Search Results (238)

Schizopygopsis younghusbandi is an endemic and ecologically important fish species on the Tibetan Plateau. However, its dietary carbohydrate requirement remains unexplored, limiting the development of cost-effective and physiological-friendly artificial feed. This study investigated the effects of different dietary carbohydrate levels on the growth performance, antioxidant capacity, and hepatointestinal morphology of S.younghusbandi. Six experimental diets were formulated with graded carbohydrate levels of 9% (C9), 12% (C12), 15% (C15), 18% (C18), 21% (C21), and 24% (C24). A total of 720 fish (initial weight 37.49 ± 0.25 g) were randomly allocated to six groups in quadruplicate (30 fish per replicate) and reared in tanks (0.6 m × 0.5 m × 0.4 m) for 8 weeks. Results demonstrated that the diet in the C12 group significantly improved weight gain rate (WGR), specific growth rate (SGR), and feed conversion ratio (FCR) (p < 0.05). Regression fitting analysis on growth performance indicated that the optimal carbohydrate level ranged from 10.42% to 10.49%. Additionally, the C12 group exhibited enhanced total superoxide dismutase (T-SOD) activities and reduced malondialdehyde (MDA) content in the liver, along with reduced interleukin-1β (IL-1β) levels in the serum (p < 0.05). Histological analysis revealed superior hepatointestinal integrity in the C12 group, characterized by lower hepatic lipid droplet accumulation, reduced vacuolation, decreased hepatosomatic index (HSI) (p < 0.05), as well as higher intestinal villus height and muscle thickness (p < 0.05). In conclusion, the C12 group optimally enhanced the growth, antioxidant response, and hepatointestinal health of S. younghusbandi, indicating that the suitable dietary carbohydrate level for this species is 12%. Full article

As aquaculture expands, there is a growing demand for sustainable and environmentally friendly feed ingredients that can replace conventional fish meal while maintaining high biological value and digestibility. The use of fishmeal has contributed to overfishing, making it an increasingly limited and unsustainable resource. Tenebrio molitor (TM) is emerging as a sustainable alternative to fishmeal (FM) in aquaculture diets, gaining attention due to its balanced protein composition profile and low environmental footprint. This review critically analyses data from the literature on the use of TM meal as a substitute for fish feed ingredient, focusing on its effects on growth performance, physiological status, and histological changes in the digestive and muscular systems. The influence on the physicochemical and sensory quality of fish meat is also evaluated. The discussion highlights both the benefits and possible adverse effects, such as intestinal inflammation or changes that may occur, depending on the replacement level. The paper presents recommendations and strategies to mitigate these effects, including the use of dietary supplements or partial replacement schemes. Overall, this paper emphasises the promising potential of TM as a sustainable alternative to FM in aquaculture feed, while highlighting the need for further research into the long-term effects, involved metabolic pathways, and standardisation of insect meal production. This review provides valuable insight into the physiological changes that may occur, particularly at high inclusion levels. As TM is utilized in both human nutrition and aquaculture diets, monitoring its physiological effects in fish is essential, since any alterations may have implications for human food safety. Full article

The increasing presence of synthetic dyes in aquatic environments presents a serious threat to ecosystems and human health. This study investigates the potential of natural biomaterials, specifically fish-derived components extracted from Cyprinus carpio (fish bladder and fish scales), for the simultaneous retention and degradation of a potentially toxic dye: Malachite Green (MG). The biomaterials were characterized using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, thermogravimetric analysis (TGA), and high-performance liquid chromatography with mass spectrometry detection (HPLC-MS) for degradation monitoring. Batch adsorption experiments were conducted under varying biomaterial dosage, contact time and pH. Results demonstrated that all tested biomaterials exhibited significant adsorption capacities, with fish scales (FS) achieving a maximum removal efficiency of 91.2%, and fish bladder (FB) reaching 82% under optimal conditions. In catalytic ozonation tests, the fish scales impregnated with vanadium (FS-V) catalyst demonstrated significantly higher degradation efficiency, reaching 63.84% at an ozone flow rate of 0.5 g O₃·h⁻¹. The comparative analysis highlights the multifunctionality of these eco-friendly biomaterials, offering both pollutant capture and partial degradation. These findings suggest that low-cost, naturally derived biomaterials can serve as effective alternatives to synthetic adsorbents in water treatment applications, contributing to sustainable environmental remediation strategies. Full article

Plastic waste is currently a major environmental issue but also plays a key role in the circular economy. Recycled plastics have become suitable for use in several applications, especially in construction, where they can improve the properties of conventional materials to enable sustainable development. This study designed new eco-gypsum composites containing recycled fishing net (FN) fibers and evaluated their mechanical, hygrothermal, fire and environmental performances. All the developed composites achieved the minimum standardized strengths. Regarding the impact hardness test, the composite with 40% recycled FN fibers (FN40%) reached a five times higher energy of rupture than the reference gypsum sample. Indeed, FN40% presented better properties in general, e.g., 33% less water absorption by capillarity, 17% lower thermal conductivity and 40% less environmental impacts. Moreover, the use of these FN40% gypsum composites was modeled in an LSF partition wall, and it was predicted that they increased the thermal resistance by 4.4%, taking traditional gypsum plasterboards (Ref.) with the same thickness as a reference. These promising results allow us to conclude that it is possible to obtain eco-friendly gypsum composite panels by incorporating recycled FN fibers, satisfying the mechanical resistance requirements (flexural and compressive) and even improving their impact hardness, as well as their functional performance regarding their hygrothermal behavior. Full article

To mitigate the impact of hydroelectric power plants on downstream fish migration, fish-friendly intakes, combining a low bar spacing rack and several bypasses, are implemented. There are still sites that can be improved thanks to a better bypass design. For this purpose, Computational Fluid Dynamics (CFD) can be a useful tool, even if such devices are still uncommon. This paper investigates the use of a 3D model based on the Reynolds-Averaged Navier–Stokes (RANS) equation for a single phase to simulate the flow in a real-scale water intake equipped with an inclined bar rack and three surface bypasses. The results of numerical simulations are compared to in situ measurements of flow velocities at four cross-sections along the rack, gauging the discharge flowing into the bypasses. The simulated velocities are in accordance with the velocities measured in situ, with a mean square error for the longitudinal velocity ($v_x$) of 0.034 (m²/s²) for the initial simulation and 0.021 (m²/s²) for the improved simulation. The split of the total bypass discharge between the three bypass entrances was satisfyingly predicted by the simulation with the true inlet velocity condition, showing the significant influence of upstream flow non-uniformity. Full article

This review explores the potential of essential oils (EOs) as natural feed additives in aquaculture, highlighting their antimicrobial, antioxidant, and immunostimulatory properties, which contribute to disease prevention and improved fish resilience. EOs, derived from aromatic plants, offer a sustainable alternative to synthetic chemicals, promoting benefits such as enhanced growth rates, feed efficiency, immune function, and reduced pathogen susceptibility. However, several challenges must be addressed to fully unravel their potential, including the optimization of dosages, effective delivery methods, and cost-efficiency. Techniques such as microencapsulation are emerging as promising solutions to improve EO stability and controlled release in aquatic feeds, though further research is needed to refine these approaches and evaluate their scalability. Additionally, there is a need for more research into the mechanisms through which EOs influence fish health, the interactions between active compounds, potential synergistic effects of EO mixtures, and their impact on the aquatic environment and microbiome. Addressing these challenges will ensure the effective and sustainable application of EOs in aquaculture, reducing reliance on synthetic chemicals while fostering a more resilient and eco-friendly industry. A key feature of this review is the systematic presentation of detailed, species-specific tables summarizing the current literature on the application of EOs and plant extracts in fish health management. Full article

This study explores innovative strategic solutions within a sustainability framework, focusing on four viable options for an integrated refrigeration system designed for fish preservation in Tarrafal de Santiago, Cape Verde. Tarrafal is a coastal town on Santiago Island, characterized by its reliance on fishing activities and the challenges posed by limited energy infrastructure and local environmental vulnerabilities. The evaluated solutions range from grid-dependent systems to fully autonomous configurations powered by renewable energy sources, incorporating various refrigeration facility designs adapted to regional conditions. The primary objective is to assess the energy efficiency, economic viability, and environmental impact of these options within the specific geographic and socioeconomic context of Tarrafal de Santiago. Four approaches were analyzed: Strategy A involves two R134a refrigeration systems powered by conventional grid electricity; Strategy B employs a transcritical CO₂ (R744) system combined with grid electricity; Strategy C integrates an R744 refrigeration system powered by autonomous renewable energy sources; and Strategy D utilizes R744 refrigeration combined with seawater-based heat exchange and autonomous renewable energy generation. The results indicate that Strategy D offers the greatest advantages, with emissions amounting to 15,882 kg of CO₂ equivalent and a return on investment within five years. Autonomous electricity generation in Strategy D leads to a 95% reduction in CO₂ emissions. Although Strategy C entails a higher initial cost, it proves financially viable and significantly enhances energy sustainability. Its autonomous energy production results in a reduction of 360,697 kg of CO₂ emissions compared to conventional systems, highlighting the substantial environmental benefits of integrating local renewable energy sources into coastal communities such as Tarrafal de Santiago. Full article

Industrial recirculating aquaculture systems (RAS) constitute an energy-saving and environmentally friendly approach to modern aquaculture production. The hydrodynamic characteristics within these systems, coupled with the ecological environment of the fish, are essential for the efficient operation of the system and for promoting optimal fish growth and welfare. These systems provide several advantages, such as high intensification, efficient water resource utilization, enhanced environmental control, and minimal environmental pollution. Consequently, it has emerged as prominent avenue for advancing aquaculture development in China. This paper begins with an examination of the fundamental concepts and primary tank structures underpinning industrial RAS. It then proceeds to elucidate the hydrodynamic characteristics within RAS and their interrelationship with fish growth and welfare. Furthermore, it offers a thorough review of tank hydrodynamic characteristics and fish interactions from various perspectives, including operational parameters, hydrodynamic drive equipment, fish behavior, and the aquaculture environment. Finally, the limitations of current studies are assessed, and potential future research directions are proposed. Full article

Aquaculture is the fastest-growing food production sector and plays a pivotal role in global food security. However, the reliance on conventional fishmeal and fish oil in aquafeeds raises sustainability concerns due to overfishing, high costs, and ecological burden. This review explores the valorisation of microalgae as a sustainable and functional alternative for aquafeed development. Microalgae are rich in proteins, polyunsaturated fatty acids, bioactive compounds, and pigments that support aquatic animal growth, immunity, and product quality. We critically examine the integration of green technologies, including cultivation systems, biomass harvesting, and eco-friendly extraction methods for optimising microalgal biomass and bioactive recovery. The review also discusses recent innovations in bioremediation and circular aquaculture systems, highlighting the role of microalgae in reducing nutrient discharge, carbon footprint, and operational cost. Challenges such as scalability, digestibility, and economic feasibility are also addressed, providing insight into pathways toward industrial adoption. This review aims to provide an updated and holistic perspective on microalgae-based aquafeeds in advancing sustainable aquaculture practices. Full article

Bacterial diseases are a major constraint to aquaculture productivity, driving extensive antibiotic use and raising concerns over antimicrobial resistance, environmental contamination, and food safety. Curcumin, a polyphenolic compound from Curcuma longa, exhibits broad-spectrum antimicrobial and immunomodulatory activities but is limited by poor water solubility, instability, and low bioavailability. This review was conducted through a literature search of Scopus, PubMed, Web of Science, and Google Scholar using targeted keywords, including curcumin nanoparticles, antibacterial, aquatic pathogens, nanotechnology, synthesis, and disease control. Titles and abstracts were screened for relevance, followed by full-text evaluation of selected studies. Key findings were critically analyzed and incorporated into the review. Findings from the literature indicate that curcumin nanoparticles, synthesized via milling, anti-solvent precipitation, ionic gelation, emulsification, spray drying, and metal/polymer nanocomposite formation, exhibit enhanced antibacterial activity against aquatic pathogens, including Aeromonas hydrophila, Vibrio parahaemolyticus, Escherichia coli, and Staphylococcus aureus. Optimally engineered curcumin nanoparticles (<100 nm, being mostly spherical, highly negatively charged) can penetrate bacterial membranes, disrupt biofilms, lower minimum inhibitory concentrations, and improve in vivo fish survival. Practical applications include dietary supplementation to boost fish immunity and growth, water disinfection to reduce pathogen loads, immersion therapy for external infections, and antimicrobial coatings for aquaculture equipment and surfaces, resulting in reduced infections and outbreaks, reduced mortality, improved water quality, and decreased antibiotic dependence. In conclusion, curcumin nanoparticles and curcumin-based nanocomposites present a versatile, eco-friendly approach to sustainable aquaculture disease management. However, further field-scale validation, safety assessment, and cost-effective production methods are necessary to enable commercial adoption. Full article

Vertical slot fishways are a crucial measure to mitigate the blockage of fish migration caused by hydraulic engineering infrastructures, but their passage efficiency is often hindered by the complex interactions between fish behavior and hydrodynamic conditions. This study combines computational fluid dynamics (CFD) simulations with behavioral laboratory experiments to identify the hydrodynamic characteristics and swimming strategies of three types of fishways—Central Orifice Vertical Slot (COVS), Standard Vertical Slot (SVS), and L-shaped Vertical Slot (LVS)—using the endangered species Schizothorax prenanti from the upper Yangtze River as the study subject. The results revealed that (1) a symmetric and stable flow field was formed in the COVS structure, yet the passage ratio was the lowest (50%); in the SVS structure, high turbulent kinetic energy (peak of 0.03 m²/s²) was generated, leading to a significant increase in the fish’s tail-beat angle and amplitude (p < 0.01), with the passage time extending to 10.2 s. (2) The LVS structure induced a controlled vortex formation and created a reflux zone with low turbulent kinetic energy, facilitating a “wait-and-surge” strategy, which resulted in the highest passage ratio (70%) and the shortest passage time (6.1 s). (3) Correlation analysis revealed that flow velocity was significantly positively correlated with absolute swimming speed (r = 0.80), turbulent kinetic energy, and tail-beat parameters (r > 0.68). The LVS structure achieved the highest passage ratio and shortest transit time for Schizothorax prenanti, demonstrating its superior functionality for upstream migration. This design balances hydrodynamic complexity with low-turbulence refuge zones, providing a practical solution for eco-friendly fishways. Full article

Plant-based foods have emerged as a major focus of the modern food industry as it tries to create more sustainable, environmentally friendly, and healthy products. Plant-based emulsion gels (PBEGs) can be used to provide valuable structures, textures, and functions in many plant-based food applications. For instance, they can be used as a matrix to form semi-solid plant-based meat, fish, egg, or dairy analogs, delivery systems for bioactive compounds in functional foods, and edible inks in 3D food printing. The most common PBEGs used in the food industry consist of oil droplets embedded within an aqueous phase containing a biopolymer network. However, PBEGs may also be formed from high-internal-phase emulsions (HIPEs) or aggregated emulsions. PBEGs combine the benefits of emulsions and gels, such as the ability to encapsulate both polar and non-polar functional ingredients, as well as to create desirable textural attributes. This review summarizes recent advances (2017–2025) in the development and application of PBEGs in the food sector, with a focus on their preparation methods, characterization techniques, and potential applications. The future perspectives and challenges associated with PBEGs are also discussed. Overall, this review provides a useful platform for directing future research efforts and for the practical implementation of PBEGs in plant-based food systems. Full article

The increasing demand for environmentally friendly alternatives to conventional plastic packaging has driven interest in the development of biodegradable edible films with functional properties. In this work, edible blend films were developed based on fish gelatin (FG), soluble soybean polysaccharide (SSPS), and tea polyphenol (TP) for active food packaging applications. The FG/SSPS/TP films were prepared by solvent casting and characterized in terms of their structural, mechanical, optical, thermal, and barrier properties. FTIR, SEM, and XRD analyses revealed TP-induced morphological and structure changes in the biopolymer matrix. The incorporation of TP significantly enhanced the antioxidant activity and UV-shielding properties of the films, while also modifying their flexibility and surface hydrophilicity. The packaging performance of FG/SSPS/TP films was evaluated using beef tallow as a model food product. Compared to neat FG/SSPS and polyethylene films, the FG/SSPS/TP films effectively suppressed lipid oxidation of the samples during storage. The results demonstrated that the prepared FG/SSPS/TP films possess strong potential for use as edible and active packaging materials for food products. Full article

The use of methane as a carbon source for producing bacterial single-cell protein (SCP) has been one of the most interesting developments in recent years. Most of these upcoming industries are using a methanotroph, Methylococcus capsulatus Bath, for SCP production using natural gas as the substrate. In the present study, we have explored the possibility of using an indigenously isolated methanotroph from a rice field in India, Methylomagnum ishizawai strain KRF4, for producing SCP from biogas [derived from cow dung]. The process was eco-friendly, required minimal instruments and chemicals, and was carried out under semi-sterile conditions in a tabletop fish tank. As the name suggests, Methylomagnum is a genus of large methanotrophs, and the strain KRF4 had elliptical to rectangular size and dimensions of ~4–5 µm × 1–2 µm. In static cultures, when biogas and air were supplied in the upper part of the growing tank, the culture grew as a thick pellicle/biofilm that could be easily scooped. The grown culture was mostly pure, from the microscopic observations where the large size of the cells, with rectangular-shaped cells and dark granules, could easily help identify any smaller contaminants. Additionally, the large cell size could be advantageous for separating biomass during downstream processing. The amino acid composition of the lyophilized biomass was analyzed using HPLC, and it was seen that the amino acid composition was comparable to commercial fish meal, soymeal, Pruteen, and the methanotroph-derived SCP-UniProtein^®. The only difference was that a slightly lower percentage of lysine, tryptophan, and methionine was observed in Methylomagnum-derived SCP. Methylomagnum ishizawai could be looked at as an alternative for SCP derived from methane or biogas due to the comparable SCP produced, on the qualitative level. Further intensive research is needed to develop a continuous, sustainable, and economical process to maximize biomass production and downstream processing. Full article

Aquatic biomass—ranging from fish scales and crustacean shells to various algae species—offers an abundant, renewable source for carbon dot (CD) synthesis, aligning with circular economy principles. This review highlights recent studies for valorizing aquatic biomass into high-performance carbon-based nanomaterials—specifically aquatic biomass-based carbon dots (AB-CDs)—briefly summarizing green synthesis approaches (e.g., hydrothermal carbonization, pyrolysis, and microwave-assisted treatments) that minimize environmental impact. Subsequent sections highlight the varied applications of AB-CDs, particularly in biosensing (including the detection of marine biotoxins), environmental monitoring of water pollutants, and drug delivery systems. Physically AB-CDs show unique optical and physicochemical properties—tunable fluorescence, high quantum yields, enhanced sensitivity, selectivity, and surface bio-functionalization—that make them ideal for a wide array of applications. Overall, the discussion underlines the significance of this approach; indeed, transforming aquatic biomass into carbon dots can contribute to sustainable nanotechnology, offering eco-friendly solutions in sensing, environmental monitoring, and therapeutics. Finally, current challenges and future research directions are discussed to give a perspective of the potential of AB-CDs; the final aim is their integration into multifunctional, real-time monitoring and therapeutic systems—for sustainable nanotechnology innovations. Full article