Search Results (582)

Seaweeds are promising third-generation biomass for biobased chemicals, yet their use for lactic acid (LA) production remains underexplored. We evaluated LA production from the dilute-acid hydrolysate of the aquacultured green alga Capsosiphon fulvescens (C.Agardh) Setchell & N.L. Gardner. The dried biomass contained 53.4% carbohydrate (dry-weight basis). HPLC showed a monosaccharide profile enriched in L-rhamnose and D-xylose, with lower levels of D-mannose, D-glucose, D-glucuronolactone, and D-glucuronic acid. Batch fermentations with three Lactobacillus strains revealed clear strain-dependent kinetics and carbon partitioning. Maximum LA titers/yields (time at maximum) were 2.0 g L⁻¹/0.49 g g⁻¹ at 9 h for L. rhamnosus, 2.3 g L⁻¹/0.30 g g⁻¹ at 36 h for L. casei, and 2.8 g L⁻¹/0.23 g g⁻¹ at 48 h for L. brevis; L. rhamnosus achieved the highest yield on sugars consumed, whereas L. brevis reached the highest titer by utilizing a broader sugar spectrum, notably xylose; L. casei showed intermediate performance with limited xylose use. Co-products included acetic and succinic acids (major) and trace 1,2-propanediol and acetaldehyde, consistent with flux through Embden–Meyerhof–Parnas versus phosphoketolase pathways. These results demonstrate that C. fulvescens hydrolysate is a viable marine feedstock for LA production and highlight practical levers—expanding pentose/uronic-acid catabolism in high-yield strains and tuning pretreatment severity—to further improve both yield and titer. Full article

Intestinal microbiota populations are constantly shaped by both intrinsic and extrinsic factors, including diet, environment, and host genetics. As a result, understanding how to assess, monitor, and exploit microbiome–host interplay remains an active area of investigation, especially in aquaculture. In this study, we analyzed the taxonomic structure and functional potential of the intestinal microbiota of European sea bass and rainbow trout, incorporating gilthead sea bream as a final reference. The results showed that the identified core microbiota (40 taxa for sea bass and 20 for trout) held a central role in community organization, despite taxonomic variability, and exhibited a predominant number of positive connections (>60% for both species) with the rest of the microbial community in a Bayesian network. From a functional perspective, core-associated bacterial clusters (75% for sea bass and 81% for sea bream) accounted for the majority of predicted metabolic pathways (core contribution: >75% in sea bass and >87% in trout), particularly those involved in carbohydrate, amino acid, and vitamin metabolism. Comparative analysis across ecological phenotypes highlighted distinct microbial biomarkers, with genera such as Vibrio, Pseudoalteromonas, and Paracoccus enriched in saltwater species (Dicentrarchus labrax and Sparus aurata) and Mycoplasma and Clostridium in freshwater (Oncorhynchus mykiss). Overall, this study underscores the value of integrating taxonomic, functional, and network-based approaches as practical tools to monitor intestinal health status, assess welfare, and guide the development of more sustainable production strategies in aquaculture. Full article

Backcrossing serves as an effective tool for interspecific gene introgression, facilitating germplasm improvement. To develop superior grouper aquaculture varieties, in this study, a backcrossed breed was constructed by crossing a male hybrid grouper, KGGG (Epinephelus moara ♀ × E. lanceolatus ♂), with a female parent kelp grouper (KG; E. moara). Here, we observed embryonic, larval development, and morphological changes in KG × KGGG. Additionally, the total length and body weight of the backcrossed breed and maternal parent were compared at 160 d post hatching (dph). The results showed that fertilization and the hatching rate were 73.23 ± 4.23% and 51.74 ± 3.67%, respectively, and the egg size was 0.89 ± 0.03 mm. Hatching occurred 23:19 h after fertilization at 25 ± 1 °C, and the newly hatched larvae were 1.94 ± 0.13 mm in length. Furthermore, at 160 dph, the total length and body weight of the backcrossed breed were 1.2-fold and 1.9-fold greater, respectively, when compared with those of the maternal parent. Importantly, it is possible that backcrossed KG × KGGG could become a dominant strain in grouper aquaculture practices. Full article

The growing demand for aquaculture has driven the search for sustainable practices and utilization of agro-industrial residues. Brown rice bran, an abundant and low-cost by-product, has emerged as a promising raw material. This dissertation aimed to evaluate solid-state fermentation (SSF) of rice bran using the fungus Rhizopus oryzae and the yeast Saccharomyces cerevisiae with the goal of improving its nutritional value for use in diets formulated for zebrafish (Danio rerio). Proximate composition analyses revealed the strong biotransformation potential of Rhizopus oryzae. Fermentation with this fungus resulted in a significant 36.45% increase in protein content, a 51.62% increase in total polyphenols, and a 13.7% reduction in lipid content. In an in vivo experiment, zebrafish fed a diet containing rice bran fermented by R. oryzae showed the best zootechnical performance, with higher weight gain, specific growth rate, and improved feed conversion. Gene expression analysis showed a significant difference only for glut6, which is related to glucose transport. In summary, the fermentation of brown rice bran with Rhizopus oryzae represents an effective strategy to enhance its nutritional profile, establishing it as a viable alternative for the formulation of more sustainable and efficient diets in aquaculture. Full article

This study presents a comprehensive dataset developed to monitor coastal water quality in the south-central region of Vietnam, focusing on Nha Trang Bay. Environmental data were collected from four research cruises conducted between 2013 and 2024. Water samples were taken at two depths: surface samples at approximately 0.5–1.0 m below the water surface, and bottom samples 1.0 to 2.0 m above the seabed, depending on site-specific bathymetry. These samples were analyzed for key water quality parameters, including biological oxygen demand (BOD₅), dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), and Chlorophyll-a (Chl-a). The data establish a valuable baseline for assessing both spatial and temporal patterns of water quality, and for calculating eutrophication index to evaluate potential environmental degradation. Importantly, it also demonstrates practical applications for environmental management. The dataset can support assessments of how seasonal tourism peaks contribute to nutrient enrichment, how aquaculture expansion affects dissolved oxygen dynamics, and how water quality trends evolve under increasing anthropogenic pressure. These applications make it a useful resource for evaluating pollution control efforts and for guiding sustainable development in coastal areas. By promoting open access, the dataset not only supports scientific research but also strengthens evidence-based management strategies to protect ecosystem health and socio-economic resilience in Nha Trang Bay. Full article

Microfluidic chips made of polydimethylsiloxane (PDMS) have shown significant application potential in aquatic environments with high microbial density, such as “marine ranches”, due to their high-throughput, high-efficiency and high-precision detection capabilities. This technology can rapidly identify pathogenic microorganisms or harmful particles in aquaculture systems, thereby providing urgently needed innovative methods for implementing preventive measures and enhancing aquaculture productivity. By regulating the micro-nano scale channel structure, microfluidic technology can precisely control fluid flow patterns, offering new insights and effective solutions for microbiological research and the separation and analysis of particulate matter. This paper first provides a concise overview of the application of microfluidic chip technology in the analysis of marine microorganisms. Subsequently, it focuses on the “compliance” phenomenon in PDMS-based microfluidic systems, systematically reviewing the potential mechanisms, latest progress and impacts of compliance behavior in mechanically elastic materials such as PDMS. Additionally, this article also investigates the role of “compliance” in key processes of microfluidic technology application, including the capture, separation, enrichment and detection of microorganisms and particles. Moreover, the relationship between surface wettability engineering and compliance phenomena is also explored. We believe that this review will contribute to enhancing the understanding and control of the mechanical behavior of microfluids and the particles they carry within microfluidic systems, providing valuable theoretical insights and practical guidance for researchers in this field. Full article

High-precision spiral trajectory tracking for aquaculture net-cage inspection is hindered by uncertain hydrodynamics, strong coupling, and time-varying disturbances acting on an underactuated autonomous underwater vehicle. This paper adapts and validates a model–data-driven learning-aided adaptive robust control strategy for the specific challenge of high-precision spiral trajectory tracking for aquaculture net-cage inspection. At the kinematic level, a serial iterative learning feedforward compensator is combined with a line-of-sight guidance law to form a feedforward-compensated guidance scheme that exploits task repeatability and reduces systematic tracking bias. At the dynamic level, an integrated adaptive robust controller employs projection-based, rate-limited recursive least-squares identification of hydrodynamic parameters, along with a composite feedback law that combines linear error feedback, a nonlinear robust term, and fast dynamic compensation to suppress lumped uncertainties arising from estimation error and external disturbances. A Lyapunov-based analysis establishes uniform ultimate boundedness of all closed-loop error signals. Simulations that emulate net-cage inspection show faster convergence, higher tracking accuracy, and stronger robustness than classical adaptive robust control and other baselines while maintaining bounded control effort. The results indicate a practical and effective route to improving the precision and reliability of autonomous net-cage inspection. Full article

Underwater wireless communication (UWC) is an emerging technology crucial for automating marine industries, such as offshore aquaculture and energy production, and military applications. It is a key part of the 6G vision of creating a hyperconnected world for extending connectivity to the underwater environment. Of the three main practicable UWC technologies (acoustic, optical, and radiofrequency), acoustic methods are best for far-reaching links, while optical is best for high-bandwidth communication. Recently, utilizing reconfigurable intelligent surfaces (RISs) has become a hot topic in terrestrial applications, underscoring significant benefits for extending coverage, providing connectivity to blind spots, wireless power transmission, and more. However, the potential for further research works in underwater RIS is vast. Here, for the first time, we conduct an extensive survey of state-of-the-art of RIS and metasurfaces with a focus on underwater applications. Within a holistic perspective, this survey systematically evaluates acoustic, optical, and hybrid RIS, showing that environment-aware channel switching and joint communication architectures could deliver holistic gains over single-domain RIS in the distance–bandwidth trade-off, congestion mitigation, security, and energy efficiency. Additional focus is placed on the current challenges from research and realization perspectives. We discuss recent advances and suggest design considerations for coupling hybrid RIS with optical energy and piezoelectric acoustic energy harvesting, which along with distributed relaying, could realize self-sustainable underwater networks that are highly reliable, long-range, and high throughput. The most impactful future directions seem to be in applying RIS for enhancing underwater links in inhomogeneous environments and overcoming time-varying effects, realizing RIS hardware suitable for the underwater conditions, and achieving simultaneous transmission and reflection (STAR-RIS), and, particularly, in optical links—integrating the latest developments in metasurfaces. Full article

The Mugilidae family comprises several euryhaline species of significant ecological and economic value in global fisheries and aquaculture. Despite close taxonomic relationships, Chelon auratus, Chelon ramada and Mugil cephalus differ notably in physiological traits, seasonal energy allocation and tissue composition, influencing both ecological roles and commercial value. This study investigates the effect of seasonality on the fish flesh quality and metabolic gene expression of these three commercially important mullet species, collected from their natural habitat in Klisova Lagoon, Greece, by analyzing proximate composition (moisture, ash, protein, lipid), hepatosomatic index (HSI) and expression of lipid metabolism genes. M. cephalus showed lower protein and lipid content than C. ramada and C. auratus. In this context, expression of key lipid metabolism genes (fabp, pparg, cpt) reflected these differences not only between species but also revealed patterns which differed between examined tissues and seasons. Notably, this study provides the first characterization of these genes in the species examined. HSI data further indicated species-specific and seasonal strategies for energy storage. The results contribute to refining harvest timing strategies, enhancing post-harvest handling practices, in an effort to promote market differentiation and eventually to improve the economic viability of the mullet fishery sector. Full article

The development of effective tools to combat viral diseases remains a major challenge for the aquaculture industry. Infectious pancreatic necrosis virus (IPNv) is one of the most devastating pathogens affecting salmonids, leading to high mortality rates and substantial economic losses worldwide. Here, we present a novel nanobody discovery pipeline based on a Type IIS restriction enzyme-driven library assembly method that enables the rapid generation of highly diverse nanobody repertoires. This streamlined approach not only shortens the time required for nanobody identification but also offers remarkable adaptability, allowing its application to virtually any protein target, including antigens from aquaculture pathogens and beyond. By integrating this strategy with density gradient–based enrichment and high-throughput screening, we successfully identified and validated a nanobody against the VP2 protein of IPNv, a key structural component essential for viral infectivity. These findings highlight the potential of this platform both as a versatile methodological advance in antibody engineering and as a practical foundation for developing innovative diagnostic and therapeutic tools. Ultimately, nanobodies generated through this pipeline could play a pivotal role in improving disease management and enhancing sustainability in aquaculture. Full article

The increasing demand for natural and health-promoting food ingredients has spotlighted seaweed-derived pigments as promising alternatives to synthetic colorants. This review explores the potential of chlorophylls, carotenoids, and phycobiliproteins extracted from various seaweed species for use in the food industry. These pigments offer not only a wide range of colors but also exhibit bioactivities such as antioxidant, anti-inflammatory, and anticancer effects. The paper discusses recent advancements in sustainable aquaculture practices, extraction, purification, and stabilization techniques, including green and microencapsulation methods, to enhance pigment yield and shelf life. Furthermore, it highlights the regulatory landscape in the European Union and the United States, identifying key differences and challenges regarding pigment approval and commercialization. Despite their potential, large-scale industrial adoption remains constrained by technical, economic, and regulatory hurdles. Bridging these gaps through optimized bioprocesses and safety assessments is essential to fully leverage seaweed pigments in food systems. Full article

Integrated aquaculture, centered around polyculture involving multiple species, is a typical practice for the sustainable development of the aquaculture industry, capable of enhancing resource utilization efficiency, environmental stability, and overall productivity through establishing symbiotic interactions among species. This study employed multi-amplicon high-throughput sequencing to assess the ecological impacts of two polyculture methods involving river crabs on sediment bacteria, fungi, and protists. One method involved polyculturing river crabs with mandarin fish, silver carp, and the stone moroko (SPC), and the other involved polyculturing river crabs with only mandarin fish and silver carp (SMC). The results showed that, compared to the SMC group, the SPC group remarkably increased the Chao1 index of bacterial communities in pond sediment and decreased the Pielou_J index of protists. The relative abundances of all fungal phyla and most dominant bacterial and protistan phyla (top 10 in relative abundance) in the SPC group were considerably different from those in the SMC group. In the co-occurrence networks of bacterial, fungal, and protistan communities, the numbers of edges and nodes were higher in the SPC group than in the SMC group, and the habitat niche breadth of bacterial community was also notably increased in the SPC group. The levels of total carbon (TC), total nitrogen (TN), and phosphates within pond sediment in the SPC group were obviously lower than those in the SMC group, and were significantly correlated with the microbial communities, with TC being identified as the primary contributor driving changes in the microbial communities. All the findings collectively demonstrate that the polyculture of river crabs with mandarin fish, silver carp, and the stone moroko enhances the stability of bacterial, fungal, and protistan communities in sediment and enhances resource utilization efficiency in aquaculture, thereby preventing the environmental risks associated with excessive nutrient accumulation in sediment. Polyculture systems integrating river crabs with mandarin fish, silver carp, and the stone moroko represent a sustainable aquaculture model with significant ecological benefits. Full article

Aeromonas hydrophila is a prevalent opportunistic pathogen in aquaculture. To establish a rapid, convenient, and accurate detection method for A. hydrophila, this study developed and evaluated Multi-Enzyme Isothermal Rapid Amplification (MIRA) assays, which could complete amplification within 20 min at a constant temperature of 39 °C. The basic MIRA assay targeting the aerolysin (aerA) gene demonstrated high specificity, showing no cross-reactivity with six related bacterial species including Aeromonas veronii, Vibrio harveyi, Pseudomonas fluorescens, Bacillus subtilis, Bacillus cereus, and Lactiplantibacillus plantarum. The fluorescent MIRA assay achieved a detection limit of 1 fg/μL (3.1 × 10² copies/μL) when using the pUC57-aerA standard plasmid, while real-time quantitative PCR achieved a detection limit of 0.1 fg/μL (31 copies/μL). Thus, the MIRA assay exhibited 10-fold lower sensitivity than qPCR but shortened the reaction time from several hours (nearly two hours) to within one hour. Both the specificity and sensitivity of the MIRA reactions were evaluated with three independent experiments. These findings suggested that the developed MIRA assays provide a rapid, specific, and practical diagnostic tool for A. hydrophila detection in aquaculture environments, particularly suitable for resource-limited field applications. Full article

Biotechnological applications in animals are increasingly developed for use in agriculture and aquaculture to tackle breeding challenges in animal production. By examining two case studies of genetically modified (GM) farmed animals relevant to the European Union, slick-haired cattle and growth-enhanced carp, we highlight the challenges for environmental risk assessment and discuss available assessment approaches to address broader societal concerns. We find that the existing guidance for environmental risk assessment of GM animals available in the European Union faces several challenges. Assessing risks of GM animals in agriculture and aquaculture requires consideration of the farming systems of these animals. In addition, we find that there is a lack of guidance and practical implementation to address wider issues, including cultural, societal, ethical, and socio-economic issues, as well as animal health and welfare issues, related to GM farmed animals. We propose using existing assessment frameworks to address the sustainability of GM farmed animals beyond environmental risk assessment. Sustainability assessment approaches should also address potential farm-level sustainability claims of GM animal applications. We note that issues related to animal health and welfare are cross-disciplinary topics that require special attention when commercializing GM farmed animals. We recommend developing a comprehensive framework, including risk assessment, sustainability assessment, and technology assessment, that will enable policymakers to better anticipate and address the societal, legal, ethical, and governance issues associated with emerging biotechnologies in farmed animals. Full article

Aquaculture wastewater is characterized by large discharge volumes and variable nitrogen concentrations, posing challenges for stable and efficient treatment. This study investigated biochar-amended bioretention systems (BBSs) under varying temperatures (8.0–26.0 °C), influent TN levels, and operation modes (intermittent and continuous flow). In intermittent runs, the 20% biochar system (BBS20) achieved 72.4% TN removal at low influent TN (9.55 mg/L) and 80.4% at high TN (29.96 mg/L), significantly outperforming the control (CBS). In continuous runs, BBS20 reduced effluent TN to 1.75 mg/L within 72 h, yielding higher average HRT, HLR, and ELR than CBS. Mechanistic analyses showed that biochar addition enhanced extracellular polymeric substance (EPS) secretion, stimulated electron transport system activity (ETSA), and increased the relative abundance of denitrifying genera and functional genes (e.g., nirS, narG). These synergistic effects optimized nitrification–denitrification coupling, particularly under low-temperature conditions. The findings demonstrate that biochar amendment is a practical and effective strategy for improving nitrogen removal from aquaculture wastewater. Full article