The bacterial disease vibriosis in farmed shrimps typically occurs when the host immunity is compromised, creating favourable conditions for pathogenic vibrios to proliferate and express virulence factors that contribute to disease development. Therefore, effective control of vibriosis requires interventions that not only enhance host immune competence but also attenuate pathogen virulence. This study evaluated whether Pandanus tectorius leaf extract (PLE) could protect farmed shrimp against vibriosis through a potentially dual mode of action: enhancing host immune responses and simultaneously suppressing virulence traits in the pathogen. To address this, germ-free brine shrimp Artemia and Vibrio campbellii were used as a host-pathogen model system. Germ-free Artemia were persistently exposed to PLE (0.2-3.0 g/L) and simultaneously challenged with V. campbellii (106 cells/mL). Host immunomodulatory effects were assessed through the expression of immune-related genes, whereas anti-virulence activity was evaluated by measuring bacterial growth, motility, and extracellular enzyme production. Exposure to PLE at 0.2-0.8 g/L significantly enhanced the survival of challenged Artemia nauplii, resulting in survival rates exceeding 90%. This protection was associated with the upregulation of key immune-related genes, including heat shock proteins (Hsp70 and Hsp60), prophenoloxidase, transglutaminase, and high mobility group box-1. Results also showed that PLE at concentrations as low as 0.2 g/L exerted direct inhibitory effects on V. campbellii, effectively reducing bacterial growth, swimming and swarming motility, and virulence-associated enzymatic activities, including caseinase, lipase, and phospholipase. No adverse effects on Artemia survival were observed within the tested doses and exposure period. Overall, the findings suggest that PLE holds strong potential as a natural immunomodulatory and anti-virulence agent for sustainable management of vibriosis in shrimp aquaculture.

Aquaculture plays a vital role in ensuring global food security. However, the use of Artemia as crucial live food in the hatchery industry is often limited by cost, availability, and nutritional variability. This study investigated the potential of Purple Non-Sulphur Bacteria isolates, specifically Rhodopseudomonas sp. strain AZR1 and Rhodopseudomonas sp. strain AZW1, isolated from a mangrove ecosystem in Terengganu, Malaysia, as a sustainable feed supplement for Artemia. Following 16 S rRNA gene sequencing, these strains were characterized for growth kinetics, carotenoid production, nutritional composition, and fatty acid profiles to determine the best isolate for use as Artemia feed. Strain AZR1 outperformed strain AZW1, exhibiting higher growth rates (maximum 4.93 g/L dry cell weight vs. 3.9 g/L), better carotenoid production (10.16 mg/g vs. 7.68 mg/g), and enhanced nutritional values (53.17

Brine shrimp (Artemia) are indispensable in global aquaculture and widely utilized as model organisms across diverse biological disciplines. Nevertheless, a considerable proportion of published studies suffer from irreproducibility and reduced reliability, often due to inadequate consideration of taxonomic resolution. In particular, the persistent and erroneous application of the binomial designation Artemia salina as a generic reference to all species, populations, and parthenogenetic lineages represents a major source of confusion. This article emphasizes that taxonomy is not merely a formal exercise in classical biology but a fundamental scientific framework for cataloguing and conserving Artemia wild biodiversity at both the population/lineage and species levels, in accordance with the International Code of Zoological Nomenclature (ICZN). In the absence of taxonomic verification and clear documentation of the geographic origin of Artemia specimens, the findings of most studies committing this A. salina fallacy cannot be reliably reproduced or independently validated.

The excessive use of antibiotics in mariculture has surpassed permitted levels, leading to their release into surrounding waters and accumulation in cultured organisms, which poses risks to human health and highlighting the urgent need for alternatives to reduce antibiotic use. Therefore, the present study aimed to test four microbes including Debaryomyces hansenii, Ruegeria mobilis, Lactobacillus plantarum and Bacillus subtilis, on lowering Vibrio, promoting population increase and survival of Brachionus plicatilis. The digestive enzymes activity including alpha-amylase, lipase and protease, microbial retention and biochemical composition of rotifers were analyzed. Rotifers with a density of 50 ind/mL were distributed into five treatments (four experimental and a control, quadruplicate, repeated thrice). Each microbe's concentration of 108CFU/mL- 1 was applied to the culture condition. L. plantarum and B. subtilis decreased Vibrio and increased the population and survival of rotifers, due to successful colonization, resulting in better nutritional utilization and retention in these groups. Higher enzymatic activity and microbial retention were observed in B. subtilis group. The present findings demonstrate that L. plantarum and B. subtilis could be promising microbes for culture of B. plicatilis to lower Vibrio and ensure higher yields. Identifying a sustainable approach to inhibit Vibrio while enhancing rotifers' performance as the primary food source for marine larviculture is undoubtedly essential.

Screw pine (Pandanus tectorius) leaf extract (PLE) has been shown to improve the tolerance of the White-leg shrimp Penaeus vannamei to various biotic and abiotic stressors. This study was a continuum to highlight the remarkable effects of this coastal plant extract in safeguarding brine shrimp Artemia franciscana, an important larval live food organism in aquaculture, from lethal heat, acidity, and salinity stress assays. Axenic Artemia nauplii were used to examine the impact of abiotic stress on the organism without being affected by microbial contamination. This approach provides greater clarity into the detrimental impacts of these stressors and allows for a more precise understanding of the molecular responses of Artemia to PLE. Exposure to 1-6 g/L PLE for 2 h was nonlethal to Artemia nauplii, with 5-6 g/L PLE demonstrated the highest protection against all three abiotic stressors, where survival increased by at least 22% as compared with the nonPLE-exposed control. Comparative transcriptome analysis revealed that multiple genes related to chitin-based cuticle (insect cuticle proteins, chitin-binding domain type 2, and structural constituent of cuticle proteins), carbohydrate metabolism (alpha-amylase, dihydrodiol dehydrogenase, and V-type H+-transporting ATPase subunit C), and the stress and innate immune responses (spaetzle, C-type lectin, CD109, major facilitator superfamily proteins) were differentially expressed. This study highlights the functional roles of PLE as a potential antistress agent in mitigating stress caused by environmental factors in farmed shrimp, promoting better health and resilience during aquaculture.

Brine shrimp nauplii are widely used as live food in fish and shellfish aquaculture but they may transmit pathogenic Vibrio to the target species causing significant economic loss. Heavy usage of antibiotics is expensive and environmentally damaging. Use of natural microbes as probiotics for disease management is a more sustainable strategy. In this study the abilities of four marine microbes—Debaryomyces hansenii, Ruegeria mobilis, Lactobacillus plantarum and Bacillus subtilis—to suppress Vibrio spp. and promote growth performance and survival of brine shrimp (Artemia franciscana) were investigated. Nauplii (Instar II) were exposed to 108 CFU mL-1 of one of the four microbes; a control without added microbes was included for comparison. The nauplii were fed daily with the microalga Nannochloropsis oculata. Population change, survival, weight gain, length gain, enzyme activity, microbial retention and body biochemical composition of the brine shrimp were measured. The results showed that B. subtilis and L. plantarum significantly decreased the body loading of Vibrio spp. in A. franciscana. Survival rate, weight gain and length gain of (A) franciscana all increased in L. plantarum and (B) subtilis treatments, but the growth performance in the D. hansenii and R. mobilis treatments was less consistent. Higher lipase and protease activities and lower body ash content in the brine shrimp were observed in the B. subtilis and L. plantarum treatments (P < 0.05). The abundance of B. subtilis in the brine shrimp was relatively stable even after 8 days of starvation. These findings demonstrate that B. subtilis was the most promising probiotic among the tested species, especially for long-term application without the need for repeated inoculation.

The brine shrimp Artemia is one of the most popular live food species used in aquaculture. The natural food for this crustacean is microalgae, bacteria, and detritus, but they can be grown using a variety of agricultural by-products, each having advantages and disadvantages. In this study, the efficacy of palm kernel expeller (PKE), a by-product of the oil palm industry, as a potential feed alternative for raising Artemia in an indoor tank culture system was investigated. Analysis on the nutritional composition showed that PKE contains 15

Pathogens associated with microplastics in harvested sea salt could increase infection in inland mariculture. In the present study, two separate sets of tests: an in vitro test to examine the effects of microplastics on biofilm formation by Vibrio harveyi, and an in vivo test to evaluate the development of brine shrimp (Artemia franciscana) cultured using harvested sea salt. The experiment included four seawater treatments, differentiated by the presence of microplastics and autoclaving: microplastic-free seawater (MFSW), autoclaved microplastic-free seawater (AMFSW), autoclaved microplastic-containing seawater (AMCSW), and microplastic-containing seawater (MCSW). In vitro testing revealed that microplastics increased biofilm concentration and thickness by significantly inhibiting bacterial dispersion; while dispersion occurred multiple times in microplastic-free groups (MFSW, AMFSW), it was reduced to only one or two events in microplastic-containing groups (AMCSW, MCSW). Biofilm concentration surged in microplastic groups, increasing from 1.8 % to 95.3 % in AMCSW and 2.23 % to 80.23 % in MCSW within 24 h. Ovoviviparous reproduction was significantly reduced in AMFSW (17 ± 1.12 ind·d-1) and MFSW (23 ± 1.15 ind·d-1). In vivo tests showed microplastics depressed growth parameters and survival in brine shrimp. In MCSW, protease (0.37 ± 0.07 U/mg protein) and lipase (0.43 ± 0.02 U/mg protein) activities decreased, while AMCSW showed significant increases. Microplastic groups had elevated Vibrio loads in/on brine shrimp, with MCSW peaking at 96.30 ± 8.03 × 103 CFU g-1. Furthermore, microplastics caused anatomical and histological abnormalities, including the disappearance of the intestinal epithelial lining and internal swelling in the intestine. In conclusion, our findings showed that the microplastics associated with harvested sea salt can thicken biofilms, hinder antibiotic efficacy, and promote the evolution of antibiotic-resistant strains. A lack of knowledge in this area could lead farmers to overuse antibiotics, posing risks to environment and human health.

Artemia (Artemia franciscana) at the umbrella stage was evaluated for the first time as a feed for newly hatched striped catfish (Pangasianodon hypophthalmus) larvae to enhance growth and survival during the early rearing period. This study also aimed to assess the potential of replacing rotifers—whose culture is more complex—with umbrella-stage Artemia, thereby simplifying larval rearing protocols for P. hypophthalmus. Larvae (initial length: 0.40 ± 0.07 cm; weight: 0.33 ± 0.04 mg) were stocked at a density of 10 individuals/L in 100-L composite tanks and subjected to five different feeding regimes: (i) rotifers (Brachionus plicatilis) for the first 3 days followed by water fleas (Moina sp.) for the remaining 18 days (Control, T1); (ii) Artemia nauplii (instar I) for 3 days followed by water fleas for 18 days (T2); (iii) Artemia at the umbrella stage for 3 days followed by nauplii for 18 days (T3); (iv) umbrella-stage Artemia for the entire 21-day period (T4); and (v) Artemia nauplii for 21 days (T5). Growth (length and weight) was monitored every 3 days, and survival was assessed at the end of the experiment. Gut content observations revealed that fish larvae were capable of ingesting both umbrella-stage and naupliar Artemia as early as day 3, with whole or partially digested Artemia visible in the digestive tract. Larvae fed exclusively on Artemia (T3, T4, T5) exhibited significantly higher growth (P < 0.05) compared to other treatments, with the highest values observed in T4 (umbrella-stage Artemia for 21 days). However, survival was significantly higher in T3 (40.7 ± 1.5

The brine shrimp Artemia are tiny crustaceans that inhabit saltwater habitats such as salt pans, coastal lagoons, and salt lakes. Also known as extremophiles, they thrive in extreme conditions including desiccation and high salinity, and are used as model organisms in scientific research across multiple disciplines, particularly in studies involving host-microbe interactions, microbiology and ecology, genetics, and environmental toxicity testing. Their sensitivity to changes in environmental conditions makes them valuable indicators of ecosystem health. Additionally, Artemia is used in aquaculture research due to its high nutritional value and importance as live prey for marine fish and crustacean larviculture. This review delves into the distinct advantages and various features contributing to its status as a valuable model organism. Several case studies were highlighted, which elaborate on the important roles played by stress proteins within Artemia, unveiling their potential as crucial components in stress mitigation, especially under extreme salinities, anoxia, and temperatures. The review underscores the significance of leveraging stress proteins, particularly in the aquaculture sector. By tapping into the mechanisms of how stress proteins function, novel strategies and tools can be developed to effectively counteract the challenges posed by the dynamically changing conditions of stress. This synthesis of knowledge not only enhances our understanding of stress resistance in Artemia but also opens avenues for practical applications in abiotic and biotic stress tolerance.

The potential functional role(s) of heat shock protein 70 (Hsp70) in the brine shrimp, Artemia franciscana, a crucial crustacean species for aquaculture and stress response studies, was investigated in this study. Though we have previously reported that Hsp70 knockdown may have little or no impact on Artemia development, the gestational survival and number of offspring released by adult females were impaired by obscuring Hsp70 synthesis. Transcriptomic analysis revealed that several cuticle and chitin synthetic genes were downregulated, and carbohydrate metabolic genes were differentially expressed in Hsp70-knockdown individuals. A more comprehensive microscopic examination performed in this study revealed exoskeleton structural destruction and abnormal eye lenses featured in Hsp70-deficient adult females 48 h after Hsp70 dsRNA injection. Cysts produced by these Hsp70-deficient broods, instead, had a defective shell and were smaller in size, whereas nauplii had shorter first antennae and a rougher body epicuticle surface. Changes in carbohydrate metabolism caused by Hsp70 knockdown affected glycogen levels in adult Artemia females, as well as trehalose in cysts released from these broods, indicating that Hsp70 may play a role in energy storage preservation. Outcomes from this work provided novel insights into the roles of Hsp70 in Artemia reproduction performance, cyst formation, and exoskeleton structure preservation. The findings also support our previous observation that Hsp70 knockdown reduced Artemia nauplius tolerance to bacterial pathogens, which could be explained by the fact that loss of Hsp70 downregulated several Toll receptor genes (NT1 and Spaetzle) and reduced the integrity of the exoskeleton, allowing pathogens to enter and cause infection, ultimately resulting in mortality.

AbstractSpecies are fundamental units of nature that need proper identification in order to assess and conserve biodiversity. Artemia is a model crustacean for population analysis and comparison in regionally endemic sexual species and parthenogenetic lineages distributed in hypersaline lakes, lagoons, and solar saltworks scattered in arid and semi-arid areas worldwide. The taxonomy of two American Artemia species has been controversial: Artemia monicaVerrill, 1869, adapted to the carbonate-rich conditions of Mono Lake (CA, USA), and Artemia franciscanaKellogg, 1906, a species broadly distributed in the Americas. The former species has been studied little, despite being listed as threatened in the IUCN Red List. In contrast, the latter has been studied extensively, is broadly distributed in the Americas, and has become established as a non-native invasive species in Europe, Asia, Africa, and Australia. Given the need to conserve A. monica, the intraspecific diversity of invasive A. franciscana, and the local species in areas invaded by this species, we reconsider their biodiversity and taxonomic status currently threatened by synonymization. In conclusion, A. monica and A. franciscana should be treated as two separate species that are isolated both ecologically and reproductively.

The ornamental fish industry has continued to flourish since eighteenth century with increased fascination by enthusiasts in the striking body colours and patterns displayed in the fishes, a beneficial outcome of rigorous selective programmes. The expression of these pigmented colours is the result of the differentiation and orientation of specialised chromatophores located within the dermal layer. The different types of chromatophores found in many ornamental fish species, are the basis of the unique colour hues and patterns. This review discusses the current approaches for enhancing the body pigmentation and pattern of ornamental fishes. Two factors are considered to be the main drivers of body colour regulation: feed additives (pigments) and rearing environment setup, i.e. tank colour and light. Potential candidate pigment genes to manipulate the ornamental fish body pigmentation and pattern have been elucidated through mapping of putative regulatory pathways, buoyed by the rapid development of next generation sequencing technologies. The effects of feed additives, tank background colour and light on various ornamental fish species, and regulatory pathways of involved genes offer valuable insights for enhanced variety production prior to genetic engineering and are herein discussed. It is hoped that the systematic analysis of the current knowledge in this review would be a boon for the ornamental fish community to step up efforts to boost the ornamental fish breeding industry.

An increasing global population has meant aquaculture, one of the fastest growing food industry sectors, faces significant sustainability challenges as it tries to address the rising global protein demand. In many sectors, production is underpinned by fishmeal as dietary ingredient, but this is a finite resource with competing users from the poultry and livestock industries. Alternatively, some (planktonic) aquatic species, especially brine shrimp Artemia, can be produced using agricultural waste to provide food or biomass to support increasing aquaculture demand. This review investigates research and production of Artemia using agricultural waste. Various systems used for Artemia production in inoculated ponds are analysed and discussed to provide options for environmentally sustainable food systems that can be applied from either an artisanal level in developing countries with a considerable labour force, or in intensive systems in countries with large volumes of under-utilised resources, for example, sugar/alcohol-based waste and inland saline areas. Using agricultural waste, single cell protein production in a separate aerobic digester can be a simple, continuous food source for Artemia to enable daily biomass harvest. This could then be used as a fishmeal replacement or possibly for human consumption to promote a circular economy by remediating waste to produce protein, like a food production mine.

Brine shrimp (Artemia) has existed on Earth for 400 million years and has major ecological importance in hypersaline ecosystems. As a crucial live food in aquaculture, brine shrimp cysts have become one of the most important aquatic products traded worldwide. However, our understanding of the biodiversity, prevalence and global connectedness of viruses in brine shrimp is still very limited. A total of 143 batches of brine shrimp (belonging to seven species) cysts were collected from six continents including 21 countries and more than 100 geographic locations worldwide during 1977-2019. In total, 55 novel RNA viruses were identified, which could be assigned to 18 different viral families and related clades. Eleven viruses were dsRNA viruses, 16 were +ssRNA viruses, and 28 were-ssRNA viruses. Phylogenetic analyses of the RNA-directed RNA polymerase (RdRp) showed that brine shrimp viruses were often grouped with viruses isolated from other invertebrates and fungi. Remarkably, most brine shrimp viruses were related to those from different hosts that might feed on brine shrimp or share the same ecological niche. A notable case was the novel brine shrimp noda-like virus 3, which shared 79.25% (RdRp) and 63.88% (capsid proteins) amino acid identity with covert mortality nodavirus (CMNV) that may cause losses in aquaculture. In addition, both virome composition and phylogenetic analyses revealed global connectedness in certain brine shrimp viruses, particularly among Asia and Northern America. This highlights the incredible species diversity of viruses in these ancient species and provides essential data for the prevalence of RNA viruses in the global aquaculture industry. More broadly, these findings provide novel insights into the previously unrecognized RNA virosphere in hypersaline ecosystems worldwide and demonstrate that human activity might have driven the global connectedness of brine shrimp viruses.

The challenges and problems of managing good biosecurity are wide-ranging and multifactorial with many compounding factors to pre-dispose farmed stocks to an increased risk of infection with consequential stock losses. Many challenges are anthropogenic in origin and may be the result of the physical location (site) and/or the poor design of the production facility (i.e., water re-use; lack of zoning based on biosecurity risk, etc.) as well as from inappropriate decisions and practices made once the site is in production (i.e., pushing the system for increased biomass production). There is a need for better regulation and health legislation across aquaculture-an industry that embraces the culture of >500 species. In the absence of regulatory frameworks and culture guidelines, it is difficult for farmers to apply certain measures such as maximum stocking densities and maximum allowed biomass, conduct disease surveillance and regular health checks, and report diseases to relevant authorities for advice. In this review, we have identified several issues which are continuing to challenge the design and implementation of efficient and effective biosecurity strategies and protocols at all levels, requiring attention over the coming decade. They are, not in any order of priority: (a) healthy seed, (b) emergency preparedness and response, (c) diagnostics, (d) microbial management at the production level, (e) disease and pathogen surveillance, (f) trade in aquatic species, (g) policies and regulatory framework, (h) welfare, (i) research and technology development, (j) antimicrobial resistance, (k) non-conventional ways of pathogen transfer, and (l) Progressive Management Pathway.

This study aimed to evaluate the effects of four potential microbial strains, consisting of Candida parapsilosis, Pseudoalteromonas flavipulchra, Lactobacillus sakei, and Bacillus natto, on the suppression of Vibrio and the increase of population growth and enzyme activity in the copepod Tigriopus japonicus. Five treatments were set up, including four experimental groups and a control, each with four replicates. For each strain a concentration 108CFU/mL-1 was applied. The results demonstrated that the use of L. sakei and B. natto, besides suppression of Vibrio, could increase the population growth and enzyme activity in copepods. The longevity of B. natto was recorded as the best in long-term inoculation in a way that after 8 days of copepod starvation, the count of B. natto after a significant decrease first, increased again. The findings showed that B. natto appears to be a promising bacterial strain for the copepod T. japonicus in the suppression of Vibrio and also in increasing the population growth, enzyme activity, and long-term inoculation potential.

Parthenogenesis is an asexual reproduction mode characterized by the development of a female oocyte without fertilization. From an evolutionary perspective, parthenogenesis seems less successful than the predominant sexual mode, though there are groups in which both reproductive types exist, an example of which is the genus Artemia Leach, 1819. This salt-tolerant crustacean inhabiting hypersaline environments contains regionally endemic sexual species and obligate parthenogenetic groups with different ploidy levels, collectively referred to as Artemia parthenogenetica. Here, we discuss the difficulties of using a common species concept in Artemia Leach, 1819. While sexual species are widespread and fit the Biological Species Concept (BSC), which emphasizes reproductive isolation to maintain species genetic integrity or cohesiveness, it does not apply to uniparental organisms originating from sexual species with major meiotic changes. We show that different ploidy levels of parthenogenetic Artemia groups with uniform nuclear gene pools are maternally independent genetic entities (or cohesive), collectively and wrongly referred to as Artemia parthenogenetica. Thus, we conclude that 'Artemia parthenogenetica' is an invalid nominal specific name. Additionally, parthenogenetic Artemia groups cannot be considered a form of Artemia species (A. urmiana and/or A. sinica). In conclusion, we recommend using the term 'parthenogenetic lineage(s)' instead of 'parthenogenetic population(s)' to describe asexual Artemia group(s), because in modern population genetics and systematics, the term 'population' refers to interbreeding individuals with sexual reproduction. Furthermore, it clarifies that parthenogenetic lineages of Artemia are native to Mediterranean biodiversity.