive than the mussel regarding alterations to the lysosomal membrane and reactive oxygen species (ROS) production, which supports the potential harmful effects of antifouling biocides on the survival of nontarget pivotal species in the coastal community. [ABSTRACT FROM AUTHOR]

Tilapia, as one of the fish widely cultured around the world, is suffering severe impact from the streptococcus disease with the deterioration of the breeding environment and the increasing of breeding density, which brings serious economic loss to tilapia farming. In this study, the surface immunogenic protein (Sip) of Streptococcus agalactiae (S. agalactiae) was selected as the potential candidate antigen and connected with bacterial nano cellulose (BNC) to construct the nanocarrier subunit vaccine (BNC-rSip), and the immersion immune effects against S. agalactiae and Streptococcus iniae (S. iniae) in Nile tilapia were evaluated on the basis of the serum antibody level, non-specific enzyme activity, the immune-related gene expression and relative percent survival (RPS). The results indicated that Sip possessed the expected immunogenicity according to the immunoinformatic analysis. Compared with the rSip group, BNC-rSip significantly induced serum antibody production and improved the innate immunity level of tilapia. After challenge, the RPS of BNC-rSip groups were 78.95% (S. agalactiae) and 67.86% (S. iniae), which were both higher than those of rSip groups,31.58% (S. agalactiae) and 35.71% (S. iniae), respectively. Our study indicated that BNC-rSip can induce protective immunity for tilapia through immersion immunization and may be an ideal candidate vaccine for controlling tilapia streptococcal disease. [ABSTRACT FROM AUTHOR]

Interaction of engineered nanomaterials (ENMs) with the immune system mainly occurs with cells and molecules of innate immunity, which are present in interface tissues of living organisms. Immuno‐nanotoxicological studies aim at understanding if and when such interaction is inconsequential or may cause irreparable damage. Since innate immunity is the first line of immune reactivity towards exogenous agents and is highly conserved throughout evolution, this review focuses on the major effector cells of innate immunity, the phagocytes, and their major sensing receptors, Toll‐like receptors (TLRs), for assessing the modes of successful versus pathological interaction between ENMs and host defences. By comparing the phagocyte‐ and TLR‐dependent responses to ENMs in plants, molluscs, annelids, crustaceans, echinoderms and mammals, we aim to highlight common recognition and elimination mechanisms and the general sufficiency of innate immunity for maintaining tissue integrity and homeostasis. [ABSTRACT FROM AUTHOR]

The pearl oyster Pinctada imbricata radiata (Leach, 1814), from the Pacific Ocean, was one of the first species to reach via Suez the Mediterranean, colonizing the eastern basin and recently spreading to the western. The species showed to be able to adapt to a wide range of climatic, hydrological, and ecological conditions. Since 2000 it reached the Strait of Messina, where is now infesting the transitional waters of the oriented natural reserve "Laguna di Capo Peloro." Due to such resistance and adaptation ability, various assays were performed. Haemocyte morpho‐functional aspects were evaluated in haemolymph samples fixed with 1% and 2% glutaraldehyde for optical and electron microscopy (TEM). The following assays were carried out: cell characterization using several dyes, detection of intra‐ and extracellular lipids, the capability of phagocytosis using the yeast Saccharomyces cerevisiae and to produce superoxide anion (O2−). Detection of several enzymes, such as acid and alkaline phosphatase, arylsulfatase, chloro‐acetylesterase and β‐glucuronidase was also assessed. Cell count was demonstrated to be abundant with a mean of 8.263 × 106 mm2 ± 0.935 × 106 (SD). Two main cell populations were noticed: granulocytes and hyalocytes, both competent for phagocytosis, to produce O2−, and characterized by lipids. Based on the granule analysis, enzymatic activity was also demonstrated. The observations under TEM confirmed all the results obtained. This study supports the hypothesis that P. imbricata radiata can be usefully employed as a model organism in environmental biomonitoring. Moreover, since the species represent potential threats to native species and ecosystems, further insights into its biological adaptations in invaded ecosystems are recommended. [ABSTRACT FROM AUTHOR]

Antibiotics are an effective means of treating infectious bacterial diseases. However, the extensive use of antibiotics in the recent past has resulted in antibiotic-resistant bacteria which interfere with disease treatment and recovery. There is an urgent need for novel medicines to treat Gram-negative infections because there are not enough antibiotics in development to address projected and present demands. One novel approach to antibiotic alternatives is the use of living predatory bacteria which can naturally prey upon other Gram-negative bacteria. These predators are ubiquitous in a wide variety of manmade and natural environments and depending upon their feeding habits are classified as obligatory or facultative predators. All the obligate predators are classified under the umbrella terminology Bdellovibrio and like organisms (BALOs). Bdellovibrio bacteriovorus is by far the most studied BALOs and have long been recognized as a potential therapeutic, water clean-up, and biocontrol agent and source for discovering novel biotechnological tools for research. Antibiotics won't be replaced by pills containing predatory microorganisms any time soon. However, understanding these bacteria could help us prepare for a time when many medications cannot treat infections that are multi-drug resistant. A paradigm change is necessary since it may appear counterintuitive to cure a bacterial infection by giving another bacterium. The burden of an infection on the host must be taken into account while evaluating the prospective implications of treating a Gram-negative bacterial infection with the administration of a live predatory bacterium. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria are the most common bacteria used as probiotics in aquaculture. This study aimed to isolate and identify lactic acid bacteria and yeasts with probiotic potential from the intestine of gilthead seabream. Five fish were randomly selected (mean weight: 279.88±17.67 gr) from Nixa Design and Development Farm located in Charak port and 25 fish fries (mean weight: 39.43±9.67 gr) from Tiab Pran Qeshm farm in Qeshm Island. The selected fish had a healthy appearance and were also chosen randomly. Lactic acid bacteria and yeasts were isolated and purified from the intestines of the specimens and identified based on morphological characteristics and molecular sequences. Then these isolates were evaluated based on fundamental probiotic indicators, including acid resistance, bile salts, antagonistic properties, and Haemolytic activity for fish. 12 isolates were purified based on color, shape, and colony size. Then, two yeasts and five bacteria with different morphology were identified using gram staining and microscopic examinations. All lactobacillus isolates had antagonistic properties against the pathogenic bacterium Vibrio harveyi. Two strains of yeast; Rhodotorula mucilaginosa CBS 316 and Wickerhamiella infanticola CBS 7922, were isolated. The lactic acid bacterium isolated from the intestine of the gilthead seabream included two genera of Enterococcus and Bacillus respectively. The results of probiotic potency tests showed that isolates 1 (bacteria), 3, and 6 (yeast) had the best performance. From the obtained data, it was concluded that the use of a combination of bacteria and yeasts as probiotics in aquaculture has higher efficiency. [ABSTRACT FROM AUTHOR]

The use of antibiotics in aquatic feed reduces the incidence of disease and enhances growth performance, although it presents harmful effects, such as development of resistant bacteria and accumulation in the natural environment. A variety of immune stimulants including probiotics, prebiotics, synbiotics, phytobiotics, organic acids, nucleotides, antioxidants, microalgae, yeast and enzymes have been used in the aquaculture industry. In recent decades, much attention has been paid to finding a variety of immunostimulants with lower cost which also affect specific and non-specific immunity and improve fish resistance against a wide range of pathogens. These stimulants strengthen the fish's immune system by increasing the number of phagocytes, lysozyme activity and level of immunoglobulin. The use of immune stimulants as an effective tool to overcome diseases and strengthen the immune system of farmed species, leads to the promotion of cellular and humoral defense mechanisms and increases resistance to infectious diseases. Among these immunostimulants used in aquaculture, β-glucans are of particular importance. Glucans are complex polysaccharide compounds extracted from the cell wall of yeasts and fungi. These compounds can stimulate fish growth, survival, and immune function. Therefore, this review discusses the role and importance of β-glucan as a food additive in aquaculture and examines the impact of these compounds on the growth performance, immunity and biochemical parameters of farmed species. [ABSTRACT FROM AUTHOR]

Tilapia tilapinevirus, known worldwide as tilapia lake virus (TiLV), is a single-stranded RNA virus that belongs to the Amnoonviridae family. The virus attacks the fish species' external and internal organs, such as the eyes, brain, and liver. Syncytial cells develop in the liver cells of infected fish, which are characterized by widespread hepatocellular necrosis and karyolytic nuclei. It is a highly infectious virus that spreads both horizontally and vertically. Despite these devastating complications, there is still no cure or vaccine for the virus. Therefore, a vaccine based on epitopes developed using immunoinformatics methods was developed against TiLV in fish. The putative polymerase basic 1 (PB1) gene was used to identify immunodominant T- and B-cell epitopes. Three probable epitopes were used to design the vaccine: CTL, HTL, and LBL. Testing of the final vaccine revealed that it was antigenic, non-allergenic, and has improved solubility. Molecular dynamics simulation revealed significant structural compactness and binding stability. Furthermore, the computer-generated immunological simulation indicated that immunization might stimulate real-life immune responses following injection. Overall, the findings of the study imply that the designed epitope vaccine might be a good option for prophylaxis for TiLV. [ABSTRACT FROM AUTHOR]

Multidrug-resistant Edwardsiella tarda has been reported as the main causative agent for massive fish mortality. The pathogen is well-known for causing hemorrhagic septicemia in fish and has been linked to gastrointestinal infections in humans. Formalin-inactivated Edwardsiella vaccination has previously been found to be ineffective in aquaculture species. Therefore, based on E. tarda's integrated core complete sequenced genomes, the study aimed to design a subunit vaccine based on T and B cell epitopes employing immunoinformatics approach. Initially, the top immunodominant and antigenic epitopes were predicted from the core complete sequenced genomes of the E. tarda genome and designed the vaccine by using linkers and adjuvant. In addition, vaccine 3D structure was predicted followed by refinement, and molecular docking was performed for the analysis of interacting residues between vaccines with TLR5, MHC-I, and MHC-II, respectively. The final vaccine constructs demonstrated strong hydrogen bond interactions. Molecular dynamic simulation of vaccine-TLR5 receptor complex showed a stable structural binding and compactness. Furthermore, E. coli used as a model organism for codon optimization proved optimal GC content and CAI value, which were subsequently cloned in vector pET2+ (a). Overall, the findings of the study imply that the designed epitope vaccine might be a good option for prophylaxis for E. tarda. [ABSTRACT FROM AUTHOR]

The present study examines host pathogen response in developmental stage of Pterophyllum scalare (angelfish) infected with Aeromonas hydrophila. The study conducted had two different experiments in which the fish were subjected to formalin‐killed Aeromonas hydrophila (FKA) and immunostimulant (β‐glucan) by immersion method. The first experiment had three treatment groups viz., immunized, non‐immunized and control groups and the exposure time ranged between 12 and 32 dph (days posthatch) of larval rearing. The immunized group exhibited a higher fold expression of RAG‐1, RAG‐2 and IgM genes compared with non‐immunized group. The results demonstrated that the vaccination of 12 dph developmental stage prior to bacterial challenge of angelfish makes it more immunocompetent against the pathogens. Moreover, another experiment using β‐glucan was conducted to further examine the development of immune responses in angelfish larvae. The study consisted four treatments containing graded levels of β‐glucan dosages such as 100, 200 and 300 mg/L including a control (0 mg/L) for 20 days from 12 to 32 dph. The higher fold change in mRNA expression of RAG‐1, RAG‐2 and IgM genes was observed in β‐glucan (200 mg/L) treated group as compared to non‐treated and control group. The highest survivability was observed in the immunized group and immunostimulant treated group in the survival analysis. Hence, the present study suggested that either immunization with FKA or β‐glucan (200 mg/L) could be used as a strategy to mitigate the mortality rate and combat infection during the early larval rearing of P. scalare. [ABSTRACT FROM AUTHOR]

The polyamine putrescine (Put) is a ubiquitous small cationic amine. It plays an essential role in controlling the innate immune response. However, little is known about its function in mollusks. In this study, the Put content was observed to increase in the serum of pearl oyster Pinctada fucata martensii after 6 and 24 h of lipopolysaccharide (LPS) stimulation. Activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) increased, and nitric oxide synthase was downregulated in the Put group (i.e., combined treatment with Put and LPS) compared with that in the LPS group (i.e., combined treatment with phosphate-buffered saline and LPS). Furthermore, activities of alkaline phosphatase and acid phosphatase were inhibited after 6 h of LPS stimulation. The expression levels of the nuclear factor kappa B, IκB kinase, Janus kinase, and signal transducer and activator of transcription proteins genes were all significantly suppressed at 12 and 24 h in the Put group. Pseudomonas aeruginosa and Bacillus subtilis grew better after being incubated with the serum from the Put group than that from the LPS group. Additionally, the Put treatment remarkably inhibited the autophagy of hemocytes mediated by the AMP-activated protein kinase-mammalian target of rapamycin-Beclin-1 pathway. This study demonstrated that Put can effectively inhibit the inflammatory response induced by LPS in pearl oysters. These results provide useful information for further exploration of the immunoregulatory functions of polyamines in bivalves and contribute to the development of immunosuppressive agents. [ABSTRACT FROM AUTHOR]

A study was conducted to assess the role of supercritical‐fluid‐extracted‐seaweed residue as a feed ingredient. 120 Labeo rohita fingerlings with an average weight of 1.83 ± 0.25 g were randomly distributed into four experimental groups and fed with diets containing seaweed waste as a dietary supplement at 0, 150, 250 and 350 g/kg of feed for a period of 60 days. The beneficial role was assessed in terms of growth‐performance, metabolic, and defense mechanism. Animals fed with seaweed‐waste showed significantly (p <.05) higher weight gain and specific growth rate (SGR). Activities of metabolic enzymes such as ALT, AST, LDH, MDH and SOD showed significantly (p <.05) lower activity in the animals fed with seaweed waste in the diet. The highest lysozyme activity was recorded in the animal's group fed with 250 g/kg of seaweed waste in the diet. Significantly, higher serum serotonin level was recorded in the animals fed with 250 g/kg of seaweed waste. It can be inferred, that the supplementation of seaweed waste as a fish feed ingredient at a 250 g/kg inclusion level improves the growth‐performance, metabolic, and defense mechanisms in fish. Inclusion of seaweed waste as feed ingredients in the aqua‐feed industry could possibly play an important role in reducing the cost of feed with added functional benefits. [ABSTRACT FROM AUTHOR]

Background: The aim of the present paper is to construct an emulator of a complex biological system simulator using a machine learning approach. More specifically, the simulator is a patient-specific model that integrates metabolic, nutritional, and lifestyle data to predict the metabolic and inflammatory processes underlying the development of type-2 diabetes in absence of familiarity. Given the very high incidence of type-2 diabetes, the implementation of this predictive model on mobile devices could provide a useful instrument to assess the risk of the disease for aware individuals. The high computational cost of the developed model, being a mixture of agent-based and ordinary differential equations and providing a dynamic multivariate output, makes the simulator executable only on powerful workstations but not on mobile devices. Hence the need to implement an emulator with a reduced computational cost that can be executed on mobile devices to provide real-time self-monitoring. Results: Similarly to our previous work, we propose an emulator based on a machine learning algorithm but here we consider a different approach which turn out to have better performances, indeed in terms of root mean square error we have an improvement of two order magnitude. We tested the proposed emulator on samples containing different number of simulated trajectories, and it turned out that the fitted trajectories are able to predict with high accuracy the entire dynamics of the simulator output variables. We apply the emulator to control the level of inflammation while leveraging on the nutritional input. Conclusion: The proposed emulator can be implemented and executed on mobile health devices to perform quick-and-easy self-monitoring assessments. [ABSTRACT FROM AUTHOR]

Prebiotics, that is, β‐1,3‐glucans are widely used immunostimulants in aquaculture. A 70‐day feeding trial was conducted to investigate the effects of dietary β‐1,3‐glucan on growth performance, feed utilization, antioxidative and immune status of Pacific white shrimp (Litopenaeus vannamei). Six iso‐energetic and iso‐nitrogenous diets with dietary β‐1,3‐glucan levels at 0, 0.04, 0.08. 0.16, 0.32 and 0.64 g kg−1 were fed to six replicates of shrimp (initial mean weight 0.98 ± 0.02 g). The diet with 0.16 g kg−1 β‐1,3‐glucan significantly improved weight gain and decreased feed conversion ratio of the shrimp. Compared with shrimp fed the basal diet, protein efficiency ratio was significantly higher in the β‐1,3‐glucan supplemented groups. Hepatopancreatic amylase activity was significantly increased by the β‐1,3‐glucan supplementation. The 0.16 g kg−1 β‐1,3‐glucan supplemented diet significantly improved serum total superoxide dismutase activity. The lowest hepatopancreatic malondialdehyde content was observed in the 0.64 g kg−1 β‐1,3‐glucan group. This study suggested that appropriate inclusion level of β‐1,3‐glucan can improve the growth performance, feed utilization and improve the antioxidative capacity of Pacific white shrimp, with optimum supplemental level being about 0.156 g kg−1 based on the weight gain in our results. [ABSTRACT FROM AUTHOR]

The study was designed to evaluate the effects of spirulina algae and the acidifying impacts of citric acid on the variation of hematological and immune indices in common carp, Cyprinus carpio. The study was completely random in design with nine treatments, 3 replicates and the control, which included using basic diet without any additives. The treatments included T1: basic diet supplemented with 0.5% citric acid; T2: basic diet supplemented with 0.1% citric acid; T3: basic diet supplemented with 0.2% spirulina extract; T4: basic diet supplemented with 0.3% spirulina extract; T5: basic diet supplemented with 0.2% spirulina extract and 0.05% citric acid; T6: basic diet supplemented with 0.3% spirulina extract and 0.01% citric acid; T7: basic diet supplemented with 0.2% spirulina extract and 0.01% citric acid; and T8: basic diet supplemented with 0.3% spirulina extract and 0.05% citric acid. For this purpose, 270 juvenile carp fish (mean weight: 11.35 ± 1.21 g) were fed with the experimental diets for 8 weeks. At the end of the trials, the number of white blood cells (WBCs), red blood cells (RBCs), Hb, HCT, differential white cells (lymphocyte, eosinophil, neutrophil and monocytes) were measured. The mean volume of red blood cells (MHC), mean concentration of cellular hemoglobin (MEHC) and immune indices of fish blood including Lysozyme, GM, and immunoglobulin were also measured. The results indicated significant differences in certain blood factors (i.e., HCT, neutrophil and lymphocyte) between experimental diet groups and the control (p < 0.05). In addition, certain immune indices in the experimental groups were at healthier levels than those in the control (p < 0.05). Finally, the study showed that spirulina algae combined with citric acid acidifier could enhance the body immune system of juvenile carp fish. [ABSTRACT FROM AUTHOR]

Canine hepatozoonosis caused by Hepatozoon canis is an emerging disease in Europe. Clinical pictures vary from subclinical to life-threatening and non-specific clinical signs are predominantly reported. A 2-month-old female puppy originating from Southern Italy was adopted and moved to Northern Italy. Then, the dog was brought to a local veterinary practice for gastrointestinal signs, migrating lameness and pruritic dermatitis, and then tested positive for Hepatozoon spp. gamonts at the blood smear. After treatment with imidocarb dipropionate and doxycycline, the dog showed an initial clinical improvement. However, gastrointestinal signs recurred, and diffuse superficial pyoderma appeared on the thoracolumbar region, along with fever, lethargy, and weight loss. Eight months from the first onset of clinical signs, the dog was referred to a veterinary clinic and subjected to complete blood count, urine and fecal analysis, along with abdominal ultrasonography, whole-body CT and gastroduodenal endoscopy. Skin biopsies and blood samples were subjected to a PCR-coupled sequencing protocol, which scored both positive for H. canis. Alterations were consistent with a pre-existing cholangiohepatitis and multiple acquired extrahepatic shunts secondary to portal hypertension. The dog was euthanatized due to a clinical worsening two months later. The potential role of H. canis in the systemic disease observed, clinic-pathological findings and epizootiological implications are discussed. [ABSTRACT FROM AUTHOR]

Several drivers have recently fostered the expansion of Angiostrongylus vasorum throughout Europe, where Vector-Borne Pathogens (VBPs) are also spreading. However, the level of simultaneous risk of infection is still unknown in canine populations. This study evaluated the simultaneous exposure to A. vasorum and major canine VBPs in dogs of Italy. Sera of 294 dogs were subjected to two ELISAs, detecting A. vasorum circulating antigens and antibodies against the parasite, and to the following assays: (i) SNAP®4DX (IDEXX Laboratories Inc.) detecting Dirofilaria immitis antigens, and antibodies vs. Borrelia burgdorferi, Anaplasma spp. and Ehrlichia spp. and (ii) IFAT for the detection of antibodies vs. Leishmania infantum, Babesia canis and Rickettsia conorii. Twenty-two (7.5%, CI: 4.8–11.1%) and six (2%, CI: 0.7–4.4%) dogs scored positive for circulating A. vasorum antibodies and antigens, respectively. Seventeen dogs (5.8%, CI: 3.4–9.1%) were positive for A. vasorum antibodies + at least one VBP, three (1%, CI: 0.2–3%) for A. vasorum antigen + at least one VBP, while one dog (0.3%, CI: 0.01–1.88%) was positive for A. vasorum antigen + A. vasorum antibodies + B. canis antibodies. These results show that dogs living in different regions of Italy are at risk of simultaneous infections with both A. vasorum and VBPs. Despite the same scenario being likely in other countries of Europe, the current knowledge is scant. Therefore, further studies are warranted to amplify current epizootiological information and to understand whether control programs should be improved. [ABSTRACT FROM AUTHOR]