The use of probiotics – live microorganisms – to enhance growth and prevent disease in mariculture species is an emerging alternative to conventional methods including antibiotics, vaccines and chemical intervention. While others have reviewed specific host organisms and probiotic genera, this review synthesises the scientific literature on the use of probiotics across a range of marine organisms to identify knowledge gaps and research opportunities. We identified widespread methodological heterogeneity, making direct inter-study comparisons difficult. Despite this limitation, 86
Urechis unicinctus is an economically important aquaculture species and an emerging model for developmental and evolutionary research; however, progress in functional genetic studies in this species has remained limited by the absence of effective genome editing approaches. Here, we establish a CRISPR/Cas9-mediated genome editing platform in U. unicinctus based on an optimized microinjection procedure. Targeting the cilia-associated gene Caveolin-1, Cas9/sgRNA ribonucleoprotein complexes were delivered into oocytes, generating mosaic G0 larvae harboring insertion–deletion mutations, as confirmed by ICE analysis and cloning-based Sanger sequencing with mutation detection rates of 68.51
This study presents a comprehensive approach to valorizing the red macroalga Bostrychia scorpioides (BS), collected from Oualidia lagoon, as a reservoir of compounds with biological activity. An extraction protocol combining ultrasound-assisted pretreatment with conventional maceration in 80
Paralytic shellfish toxins (PSTs) are widely distributed neurotoxins that accumulate and transform in bivalves, but the metabolic mechanisms after exposure of Azumapecten farreri (A. farreri) to PSTs remain unknown. To verify the phase I (cytochrome P450, CYP450)-II (glutathione S-transferase, GST)-III (ABC transport) metabolic genes for PSTs, we used RNA interference (RNAi) to silence target genes (CYP46A1, GSTM1, and ABCF2), measured PSTs content, and performed single nucleotide polymorphism (SNP) screening. Injection of small interfering RNA (siRNA) fragments into the scallop adductor muscle silenced target genes in multiple tissues. The three most effective fragments were selected. Secondary injection of screening fragments prolonged the silencing duration, with a silencing efficiency of 12.0
Tetrodotoxin (TTX), commonly known as pufferfish toxin, is widely distributed among marine organisms. In the past decade, TTX has been detected in edible bivalves along coasts worldwide, raising concerns about unexpected food poisoning. Recent research suggests that planktonic larvae of the TTX-bearing flatworm Planocera multitentaculata are involved in the toxification of bivalves. However, some uncertainties remain: although these flatworms contain large amounts of 5,6,11-trideoxytetrodotoxin (TDT), TDT is generally not detected in bivalves, even when TTX is present. The aim of this study was to characterize the accumulation and excretion of TTX and TDT in the mussel Mytilus galloprovincialis after ingestion of toxic P. multitentaculata larvae and to determine whether differences in their excretion could explain the rarity of TDT in naturally contaminated bivalves. LC–MS/MS analysis revealed that the toxified mussels accumulated both TTX and TDT in the midgut gland. However, the concentrations of both compounds decreased over time, with TDT showing a faster decline than TTX. These findings provide the first evidence for the accumulation and excretion of TDT in bivalves and suggest that its faster elimination contributes to its rare detection in naturally contaminated specimens. The results also indicate that detection of TDT in wild bivalves may reflect relatively recent ingestion of TTX-bearing organisms, providing new insights into TTX analog dynamics and contributing to seafood safety monitoring.
Ulva prolifera (U. prolifera), a large green alga widely distributed along coastlines worldwide, can trigger marine ecological issues such as “green tides” when over-proliferating. Nevertheless, it is abundant in various nutrients and bioactive compounds, making the utilization of this alga an urgent task. In this study, an antioxidant peptide fraction (UCP‑1) was isolated and purified from U. prolifera. LC‑MS/MS analysis indicated that the peptide composition and molecular weight distribution of UCP‑1 possess typical characteristics of antioxidant peptides. In vitro experiments demonstrated that UCP‑1 at a concentration of 1 mg mL⁻¹ exhibited a DPPH radical scavenging capacity of 38.86 ± 2.7
This study evaluated the effects of alginate nanoparticles (NPs-A) extracted from Sargassum polycystum on gut bacterial community composition and intestinal histology in tilapia (Oreochromis sp.). NPs-A were prepared using ball milling to obtain nanoscale alginate with improved functional properties. Five dietary treatments were evaluated in triplicate: a negative control, a positive control (2 g alginate kg⁻¹ feed), and diets supplemented with 0.5, 1.5, or 2 g NPs-A kg⁻¹ feed. Tilapia (10.3 ± 0.11 cm) were stocked at a density of 125 fish m⁻³ in conical fiber tanks with a diameter of 100 cm and fed the experimental diets for 60 days. Intestinal samples were collected on days 0 and 60 for histological evaluation and bacterial community profiling based on the V3–V4 region of the 16 S rRNA gene. Dietary NPs-A supplementation was associated with differences in gut bacterial community composition and intestinal histological characteristics among treatments. Bacterial communities were dominated by Fusobacteriota and Bacteroidota across all treatments, indicating the presence of a relatively stable core microbiota, while Cetobacterium remained the dominant genus. Among the evaluated treatments, supplementation with 0.5 g kg⁻¹ NPs-A showed the most favorable overall response, characterized by the highest villus length and villus-to-intestinal diameter ratio, together with distinct bacterial community profiles. Higher NPs-A doses (1.5–2 g kg⁻¹) were associated with greater intestinal muscle thickness but lower villus development. Overall, dietary NPs-A derived from S. polycystum was associated with changes in gut microbiota composition and intestinal histology in tilapia. However, because gut microbiota analyses were based on pooled intestinal samples and microbial community differences were evaluated descriptively, further studies incorporating biological replication and functional analyses are required to validate these findings.
Salinity fluctuations pose critical physiological challenges to the sea cucumber Apostichopus japonicus. This review elucidated its molecular salinity response mechanisms, focusing on miRNA-mediated regulation and core pathways. We highlight a hierarchical network in which 8 key miRNAs fine-tune responses. let-7 targeted Solute Carrier Family 34 Member 2 (SLC34A2) and Cystathionine Gamma-Lyase (CTH), coordinating ion transport and amino acid metabolism, respectively. miR-10 targeted genes Nicotinamide Phosphoribosyltransferase (NAMPT) in energy homeostasis and TGF-Beta Activated Kinase 1 (MAP3K7) Binding Protein 1 (Table 1) to regulate MAPK/ERK signaling. miR-278-3p targeted 5-Hydroxytryptamine Receptor 2B (Htr2b) and Chloride Channel Accessory 1 (CLCA1) to modulate GPCR signaling and chloride transport. miR-2008, miR-3, miR-16, miR-22, and miR-14 coordinate vesicular trafficking, transcription, apoptosis, and autophagy via targeting Pleckstrin Homology Domain Containing A3 (PLEKHA3), Upstream Binding Transcription Factor (UBTF), ATP Binding Cassette Subfamily C Member 2 (ABCC2), Polypeptide N-Acetylgalactosaminyltransferase 2 (GALNT2), Glutamic-Oxaloacetic Transaminase 2 (Got2), Aconitase 2 (Aco2), and RNA Polymerase II Associated Protein 2 (Rpap2). Salinity sensing initiates GPCR-mediated cAMP/PKA and MAPK/ERK cascades, activating transcription factors (UBTF) to drive stress gene expression. Ion transporters (SLC family), ABC transporters, and vesicular transport maintain cellular homeostasis. Cullin Associated and Neddylation Dissociated 1 (CAND1)/Listerin E3 ubiquitin protein ligase 1 (Ltn1) are involved in amino acid/protein metabolism and ubiquitinated proteins to participate in vesicular transport for protein sorting and secreting. These secreted molecules (Glyare/Taurine) act as ligands to bind membrane receptors and trigger GPCR pathways and energy metabolism and redox balance. Aco2/Got2/NAMPT supply ATP for adaptation and apoptosis/autophagy, repair damage and maintain homeostasis, alleviate oxidative damage, supported by innate immunity genes. These findings establish a framework for understanding sea cucumbers salinity adaption, further exploration of additional genes is needed to refine mechanistic details.
The utilization of plant protein in aquafeeds to reduce dependence on fishmeal has become an important strategy for improving the sustainability of marine aquaculture. This study investigated the effects of low-fishmeal plant protein diets on growth performance and gut–liver molecular responses in large yellow croaker. A total of 2,048 fish were fed two diets for 206 days: a commercial-like control diet containing 280 g/kg fishmeal (C group) and a low-fishmeal diet containing 100 g/kg fishmeal with increased inclusion of plant protein sources (P group). Growth trials indicated that fish in the C group had significantly higher weight gain rate and specific growth rate than those in the P group (p < 0.001). Transcriptomic analysis identified 546 and 724 differentially expressed genes (DEGs) in the hindgut and liver, respectively. Hindgut DEGs were mainly enriched in pathways associated with lipid metabolism, immune responses, and signal transduction, whereas liver DEGs were primarily involved in lipid metabolism, immune regulation, and apoptosis. Several pathways, including fat digestion and absorption, complement and coagulation cascades, taurine and hypotaurine metabolism, antigen processing and presentation, and cytokine–cytokine receptor interaction, were enriched in both tissues, suggesting coordinated gut–liver regulation. Representative genes involved in lipid metabolism and immune regulation, including apob, scarb1, c3, b2m, and ccr9, exhibited tissue-specific and coordinated expression changes. PPI network analysis further identified c3, scarb1, vwf, and apob as key regulatory nodes potentially involved in coordinated metabolic and immune adaptation. Collectively, these findings provide new insights into the molecular mechanisms underlying gut–liver adaptation to plant-based diets in marine fish.
Macrobrachium rosenbergii is a pillar species in global freshwater crustacean aquaculture. Decapod iridescent virus 1 (DIV1) causes 60
The silver pomfret (Pampus argenteus) represents a commercially vital marine fish species. However, its aquaculture potential, especially in temperate northern regions, is critically constrained by pronounced cold sensitivity. Building upon preliminary investigations which demonstrated a significant inverse correlation between dusp5 expression levels and ambient water temperature, this study aimed to elucidate the functional mechanism of dusp5-a cold-inducible dual-specificity phosphatase affecting the MAPK pathway-in mediating cold stress adaptation. Utilizing cellular models subjected to dusp5 knockdown (KO) and overexpression (OE), we systematically evaluated its impact on cold stress responses. Functional analysis revealed that dusp5 OE conferred significant cytoprotection: it effectively suppressed cold-induced DNA fragmentation indicative of apoptosis (quantified by TUNEL assay), ameliorated mitochondrial dysfunction (assessed via JC-1 staining and TEM ultrastructural examination), and diminished oxidative stress (indicated by reduced malondialdehyde/MDA levels). Subsequent qPCR profiling demonstrated that dusp5 OE modulated the expression of selected genes associated with MAPK signaling cascades, apoptotic pathways, endoplasmic reticulum (ER) stress response, and mitochondrial functional integrity under cold duress. Furthermore, employing dual-luciferase reporter assays, we identified atf2, atf4, jund, and stat1 as putative regulators of dusp5 promoter activity. Complementary histidine affinity chromatography facilitated the identification of candidate dusp5-associated proteins predominantly localized to the ER and mitochondrial compartments, with functional annotations implicating roles in ER homeostasis, autophagic processes, and peroxisome metabolism. Collectively, this work provides the preliminary mechanistic insights of dusp5 in promoting cold tolerance within P. argenteus, yielding novel and fundamental insights into the molecular regulators underpinning low-temperature adaptation mechanisms in marine teleosts.
This study presents a streamlined electroporation-based method for efficient macromolecular delivery into zebrafish embryos. We first characterized the physical barrier posed by the chorion using TEM (Transmission Electron Microscope) and established that its removal is prerequisite for effective delivery. A systematic optimization of electroporation parameters for dechorionated embryos identified optimal conditions (e.g., poring pulse: 25 V, 20 ms; transfer pulse: 5 V, 50 ms) that ensured high embryo survival and robust eGFP mRNA transfection. Applying this protocol, we achieved targeted gene knockout by electroporation-mediated delivery of Cas9 ribonucleoproteins (RNPs) against multiple loci. Targeting the tyr locus resulted in a phenotypic albinism rate of (38.6 ± 3.30)
This study was conducted to determine whether early dietary supplementation with an intermediate vitamin D metabolite could improve metabolic efficiency and liver function in rainbow trout. Over a 20-week feeding trial from first feeding, rainbow trout were fed either a control diet containing vitamin D 3 alone or a diet additionally supplemented with 80 µg/kg 25-OH-D 3 . Plasma analysis confirmed that 25-OH-D 3 was efficiently absorbed, with detectable levels of 25-OH-D 3 and its epimer, indicating enhanced vitamin D status. While growth was similar between the experimental groups, fish receiving 25-OH-D 3 exhibited a significantly improved feed efficiency, indicating a better nutrient utilization. Whole-body composition analysis revealed higher protein and ash content and reduced lipid levels, consistent with transcriptomic evidence of modulated cholesterol and bile acid metabolism. Transcriptome profiling revealed 1301 differentially expressed genes in the liver, with strong modulation of pathways related to vitamin D metabolism, lipid handling, bile acid recycling, and ferroptosis. Additional signatures suggested improved nutrient partitioning and metabolic efficiency, potentially mediated by transcriptional and post-transcriptional mechanisms, including mRNA splicing. Consistent with its role on genome regulation via the vitamin D receptor, the data support the role of an active vitamin D system as a key potent modulator of efficient hepatic metabolism and function supporting improved feed utilization and long-term health outcomes in aquaculture.
This study investigated the effects of dietary synthetic astaxanthin on growth performance, body color, digestive physiology, antioxidant capacity, and immune responses in Plectropomus leopardus. Four experimental diets containing different levels of synthetic astaxanthin were formulated: T0 (0‰), T1 (1‰), T2 (2‰), and T3 (3‰). A total of 504 juvenile fish (initial body weight: 323.56 ± 14.64 g) were randomly assigned to four treatment groups with three replicates per treatment (42 fish per tank) and fed the experimental diets for 90 days. The results showed that dietary astaxanthin supplementation significantly improved growth performance, as evidenced by increased final body weight (FBW), weight gain rate (WGR), and specific growth rate (SGR) (P < 0.05). Synthetic astaxanthin supplementation also enhanced body color by increasing chromatophore density and significantly elevating skin redness (a*) and yellowness (b*) values (P < 0.05). Furthermore, digestive enzyme activities (LPS, AMS, TPA and CPA) were significantly increased in the astaxanthin-fed groups (P < 0.05), indicating enhanced digestive and nutrient utilization capacities. Synthetic astaxanthin also improved physiological health by increasing antioxidant enzyme activities (SOD, CAT and T-AOC), while reducing lipid peroxidation levels (P < 0.05). In addition, immune-related parameters(ACP, AKP and LZM) were significantly enhanced, suggesting improved innate immune function and resistance to oxidative stress. Among the treatments, fish fed the T2 diet generally exhibited the most favorable responses in growth, pigmentation, antioxidant status, and immune performance. These findings suggest that dietary synthetic astaxanthin promotes growth, body color, digestive efficiency, antioxidant defense, and immune competence in P. leopardus, and that a supplementation level of approximately 2‰ may represent an optimal dietary inclusion level for this species.
Photoperiod can influence the gonads of fish. This study examined the effects of different light cycles on the gonads of Channa argus var.(C. argus var.). Over a 14-day rearing period, C. argus var. were subjected to five photoperiods: 0 L:24D, 6 L:18D, 12 L:12D, 18 L:6D, and 24 L:0D. On day 14, samples of blood and gonad tissue were collected at 12:00 (noon) to measure enzyme activities and perform transcriptomic analyses. The results showed that prolonged light exposure generally increased ovarian levels of estradiol (E2), progesterone (P), follicle-stimulating hormone (FSH), and vitellogenin (VTG). Melatonin(MT) concentrations in both plasma and ovaries also rose with increasing light duration. Notably, at 18 h of light, both melatonin and sex hormone levels were high. Additionally, transcriptional analysis indicates that the cyclic adenosine monophosphate (cAMP) signaling pathway may be activated in concert by the key factor hrt4 and E2 to stimulate phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt) signaling pathway, thereby promoting FSH secretion and facilitating the accumulation and transport of yolk substances, thereby promoting ovarian development and oocyte maturation. In summary, photoperiod regulates melatonin synthesis, signals related to the cAMP pathway, and the PI3K-Akt signaling pathway, as well as the expression of the key factor hrt4, which in turn influences sex hormone secretion, lipid metabolism, and yolk deposition. Integrated analysis suggests that a day length of 18 h is most favorable for ovary development in C. argus var.
Increasing environmental releases of vanadium (V) by industrial plants pose significant risks of soil, water, and ecosystem contamination. Microbes reduce this toxic compound by producing a vanadate reductase enzyme that converts V5+ to a less toxic compound, V4+. This study describes the cloning, expression, and characterization of an asparaginyl-tRNA synthetase (AsnRS) from the marine bacterium Shewanella sp. HU-ET00281. The Shewanella-AsnRS (Sh-AsnRS) recombinant protein reduced V5+ to V4+ under ambient conditions. The Km and Vmax values were 8.70 mM and 4.45 mol-V4+/min/mol-protein respectively. Activity was enhanced by up to 75
The skin, the body’s largest organ, acts as the primary barrier against infections, but this function can be compromised by wounds. While antibiotics are commonly used for treating skin infections, their misuse has led to antibiotic-resistant pathogens, emphasizing the need for safer alternatives. Fucoidan has shown antibacterial and anti-inflammatory properties. However, its biological activity can vary due to differences in species and geographical origin. In this study, fucoidan was isolated from Sargassum polycystum collected in the intertidal zone of South Sulawesi, Indonesia, and its wound-healing potential was tested in Staphylococcus aureus-infected rats. Fucoidan was extracted using hot ethanol-water extraction and CaCl₂-ethanol precipitation, and characterized by FTIR, ¹H NMR, and ¹³C NMR. Toxicity was assessed with a hemolysis assay, and wound healing was evaluated in rats with 6 mm excision wounds infected with Staphylococcus aureus (0.1 mL, 10⁷ CFU/mL). Results showed that fucoidan was non-toxic and that a 2.4
Fatty acids are crucial for steroidogenesis and gonadal development in fish. A 90-day feeding experiment was conducted before maturation to assess the effects of different dietary levels of linoleic acid (LA) and linolenic acid (LNA) on gonadal development and reproductive performance in Channa striata broodstocks. A total of 300 male and female broodstocks were divided into five treatment groups, each with three replicates, using a completely randomized design. The fish were fed five experimental diets that were isonitrogenous (42
This study evaluated the effects of dietary supplementation with graded levels of N-carbamylglutamate (NCG) on growth performance and muscle quality in triploid crucian carp (TCC). Six isonitrogenous (35.00
Pseudoalteromonas species are ecologically versatile marine bacteria widely recognized for their capacity to synthesize diverse bioactive metabolites and psychrophilic enzymes with biotechnological relevance. Here, we present a comprehensive comparative genomic analysis of 53 reference genomes to elucidate the dynamics, functional diversity, and biosynthetic potential of this genus. Reference genomes representing each deposited species were selected in order to avoid bias associated with unequal numbers of genomes per species. Pangenome reconstruction revealed an open structure comprising a small core genome (1,350 gene families) and a large proportion of accessory and strain-specific genes, reflecting extensive genomic plasticity. Functional annotation indicated that accessory regions are enriched for genes involved in secondary metabolism, stress adaptation, and environmental resilience. Notably, biosynthetic gene cluster (BGC) mining uncovered a rich repertoire of potentially novel RiPPs and other secondary metabolite clusters, underscoring Pseudoalteromonas as a promising source of unexplored bioactive compounds. Statistical analyses revealed that pigmented strains harbor significantly higher numbers of BGCs compared to non-pigmented strains, while only a weak and non-significant correlation was observed between BGC abundance and carbohydrate-active enzyme (CAZyme) content. No significant effect of the isolation source was detected on either BGC or CAZyme distributions. Together, these findings provide new insights into the genomic basis of ecological adaptation and metabolic diversification in Pseudoalteromonas, supporting the role of pigmentation as a proxy for enhanced biosynthetic potential, while carbohydrate utilization capabilities evolve more independently and offering a framework for targeted bioprospecting of marine-derived metabolites with industrial and environmental applications.
