Brine Shrimp Artemia Research Articles

Engineered Biocorona on microplastics as a toxicity mitigation strategy in marine environment: Experiments with a marine crustacean Artemia salina

The marine environment has become a major sink for microplastics (MPs) wastes. When MPs interact with biological macromolecules, the biocorona forms on their surface, which can alter their biological reactivity and toxicity. In this study, we investigated the impact of biocorona formation on the toxicity of aminated (NH2) and carboxylated (COOH) polystyrene MPs towards the marine crustacean Artemia salina. Biocoronated MPs were prepared using cell-free extracts (CFEs) from microalgae Chlorella sp. (phytoplankton) and the brine shrimp Artemia salina (zooplankton). The results revealed that biocorona formation effectively reduced the toxicity of MPs. Pristine NH2-MPs exhibited higher reactive oxygen species production (ROS) (182%) compared to COOH-MPs (162%) in Artemia salina. Notably, NH2-MPs coronated with brine shrimp CFE exhibited a substantial reduction in ROS production (127%) than those coronated with algal CFE, with COOH-MPs showing a similar trend (120%). Biocorona formation also significantly decreased malondialdehyde (MDA) levels and antioxidant activity compared to pristine MPs. Molecular docking and dynamics simulations demonstrated a strong binding between polystyrene and acetylcholinesterase (AChE). In vitro studies indicated that pristine NH2-MPs exhibited more reduction in AChE activity (84%) compared to COOH-MPs (95%). However, no significant reduction in AChE activity was observed upon exposure to MPs coronated with either algal or brine shrimp cell-free extracts. Independent action modeling indicated an antagonistic interaction for MPs coronated with both the CFEs. Pearson correlation and cluster heatmap analysis suggested that the toxicity reduction in Artemia salina might be driven by decreased oxidative stress followed by the corona formation. Overall, this study provides valuable insights into the potential of biomolecules from phytoplankton and zooplankton to reduce MPs toxicity in Artemia salina, while highlighting their role in modulating the toxicity of other marine pollutants.

Application of Test Battery for Assessing the Toxicity of Marine Sediments in Vostok Bay (Peter the Great Bay, Sea of Japan)

This paper presents the results of a toxicity assessment of marine sediments from Vostok Bay based on responses of three testing organisms: the diatom Phaeodactylum tricornutum (Bohlin, 1897), nauplii of the brine shrimp Artemia salina (Linnaeus, 1758), and embryos and larvae of the sand dollar Scaphechinus mirabilis (Agassiz, 1864). The A. salina nauplii survival test has proven to be the least sensitive, showing a weak response in only two samples. The results of the experiments using microalgae cells and sand dollar larvae correlated both with each other and with long-term environmental monitoring data, thus, confirming the high degree of sediment toxicity off the western coast of the bay (Gaydamak and Srednyaya coves).

Toxicity Assessment of Local Tobacco Products Bidi and Gul of Bangladesh Using Brine Shrimp (Artemia salina) Lethality Assay

Abstract Background: Bidi and gul are two locally produced nicotine-containing tobacco consumables with considerable negative health and environmental impacts, while at the same time, there is a dearth of published data on their toxicology. The LD50 (lethal dose, 50%) approach was employed in this investigation, which is the first study of its type in Bangladesh. As far as, the authors are aware. Aims and Objectives: The study determined and compared the toxicity levels of nicotine present in locally manufactured bidi and gul products. Materials and Methods: Nicotine extracts from bidi and gul were tested on Artemia salina bioassay. We found that there was significant variation in the LD50 values of the different tobacco products within their respective categories. Of the bidis tested, the most toxic brand was found to have an LD50 of 40.85 ppm, while in case of gul brands, it was 45.09 ppm which is more than double of the average nicotine content in a cigarette. Conclusion: Our results indicated that locally manufactured tobacco products (bidi and gul) have significant toxicity risk to health and environment.

Brine shrimp Artemia salina to evaluate the impact of environmental concentrations of BMAA and isomers, DAB and AEG, via mortality (nauplii) and behavioural (adult) tests

BMAA and its isomers, DAB and AEG, are toxins mainly produced by cyanobacterial blooms and represent an emerging risk worldwide. Anthropization and climate changes are expanding blooms and the presence of these toxins has been evidenced in different environments including water and air. Investigated since decades, BMAA is a recognized danger in cases of bioaccumulation or when directly exposed to relatively high doses (μg/L). However, little is known about its isomers, DAB and AEG, and in general about toxicity at environmental doses (ng/L). With the present study we investigated the effect of environmental concentrations of BMAA, AEG and DAB on a model representative of aquatic organisms, the crustacean Artemia salina. Toxicological effects of these molecules were tested at two different developmental stages. Mortality experiments were developed on artemia nauplii while behavioural tests were performed on adult artemia. BMAA was evidenced as the most toxic compound in mortality essays showing a statistically significant impact already after 24 h of exposure. DAB and AEG reached a statistically significant effect only following 48 h of exposure, a result that was of reduced intensity when compared to BMAA. Furthermore, all tested molecules altered the behavioural tests performed on adult artemia 1 h after exposure. Male artemia demonstrated to be more impacted than females thus suggesting possible sex differences in the involved toxicological pathways.

Toxicological Evaluation of Ginger (Zingiber afficinale) and Kayu Secang (Biancaea sappan) Extracts using Brine Shrimp (Artemia Salina L.)

Ginger (Zingiber oficinale) and sappan wood (Biancaeae sappan) are herbaceous plants that are commonly used as herbal decoctions. Due to their wide biological and pharmacological activity, many natural compounds can serve as the foundation for the creation of modern medicines. Some of them are also known to have toxicological characteristics that are important in the development of cancer drugs. Objective: This study aims to evaluate the toxic effects of secang wood extract (Biancaeae sappan) and ginger (Zingiber oficinale) on saltwater shrimp (Artemia salina L.).Methods: The design of this study was a laboratory experimental analysis using the Brine Shrimp (Artemia Salina L.) method. The extract was prepared using standard methods and its toxicity was evaluated using a saltwater shrimp death test. Results: The results of the study were shown by determining its lethal concentration (LC50) which affects 50% of the shrimp population. showed that ginger extract was very toxic to shrimp brine with an LC50 value of 12.91. This shows that both extracts have high toxicity and can have a good effect on cells undergoing carcinogenesis even at relatively low concentrations. Conclusion: These findings highlight the importance of careful use and proper handling of extracts to minimize the potential health risks associated with the toxicity of herbal extracts. Further research is needed to elucidate the specific components responsible for the observed toxicity and to explore the potential use of herbal extracts as anti-cancer and antioxidants.

Thermal adaptation affects expression and regulation of metabolism-, stress-, and immune-related genes in Artemia franciscana populations

Brine shrimp Artemia franciscana is a commercially important species in aquaculture and is well adapted to harsh environmental conditions. In this study, an A. franciscana population selectively bred for induced thermotolerance over 12 generations (TF12) was subjected to transcriptomic analysis relative to the non-selective population (CF12) to determine the effect of selective breeding for induced thermotolerance (SITT). The transcriptomic response of CF12 to non-lethal heat stress (NLHS) from induced thermotolerance (ITT) within one generation was also investigated. A total of 232 and 218 differentially expressed genes (DEGs) were upregulated and downregulated in TF12, respectively, whereas fewer DEGs were upregulated (114) and downregulated (180) in CF12 exposed to NLHS, suggesting a more complex mechanism of thermal adaptation in SITT than in ITT. The TF12 population exhibited a reduction in immune processes as indicated by the downregulation of several pattern-recognition receptors. Conversely, stress protein genes such as those of heat shock proteins (HSPs) and of antioxidant enzymes and genes involved in carbohydrate metabolism, were highly upregulated. ITT downregulated immune-related and growth-related genes, whereas genes involved in energy production and electron carrier activity were upregulated. Our findings suggest possible immunological and physiological mechanisms and molecular pathways involved in adaptation of A. franciscana to thermal stress.

Exploring the Safety of the Sustainable Toxicity Testing in Zebrafish and Brine Shrimp Using Nanoemulsions Formulated from Fish Byproducts and Lemon Oil

Nanoemulsions, characterized by their nanosized particles ranging from 20 to 200 nm, are effective carriers for drug molecules. Our novel oil-in-water nanoemulsion, NE-FLO™, formulated from lemon and fish byproduct oils, demonstrates promising antioxidant and anti-inflammatory activities, with initial studies indicating nontoxicity to normal skin cells. This study investigated the safety of NE-FLO™ using brine shrimp (Artemia salina) and zebrafish (Danio rerio) models, focusing on concentration-dependent effects and LC50 values. At lower concentrations (0.1 mg·L−1, 0.01 mg·L−1, and 0.001 mg·L−1), NE-FLO™ showed minimal toxicity without adverse effects. However, at 1 mg·L−1, reduced survival rates indicate potential toxicity. Specifically, this concentration also induces altered swimming behaviors in zebrafish. LC50 values are 8.7474 mg·L−1 for brine shrimp and 0.316 mg·L−1 for adult zebrafish. These results underscore the necessity for further detailed investigations into NE-FLO™, balancing its therapeutic benefits with potential toxicity risks. This study emphasizes the importance of optimizing nanoemulsion formulations from fish oil and conducting comprehensive safety assessments to meet regulatory standards.

Phytochemical profiling and biological evaluation of the residues from industrial hemp (Cannabis sativa L.) inflorescences trimming: Focus on water extract

The study focused on investigating the phytochemical composition and bio-pharmacological properties of a water extract obtained from industrial hemp by-products, after trimming female inflorescences of Cannabis sativa L., cultivar Kompolti. The extract was found to be rich in phenolic compounds, particularly gallic acid, catechin, coumaric acid, ferulic acid, and benzoic acid. It also contained significant amounts of cannabidiolic acid and cannabigerolic acid as the main terpenophenols. To assess the biological potential of the extract, various ecotoxicological assays were conducted. The extract did not show significant phytotoxic effects on seedling germination in the allelopathic assay. In the brine shrimp (Artemia salina) lethality test, the LC50 value was 1.726 mg/mL, and in the Daphnia magna test, the extract showed no cardiotoxicity effects at the same concentration; thus, confirming its biocompatibility with these eukaryotic organisms. Additionally, the extract did not induce cytotoxicity in the murine C2C12 cell line till to the concentration of 1000 μg/mL. In isolated mouse prostate specimens, the extract (10–1000 μg/mL) also prevented LPS-induced gene expression of pro-inflammatory cytokines, namely tumor necrosis factor (TNF)α, interleukin (IL)-6, and IL-1β. Furthermore, the extract exhibited inhibitory effects on the growth of pathogenic bacterial, fungal, and dermatophyte species commonly associated with prostatitis. These results suggest that the residual powder from female inflorescence trimming can be considered an innovative plant material from the industrial hemp supply chain that deserves to be valorised in terms of recycling and upcycling; thus, reducing the environmental impact of the by-products and also opening the way for innovative health-promoting agents.

Effects of Temperature and Salinity on the Growth, Reproduction, and Carotenoid Accumulation in Artemia sinica and Transcriptome Analysis

Brine shrimp (Artemia), rich in carotenoids, are widely used in intensive aquaculture to supplement nutrients and enhance the coloration of farmed organisms. This study investigates the growth, reproduction, and carotenoid accumulation in Artemia sinica under varying salinity and temperature conditions. The results showed that temperature and salinity displayed significant interactions with survival, body length, and carotenoid accumulation in the body. The optimal survival and growth conditions of A. sinica (Bohai Sea Gulf) were a temperature range of 25–30 °C and a salinity range of 30–50‰. High temperatures accelerated growth and sexual maturity at the expense of survival rates, while temperatures below 20 °C prevented ovigerous development. Extreme salinity levels negatively affected survival and growth, though high salinity promoted sexual maturity. Carotenoids in A. sinica mainly accumulate as echinenone and canthaxanthin form. Carotenoid accumulation decreased with increased temperature and salinity, and the temperature effect decreased with rising salinity. A. sinica cultivated at a salinity of 10‰ and a temperature of 25 °C exhibits the highest carotenoid content. Transcriptomic analysis revealed that high temperatures primarily affected genes related to stress response and metabolism, while high-salinity regulated genes associated with ion balance and signaling pathways. These findings provide a theoretical basis for enhancing Artemia sinica aquaculture and optimizing cultivation conditions, offering novel insights into nutritional and environmental impacts on brine shrimp biology.

Brine Shrimp Integration in Hydroponics: The Role of Brine Shrimp in Nutrient Optimization

This research investigates the potential benefits of integrating brine shrimp (Artemia spp.) into hydroponic systems to enhance plant growth through increased nitrogen availability. Over a 30-day simulation, plants were monitored for growth patterns with brine shrimp supplementation. Findings indicate that brine shrimp, containing 71% protein, significantly contributed to nitrogen levels when converted by fish, resulting in a cumulative growth of 12 cm, with a notable 50% increase in the second half of the study. This study highlights the potential of using brine shrimp to optimize hydroponic systems and suggests further exploration into sustainable aquaponic practices.

PirA- or PirB-binding nanobodies can protect whiteleg shrimp from the acute hepatopancreatic necrosis disease toxin.

Acute hepatopancreatic necrosis disease (AHPND) is a devastating shrimp disease caused by a binary toxin, PirAB, produced by Vibrio parahaemolyticus and other closely related bacteria. To address AHPND, over 300 unique single-domain antibodies (also known as nanobodies) derived from the VHH domains of Lama glama heavy-chain-only antibodies were raised against either PirA or PirB and characterized. Nanobodies were shortlisted based on their affinities for either PirA or PirB, their relative stability in intestinal fluids, and their ability to reduce PirAB-induced death in brine shrimp Artemia salina. From these data, a subset of nanobodies was tested for their ability to reduce AHPND in whiteleg shrimp Penaeus vannamei, and nanobodies targeting either PirA or PirB provided significant disease protection to whiteleg shrimp. These results show that nanobodies can be a new option for shrimp farmers to reduce or eliminate the impact of AHPND on their operations.

Trophic transfer induced gut inflammation, dysbiosis, and inflammatory pathways in zebrafish via Artemia franciscana: A differential analysis of nanoplastic toxicity

Rising glbal population and plastic consumption have caused a dramatic increase in plastic waste, leading to micro- and nanoplastic ingestion by aquatic organisms and subsequent bioaccumulation in their tissues. This transfer to higher trophic levels raises nanoplastic concentrations and bioavailability, potentially harming organisms' health and development. This poses a risk to human health via seafood. To address these issues, this study assesses the toxicological impacts of nanoplastics (NPs) on brine shrimp (Artemia franciscana) and their trophic transfer to zebrafish. The research unveiled concentration-dependent bioaccumulation of NPs in zebrafish and Artemia franciscana (A. franciscana). Polystyrene nanoplastics (PS-NPs) exhibited higher accumulation in A. franciscana whereas PP-NPs showed greater accumulation in zebrafish gut. Histopathological analysis under PS-NPs exposure revealed significant tissue alterations, indicative of inflammatory responses and impaired mucosal barrier integrity. Gene expression analyses confirmed these findings, showing activation of the P38-MAPK pathway by PS-NPs, which correlated with increased inflammatory cytokines. Additionally, PE-NPs activated the JNK-MAPK pathway, while PP-NPs exposure triggered the NOD-like receptor signaling pathway. Moreover, the composition of gut microbiota shifted to a dysbiotic state, characterized by an increase in pathogenic bacteria in the PS-NPs and PP-NPs groups, elevating the risk of developing Inflammatory Bowel Disease (IBD). PS-NPs were regarded as the most toxic due to their lower stability and higher aggregation tendencies, followed by PP-NPs and PE-NPs. Taken together, the overall study highlighted the complex interactions between NPs, gut microbiota, and host health, emphasizing the importance of thoroughly assessing the ecological and physiological impacts of nanoplastic pollution.

Mixed toxic effects of aluminium oxide nanoparticles with hexavalent chromium, tetracycline, and humic acid towards marine crustacean Artemia salina

ABSTRACT Aluminium oxide nanoparticles (Al2O3 NPs) are prevalent in natural water bodies due to their commercial applications, necessitating an evaluation of their toxicity to aquatic life. This study assessed the toxicity of Al2O3 NPs both alone and in combination with pollutants like chromium (Cr VI) and tetracycline (TC), as well as with organic matter such as humic acid (HA) on brine shrimp (Artemia salina). The addition of Cr (VI) enhanced the aggregation of Al2O3 NPs. Acute toxicity tests showed a concentration-dependent increase in A. salina mortality, primarily due to the early absorption of Al2O3 NPs. The presence of TC and HA reduced toxicity by binding to the nanoparticles. Additionally, HA influenced Al2O3 aggregation, while reactive oxygen species (ROS) production, protein concentration, and lipid peroxidation supported the toxicity findings. This research ultimately highlights the ecological implications of Al2O3 NPs on aquatic ecosystems.

Larval Rearing of the Giant Trevally, Caranx ignobilis (Forsskål, 1775), Fed Live Food Combinations of Rotifers, Copepods and Artemia salina

The giant trevally, Caranx ignobilis, is a high value fish which has been studied for spawning in captivity and domestication in the Philippines in view of its aquaculture potential. Initial larval rearing of the species encountered mortality issues, and this study attempts to address the problem to improve their survival. Hatchery-bred C. ignobilis larvae were reared for 40 days in nine units of 100 L conical fiberglass tanks at a stocking density of 500 larvae.tank-1 under three feed treatments with different combinations of rotifers (Brachionus plicatilis), brine shrimp (Artemia) and copepods (Pseudodiaptomus spp.): T1- Brachionus plicatilis + Artemia, T2- Brachionus plicatilis + Pseudodiaptomus spp., and T3-Brachionus plicatilis + Pseudodiaptomus spp. + Artemia fed at 0800 h and 1600 h. The results showed that the inclusion of copepods in the feeding regimen had positive effects on survival. Survival rate was significantly higher (P < 0.05) in T2 (23.47 ± 3.18 %) than T1 (11.67 ± 1.90 %) but was not statistically different from T3 (14.37 ± 3.88 %). Length increment was significantly different (P < 0.05) among treatments but with no statistical difference in specific growth rate (P > 0.05). The erratic swimming behaviour leading to mortality associated with insufficient levels of highly unsaturated fatty acids in Artemia was not observed in T2, thus, validating the assumption that the feeding with copepods will increase survival during larval rearing. The use of copepods for C. ignobilis larviculture is seen to play an important role in the success of the seed production protocol for this species. However, a sustainable supply of copepods through appropriate mass propagation techniques must be ensured to achieve higher production of C. ignobilis seeds in the hatcheries.

Impacts of graphene oxide contamination on a food web: Threats to somatic and reproductive health of organisms

Contamination of aquatic food webs with nanomaterials poses a significant ecological and human health challenge. Ingestion of nanomaterials alongside food disrupts digestion and impairs physiological processes, with potential consequences for organism fitness and survival. Complex interactions between nanomaterials and biota further exacerbate the issue, influencing life-history strategies and ecosystem dynamics. Accumulation of nanomaterials within autotrophic and detritus-based food webs raises concerns about biomagnification, especially for top-level consumers and seafood-dependent human populations. Understanding the extent and impact of nanomaterial contamination on aquatic biota is crucial for effective mitigation strategies. To address this challenge, we conducted a comprehensive study evaluating the bioaccumulation effects of graphene oxide (GO), a commonly used nanomaterial, within an aquatic food chain. Using a gnotobiotic freshwater microcosm, we investigated the effects of micro- and nano-scale GO sheets on key organisms: green algae (Chlorella vulgaris), brine shrimp (Artemia salina), and zebrafish (Danio rerio). Two feeding regimes, direct ingestion and trophic transfer, were employed to assess GO uptake and transfer within the food web. Direct exposure involved individual organisms being exposed to either nano- or micro-scale GO sheets, while trophic transfer involved a sequential exposure pathway: algae exposed to GO sheets, artemias feeding on the algae, and zebrafish consuming the artemias. Our study provides critical insights into nanomaterial contamination in aquatic ecosystems. Physicochemical properties of GO sheets, including ζ-potential and dispersion, were influenced by salt culture media, resulting in aggregation under salt conditions. Microscopic imaging confirmed the bioaccumulation of GO sheets within organisms, indicating prolonged exposure and potential long-term effects. Notably, biodistribution analysis in zebrafish demonstrated the penetration of nano-sized GO into the intestinal wall, signifying direct interaction with vital organs. Exposure to GO resulted in increased zebrafish mortality and impaired reproductive performance, particularly through trophic transfer. These findings emphasize the urgent need to address nanomaterial contamination in aquatic food webs to protect ecosystem components and human consumers. Our study highlights the importance of developing effective mitigation strategies to preserve the integrity of aquatic ecosystems, ensure resource sustainability, and safeguard human well-being. In conclusion, our study provides crucial insights into the impact of nanomaterial pollution on aquatic biota. By recognizing the challenges posed by nanomaterial contamination and implementing targeted interventions, we can mitigate the adverse effects, preserving the integrity of aquatic ecosystems and safeguarding human health.

Extraction of polysaccharide fraction from cadamba (Neolamarckia cadamba) fruits and evaluation of its in vitro and in vivo antioxidant activities

In this study, polysaccharide fraction (PFFNC) derived from Neolamarckia cadamba fruits showed remarkable antioxidant activity. The PFFNC was successfully extracted from the fruits by the hot water extraction process, followed by decolorization, defatting, and deproteinization. The chemical composition of PFFNC was effectively characterized by the use of UV–Vis, FT-IR, CHN, GC–MS, and 13C NMR spectroscopy. The findings indicated that PFFNC had an average molecular weight of 292 kDa and was predominantly composed of carbohydrates (76 %), with notable contributions from uronic acids (37.22 %) and proteins (12.35 %). The primary components of the sugar content were glucose (19.24 %), galactose (10.19 %), mannose (4.09 %), and glucuronic acid (2.8 %). The tertiary structural study verified the existence of a triple-helical structure. PFFNC exhibited a strong reducing power in vitro as determined by ABTS (IC50: 121 ± 0.12 μg/mL), DPPH (IC50: 146.065 ± 0.54 μg/mL), FRAP (677.788 ± 24.189 mM Fe (II)/g), hydroxyl radical scavenging (IC50: 78.736 ± 0.32 μg/mL), and phosphomolybdate assay (90.7 ± 0.43 mg AAE/g). In addition, the PFFNC furthermore showed significant in vivo antioxidant capacity, as determined using the brine shrimp (Bsmp) (Artemia salina Leach) model. The PFFNC exhibits significant antioxidant potential, suggesting broad spectrum applications in pharmaceuticals, nutraceuticals, and oxidative stress-related disorders.

Size-dependent toxicity of microplastics induced gut cell apoptosis in brine shrimp Artemia parthenogenetica through p53 signaling pathway

Size-dependent toxicity of microplastics induced gut cell apoptosis in brine shrimp Artemia parthenogenetica through p53 signaling pathway

Synthesis and toxicity of monothiooxalamides against human red blood cells, brine shrimp (Artemia salina), and fruit fly (Drosophilamelanogaster)

A new family of monothiooxalamides derived from 2-aminobenzimidazole was synthesized, and their structures were confirmed by 1H and 13C one-dimensional and 2D NMR experiments (COSY, HSQC, and HMBC). The antioxidant capacity was evaluated by free radical scavenging assays: 1,1-diphenyl-2-picrylhydrazyl (DPPH•), 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS•+), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and the Fe(II) chelating ability. Our work group has previously reported the synthesis and antioxidant activity of monothiooxalamides derived from 2-aminopyridine (I). In this study, the in vitro hemolytic activity of compounds from the 2-aminopyridine (I) and 2-aminobenzimidazole (II) families was evaluated against human red blood cells (RBCs). The concentration at which monothiooxalamides showed no hemolytic activity was chosen to assess their ability to inhibit free radical-induced membrane damage in human RBCs, acute toxicity in brine shrimp, and in vivo toxicity against Drosophila melanogaster. Compounds with morpholine fragments (1g, 1h, 2g, and 2h) showed time- and concentration-dependent protective effects against radical-induced oxidative hemolysis. Moreover, they had the lowest acute toxicity in the brine shrimp lethality assay and a significant increase in chelating activity compared with the other molecules. In particular, monothiooxalamide 2g showed lower toxicity and can be considered for further biological screening and application trials.

Characterization of the Unarmored Dinoflagellate Karlodinium decipiens (Dinophyceae) from Jiaozhou Bay, China

The dinoflagellate genus Karlodinium J. Larsen is well known to form harmful algal blooms (HABs), some of which can produce karlotoxins or other ichthyotoxins and thus cause fish-killing events. Among the 16 currently accepted species of Karlodinium (about half of which are reported to be toxic), six species (K. australe, K. decipiens, K. digitatum, K. elegans, K. veneficum, and K. zhouanum) have been reported or described in the coastal waters of China. However, a fine morphological and molecular characterization of the seldom-observed species K. decipiens has not been conducted; moreover, the negative effects of this species on aquatic animals have not been investigated. This work reports the morphological and phylogenetic characterization of a strain of K. decipiens isolated from Jiaozhou Bay, China, in 2019. The characterization of the strain was conducted using light and scanning electron microscopy, LSU, SSU rDNA, and ITS sequences-based systematic analyses, pigment analysis, and a detailed investigation of its potential toxic/harmful activity on aquatic animals. We observed the typical diagnostic features of K. decipiens, including its relatively large size, ellipsoidal or ovoid cell shape, ventral pore, ventral ridge connecting the two displaced ends of the cingulum, cingulum with a displacement of about one-third of the cell length, numerous polyhedral or slightly elongated chloroplasts distributed peripherally, and large nucleus located centrally. However, we also observed a large amphiesmal vesicle at the dorsal end of the ASC at the dorsal epicone, which is a novel feature that has never been reported from any species of the genus. Based on the results of this study, it is not clear whether this feature is a specific structure of the species or a common characteristic of the genus; therefore, this novel feature is worthy of further examination. Fucoxanthin was the most abundant pigment among all the carotenoids detected. The phylogenies inferred using Bayesian inference (BI) and maximum likelihood (ML) techniques confirmed the conspecificity of our isolate with the holotype K. decipiens (accession no. EF469236). In molecular trees, K. decipiens and K. antarcticum form a separate clade from other species of Karlodinium, and it should be examined whether a large amphiesma vesicle may be a characteristic of this clade. The exposure bioassays using brine shrimp (Artemia salina) indicated that K. decipiens exhibited toxicity to zooplankton, with 100% and 68% mortality observed in brine shrimp using live cell cultures and cell culture lysates over 120 h, respectively. Our work provides a detailed morphological and molecular characterization of K. decipiens from China. The results of this study broaden the known geographical distribution of this species and demonstrate it to be a harmful dinoflagellate.

Evaluating the Effect of Live Brine Shrimp (Artemia franciscana) on Growth Performance in Ornamental Fish, Cyprinus rubrofuscus (Lacepede, 1803)

Feeding is a critical factor for both cultured and ornamental fish species. This study aimed to evaluate the effects of live brine shrimp (Artemia franciscana) on the growth and biochemical composition of fish. In the present study, sixty days feeding trail was conducted on the growth performance of ornamental fish, koi carp (Cyprinus rubrofuscus). The type of food such as live feed, nutrient-enriched prepared feed and commercial feed exerted a significant impact on the growth and body composition of fish. The specific growth rate is high in live brine shrimp fed fishes followed by prepared food. After 60 days experiment showed that the maximum length and weight of live brine shrimp fed fishes were 7.5 ± 0.9 cm and 5.3 ± 1.7 gm, respectively. The survival rates of the fish were 100 % under all feeding groups. The biochemical profiles of the fish varied significantly between the different feeding regimes. These results suggest that live feed is more effective than pelletized feed for ornamental fish culture.