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Shrimp aquaculture has been growing rapidly over the last three decades. However, high-density aquaculture together with environmental degradation has led to increased incidence of shrimp infections. Thus, devising and implementing effective strategies to predict, diagnose and control the spread of infections of shrimps are crucial, also to ensure biosecurity and sustainability of the food industry. With the recent advancements in biotechnology, more attention has been given to develop novel promising therapeutic tools with potential to prevent disease occurrence and better manage shrimp health. Furthermore, owing to the advent of the next-generation sequencing (NGS) platforms, it has become possible to analyze the genetic basis of susceptibility or resistance of different stocks of shrimps to infections and how sustainable aquaculture could be made free of shrimp diseases. [ABSTRACT FROM AUTHOR]

The prevalence of hepatopancreatic diseases in cultured shrimp has increased in recent years. Decapod Hepanhamaparvovirus 1 (DHPV) infection was identified by histology in samples that could not be detected by PCR-based assay for this virus. Employing Laser Microdissection (LMD), we dissected cells containing intranuclear inclusion bodies pathognomonic for DHPV infection from histological sections. Whole Genome Amplification and NGS were used to generate five complete genomes of the novel DHPV isolate that showed identities ranging from 77% to 98% to previously reported isolates. Phylogenetic analyses revealed the DHPV isolate represents a novel genotype, Genotype V. We developed PCR and in situ hybridization methods tailored for the specific detection of this genotype. Our approach of combining LMD with NGS opens avenues for rapid identification of emerging viral pathogens and retrospective studies to understand origin and evolution of viruses showcasing the transformative potential of the innovative approach used in this study. [ABSTRACT FROM AUTHOR]

Infectious hypodermal and hematopoietic necrosis virus (IHHNV) is a harmful virus that is responsible for the remarkable economic loss of Litopenaeus vannamei culture. IHHNV was first observed in shrimps, which were characterized by light microscopy, SEM, and TEM. The infected shrimps showed severe morphological deformity, including reduced body size, bent rostrum, shrunken and twisted antenna, rough cuticles, shrunken eyes, and rigid muscles. The antennal segments of the infected shrimps were fused together, puffy, dented, bent, and rough, as observed under a scanning electron microscope. The affected shrimps also showed tumor-like growth (hyperplasia) at the lateral position of the carapace in which the gastrofrontal sulcus was bent. This hyperplasia was found to be soft. In addition, the connective tissue of the diseased shrimp was in a degraded state, and the muscle fibers were despoiled. The nucleus of the cells from the infected gill cells of the shrimps was almost occupied by viral icosahedral particles, which TEM revealed. These viral particles were also found in the cytoplasm in a scattered manner within the same cells and were identified as IHHNV, as confirmed by polymerase chain reaction. [ABSTRACT FROM AUTHOR]

The present study was conducted to select Streptomyces strains that exhibited characteristics of probiotics for application in aquaculture. Streptomyces were isolated from soil and sediment samples collected from various habitats such as riverside, shrimp ponds, pangasius ponds, mangrove forests, or estuaries along the coast of Vietnam. Two strains of Streptomyces (AG12.2 and ND10.1) were selected due to (1) their potent antimicrobial activity against common pathogens that cause serious diseases in shrimp and pangasius such as E. ictaluri, A. hydophila, V. harveyi, V. parahaemolyticus, and (2) their superior ability to produce several extracellular enzymes that strongly hydrolyze organic compounds such as starch, CMC, and skimmed milk, compared to other strains. AG12.2 and ND10.1 can tolerate salinity from 0 ppt to 5 ppt and pH from 3 to 8; however, their growth is most vigorous at salt concentrations and pH between 0 ppt to 2 ppt, and 7.2 to 8, respectively. In vivo evaluation on L. vannamei in this study shows that shrimp that were fed with diets containing AG12.2 and ND10.1 had WG (%) increasing by 1.59 times and 1.61 times respectively, DGW (g/day) increasing by 1.64 times, and FCR decreasing by 1.30 times and 1.35 times respectively. The shrimp treated with AG12.2 and ND10.1 were then challenged with V. parahaemolyticus, resulting in a survival rate increase of 3.9 times and 3.71 times, respectively. Phylogenetic analysis revealed that strains AG12.2 and ND10.1 belong to Streptomyces kunmingensis and Streptomyces angustmyceticus, respectively. The findings of the present study led to the conclusion that Streptomyces kunmingensis AG12.2 and Streptomyces angustmyceticus ND10.1 are excellent candidates for producing beneficial probiotics for aquaculture. [ABSTRACT FROM AUTHOR]

Simple Summary: Acute hepatopancreatic necrosis disease (AHPND) is a plasmid-encoded PirA/B toxin mediated bacterial disease that causes significant economic losses to the global shrimp industry. Since the first AHPND outbreak of Penaeus vannamei cultures in Korea in 2016, AHPND-associated Vibrio parahaemolyticus (VpAHPND) is still considered a major threat to the Korean shrimp industry. Although several diagnostic methods have been developed against AHPND, several concerns have been raised about the misdiagnosis of the pathogen due to the transferability and mutation of the plasmid. In this study, we report the emergence of a natural mutant VpAHPND (pirA−, pirB+), which was isolated from cultured P. vannamei in Korea, and also provide its detailed genomic and pathological characteristics. Acute hepatopancreatic necrosis disease (AHPND) is one of the most important diseases in the global shrimp industry. The emergence of mutant AHPND-associated V. parahaemolyticus (VpAHPND) strains has raised concerns regarding potential misdiagnosis and unforeseen pathogenicity. In this study, we report the first emergence of a type II (pirA−, pirB+) natural mutant, VpAHPND (strain 20-082A3), isolated from cultured Penaeus vannamei in Korea. Phenotypic and genetic analyses revealed a close relationship between the mutant strain 20-082A3 and the virulent Korean VpAHPND strain 19-021-D1, which caused an outbreak in 2019. Detailed sequence analysis of AHPND-associated plasmids showed that plasmid pVp_20-082A3B in strain 20-082A3 was almost identical (>99.9%) to that of strain 19-021-D1. Moreover, strains 20-082A3 and 19-021-D1 exhibited the same multilocus sequence type (ST 413) and serotype (O1:Un-typeable K-serogroup), suggesting that the mutant strain is closely related to and may have originated from the virulent strain 19-021-D1. Similar to previous reports on the natural mutant VpAHPND, strain 20-082A3 did not induce AHPND-related symptoms or cause mortality in the shrimp bioassay. The emergence of a mutant strain which is almost identical to the virulent VpAHPND highlights the need for surveillance of the pathogen prevalent in Korea. Further investigations to elucidate the potential relationship between ST 413 and recent Korean VpAHPND isolates are needed. [ABSTRACT FROM AUTHOR]

Taura syndrome in shrimp, caused by Taura syndrome virus (TSV), is a disease listed by the World Organisation for Animal Health (OIE) that has been identified in five continents, causing serious economic losses in years. Due to the lack of specific drugs available to treat Taura syndrome, an effective TSV detection method is urgently needed to ensure pathogen prediction and disease control. In this study, we developed and evaluated an isothermal enzymatic recombinase amplification–based assay (TSV-ERA) that was able to diagnose TSV within 20 min at an optimal temperature of 42 °C. In the reaction system, the optimal concentrations of the primer and the probe were 500 nM and 120 nM, respectively. When the plasmid standards were used as a detection template, the check-out time of TSV-ERA was 12 min (21.76 ± 0.60 Ct), and the limit of detection (LOD) was 3.6 × 101 copies/µL. Compared to the sensitivity of the TSV detection method recommended by the OIE, TSV-ERA was equal to real-time PCR (qPCR) and higher than one-step PCR. This assay was highly specific for TSV and had no cross-reactivity with Enterocytozoon hepatopenaei (EHP), white spot syndrome virus (WSSV), Vibrio parahaemolyticus strain causing acute hepatopancreatic necrosis disease (VpAHPND), infectious hypodermal and hematopoietic necrosis virus (IHHNV), and the genomic DNA of specific pathogen-free (SPF) shrimp. Compared with the common detection methods, the TSV-ERA assay was able to shorten the detection time and decrease the detection temperature while sustaining accurate sensitivity. Based on these results, our TSV-ERA detection method is simple, rapid, and effective, and has great potential in the detection of TSV. [ABSTRACT FROM AUTHOR]

Vibriosis is a disease that frequently infects shrimp and financially devastates the shrimp industry worldwide. Because of the detrimental effects of antibiotic use in shrimp disease management, such as the emergence of various antibiotic-resistant bacteria, decreased antibiotic efficacy due to long-term use, and residues remaining in sediments, water, and shrimp body tissues, researchers are developing alternatives to vibriosis disease control through biocontrol technologies that are more effective, economical, and environmentally friendly. Biological agents such as microalgae, viruses, fungi, and bacteria are used in several biocontrol technologies. Despite its widespread use, several aspects of bacteria-based Vibrio biocontrol remain poorly known, including the most effective pathogen suppression mechanism and how it interacts with shrimp as a host. In this review, the development of biocontrol technologies for vibriosis in shrimp, especially those that use bacteria as agents, such as green water technology, biofloc, probiotics, and synbiotics, as well as the biocontrol mechanism of action and its interactions with the host and opportunities for further studies, are discussed to enrich our understanding of controlling Vibrio in shrimp in the future. [ABSTRACT FROM AUTHOR]

Aquaculture plays a vital role in meeting global food demand, and shrimp farming is a major contributor to this industry. Despite the immense economic importance of farmed shrimp, disease outbreaks continue to pose a significant challenge. This was attributed to fluctuations in various biotic and abiotic factors such as temperature, salinity, nutrition absorption, and water quality, which favor the abundance of invaders or opportunistic pathogens. Furthermore, the alterations in the gut microbiota, particularly decreased levels of commensals and increased prevalence of pathogens were reported during disease outbreaks. Shrimp physiology and immune function are intimately intertwined with the gut microbiome, leading to a dynamic interplay where the host shapes the microbial community through selection, while the microbes in turn influence the host's metabolism and immune responses. Although various literatures report the change in gut microbial diversity and the immune responses generated by the host against various pathogens, a crucial knowledge gap exists regarding the intricate communication between these two systems. This review bridges this gap by deciphering the intricate interplay between host immunity and gut microbes, elucidating on the mechanisms underlying successful shrimp disease establishment. Thus, this review could offer possibilities for generating ideas to carry out effective aquaculture practices. [ABSTRACT FROM AUTHOR]

AbstractInfectious disease remains one of the major impediments to the growth and sustainability of shrimp farming worldwide. Despite extensive efforts, including surveillance and diagnostic testing, movement of infected broodstock and post-larvae across countries and continents has been a primary driver of disease introduction into new geographic locations. Often the etiology of a disease and diagnostic tools used to prevent its spread were developed only after the disease was detected somewhere new. From the 1970s to the mid-1990s, disease diagnosis in shrimp hatcheries and farms depended on clinical presentation, farm records, histopathology, and traditional microbial culture techniques for bacterial and fungal pathogens; followed by characterization of the isolated microbes. For viral pathogens, histopathology and electron microscopy were the primary tools for disease discovery and basic characterization since there was (and still is) no immortal cell line for crustaceans. In the late 1990s and early 2000s, molecular techniques supporting genomic characterization of pathogens and polymerase chain reaction (PCR)-based diagnostic tools started gaining momentum in the realm of pathogen discovery and disease diagnosis. The late 2000s saw rapid development of molecular diagnostic tools for a wide array of shrimp pathogens and today PCR-based assays have become the most widely relied upon methods of disease diagnosis and surveillance in the shrimp industry. Molecular diagnostics have a number of strengths, including high sensitivity, specificity, speed, and robustness, but like every modality, also have limitations. PCR-based diagnostics detect only those pathogens being targeted and fail to detect unknown pathogens or even newly emerged strains or genotypes of a known target pathogen. Beyond the presence or absence of a target pathogen, PCR-based diagnostics do not provide information about overall health status or disease state of an animal. Progressive over reliance on molecular diagnostics and concurrent neglect of histopathology is creating unforeseeable challenges for shrimp farming worldwide. In this commentary, we provide empirical evidence of how overreliance on PCR-based diagnostics can lead to erroneous diagnoses and failure to detect a new genotype of an existing World Organization for Animal Health (WOAH, Paris, France)-listed pathogen, and an emerging pathogen. These findings illustrate the risks of over reliance on a single methodological approach and emphasize the need to preserve the practice of pairing molecular diagnostics with conventional histopathology. Concurrent utilization of histopathology and molecular diagnostics are critical components of safeguarding the global shrimp farming industry by reducing detection failures of new or rapidly evolving pathogens, improving disease detection and identification, and improving animal health management practices. [ABSTRACT FROM AUTHOR]

Objective: The World Organization for Animal Health still regulates the infectious hypodermal and hematopoietic necrosis virus (IHHNV) in shrimp. The existing disease identification approach is time consuming, necessitates expensive equipment, and requires specialized expertise, thereby limiting the accessibility of shrimp disease screening on farms. Loop‐mediated isothermal amplification (LAMP) is recognized for its ability to detect inhibitory substances with high sensitivity and specificity. Methods: We developed a real‐time triplex LAMP assay that combines the simplicity of point‐of‐care testing with the accuracy of a turbidimeter. Using a set of three LAMP primers, our technology enables rapid DNA amplification in a single reaction within 45 min and with a low detection limit (10 copies/reaction). Result: We tested 192 shrimp samples from different sources and demonstrated the clinical utility of our method, achieving 100% specificity (95% confidence interval = 93.40–100.00%), 100% sensitivity (97.36–100.00%), and 100% accuracy (98.10–100.00%) in detecting IHHNV DNA, with a high Cohen's kappa value (1) compared to the standard quantitative polymerase chain reaction assay. Conclusion: The high technology readiness level of our method makes it a versatile platform for any real‐time LAMP assay, and its low cost and simplicity make it well suited for fast deployment and use in shrimp farming. Impact statementIntroducing our real‐time triplex LAMP assay, a game‐changer in shrimp disease detection. Combining simplicity with precision, our technology delivers results in under 45 min, enabling timely disease management. With high sensitivity and specificity, it outperforms quantitative polymerase chain reaction, offering a cost‐effective and versatile solution for shrimp farming. [ABSTRACT FROM AUTHOR]

The shrimp farming sector has faced significant hurdles due to acute hepatopancreatic necrosis disease (AHPND). In this study, an attempt was made to combine the enzymatic recombinase amplification (ERA) assay and CRISPR-Cas12a (ERA-Cas12a) for the rapid detection of AHPND. A set of crRNA and ssDNA with high sensitivity and good specificity was screened, and the best optimized one-tube system was obtained. Our additional analysis focused on the sensitivity and specificity of ERA-Cas12a, contrasting it with the established methodology of the World Organization for Animal Health (WOAH). The ERA-Cas12a could deliver the desired outcomes in under 40 min with a detection limit of 2 × 103 copies/µL and showed no interaction with white spot syndrome virus (WSSV), infectious hypodermal and hematopoietic necrosis virus (IHHNV), Enterocytozoon hepatopenaei (EHP), Taura syndrome virus (TSV), covert mortality nodavirus (CMNV), and decapod iridescent virus 1 (DIV1). Our actual sample detection results showed that the ERA-Cas12a system has the advantage of being more intuitive and fast without losing too much sensitivity compared with the nested PCR and quantitative real-time PCR (qPCR). Moreover, the detection results could be directly observed under blue light irradiation. All these results indicate that ERA-Cas12a provides a rapid and specific diagnosis of AHPND, which could further reduce the dependence on the instrument and effectively reduce aerosol pollution. It could be helpful in the prevention of shrimp disease and in reducing the economic loss of shrimp aquaculture. [ABSTRACT FROM AUTHOR]

White feces syndrome (WFS) in Penaeus vannamei has a dynamic etiology in shrimp culture. The etiological factors associated with WFS, namely Enterocytozoon hepatopenaei (EHP), aggregated transformed microvilli (ATM), midgut parasites, and environmental factors (temperature, pH, salinity, ammonia, nitrate, and nitrite) were investigated within shrimp farms in the coastal districts of Tamil Nadu. The investigation encompassed 62 WFS-affected shrimp farms, along with a subset of three WFS-negative farms to ensure a comprehensive analysis. Severity scores (0, 1, and 2) were assigned for each factor and their interrelationship was investigated using principal component analysis (PCA). The PCA analysis highlights the endemic presence of EHP (52 farms), along with elevated nitrate, ammonia, and water salinity, as key driving factors of WFS in shrimp farms among the coastal districts of Tamil Nadu. Histological evidence unveils the high prevalence of ATM structures (54 farms) in the hepatopancreas of WFS-affected shrimps. Micro eukaryotes, including gregarines, cestodes, and digeneans, were commonly observed parasites in the white midgut of WFS-affected shrimps. The occurrence of WFS appears to be more frequent during rainy days and is particularly prevalent between 40 and 50 days of culture (DOC). The insights on the interrelationship between the etiological factors associated with WFS can contribute to a better understanding of management strategies and aid in the development of preventive measures to mitigate the occurrence of WFS in shrimp farms across Tamil Nadu, India. [ABSTRACT FROM AUTHOR]

The use of measures to prevent disease and enhance immune competence in shrimp is essential to ensure the sustainability of shrimp aquaculture. We assessed here differences in the immunological status of juvenile Litopenaeus vannamei reared in a mature chemoautotrophic biofloc system (BFT.C) compared to a less stable heterotrophic biofloc system (BFT.H). After 72 days of culture, we examined different standard hemato-immunological parameters (hemograms, phenoloxidase activity, total serum protein concentration, and hemolymph agglutination capacity), the expression of 50 immune-related genes in the midgut, and the transcriptional 16S rRNA levels of the predominant bacterial groups associated with the shrimp gut. Overall, BFT.C demonstrated greater environmental stability than BFT.H, leading to enhanced immunocompetence in the animals. Biofloc-reared shrimp showed enhanced Vibrio agglutination, indicating a superior ability to identify and immobilize bacterial invaders in the hemolymph. Besides, four genes involved in antimicrobial and antiviral defenses (Litvan ALF-A, Lvan-Stylicin1, LvPPAE2, and LvDicer1) showed to be differentially transcribed at basal levels in the midgut of shrimp from both systems of biofloc maturation. Finally, the 16S rRNA transcriptional profiling revealed a greater abundance and viability of Actinobacteria and Firmicutes in the midgut from shrimp reared in BFT.C and BFT.H, respectively. In conclusion, our study evidenced that the biofloc maturation system impacts both hemolymph- and intestine-based immunities of shrimp as well as their midgut bacterial communities. These findings may help to understand how the environment, shrimp immunity, and the bacterial microbiome interact to prevent disease in shrimp farming. [ABSTRACT FROM AUTHOR]

The release of ornamental pets and associated pathogens outside their native range might directly or indirectly impact the recipient community. In temperate regions, e.g., central Europe, feral freshwater species of tropical and sub-tropical origins are mainly constrained to thermally polluted waters and thermal springs. However, species with high environmental plasticity and reproduction rates, such as the shrimp Neocaridina davidi, may adapt to colder water regimes over time. A widening thermal niche may eventually overcome thermal barriers, further expanding the range and enhancing transmission opportunities for host generalist parasites. This study assesses the observed (field observations) and theoretical (species distribution models) range expansion of N. davidi and associated parasites in Europe. We report three newly established N. davidi populations from thermally polluted waters in central Europe (Germany, Hungary, and Slovakia) and provide further evidence of its range expansion into colder environments. Species distribution models predict thermally suitable habitats in the Mediterranean and a foreseeable expansion into Western Europe and the Balkans by 2050. We confirm the presence of the microsporidian parasite Ecytonucleospora hepatopenaei in feral N. davidi populations across Europe and expand the list of microsporidians found in this host from two to four. Furthermore, we provide the first evidence of parasite spillover from/to the invasive crayfish Procambarus clarkii, suggesting that parasite exchange with native biota might be possible. Such possibility, coupled with an ongoing range expansion of N. davidi bolstered by human-mediated introductions and climate change, will likely exacerbate the impact on native biota. [ABSTRACT FROM AUTHOR]

Infectious disease is a major challenge in fish and shrimp farming systems caused by microorganisms including bacteria, viruses and parasites. Physical detection has limitations in detecting diseases in cultivated animals earlier, because of the varied clinical symptoms. The aims of this study was to identify the physical and molecular presence of infectious pathogens in fish and shrimp cultivated in several ponds in West Java, Banten and Jakarta. Monitoring was carried out in two stages, namely the period March–April 2021 and September 2021 by taking samples from several ponds in Bogor, Tangerang, Depok and Jakarta. The sample criteria used were fish and shrimp showing normal and clinical symptoms of being attacked by a disease which were collected by purposive sampling. The collected samples were examined in two stages, namely physical examination of clinical symptoms and molecular examination using PCR. The results showed that of the 24 species samples collected, 17 species showed normal clinical symptoms and seven species showed clinical symptoms. Of the 24 fish and shrimp samples, four samples were infected (2 samples from normal species and 2 samples with clinical symptoms). The infected normal samples were Osphronemus goramy and Litopenaeus vannamei. The infected samples with clinical symptoms were Carassius auratus by Aeromonas salmonicida and red zebra cichlid (Metriaclima estherae) by Red Sea Bream Iridoviral Disease (RSBIV). Physical testing supported by molecular detection of aquatic animals can be an effort to manage aquaculture systems in Indonesia. [ABSTRACT FROM AUTHOR]

Penaeus vannamei, or white shrimp, is an economically significant species that dominates shrimp production and represents a rapidly growing industry. However, the culture faces challenges due to high mortality rates due to bacterial and viral diseases. Unlike vertebrates, shrimp rely solely on their innate immunity for defense against pathogens. Introducing probiotics into shrimp culture can enhance growth, survival rates, and immune responses against disease outbreaks caused by pathogenic bacteria or viruses. Common diseases affecting shrimp farms include vibriosis, white spot disease, acute hepatopancreatic necrosis and black gill disease. These diseases can cause severe infections, which lead to high mortality rates. The application of probiotics, such as Bacillus cereus, B. licheniformis, B. subtilis, Lactobacillus sp., Paenibacillus, Pseudomonas sp., Pseudoaltermonas, and yeast, either through diet or direct administration, has demonstrated positive impacts on shrimp health, including enhanced growth, increased immunostimulation, improved gut microbiota, and better water quality parameters. In recent decades, aquafeed has explored effective solutions, such as microdiets, co-feeding (combining commercial feed and probiotics), and various microdiets types, to address aquaculture disease problems. Combining microdiets containing essential nutrients with probiotics has proven to be safer than antibiotics, which can adversely affect animals and the environment. However, further studies are needed to optimize the efficiency of feeding techniques by incorporating probiotics and commercial feed for disease resistance in penaeid shrimp culture. This review discusses commercial feeds and microdiets incorporated with probiotics for P. vannamei culture for growth and disease resistance to enhancement. [ABSTRACT FROM AUTHOR]

According to Food and Agriculture Organization of the United Nations (FAO), aquaculture has grown faster and its expansion aimed at meeting the increase of world fish demand, and preserving natural fish stocks. Currently, to produce fish in quantity and quality requires reduction of the environmental impact from aquaculture, through the improvement of culture systems. Disease is the major factor affecting the development and expansion in aquaculture. Losses due to disease in shrimp farming are high. Various approaches to minimize the impact of disease on production are possible. Another approach to keep the pathogen pressure low is polyculture of shrimp and finfish. This practice makes shrimp farming more sustainable by reducing the environmental impact and the incidence of shrimp disease. Antimicrobial peptides in the fish skin kill shrimp pathogens, keeping pathogen pressure of bacteria and viruses low. In polyculture, shrimps can eat tilapia faeces and unused fish feed, while tilapia filter phytoplankton, reducing the risk of low dissolved oxygen levels at night. In addition, shrimp bioturbation at the pond bottom returns nutrients to the water column, enhancing phytoplankton production and consequently the natural feed available for the tilapia. Biofloc technology (BFT) is one of the most applicable and promising systems for sustainable aquaculture development. This technology is essentially based on the recycling of nutrients via microorganisms, primarily (i) heterotrophic bacteria, which convert nitrogen compounds into microbial biomass, in addition to serves as a source of food for aquatic organisms, and (ii) chemoautotrophic bacteria, which convert ammonia to nitrite and nitrate. [ABSTRACT FROM AUTHOR]

Intestinal microbiome contains several times of functional genes compared to the host and mediates the generation of multiple metabolic products, and therefore it is called "second genome" for host. Crustaceans rank second among the largest subphylum of aquaculture animals that are considered potentially satisfy global substantial food and nutrition security, among which the Pacific white shrimp (Litopenaeus vannamei) ranks the first in the production. Currently, increasing evidences show that outbreaks of some most devastating diseases in shrimp, including white feces syndrome (WFS) and acute hepatopancreatic necrosis disease (AHPND), are related to intestinal microbiota dysbiosis. Importantly, the intestine microbial composition can be altered by environmental stress, diet, and age. In this review, we overview the progress of intestinal microbiota dysbiosis and WFS or ANPHD in shrimp, and how the microbial composition is altered by external factors. Hence, developing suitable microbial micro-ecological prevention and control strategy to maintain intestinal balance may be a feasible solution to reduce the risk of disease outbreaks. Moreover, we highlight that defining the "healthy intestine microbiota" and evaluating the causality of intestinal microbiota dysbiosis and diseases following the logic of "Microecological Koch's postulates" should be the key goal in future shrimp intestinal field, which help to guide disease diagnosis and prevent disease outbreaks in shrimp farming. Key points: • Intestinal microbiota dysbiosis is relevant to multiple shrimp diseases. • Microecological Koch's postulates help to evaluate the causality of shrimp diseases. [ABSTRACT FROM AUTHOR]

Vibrio harveyi and Vibrio parahaemolyticus are species of the Vibrio genus that often cause disease and mass mortality in crustaceans. If not handled quickly and appropriately, these diseases can cause considerable losses to farmers. Therefore, it is necessary to find a solution with safe and environmentally friendly disease prevention technology using natural ingredients, among others from plants, namely oil palm. Some parts of oil palm, namely leaves, fronds, fibres and oil palm pulp, which are palm waste, contain antibacterial compounds. This study aimed to assess the antibacterial activity of palm waste extracts, namely pulp, leaves, fronds and fibres using n‐hexane, ethyl acetate, chloroform, ethanol and water maceration solvents against pathogenic bacteria V. harveyi and V. parahaemolyticus, and identify active compounds contained in palm waste. The results of the research are expected to produce innovative and sustainable solutions to control diseases in shrimp farming, contribute to the development of a sustainable fishing industry and open up the potential for utilizing palm waste as a value‐added resource in the field of aquatic health. The results of observations on antibacterial activity tests and identifying the content of palm waste extract compounds were analysed descriptively displayed in the form of figures, tables and graphs. The results showed that palm waste extracts (pulp, leaves, fronds and fibres) with ethyl acetate and ethanol maceration solvents had very strong antibacterial potential, namely 20.14 ± 0.31 mm–25.52 ± 1.42 mm on V. harveyi bacteria and 20.41 ± 0.55 mm–25.00 ± 0.51 mm on V. parahaemolyticus bacteria. Palm extracts with n‐hexane (>20 mm) and chloroform solvents generally have strong category antibacterial potential (10–20 mm), and palm extracts in water solvents have medium category potential (5–10 mm) against V. harveyi and V. parahemolyticus bacteria. The results of phytochemical tests on palm waste extracts with ethyl acetate and ethanol maceration solvents contain bioactive compounds of flavonoids, saponins, polyphenols and alkaloid tannins, steroids and triterpenoids. Palm extracts with n‐hexane and chloroform solvents generally contain saponins, alkaloids, steroids and triterpenoids, while palm waste extracts with water solvents contain saponins. [ABSTRACT FROM AUTHOR]

ObjectiveIn recent years, there has been a steady increase in the occurrence and fatality rates of shrimp diseases, causing substantial impacts in shrimp aquaculture. These diseases are marked by their swift onset, high infectivity, complex control requirements, and elevated mortality rates. With the continuous growth of shrimp factory farming, traditional manual detection approaches are no longer able to keep pace with the current requirements. Hence, there is an urgent necessity for an automated solution to identify shrimp diseases. The main goal of this research is to create a cost-effective inspection method using computer vision that achieves a harmonious balance between cost efficiency and detection accuracy. The improved YOLOv8 (You Only Look Once) network and multiple features were employed to detect shrimp diseases.MethodsTo address the issue of surface foam interference, the improved YOLOv8 network was applied to detect and extract surface shrimps as the primary focus of the image. This target detection approach accurately recognizes objects of interest in the image, determining their category and location, with extraction results surpassing those of threshold segmentation. Taking into account the cost limitations of platform computing power in practical production settings, the network was optimized by reducing parameters and computations, thereby improving detection speed and deployment efficiency. Additionally, the Farnberck optical flow method and gray level co-occurrence matrix (GLCM) were employed to capture the movement and image texture features of shrimp video clips. A dataset was created using these extracted multiple feature parameters, and a Support Vector Machine (SVM) classifier was trained to categorize the multiple feature parameters in video clips, facilitating the detection of shrimp health.Results and DiscussionsThe improved YOLOv8 in this study effectively enhanced detection accuracy without increasing the number of parameters and flops. According to the results of the ablation experiment, replacing the backbone network with FasterNet lightweight backbone network significantly reduces the number of parameters and computation, albeit at the cost of decreased accuracy. However, after integrating the efficient multi-scale attention (EMA) on the neck, the mAP0.5 increased by 0.3% compared to YOLOv8s, while mAP0.95 only decreased by 2.1%. Furthermore, the parameter count decreased by 45%, and FLOPs decreased by 42%. The improved YOLOv8 exhibits remarkable performance, ranking second only to YOLOv7 in terms of mAP0.5 and mAP0.95, with respective reductions of 0.4% and 0.6%. Additionally, it possesses a significantly reduced parameter count and FLOPS compared to YOLOv7, matching those of YOLOv5. Despite the YOLOv7-Tiny and YOLOv8-VanillaNet models boasting lower parameters and Flops, their accuracy lags behind that of the improved YOLOv8. The mAP0.5 and mAP0.95 of YOLOv7-Tiny and YOLOv8-VanillaNet are 22.4%, 36.2%, 2.3%, and 4.7% lower than that of the improved YOLOv8, respectively. Using a support vector machine (SVM) trained on a comprehensive dataset incorporating multiple feature, the classifier achieved an impressive accuracy rate of 97.625%. The 150 normal fragments and the 150 diseased fragments were randomly selected as test samples. The classifier exhibited a detection accuracy of 89% on this dataset of the 300 samples. This result indicates that the combination of features extracted using the Farnberck optical flow method and GLCM can effectively capture the distinguishing dynamics of movement speed and direction between infected and healthy shrimp. In this research, the majority of errors stem from the incorrect recognition of diseased segments as normal segments, accounting for 88.2% of the total error. These errors can be categorized into three main types: 1) The first type occurs when floating foam obstructs the water surface, resulting in a small number of shrimp being extracted from the image. 2) The second type is attributed to changes in water movement. In this study, nanotubes were used for oxygenation, leading to the generation of sprays on the water surface, which affected the movement of shrimp. 3) The third type of error is linked to video quality. When the video's pixel count is low, the difference in optical flow between diseased shrimp and normal shrimp becomes relatively small. Therefore, it is advisable to adjust the collection area based on the actual production environment and enhance video quality.ConclusionsThe multiple features introduced in this study effectively capture the movement of shrimp, and can be employed for disease detection. The improved YOLOv8 is particularly well-suited for platforms with limited computational resources and is feasible for deployment in actual production settings. However, the experiment was conducted in a factory farming environment, limiting the applicability of the method to other farming environments. Overall, this method only requires consumer-grade cameras as image acquisition equipment and has lower requirements on the detection platform, and can provide a theoretical basis and methodological support for the future application of aquatic disease detection methods.

Climate change and disease threaten shrimp farming. Here, we studied the beneficial properties of a phytogenic formulation, Shrimp Best (SB), in whiteleg shrimp. Functional studies showed that SB dose-dependently increased shrimp body weight and decreased feed conversion ratio. We found that SB protected against Vibrio parahaemolyticus as evidenced by survival rate, bacterial load, and hepatopancreatic pathology in shrimp. Finally, we explored the likely mechanism by which SB affects growth performance and vibriosis in shrimp. The 16S rRNA sequencing data showed that SB increased 6 probiotic genera and decreased 6 genera of pathogenic bacteria in shrimp. Among these, SB increased the proportion of Lactobacillus johnsonii and decreased that of V. parahaemolyticus in shrimp guts. To dissect the relationship among SB, Lactobacillus and Vibrio, we investigated the in vitro regulation of Lactobacillus and Vibrio by SB. SB at ≥ 0.25 μg/mL promoted L. johnsonii growth. Additionally, L. johnsonii and its supernatant could inhibit V. parahaemolyticus. Furthermore, SB could up-regulate five anti-Vibrio metabolites of L. johnsonii, which caused bacterial membrane destruction. In parallel, we identified 3 fatty acids as active compounds from SB. Overall, this work demonstrated that SB improved growth performance and vibriosis protection in shrimp via the regulation of gut microbiota. [ABSTRACT FROM AUTHOR]

Acute ammonia exposure has detrimental effects on shrimp, but the underlying mechanisms remain to be fully explored. In the present study, we investigated the impact of acute ammonia exposure on the gut microbiota of the white shrimp Litopenaeus vannamei and its association with shrimp mortality. Exposure to a lethal concentration of ammonia for 48 h resulted in increased mortality in L. vannamei, with severe damage to the hepatopancreas. Ammonia exposure led to a significant decrease in gut microbial diversity, along with the loss of beneficial bacterial taxa and the proliferation of pathogenic Vibrio strains. A phenotypic analysis revealed a transition from the dominance of aerobic to facultative anaerobic strains due to ammonia exposure. A functional analysis revealed that ammonia exposure led to an enrichment of genes related to biofilm formation, host colonization, and virulence pathogenicity. A species-level analysis and experiments suggest the key role of a Vibrio harveyi strain in causing shrimp disease and specificity under distinct environments. These findings provide new information on the mechanism of shrimp disease under environmental changes. [ABSTRACT FROM AUTHOR]

[Objective] In recent years, there has been a steady increase in the occurrence and fatality rates of shrimp diseases, causing substantial impacts in shrimp aquaculture. These diseases are marked by their swift onset, high infectivity, complex control requirements, and elevated mortality rates. With the continuous growth of shrimp factory farming, traditional manual detection approaches are no longer able to keep pace with the current requirements. Hence, there is an urgent necessity for an automated solution to identify shrimp diseases. The main goal of this research is to create a cost-effective inspection method using computer vision that achieves a harmonious balance between cost efficiency and detection accuracy. The improved YOLOv8 (You Only Look Once) network and multiple features were employed to detect shrimp diseases. [Methods] To address the issue of surface foam interference, the improved YOLOv8 network was applied to detect and extract surface shrimps as the primary focus of the image. This target detection approach accurately recognizes objects of interest in the image, determining their category and location, with extraction results surpassing those of threshold segmentation. Taking into account the cost limitations of platform computing power in practical production settings, the network was optimized by reducing parameters and computations, thereby improving detection speed and deployment efficiency. Additionally, the Farnberck optical flow method and gray level co-occurrence matrix (GLCM) were employed to capture the movement and image texture features of shrimp video clips. A dataset was created using these extracted multiple feature parameters, and a Support Vector Machine (SVM) classifier was trained to categorize the multiple feature parameters in video clips, facilitating the detection of shrimp health. [Results and Discussions] The improved YOLOv8 in this study effectively enhanced detection accuracy without increasing the number of parameters and flops. According to the results of the ablation experiment, replacing the backbone network with FasterNet lightweight backbone network significantly reduces the number of parameters and computation, albeit at the cost of decreased accuracy. However, after integrating the efficient multi-scale attention (EMA) on the neck, the mAP0.5 increased by 0.3% compared to YOLOv8s, while mAP0.95 only decreased by 2.1%. Furthermore, the parameter count decreased by 45%, and FLOPs decreased by 42%. The improved YOLOv8 exhibits remarkable performance, ranking second only to YOLOv7 in terms of mAP0.5 and mAP0.95, with respective reductions of 0.4% and 0.6%. Additionally, it possesses a significantly reduced parameter count and FLOPS compared to YOLOv7, matching those of YOLOv5. Despite the YOLOv7-Tiny and YOLOv8-VanillaNet models boasting lower parameters and Flops, their accuracy lags behind that of the improved YOLOv8. The mAP0.5 and mAP0.95 of YOLOv7-Tiny and YOLOv8-VanillaNet are 22.4%, 36.2%, 2.3%, and 4.7% lower than that of the improved YOLOv8, respectively. Using a support vector machine (SVM) trained on a comprehensive dataset incorporating multiple feature, the classifier achieved an impressive accuracy rate of 97.625%. The 150 normal fragments and the 150 diseased fragments were randomly selected as test samples. The classifier exhibited a detection accuracy of 89% on this dataset of the 300 samples. This result indicates that the combination of features extracted using the Farnberck optical flow method and GLCM can effectively capture the distinguishing dynamics of movement speed and direction between infected and healthy shrimp. In this research, the majority of errors stem from the incorrect recognition of diseased segments as normal segments, accounting for 88.2% of the total error. These errors can be categorized into three main types: 1) The first type occurs when floating foam obstructs the water surface, resulting in a small number of shrimp being extracted from the image. 2) The second type is attributed to changes in water movement. In this study, nanotubes were used for oxygenation, leading to the generation of sprays on the water surface, which affected the movement of shrimp. 3) The third type of error is linked to video quality. When the video's pixel count is low, the difference in optical flow between diseased shrimp and normal shrimp becomes relatively small. Therefore, it is advisable to adjust the collection area based on the actual production environment and enhance video quality. [Conclusions] The multiple features introduced in this study effectively capture the movement of shrimp, and can be employed for disease detection. The improved YOLOv8 is particularly well-suited for platforms with limited computational resources and is feasible for deployment in actual production settings. However, the experiment was conducted in a factory farming environment, limiting the applicability of the method to other farming environments. Overall, this method only requires consumer-grade cameras as image acquisition equipment and has lower requirements on the detection platform, and can provide a theoretical basis and methodological support for the future application of aquatic disease detection methods. [ABSTRACT FROM AUTHOR]

Background: The lack of focus on the health status of shrimp cultivators by previous studies while the production of shrimp has been rising over the years after the introduction of the blue revolution in India. The present study estimated the burden of diseases among shrimp cultivators in India. Methods: Primary data were collected by using simple random sampling. The sample size was 357. The classification of diseases were made by using the international classification of diseases, tenth revision (ICD-10), version 2019. Disability-adjusted life years (DALY) were used to measure the health status of shrimp cultivators. DALY is the summation of the burden of disease from mortality and morbidity. Sensitive and uncertainty analysis was used by changing the value of the parameter and method, respectively. Results: The burden of disease among shrimp cultivators in 2020 ranges from 101.03 DALY based on equal age weightage, without discount rate, and potential life expectancy (DALY0,0,PLE) to 84.02 DALY based on unequal age weightage, discount rate, and standardized life expectancy (DALY1,0.03,SLE). The burden of disease per 100,000 shrimp cultivators was 28,477.74 DALY and 23,600.84 DALY when calculated by using DALY0,0,PLE and DALY1,0.03,SLE method, respectively. The higher burden of diseases from non-communicable diseases was followed by injury and communicable diseases for both methods. The disease burden from mortality was more than two-thirds of the total burden of disease and the rest from morbidity. The burden of disease among shrimp cultivators was sensitive to parameter changes because it changes between 92.10 DALY and 63.03 DALY with the change in the parameter. Uncertainty in the burden of disease among them was due to method variation, which ranges from 120.03 DALY to 74.06 DALY. Conclusion: The higher burden of non-communicable diseases, and the lower burden of communicable, and injuries per 100,000 shrimp cultivators compared to the national level in India. [ABSTRACT FROM AUTHOR]

Objective: In the context of the fast-expanding shrimp farming industry in Sri Lanka, this study aimed to evaluate the distribution and understanding of BMPs, examine the relationship between BMPs and disease outbreaks, and analyze the current antibiotic usage trends through a fact-finding survey. Materials and Methods: A questionnaire survey was conducted in 131 shrimp farms located in Puttalam District in North Western Province, where shrimp farming is thriving in Sri Lanka. The survey was conducted from September to October 2021. In addition, in August 2022 and August 2023, interviews were conducted with shrimp farms in Puttalam district and Batticaloa district, shrimp hatcheries, and export companies. Data were analyzed using descriptive statistics, Probit, and Tobit regression analysis. Results: The item-count technique revealed a significant (p < 0.05) difference in the use of antibiotics without consulting experts, signifying inappropriate use. No aquaculture farmer reported being unaware of BMPs, and among the 45 farmers who attended a BMPs seminar, 30 claimed to possess a good understanding of BMPs. Probit and Tobit regression results revealed that the rate of understanding of BMPs, education level, and obtaining information on the sanitation management of shrimp farming from extension and guidance organizations were inversely associated with both disease incidence in shrimp farming and shrimp discards. Conclusion: Although the use of antibiotics is prohibited in BMPs, the analysis results suggest inappropriate use of antibiotics. The findings indicate that enhanced BMP understanding can reduce disease incidence and shrimp discards, emphasizing the need for incentives to promote BMP adoption and reduce the necessity for antibiotics. [ABSTRACT FROM AUTHOR]

The success of contemporary disease management strategies in shrimp aquaculture, such as the 'systems' approach, is predicated on robust knowledge of the conditions and interactions between the host, pathogen and environment that promote disease. Pathogen challenge experiments (PCEs) are a power tool for investigating these conditions and interactions. However, absence of accurately reported experimental detail in published PCEs limits scientific transparency, reproducibility, and the potential for the research to make progressive advancements contributing to contemporary shrimp disease management strategies. This review identifies and discusses key factors relating to the host (shrimp), pathogen (virus), and environment that should be carefully considered during the design and publication of PCEs. We offer substantial evidence of their impact on viral disease outcomes, drawn from the existing body of literature, to supporting their consideration. The prevalence of reported experimental details for these factors across 186 viral PCEs in shrimp were evaluated. The review highlights a concerning paucity of experimental detail reported in published shrimp PCEs. We propose a checklist for the minimum reportable information in the publication of shrimp viral PCEs, hereafter referred to as the Shrimp PCE Reporting Guidelines (SPERG). The guidelines aim to enhance the transparency and standardisation of reporting in published PCEs, ensuring that key factors pertaining to the shrimp, pathogen, and environment are adequately considered and documented. Adoption of SPERG is envisaged to empower researchers, reviewers, and readers to assess the internal and external validity of PCEs, facilitating critical evaluation and improved utility of PCE findings for contemporary disease management. [ABSTRACT FROM AUTHOR]

Viral diseases are one of the constraints affecting the sustainability of the shrimp farming industry worldwide. The common causes of viral infections include white spot syndrome virus, infectious hypodermal and haematopoietic necrosis virus, hepatopancreatic parvovirus, Penaeus monodon nudivirus, decapod iridescent virus 1, Taura syndrome virus, yellow head virus, infectious myonecrosis virus and Macrobrachium rosenbergii nodavirus. Accurate diagnostic methods are necessary for preventing the spread of these transboundary diseases. Many molecular diagnostic methods for shrimp viral diseases have been developed and are currently in use, including conventional polymerase chain reaction (PCR), nested PCR, loop‐mediated isothermal amplification PCR, recombinase polymerase assay and real‐time PCR. Although the World Organization for Animal Health (founded as OIE) recommends several PCR methods for shrimp disease diagnosis, there has been a lack of efforts to comparatively evaluate the performance of the available methods, resulting in a significant knowledge gap. Therefore, in this review, we compare various PCR assays and commercial PCR‐based diagnostic kits that have been developed and/or published previously, and discuss pros and cons of each of these methods. Our objective of this review is to offer enhanced clarity and a comprehensive overview of molecular diagnostic methods for shrimp viral diseases. This endeavour would serve as an important resource for researchers engaged in relevant studies and professionals within the shrimp‐farming industry, providing valuable guidance and insights. [ABSTRACT FROM AUTHOR]

White spot disease (WSD) occurred by the highly devastating white spot syndrome virus (WSSV) poses a serious impediment toward global shrimp production. We investigated molecular diagnosis and natural infection with WSSV in cultured tiger shrimp (Penaeus monodon) and inspected histopathology of WSD. The incidence of WSSV infection was recorded in six small-scale shrimp farms situated in two districts of Bangladesh, namely Bagerhat and Satkhira. One- and two-step nested polymerase chain reaction models were applied to check the presence of WSSV DNA in shrimp samples. By one-step PCR, 25 of the 36 shrimp samples were WSSV-positive, while the remaining 11 samples were found to be WSSV-negative. After the negative samples underwent a two-step PCR process, only three samples were detected WSSV negative. In Satkhira and Bagerhat districts, the prevalence rates of WSSV infection were 83.33% and 55.56%, respectively, as confirmed by one-step PCR; following two-step nested PCR, the prevalence rates remained unchanged for Satkhira but increased to 100% for Bagerhat sourced samples. One-step PCR was less effective than two-step nested PCR in diagnosing viral infection; instantly evident that the overall prevalence rate rose from 69.44% to 91.67% when switching to two-step nested PCR. In a different experiment, histological analyses of PCR-confirmed WSSV-positive shrimp specimens revealed degenerated tubule lumen and degenerated hepatopancreas with necrosis, while the infected muscle tissues showed muscle fiber fragmentation and separation. Based on effective PCR technique and histopathological evidence of WSSV infection, the study demonstrated the occurrence of WSSV infection in small-scale shrimp farms. The combined practices of the diagnostic tools and information will be useful in understanding the white spot disease and managing its prevention in shrimp production systems.

Since the 1980s, modern shrimp aquaculture has been seriously affected by shrimp diseases worldwide. Shrimp aquaculture cooperates with scientists in the lab to develop biosecurity strategies and biotechnology products, such as specific-pathogen-free shrimp, vaccines and probiotics, to tackle the risk of shrimp disease. Securing shrimp health needs to manage the breeding environment, particularly water quality and water ecologies. Shrimp and water travel between the lab and the field for monitoring, experimentation and disease prevention. This article proposes the notion of hydro-social life to analyse how biosecurity strategies and biotechnology products are developed in the lab and deployed in the field by visiting private, governmental and university laboratories in the Vietnamese Mekong Delta, Hô' Chí Minh City, and Taiwan. I argue that scientists innovate biotechnology products to improve biosecurity strategies by reconfiguring hydro-social lives, like managing shrimp health and water quality. The development and deployment of biosecurity from the lab to the field are influenced by capitalist forms of life and social relations. [ABSTRACT FROM AUTHOR]

In this study, Pacific white shrimp (Penaeus vannamei), pond water, crab, Helice tridens, and live food samples were collected from farms in three provinces of Korea to investigate the presence of white spot syndrome virus (WSSV) and decapod hepanhamaparvovirus (DHPV). By polymerase chain reaction (PCR), DHPV was detected in all shrimp samples (83 of 83); among these, 41 samples were detected with WSSV. Amplicon sequencing and phylogenetic analyses indicated that all DHPV samples were classified as a novel genotype of DHPV. Additionally, the collected squid, polychaeta, and crab were also confirmed to be detected with novel genotypes of DHPV. By WSSV quantitative PCR, the average concentrations of viruses detected in shrimp and pond water samples were 2.58 × 107 copies/μL and 1.27 × 102 copies/μL, respectively. Simultaneous detection of WSSV and DHPV was observed in shrimp, pond water, and crab samples, and co‐infection with both viruses in shrimp could be demonstrated by histopathological analysis. Viral infection can result in significant economic losses in shrimp production. Therefore, precise monitoring and management of WSSV and DHPV prevalence in pond water, live food, and habitats are essential to preventing the spread of viral diseases in the Korean shrimp culture industry. [ABSTRACT FROM AUTHOR]

Acute Hepatopancreatic Necrosis Disease (AHPND) or Early Mortality Syndrome (EMS) is a bacterial disease in shrimps caused by pathogen Vibrio parahaemolyticus. It has culminated in huge loss in global shrimp production due to mass mortality. A probiotic strain Lactococcus lactis strain FA1 was recently isolated from shark intestine, showing inhibition towards the growth of the pathogen. Due to inhibitory potential, the effect of probiotics strain on growth performance of shrimp infected with V. parahaemolyticus was evaluated. The probiotic strain was incorporated into feed for juvenile shrimps Litopanaeus vannamei for 3 weeks before which they were then challenged with pathogen Vibro parahaemolyticus. The study compares 4 shrimp groups: Control (Without any treatment); Group A (Probiotic treated, uninfected); Group B (Probiotic treated, infected) and Group C (No probiotic, infected). The survival and growth performance (weight and length gain) of shrimps were evaluated in the following 30 days. Statistical analyses (ANOVA; Post Hoc Tukey) were used to compare between shrimp groups. In general, infected shrimp demonstrated some of the key symptoms of AHPND (pale or white hepatopancreas), transparent body and erratic swimming behaviour. The supplementation of probiotics resulted in an improved survivability (65±1%) compared to infected shrimp (45±1%). The probiotic treated shrimp group showed to have better % body weight gain, in which weight gain between group B (treated/infected) and group C (untreated/infected) were significantly different (at P=0.046); and so, to group A (treated/uninfected) when compared with group C (P=0.047). There is however no significant difference in % length gain between the groups. Meanwhile, some of the infected shrimps were able to show recovery from the infection. Pre-infection probiotic treatment showed better performance compared to post-infection probiotic treatment. This indicated that the strain Lactococcus lactis is highly suitable for use as the future probiotic in shrimp aquaculture. [ABSTRACT FROM AUTHOR]

Penaeid shrimp are economically important marine crustaceans that include species such as the black tiger shrimp, whiteleg shrimp, Atlantic white shrimp, and Indian white shrimp. Shrimp aquaculture has become a significant contributor to the fisheries industry, particularly in Asia where India is the world's second-largest producer of whiteleg shrimp. However, disease outbreaks and breeding problems remain major obstacles to the sustainable growth of shrimp aquaculture, resulting in decreased revenues and inefficient output for shrimp farmers. Recent studies have shown that the gut microbiome plays a crucial role in shrimp development and health. Next-generation sequencing technologies have contributed significantly to the metagenomic resources of crustaceans, enabling functional investigation of the gut microbiome and providing insights into the precise role of this bacterial ecosystem in shrimp diseases and development. This review summarizes the microbial diversity in the gastrointestinal tract of penaeid shrimps and how they impact the health and development of the organism. [ABSTRACT FROM AUTHOR]

The emergence of disease in shrimp has governed much concern in food safety and security among consumers with the recent reports on hepatopancreatic microsporidiosis (HPM) caused by Enterocytozoon hepatopenaei (EHP). The microsporidians present in shrimp remain a silent pathogen that prevents optimal shrimp growth. However, the biggest threat is in its food safety concerns, which is the primary focus in ensuring food biosecurity and biosafety. Hence, the objective of this review is to summarise the current knowledge of EHP and its infection in shrimp with food safety concerns. This paper provides an analysis of the diagnostic methods for detecting EHP infections in shrimp aquaculture. Interventions with current molecular biology and biotechnology would be the second approach to addressing EHP diseases. Finally, a systematic guideline for shrimp food safety using diagnostic and intervention is proposed. Thus, this review was aimed to shed light on effective methods for the diagnosis and prevention of EHP infection in shrimp. We also include information on molecular and genomics tools as well as innate immune biomolecules as future targets in the intervention strategies on the microsporidsosis life cycle in shrimp and its environment. Overall, this will result in reduced disease outbreaks in shrimp aquaculture, ensuring the shrimp food safety in the future. [ABSTRACT FROM AUTHOR]

Recently, the spread of white spot disease in shrimps has a major impact on the aquaculture activity worldwide affecting the economy of the countries, especially South-East Asian countries like Vietnam. This deadly disease in shrimps is caused by the White Spot Syndrome Virus (WSSV). Researchers are trying to understand the spread and control of this disease by doing field and laboratory studies considering effect of environmental conditions on shrimps affected by WSSV. Generally, they have not considered spatial factors in their study. Therefore, in the present study, we have used spatial (distances to roads and factories) as well as physio-chemical factors of water: Chemical Oxygen Demand (COD), Dissolved Oxygen (DO), Salinity, NO3, P3O4 and pH, for developing WSSV susceptibility maps of the area using Decision Tree (DT)-based Machine Learning (ML) models namely Random Tree (RT), Extra Tree (ET), and J48. Model's performance was evaluated using standard statistical measures including Area Under the Curve (AUC). The results indicated that ET model has the highest accuracy (AUC: 0.713) in predicting disease susceptibility in comparison to other two models (RT: 0.701 and J48: 0.641). The WSSV susceptibility maps developed by the ML technique, using DT (ET) method, will help decision makers in better planning and control of spatial spread of WSSV disease in shrimps. [ABSTRACT FROM AUTHOR]

Purpose: Although shrimp aquaculture in Sri Lanka has mainly been plagued by recurrent outbreaks of White Spot Syndrome Virus (WSSV), recent symptomatic and analytical field data of shrimps were incoherent with typical WSSV infections. As transboundary infection of new diseases is not uncommon in world shrimp aquaculture, the possibility of new diseases established in the country surfaced. Hence, the present study was aimed at evaluating the stock health of shrimps in Sri Lanka for additional six diseases commonly available in the Asian region, namely Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV), Infectious Myonecrosis Virus (IMNV), Taura Syndrome Virus (TSV), Yellow Head Virus (YHV), Acute Hepatopancreatic Necrosis (AHPND) and Necrotizing Hepatopancreatitis Bacterium (NHPB). Research Method: Sampling was performed using broodstocks, postlarvae, cultured Penaeus monodon, wild P. semisulcatus, P. indicus and P. monodon from different locations and broodstock collecting areas in the country. Other crustacean species were also collected as possible carrier species. The presence of pathogenic organisms was identified by Polymerase Chain Reaction using respective IQ 2000TM test kits and a total of 2060 PCR tests were conducted. Findings: Of all the samples tested, no samples were positive for IMNV, TSV, YHV, AHPND and NHPB. However, confirmatory evidence was found in Sri Lanka for the presence of IHHNV with the prevalence of 31.3% in broodstock samples, 24.07% in hatchery-produced postlarvae and 18.03% in cultured shrimps. WSSV was also recorded with a prevalence of 10.34% in broodstock samples and 55.56% in cultured shrimp samples collected. None of the wild collected samples was positive for any of the tested diseases. Originality/value: Reinstating the presence of WSSV in the Sri Lankan shrimp industry, provides confirmatory evidence of the presence of IHHNV in the country, highlighting the possibility of the emergence of new diseases in shrimp farming in Sri Lanka. Also, commonly suggested disease carriers seem to be not the major cause of disease spread during the sampling time. This study, therefore, provides much-needed information about the stock health of shrimps in Sri Lanka. [ABSTRACT FROM AUTHOR]

Acute Hepatopancreatic Necrosis Disease (AHPND), a highly destructive shrimp disease, has inflicted severe setbacks on the shrimp farming industry worldwide. As the use of antibiotics is discouraged due to emerging antibiotic-resistant bacteria and the pollution of ecosystems, there is a pressing demand for novel, sustainable alternatives. Hence, the influence of bovine lactoferrin (bLF) and hen ovotransferrin (OT), two natural antimicrobial proteins, on the growth of three AHPND-causing Vibrio parahaemolyticus (Vp) strains (M0904, TW01 and PV1) was examined. Additionally, we explored their potential to affect selected Vp virulence factors such as biofilm formation, swimming and swarming, cell surface hydrophobicity, and activity of released lipases and caseinases. Lag phases of all bacterial growth curves were significantly prolonged in the presence of bLF or OT (1, 5 and 10 mg/mL), and bLF (5 and 10 mg/mL) completely inhibited growth of all strains. In addition, bLF or OT significantly reduced biofilm formation (all tested bLF and OT concentrations for Vp M0904 and Vp PV1), bacterial swimming motility (0.5 mg/mL bLF and OT for Vp M0904 and Vp TW01; 1 mg/mL bLF and OT for all strains), cell surface hydrophobicity (for all strains, all bLF and OT concentrations tested except for 0.125 mg/mL OT for Vp PV1) and lipase activity (1 mg/mL bLF and OT for all strains and 0.5 mg/mL bLF and OT for Vp PV1). These promising in vitro results suggest that bLF and/or OT might be used as novel agents for combating AHPND and warrant further research to elucidate the underlying mechanisms of action to fully unlock their potential for AHPND disease management. [ABSTRACT FROM AUTHOR]

Dysbiosis in the gut microbiota has been intimately implicated in shrimp (Litopenaeus vannamei, Penaeidae) diseases. However, considering the variety of shrimp diseases and the variability in experimental conditions, studies addressing common features of the gut microbiota−shrimp disease relationship are limited. Through an unbiased subject‐level meta‐analysis framework, 463 shrimp gut bacterial communities from 27 studies were re‐analysed, including six lifestages and eight diseases of shrimp, with the causal agents of viral, bacterial, eukaryotic, and unknown pathogens. Shrimp lifestages and diseases were the predominant factors governing the gut microbiota. After ruling out the top lifestage‐ and disease‐specific discriminatory amplicon sequence variants (ASVs) from the gut microbiota, the top 27 disease common‐discriminatory ASVs were identified, contributing to an overall accuracy of 95.9% in diagnosing shrimp health status. By using these optimisation procedures, the accuracy of our diagnosis model was unbiased by shrimp lifestage, specific disease, sampling size, hypervariable region and sequencing platform. The shrimp eight diseases consistently and significantly increased the relative importance of stochasticity, the relative abundance of pathogenic potentials and diversified core ASVs, whereas decreased the diversity and stability of gut microbiota. Collectively, these findings illustrate the effectiveness of meta‐analysis in determining the robust and common features of the shrimp gut microbiota in response to diverse diseases. In particular, disease common‐discriminatory ASVs could accurately diagnose shrimp health status, although the data are divergent in biotic and technical variances. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the effect of hyperthermia on the immune response of shrimp infected by IMNV. Vannamei shrimp were challenged with IMNV and reared at temperatures 30ºC (Sk30), 31ºC (S31), 32ºC (S32) and 33ºC (S33) repectively. The temperature of shrimp without IMNV infection was 300C as control. During the study, shrimp immune response measurements were Total Hemocyte Count (THC), Differential Hemocyte Count (DHC), Respiratory Burst (RB) activity and Phenoloksidase (PO) activity. Generally, the results showed that the response of shrimp decreased along with hyperthermic condition. Shrimp infected with IMNV, decreased immune response especially at temperatures of 32ºC and 33ºC. [ABSTRACT FROM AUTHOR]

Background: Shrimp cultured in a biofloc system (BFS) have a lower disease incidence than those farmed in a water exchange system (WES). Although a number of studies have reported that the gut bacterial community induced by BFS is highly associated with shrimp disease resistance, the causal relationship remains unknown. Here, the promotive roles of gut bacterial community induced by BFS in pathogenic Vibrio infection resistance and its potential micro-ecological and physiological mechanisms were investigated by gut bacterial consortium transplantation and synthetic community (SynCom) construction. Results: The BFS induced a more stable and resistant gut bacterial community, and significantly enriched some beneficial bacterial taxa, such as Paracoccus, Ruegeria, Microbacterium, Demequina, and Tenacibaculum. Transplantation of a gut bacterial consortium from BFS shrimp (EnrichBFS) greatly enhanced the stability of the bacterial community and resistance against pathogenic V. parahaemolyticus infection in WES shrimp, while transplantation of a gut bacterial consortium from WES shrimp significantly disrupted the bacterial community and increased pathogen susceptibility in both WES and BFS shrimp. The addition of EnrichBFS in shrimp postlarvae also improved the pathogen resistance through increasing the relative abundances of beneficial bacterial taxa and stability of bacterial community. The corresponding strains of five beneficial bacterial taxa enriched in BFS shrimp were isolated to construct a SynComBFS. The addition of SynComBFS could not only suppress disease development, but also improve shrimp growth, boost the digestive and immune activities, and restore health in diseased shrimp. Furthermore, the strains of SynComBFS well colonized shrimp gut to maintain a high stability of bacterial community. Conclusions: Our study reveals an important role for native microbiota in protecting shrimp from bacterial pathogens and provides a micro-ecological regulation strategy towards the development of probiotics to ameliorate aquatic animal diseases. 1NpdyYjfCEzGqNeY6CWHQH Video Abstract [ABSTRACT FROM AUTHOR]

White Spot Syndrome Virus (WSSV) is a major virus found in shrimp that causes huge economic loss in shrimp farms. A selective diagnostic approach for WSSV is required for the early diagnosis and protection of farms. This work proposes a novel recognition method based on improved Convolutional Neural Network (CNN) namely Dense Inception Convolutional Neural Network (DICNN) for diagnoses of WSSV disease. Initially, the process of data acquisition and data augmentation is carried out. The Inception structure is then used to improve the performance of multi-dimensional feature extraction. As a result, the proposed work has the highest accuracy of 97.22% when compared to other traditional models. The proposed work is targeted to Litopenaeus Vannamei (LV), and Penaeus Monodon (PM) diversities for major threats detection of White Spot Syndrome (WSS). Performance metrics related to accuracy have been compared with other traditional models, which demonstrate that our model will efficiently recognize shrimp WSSV disease. [ABSTRACT FROM AUTHOR]

Shrimp aquaculture has become a vital industry, meeting the growing global demand for seafood. Shrimp viral diseases have posed significant challenges to the aquaculture industry, causing major economic losses worldwide. Conventional treatment methods have proven to be ineffective in controlling these diseases. However, recent advances in RNA interference (RNAi) technology have opened new possibilities for combating shrimp viral diseases. This cutting-edge technology uses cellular machinery to silence specific viral genes, preventing viral replication and spread. Numerous studies have shown the effectiveness of RNAi-based therapies in various model organisms, paving the way for their use in shrimp health. By precisely targeting viral pathogens, RNAi has the potential to provide a sustainable and environmentally friendly solution to combat viral diseases in shrimp aquaculture. This review paper provides an overview of RNAi-based therapy and its potential as a game-changer for shrimp viral diseases. We discuss the principles of RNAi, its application in combating viral infections, and the current progress made in RNAi-based therapy for shrimp viral diseases. We also address the challenges and prospects of this innovative approach. [ABSTRACT FROM AUTHOR]

This study evaluated the inhibitory function of probiotics isolated from three commercial products used in shrimp farming management. Five species of probiotics were isolated from the commercial products, which were B. subtilis, B. megaterium, B. velezensis, B. licheniformis, and B. amyloliquefaciens. The inhibitory function of the isolated probiotics on the growth of an acute hepatopancreatic necrosis disease (AHPND)-causing V. parahaemolyticus (VPAHPND), nonpathogenic V. parahaemolyticus, and Vibrio spp. isolated from shrimp farming samples were examined by disc diffusion and bacteriocin-like inhibitory substance test. Disc diffusion and bacteriocin-like inhibitory substance screening indicated that only B. velezensis could inhibit all Vibrio spp. Inhibitory efficiency of B. velezensis was further evaluated in the liquid media using the co-culture technique. With the assistance of a growth curve-monitoring system, we could examine multiple co-culture factors that affected the probiotic efficiency in the same experiment. The results demonstrated that the inhibitory efficiency of B. velezensis was increased with its concentration. The inhibitory efficiency of B. velezensis incubating in tryptic soy broth at pH 7.4 with 2% NaCl (TSB+) and Luria-Bertani broth at pH 7.4 with 1% NaCl (LB) was better than in alkaline peptone water broth at pH 8 with 2% NaCl (APW). [ABSTRACT FROM AUTHOR]

Aquaculture assumes a pivotal role in meeting the escalating global food demand, and shrimp farming, in particular, holds a significant role in the global economy and food security, providing a rich source of nutrients for human consumption. Nonetheless, the industry faces formidable challenges, primarily attributed to disease outbreaks and the diminishing efficacy of conventional disease management approaches, such as antibiotic usage. Consequently, there is an urgent imperative to explore alternative strategies to ensure the sustainability of the industry. In this context, the field of epigenetics emerges as a promising avenue for combating infectious diseases in shrimp aquaculture. Epigenetic modulations entail chemical alterations in DNA and proteins, orchestrating gene expression patterns without modifying the underlying DNA sequence through DNA methylation, histone modifications, and non-coding RNA molecules. Utilizing epigenetic mechanisms presents an opportunity to enhance immune gene expression and bolster disease resistance in shrimp, thereby contributing to disease management strategies and optimizing shrimp health and productivity. Additionally, the concept of epigenetic inheritability in marine animals holds immense potential for the future of the shrimp farming industry. To this end, this comprehensive review thoroughly explores the dynamics of epigenetic modulations in shrimp aquaculture, with a particular emphasis on its pivotal role in disease management. It conveys the significance of harnessing advantageous epigenetic changes to ensure the long-term viability of shrimp farming while deliberating on the potential consequences of these interventions. Overall, this appraisal highlights the promising trajectory of epigenetic applications, propelling the field toward strengthening sustainability in shrimp aquaculture. [ABSTRACT FROM AUTHOR]

The polymorphism of the simple sequence repeat (SSR) in the 5′ untranslated coding region (5′-UTR) of the antiviral gene IRF (LvIRF) has been shown to be implicated in the resistance to viral pathogens in shrimp Litopenaeus vannamei (L. vannamei). In this study, we explored the potential of this (CT)n-SSR marker in disease resistance breeding and the hereditary property of disease resistance traits in offspring. From 2018 to 2021, eight populations were generated through crossbreeding by selecting individuals according to microsatellite genotyping. Our results demonstrated that shrimp with the shorter (CT)n repeat exhibited higher resistance to white spot syndrome virus (WSSV) or Decapod iridescent virus 1 (DIV1); meanwhile, these resistance traits could be inherited in offspring. Interestingly, we observed that the longer (CT)n repeats were associated with bacterial resistance traits. Accordingly, shrimp with longer (CT)n repeats exhibited higher tolerance to Vibrio parahaemolyticus infection. Taken together, these results indicate that the single (CT)n-SSR marker could be used to selective breeding for both resistance to virus and bacteria in shrimps. [ABSTRACT FROM AUTHOR]

White spot disease in penaeid shrimp is caused by white spot syndrome virus and causing serious threat to shrimp farming industry. The present study was carried out to determine the antiviral activity of Turbinaria ornata against WSSV in freshwater carbs Paratelphusa hydrodromous. The crabs were injected with acetone extract of T. ornata along with WSSV and the experimental groups were observed for more than 60 days post-infection. The efficacy of the T. ornata acetone extract was confirmed by bioassay, histopathology, and in silico analysis. GC–MS analysis of T. ornata acetone extract identified 16 compounds respectively. Docking studies recommended that pregnane-3,20-dione, 17,21-[(methylborylene)bis(oxy)]-, (5. beta)- had the highest binding energy of − 7.1 kcal/mol and could be used as a potent antiviral compound. The results of the present study confirmed that acetone extract of T. ornata has significant antiviral activity against WSSV and it can be used as a possible prophylactic in shrimp culture for prevention of WSSV infection. [ABSTRACT FROM AUTHOR]

Viral infection of farmed fish and shellfish represents a major issue within the aquaculture industry. One potential control strategy involves RNA interference of viral gene expression through the oral delivery of specific double-stranded RNA (dsRNA). In previous work, we have shown that recombinant dsRNA can be produced in the chloroplast of the edible microalga Chlamydomonas reinhardtii and used to control disease in shrimp. Here, we report a significant improvement in antiviral dsRNA production and its use to protect shrimp against white spot syndrome virus (WSSV). A new strategy for dsRNA synthesis was developed that uses two convergent copies of the endogenous rrnS promoter to drive high-level transcription of both strands of the WSSV gene element in the chloroplast. Quantitative RT-PCR indicated that ~119 ng dsRNA was produced per liter of culture of the transgenic microalga. This represents an ~10-fold increase in dsRNA relative to our previous report. The engineered alga was assessed for its ability to prevent WSSV infection when fed to shrimp larvae prior to a challenge with the virus. The survival of shrimp given feed supplemented with dried alga containing the dsRNA was significantly enhanced (~69% survival) relative to a negative control (<10% survival). The findings suggest that this new dsRNA production platform could be employed as a low-cost, low-tech control method for aquaculture. [ABSTRACT FROM AUTHOR]

The Infectious Hypodermal and Hematopoietic Necrosis virus has been responsible in the last 30 years for the decrease in production and the low survival of some species of farmed penaeid shrimp. Due to its increase in recent years, this illness is now the subject of intense debates and investigations on a global scale. Although Cuba is not affected by the disease, there are great concerns on the part of the competent authorities as regards the movements in and out of their country of those living and refrigerated organisms. The present study was carried out to determine specific biosafety lines for this virus in Penaeus vannamei shrimp farming. Although matrix methods are common in biological risk analysis, the three-dimensional risk matrix is more comprehensive because it includes the role of defenses in the accidental sequences that represent the introduction and disease spread. To apply the method, the code SECUREMR-FMEA was used. The results identify the most contributing risks for shrimp farming in the Cuban scenario based on the degradation of defenses, which characterize good practices in an ideal case, as well as describe the most important defense measures in such conditions. The use of this method and its results constitute a novelty in the field of biosafety research. The study assists in developing a specialized biosafety strategy for this shrimp disease, which poses a significant financial danger to this productive region. [ABSTRACT FROM AUTHOR]

Diseases are a major obstacle in shrimp farming because they can cause relatively high mortality and decrease the quality of the aquaculture environment. One dangerous shrimp disease is caused by Vibrio bacteria. Today, people are turning to biological control methods by utilizing lactic acid bacteria that live as microflora in the digestive tract of aquaculture animals. This study aimed to analyze the potential of lactic acid bacteria isolates from the gut of vannamei shrimp as probiotic candidates and to analyze selected lactic acid bacteria isolates that were effective in increasing the immune response and survival of vannamei shrimp infected with Vibrio parahaemolyticus bacteria. Four BAL isolates were isolated, designated as 8A, 11B, F1, and G2. BAL isolates showed antibacterial activity against Vibrio parahaemolyticus bacteria with an inhibition zone of up to 11.5 mm, capable of living at acidic to alkaline pH (1.5-7.2), bile salts (3000 ppm) and negative catalase. The characterization of several tests such as gram-positive, inhibition test and sugar fermentation test and comparison of LAB characterization showed that LAB isolates (G2) from the intestine of vannamei shrimp were classified as Pediococcus acidilactici. The application of probiotics, namely LAB (G2) to vannamei shrimp through feed can stimulate the vaname shrimp immune system after being challenged with V. parahaemolyticus, as indicated by an increase in the number of hemocytes (THC), phagocytosis activity, and suppressing the population of V. parahaemolyticus in vannamei shrimp. [ABSTRACT FROM AUTHOR]