Search Results (9,538)

All-trans retinoic acid (atRA) is known to regulate lipid metabolism, adipocyte differentiation, and the immune system in mammals and other aquatic species. However, studies on atRA in crustaceans, especially in Eriocheir sinensis, are still scarce. The present study aimed to investigate the regulatory effects of dietary or injected atRA on female crabs during the fattening period. In the dietary regulation experiment, 270 female crabs were fed diets containing different doses of atRA (0, 150, 300, 600, 1200, and 2400 mg/kg) for a total of 49 days. In the in vivo injection experiment, 90 females were divided into an experimental group (injected with a 0.3 μg/g dose of atRA) and a control group (injected with the same amount of DMSO solvent). Injections were given weekly throughout the 35-day experimental period. Results: Both dietary atRA and atRA injection promoted ovarian development, as evidenced by increased GSI, elevated serum Vg levels, decreased GIH, and upregulated expression of vg, vgr, and rxr genes. In terms of mechanism, dietary atRA promoted ovarian development via the upregulation of pyrimidine nucleotides and dehydroepiandrosterone, which supplied nucleic acid precursors and hormonal support. Furthermore, RXR was identified as a potential key target of atRA in inducing ovarian development, as molecular docking revealed that atRA could spontaneously bind to RXR. Moreover, following atRA injection, the expression of rxr, along with key genes involved in ovarian development, lipid synthesis, and lipid transport, was significantly upregulated. In addition, the atRA diet created a favorable microenvironment for ovarian development by reducing pro-inflammatory lipid levels in the ovary. Transcriptomic and metabolomic analyses revealed that atRA modulates energy and lipid metabolism by activating the AMPK pathway. In terms of the bacterial community structure, the atRA diet significantly decreased Fusobacterium abundance and enriched Parabacteroides as the signature beneficial bacterium. In terms of nutritional quality, the atRA diet markedly reduced saturated and trans-fatty acids while increasing monounsaturated fatty acids and various key essential amino acids. Conclusions: This study revealed that atRA plays a key role in promoting ovarian development, improving nutritional quality, and modulating the structure of the microbiota, thereby providing theoretical support for healthy aquaculture of female crabs during the fattening period. Full article

Background/Objectives: Course-based Undergraduate Research Experiences (CUREs) represent a form of student crowdsourcing in which individuals perform authentic discovery-based research in a class setting with interest to outside stakeholders. Here, the renowned Tiny Earth (TE) CURE is being utilized to teach microbiology and perform natural product discovery research by students in the course. Methods: In our TE CURE, students collect soil samples from their hometown and characterize bacteria that can inhibit plant and animal pathogens. This unique growing collection of isolates from across Ohio has provided opportunities to facilitate drug discovery and establish biotechnology collaborations. Results: In this study, we describe two outcomes using our environmental strain collection that initiated biotechnology collaborations and identified bacterial candidates for drug discovery. Results from one project led to a partnership with an aquaculture company. A novel biosynthetic gene cluster involved in antagonistic activity was identified, whose product inhibits Aeromonas pathogens, which cause disease in freshwater fish. The other project involves a collaboration with a global commercial cleaning and equipment company to identify lipase activity among Bacillus strains for its potential use in bioremediation. Conclusions: The unique strain collection generated by students in the CURE led to collaboration with biotechnology companies, which contributed to natural product discovery of an antimicrobial product and active enzymatic activity, all of which benefit education and scientific discovery. Full article

Vibrio splendidus is an important opportunistic pathogen that causes diseases in aquatic animals, and its persisters increase the difficulty of aquaculture disease control. The stringent response is a central pathway in bacteria for coping with environmental stress, and the signaling molecule (p)ppGpp, synthesized under the regulation of RelA/SpoT homologs, is closely associated with persister formation and virulence modulation. However, the regulatory mechanisms linking the stringent response to persister formation and virulence in V. splendidus remain unclear. In this study, the core gene deletion strains ΔrelA and ΔrelAΔspoT were constructed via homologous recombination. Combined with D₂O single-cell Raman spectroscopy, transcriptomics, and phenotypic assays, we systematically characterized the biological effects of stringent response inactivation. The results showed that the loss of relA and spoT significantly reduced persister formation and key virulence traits while enhancing biofilm formation. Single-cell Raman spectroscopy analysis indicated that persisters remained metabolically active, accompanied by changes in different cellular components. Transcriptome analysis revealed that the absence of stringent response affected multiple pathways, including ribosomal function, energy metabolism, two-component systems, and quorum sensing. Additionally, the sigma factor RpoS may potentially exert a compensatory function in ΔrelAΔspoT strain, but this requires further validation. In conclusion, the stringent response positively regulates persister formation and virulence in V. splendidus, despite the existence of complex regulatory mechanisms. This study provides a theoretical basis for the development of anti-infective strategies targeting stringent response in aquatic pathogens. Full article

Folate is a central nutrient in one-carbon metabolism, contributing to nucleotide biosynthesis, methionine cycling, methyl-donor supply, and epigenetic regulation. In animals, the intestine is both a principal site of folate absorption and a key target organ for folate action. This narrative review focuses primarily on livestock, poultry, aquaculture species, ruminants, and animal-source food enrichment, while also using rodent, human, and in vitro studies as mechanistic or translational evidence. We synthesize evidence on folate absorption, transport, and metabolism and evaluate the mechanisms through which folate influences intestinal health. Available evidence suggests that adequate folate supply may support epithelial renewal, tight-junction integrity, mucosal immune balance, antioxidant capacity, gut microbiota stability, short-chain fatty acid production, and epigenetic regulation of intestinal development. These effects have been reported in poultry, pigs, fish, ruminants, rodents, and maternal–offspring models. However, the evidence is uneven across species, and dose–response relationships, folate forms, bioavailability, and species-specific requirements remain major limitations for translating current knowledge into animal production. Future studies should compare folic acid, 5-methyltetrahydrofolate, natural reduced folates, microbiota-derived folate, and folate-producing probiotics; quantify the contribution of microbiota-derived folate to host methyl-donor pools; and develop precision strategies that integrate folate with other one-carbon nutrients, probiotics, and product-enrichment technologies. Full article

This study evaluated locally available dry feed formulations (FFs) as practical alternatives to fresh Chlorella sp. for culturing the freshwater fairy shrimp Streptocephalus sirindhornae. Seven dietary treatments were evaluated, including fresh Chlorella sp. at 1 × 10⁶ cells mL⁻¹ (FF1; control) and six mixed dry diets (FF2–FF7) formulated from spirulina powder, commercial shrimp feed, fish meal, and rice bran. Fairy shrimp were cultured for 20 days in a completely randomized design with three replicates per treatment at a stocking density of 30 individuals L⁻¹. Growth performance (body length and wet body weight) and survival were assessed across three developmental stages (1–5, 6–10, and 11–20 days post-hatch). Across all developmental stages, FF2 (50% spirulina powder + 50% commercial shrimp feed) consistently supported culture performance comparable to that of the control treatment. During the early developmental stage (1–5 days post-hatch), shrimp fed FF2 exhibited growth and survival rates comparable to those of the control group and significantly higher (p < 0.05) than those observed in several other dry diet treatments. During the late developmental stage (11–20 days post-hatch), survival of shrimp fed FF2 (62.45 ± 5.28 percent) did not differ significantly from that of the control group (61.85 ± 4.25 percent) but was significantly higher (p < 0.05) than survival in the other dry diet treatments. In addition, shrimp biomass produced with FF2 showed greater protein, lipid, carotenoid, and amino acid contents than shrimp fed fresh Chlorella sp. Protein, lipid, and amino acid contents were determined using standard AOAC methods, and carotenoid content was analyzed by HPLC. These findings suggest that FF2 may serve as a practical algae-independent diet for maintaining growth and survival of S. sirindhornae under controlled hatchery conditions. Full article

Paracentrotus lividus (Lamarck, 1816) is a commercially valuable species in the Mediterranean Sea, and the development of suitable feeds for juvenile rearing remains an important challenge for full-cycle aquaculture. In this study, we evaluated two experimental formulated diets containing anchovy-processing by-products and carrot peels as main ingredients, using a commercial diet as control. The diets were tested for 84 days on three size classes of P. lividus under controlled recirculating aquaculture conditions. Growth, feed intake, somatic growth rate, feed conversion ratio, gross apparent digestibility, and nitrogen assimilation were assessed. Our results demonstrated that both experimental diets could sustain the growth of sea urchins. However, growth varied significantly across diets and size classes and the two diets showed different results in terms of somatic growth rate and feed conversion ratio. Our findings suggest that eco-friendly feeds derived from industrial waste by-products can be used for sea urchin aquaculture. However, further research is needed to optimize feeding protocols and understand the underlying mechanisms affecting growth performance and feed assimilation efficiency. The utilization of food waste in aquaculture can contribute to the conservation of overexploited sea urchin stocks and promote sustainable practices in marine resource management. Full article

Water-quality monitoring is critical for maintaining the symbiotic balance and productivity of aquaponic systems. This study presents the design, implementation, and evaluation of a remote, real-time monitoring system based on the Internet of Things (IoT) paradigm. The system continuously monitors the key parameters of temperature, pH, electrical conductivity, total dissolved solids, salinity, dissolved oxygen, turbidity, and total suspended solids. Utilizing a modular architecture, the platform provides real-time visualization, cloud-based data management, and automated alerts via SMS and e-mail to notify operators of deviations from established tolerance ranges. The system was experimentally validated over a six-month period in a pilot-scale aquaponics system cultivating common carp (Cyprinus carpio). Statistical analysis demonstrated a 97% data acquisition reliability rate. Furthermore, no statistically significant differences (p > 0.05) were observed between the sensor-based measurements and reference laboratory analyses, confirming the system’s high accuracy. This versatile and cost-effective tool enables data-driven decision-making, facilitates timely interventions to reduce production losses, and ensures the long-term environmental stability of integrated aquaculture systems. Full article

The replacement of fishmeal with plant protein is a key strategy for sustainable aquaculture, but reduced feed intake and digestive efficiency remain major constraints. This study evaluated the effects of dietary dimethyl-β-propiothetin (DMPT) supplementation on feed intake, digestive function, antioxidant capacity, and intestinal microbiota in narrow-clawed crayfish (Pontastacus leptodactylus) fed an all-plant protein diet. Three isonitrogenous and isolipidic diets were formulated: a plant protein diet (PPD), an animal protein diet (APD), and a PPD supplemented with 0.5% DMPT. After a 4-week feeding trial, results showed that PPD significantly reduced feed intake and digestive enzyme activities compared to APD, whereas DMPT supplementation restored feed intake to a level comparable to APD, maintained growth-related parameters at intermediate levels, and significantly enhanced α-amylase (AMS), lipase (LPS), and trypsin (TPS) activities. Additionally, DMPT markedly improved hepatopancreatic antioxidant capacity, as indicated by increased total antioxidant capacity (T-AOC), glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD) levels, without affecting muscle composition or intestinal morphology. Microbiota analysis revealed that DMPT altered community structure, increased Bacillota abundance, and promoted microbial network stability. Overall, DMPT supplementation effectively mitigates the limitations of plant protein diets and supports the replacement of animal protein in crayfish aquafeeds. Full article

This study evaluated the genetic variability and traceability potential of farmed European sea bass (Dicentrarchus labrax) and gilthead seabream (Sparus aurata) populations from a fish farm located in Petrosino (Marsala, Sicily) (FAO 37), using microsatellite markers. A total of 64 D. labrax and 63 S. aurata individuals were genotyped with species-specific multiplex panels (9 and 10 loci, respectively). High levels of polymorphism were observed in both species, with an average of 12 alleles per locus in D. labrax and 9.1 alleles per locus in S. aurata. Mean observed heterozygosity (Ho) was 0.530 in D. labrax and 0.459 in S. aurata, while expected heterozygosity (He) reached 0.762 and 0.702, respectively. The fixation index (F) indicated moderate heterozygote deficiency in both populations (0.320 in D. labrax and 0.352 in S. aurata). Significant deviations from Hardy–Weinberg equilibrium were detected at most loci in both species, suggesting non-random mating, genetic drift, or population substructure. The probability of identity (PI) values across loci confirmed the high discriminatory power of the microsatellite panels, supporting their suitability for individual identification and genetic traceability applications in aquaculture. Overall, the results highlight that, despite substantial genetic variability, the observed heterozygote deficiency and deviations from equilibrium may reflect suboptimal breeding management practices. These findings underline the importance of implementing regular genetic monitoring and integrating molecular tools into broodstock management to maintain genetic diversity, reduce inbreeding, and support sustainable aquaculture production. Full article

The CD40–CD154 receptor-ligand axis is a core costimulatory regulator of antiviral immunity in mammals, but its functional role in teleosts remains largely unknown. Here, we identified the CD40 and CD154 homologs (MsCD40 and MsCD154) from largemouth bass (Micropterus salmoides), a globally farmed perciform teleost. Bioinformatic analysis confirmed that MsCD40 and MsCD154 harbor the conserved domain architectures of tumor necrosis factor receptor superfamily and TNF superfamily, respectively, with a teleost-specific phylogenetic clustering pattern. Both genes were ubiquitously expressed in immune-relevant tissues, and their transcription was dynamically regulated in response to viral hemorrhagic septicemia virus (VHSV) and largemouth bass virus (LMBV) challenge in vivo. Co-immunoprecipitation and immunofluorescence co-localization assays verified that MsCD40 and MsCD154 physically interact at the plasma membrane, forming a functional receptor-ligand complex. Functional assays showed that overexpression of either MsCD40 or MsCD154 significantly suppressed VHSV and LMBV infection in vitro. Furthermore, MsCD40 and MsCD154 overexpression dose-dependently activated nuclear factor-κB (NF-κB) reporter activity, and markedly upregulated the transcription of NF-κB downstream effector genes, including IL-8, NLRP3 and P105, under both VHSV and LMBV infection. Collectively, our findings demonstrate that the teleost CD40–CD154 costimulatory axis restricts both RNA and DNA viral infection in largemouth bass through NF-κB-mediated immune activation, which provides promising molecular targets for the development of broad-spectrum antiviral strategies in largemouth bass aquaculture. Full article

Ammonia exposure can induce oxidative stress in aquatic animals. The p62 protein is a selective autophagy receptor that participates in protein degradation and oxidative stress regulation. In this study, the role of Lv-p62 in the response of Litopenaeus vannamei to ammonia exposure was investigated using RNA interference. The results showed that Lv-p62 expression was significantly induced in the hepatopancreas, gills, and intestine of L. vannamei after ammonia exposure (p < 0.05). Lv-p62 expression peaked at 6 h in the gills and 24 h in the intestine, whereas a biphasic response was observed in the hepatopancreas, with an initial peak at 12 h and a higher second peak at 48 h. In the RNAi experiment, Lv-p62 knockdown altered the expression of antioxidant-related genes (Trx, Gst, and Gpx) in a tissue-specific manner, with Gpx expression being prominently increased in the gills and intestine but not in the hepatopancreas under ammonia exposure. Autophagy-related genes (ATG4 and ATG10) also showed time-dependent and tissue-specific expression changes after Lv-p62 knockdown. The expression of apoptosis-related genes, including caspase 3 and p53, was tissue-specific and was generally lower in the dsRNA-Lv-p62+NH₃ group than in the dsRNA-EGFP+NH₃ group at most time points. Histopathological observations showed that hepatopancreatic acinar vacuolation and structural damage were alleviated, and the hepatopancreatic apoptosis rate was reduced in L. vannamei in the dsRNA-Lv-p62+NH₃ group. These findings suggest that Lv-p62 participates in the response of L. vannamei to ammonia exposure, possibly by regulating antioxidant defense, autophagy-related processes, and apoptosis, thereby affecting hepatopancreatic oxidative damage and tissue injury. Full article

Marine macroalgae are widely distributed renewable resources that offer substantial economic and environmental benefits. This review comprehensively examines seaweeds from the phyla Chlorophyta, Heterokontophyta, and Rhodophyta, highlighting key advances and persistent challenges. Global seaweed production is highly concentrated: Asia accounts for 97% of the total, with China as the dominant producer. These seaweeds synthesize a diverse array of bioactive compounds, including sulfated polysaccharides, phlorotannins, terpenoids, proteins, peptides, polyunsaturated fatty acids, and pigments. Notably, brown algae represent the richest source of both phlorotannins and polyunsaturated fatty acids. To recover these valuable compounds efficiently, a range of advanced green extraction techniques have been developed, such as enzyme-assisted, microwave-assisted, ultrasound-assisted, and supercritical fluid extraction, along with natural deep eutectic solvents. These methods consistently outperform conventional approaches in terms of yield, extraction time, and environmental sustainability. The isolated compounds exhibit a broad spectrum of validated pharmacological activities, including immunomodulatory, anti-inflammatory, anti-diabetic, neuroprotective, antitumor, and antiviral effects. Consequently, they have found diverse applications in functional foods, biomedicine, cosmetics, agriculture, aquaculture, and environmental protection. Despite this promise, critical challenges remain in elucidating structure–activity relationships, developing scalable and sustainable extraction protocols, and advancing clinical translation. Future research should prioritize the discovery of novel marine bioactives, the enzymatic production of oligosaccharides, efficient purification of algal proteins and peptides, and the scaling-up of industrial processes to fully realize the pharmaceutical and biotechnological potential of marine macroalgae. Full article

Carotenoid nutrition plays a crucial role in crustacean aquaculture by regulating antioxidant defense, pigmentation, physiological performance, and edible quality. This study evaluated the combined effects of dietary astaxanthin and β-carotene on antioxidant status, pigmentation, muscle quality, and flavor profile in male and female Macrobrachium rosenbergii. Seven isonitrogenous and isolipidic diets were formulated, including a carotenoid-free control and six diets supplemented with different astaxanthin and β-carotene combinations. After a 77-day feeding trial, growth performance, antioxidant parameters, digestive enzyme activities, carotenoid deposition, body coloration, muscle texture, free amino acids, flavor nucleotides, equivalent umami concentration, and volatile flavor compounds were systematically assessed. Dietary carotenoid supplementation improved growth performance in both sexes, although the response patterns differed between males and females. In males, astaxanthin contributed more prominently to growth and several physiological traits, whereas in females, astaxanthin, β-carotene, and their interaction significantly affected multiple response variables. Carotenoid supplementation enhanced antioxidant capacity, carotenoid deposition, body redness, muscle texture, and flavor-related traits. GC-IMS analysis further revealed sex-dependent remodeling of volatile flavor profiles under different carotenoid combinations. Among all treatments, the combined high-dose diet containing 160 mg/kg astaxanthin and 160 mg/kg β-carotene showed the best overall performance in both sexes. These findings indicate that dietary astaxanthin and β-carotene combinations exert compound- and sex-dependent effects in M. rosenbergii and provide a basis for developing sex-specific functional feeds. Full article

Vibriosis caused by V. harveyi led to high mortality and enormous economic losses in Chinese tongue sole aquaculture. However, the intestinal metabolic alterations associated with V. harveyi infection remain unclear. In this study, ultra-performance liquid chromatography–mass spectrometry (LC-MS)-based metabolomics was used to investigate the variations in intestinal metabolic phenotypes among control, susceptible, and resistant Chinese tongue sole after 7 days of V. harveyi infection. Histopathological examination revealed severe intestinal damages in susceptible fish, whereas resistant fish displayed only mild changes. Principle components analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) revealed distinct separation of intestinal metabolites among three groups. A total of 2948 metabolites were identified, with 437 and 794 differential metabolites detected in the resistant and susceptible groups, respectively. The KEGG enrichment analysis revealed that resistant individuals primarily enriched amino acid metabolism and TCA cycle to support immunity and tissue repair, whereas susceptible individuals enriched sphingolipid and cGMP-PKG signaling pathways linked to inflammation and apoptosis, indicating divergent metabolic strategies during V. harveyi infection. Thirty-two potential metabolite biomarkers (area under the curve (AUC) = 1) were screened, which could effectively distinguish susceptible and resistant individuals. Correlation analysis further demonstrated strong interactions among these metabolite markers, host immune-related differentially expressed genes (DEGs), and intestinal microbes. Collectively, our findings reveal distinct intestinal histopathological changes and metabolic reprogramming in resistant and susceptible individuals following V. harveyi infection and identify a set of candidate biomarkers, providing a theoretical foundation for developing targeted prevention strategies and immune enhancement approaches against V. harveyi infection in Chinese tongue sole. Full article

Due to its high prevalence and significant impact on modern society, Alzheimer’s disease (AD) is one of the most important neurodegenerative disorders. It is more common among individuals over the age of 65, and its incidence has increased sharply as a result of rising life expectancy. Several factors have made it challenging to identify an effective treatment for AD. One major difficulty lies in its complexity, as the mechanisms involved in its progression are not yet fully understood. Nevertheless, the role of diet and lipids has been highlighted by numerous studies, underscoring their potential influence on this pathology. Due to the intricacy of its biochemical and metabolic interactions, this subject continues to be of particular interest, highlighting the need for further research. In this sense, this comprehensive and updated review aimed to elucidate these aspects, especially regarding marine-derived lipids, whose bioactive potential may become an irreplaceable tool in the management of AD, whether in terms of its treatment or prevention. Full article