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Water quality in land-based fish production can be controlled through either instantaneous water exchange or costly wastewater treatment followed by recirculation. Agricultural-aquaculture integration is an excellent alternative technique for reducing nutrient discharge levels, boosting profitability, and converting fish culture wastewater into valuable products. The current study employed a solar energy system to power two separate IMTA-aquaponics systems (Nutrient Film Technique, NFT, and Floating Raft Systems, FRS) for the cultivation of Nile tilapia, African catfish, thin-lipped grey mullet, freshwater crayfish, freshwater mussels, and a variety of vegetables. Tilapia and catfish were fed exclusively on diets under the IMTA system. All wastewater from tilapia and catfish ponds, both dissolved and solid, flows sequentially to ponds containing other cultivated species. The water then flows through the IMTA system's terminal point to the NFT and FRS systems before returning to the tilapia and catfish ponds, allowing complete control of the nutrient flow throughout this entire circular system. Two 147-day production cycles were concluded. The results from the second production cycle are reported. Total biomass gain for aquatic species in the IMTA system was 736.46 kg, compared to 145.49 kg in the tilapia and 271.01 kg in the catfish monoculture systems. The current IMTA system had a cumulative feed conversion ratio (FCR) of 0.90, while the FCRs for tilapia and catfish were 1.28 and 1.42, respectively. Nile tilapia and catfish consumed 571.90 kg of feed containing 25.70 kg of nitrogen (N) and 9.70 kg of phosphorus (P), reflecting, and gaining 11.41 and 3.93 kg of dietary N and P, representing 44.40 and 40.46% dietary N and P retention, respectively. In the IMTA system, the addition of mullet and prawn as detrivores aquatic animals improves dietary N and P utilization efficiency to 59.06 and 51.19%, respectively, while the addition of mussels as herbivore animals improves dietary N and P utilization efficiency to 65.61 and 54.67%, respectively. Finally, using FRS and NFT as hydroponic systems increased dietary N and P efficiency to 83.51% N and 96.82% P, respectively. This study shows that the IMTA-Aquaponic system, as a bio-integrated food production system, can convert the majority of fish-fed residues into valuable products suitable for desert, rural, and urban areas in impoverished and developing countries. [ABSTRACT FROM AUTHOR]

AbstractAquaponics is a promising solution for addressing food security concerns. Nonetheless, an effective water-purification system is necessary to achieve high and stable yields of fish and vegetables. This study aimed to evaluate the nitrification and oxygen transfer performance of a laboratory-scale down-flow hanging sponge (DHS) reactor with a Brassica oleracea aquaponics system to treat water in an Oreochromis niloticus closed-aquaculture system. The DHS reactor showed a higher oxygen transfer coefficient (KLa) than the conventional aerator and provided an adequate dissolved oxygen (DO) concentration of approximately 5.5 mg/L essential for O. niloticus growth throughout the experimental period. The evaluated DHS-based aquaponic system maintained high water quality in an aquaculture tank, with a survival rate of 97%. The O. niloticusgrew at a low feed conversion ratio of 1.5–2.1 and a low feeding rate of 0.5% at high stocking densities of 17.5–22.2 kg-fish-weight/m3. 16S rRNA gene sequencing indicated that the DHS sponge carrier effectively retained nitrifying bacteria such as Nitrosomonas and Nitrospira. This study demonstrated that the DHS reactor provided a high DO concentration and that a simultaneous DHS reactor with a hydroponic tank provided a low-cost aquaponic system that could be applied for food production in the aquaculture industry. [ABSTRACT FROM AUTHOR]

Simple Summary: The Internet of Things (IoT) can improve small-scale aquaponics, a sustainable farming method that combines fish farming with plant growing in water without soil, by making the process more efficient and profitable by optimizing resource use, closely monitoring water quality, and ensuring the best conditions for both fish and plants to thrive. Aquaponics is beneficial for the environment and can help ensure a steady food supply but presents challenges for small-scale farmers due to a lack of expertise in water chemistry and system upkeep, as well as high operational costs. Identified challenges in aquaponics operation include high water and energy costs, maintaining the right balance of fish and plants, and the risk of mosquitoes breeding in the water. This systematic review offers a comprehensive guide to setting up and maintaining an aquaponics system, including choosing the right fish and plants, designing the system, monitoring water quality, and feeding the fish. The importance of knowledge sharing among farmers is also highlighted to improve aquaponics practices. The integration of IoT into these systems can reduce the need for manual work and improve the availability of information related to system control, which could facilitate further adoption and optimization of aquaponics farming practices. Aquaponics combines aquaculture and hydroponics to offer a sustainable approach to agriculture, addressing food security issues with minimal environmental harm. However, small-scale practitioners face challenges due to a lack of professional knowledge in water chemistry and system maintenance. Economic hurdles, such as operational costs and energy-intensive components, hinder the viability of small-scale aquaponics. Selecting suitable fish and plant species, along with appropriate stocking densities, is crucial. Media Bed (MB), Deep Water Culture (DWC), and the Nutrient Film Technique (NFT) are commonly used hydroponic techniques. This study outlines optimal conditions, including water quality, temperature, pH, and nutrient concentrations, essential for symbiotic fish and plant cultivation. Integrating IoT technology enhances efficiency and profitability by optimizing resource utilization, monitoring water quality, and ensuring optimal growth conditions. Knowledge sharing among practitioners fosters innovation and sustainability through collaborative learning and best practices exchange. Establishing a community for knowledge sharing is vital for continuous improvement, advancing small-scale aquaponics towards a more efficient and sustainable future. [ABSTRACT FROM AUTHOR]

In aquaponic farming, there is a potential risk that heavy metals will contaminate the water, which can lead to heavy metal accumulation in the plants. Our research investigated the accumulation of mercury (Hg) and lead (Pb) under aquaponic conditions and the effect of their increased presence on the uptake of other macro- and micronutrients using watercress (Nasturtium officinale) as a model plant. The potential modifying effect of humic acid on heavy metal accumulation was also investigated. Adding Hg and Pb increased the mercury and lead levels of the watercress plants to over 300 µg kg−1, while the addition of humic acid significantly reduced the concentration of both mercury and lead in the plants compared to plants treated with heavy metals alone, from 310.647 µg kg−1 to 196.320 µg kg−1 for Hg and from 313.962 µg kg−1 to 203.508 µg kg−1 for Pb. For Fe and Mn, higher values were obtained for the Hg + humic acid treatments (188.13 mg kg−1 and 6423.92 µg kg−1, respectively) and for the Pb + humic acid treatments (198.26 mg kg−1 and 6454.31 µg kg−1, respectively). Conversely, the Na, K, Cu levels were lower compared to those in plants treated with heavy metals alone. Our results demonstrated that watercress can accumulate mercury, leading to high levels, even above food safety standards, highlighting the importance of water quality control in aquaponic systems. Furthermore, these results suggest that watercress could be used as a natural filter in recirculation systems. The addition of humic acid significantly reduced the accumulation of heavy metals and altered the element content in the plant. [ABSTRACT FROM AUTHOR]

BACKGROUND: Aquaponic systems are sustainable processes of managing water and nutrients for food production. An innovate nutrient‐efficient catfish‐based (Clarias gariepinus) aquaponics system was implemented for producing two cultivars of two leafy vegetables largely consumed worldwide: lamb's lettuce (Valerianella locusta var. Favor and Valerianella locusta var. de Hollande) and arugula (Eruca vesicaria var. sativa and Eruca sativa). Different growing treatments (4 × 2 factorial design) were applied to plants of each cultivar, grown at two light intensities (120 and 400 μmol m−2 s−1). During growth, several morphological characteristics (root length, plant height, leaf number, foliage diameter and biggest leaf length) were measured. At harvest, plants were weighed and examined qualitatively in terms of greenness and health status. Additionally, leaf extracts were obtained and used to determine total phenolic contents, antioxidant capacities, and levels of cytotoxicity to Caco‐2 intestinal model cells. RESULTS: After a 5‐week growth period, both lamb's lettuce cultivars presented high levels of greenness and health status, at both light intensities, particularly the var. de Hollande that also showed higher average performance in terms of plant morphology. In turn, arugula cultivars showed lower levels of greenness and health status, especially the cultivar E. vesicaria var. sativa submitted to direct sunlight during growth. In addition, plant specimens submitted to higher levels of light intensity showed higher contents in antioxidants/polyphenols. Cultivars with a higher content in antioxidants/polyphenols led to higher Caco‐2 cell viability. CONCLUSION: For successful industrial implementation of the aquaponics technology, different and optimized acclimatizing conditions must be applied to different plant species and cultivars. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This publication presents an innovative tower cultivation device designed to significantly increase vertical farming's efficiency. The device divides the cultivation system into separate chambers. One division corresponds to the different growth phases of the plants, while another reflects the daily variation in conditions. Each chamber presents slightly different conditions and cultivation patterns from the others. For the early stages, crops are grown horizontally in trays; once they mature, they are transplanted into mobile cultivation towers. The closed circulation of ventilation and irrigation reduces water consumption by up to 95%. A unique separate day–night division optimises light, temperature, and humidity conditions, mimicking natural growth patterns. This approach not only saves water and energy but also improves cultivation in a three-dimensional space. The presented solution focuses on the often-overlooked aspects of cultivating in vertical farms and makes this method of growing much more cost-effective and feasible to implement on a large scale. Our comparative analysis with other vertical farming solutions is based on publicly available data and provides valuable insights, while acknowledging the potential limitations at play. [ABSTRACT FROM AUTHOR]

Introduction: Aquaponics provide multiple benefits due to the simultaneous yield of vegetables and fish, however they are characterized by increased greenhouse gas emissions owing to intensive production system. The most appropriate method for quantifying the environmental effects of these systems is Life Cycle Assessment with which the identification of hotspots and the suggestion of improved production plans can be achieved. The purpose of the present study was to evaluate the environmental impact of a pilot high-tech aquaponic system utilized for the simultaneous production of baby lettuce and rocket as well as rainbow trout, in indicators such as Global Warming Potential. Materials and methods: To achieve this goal, data on inputs and outputs were collected from 12 case studies that were implemented, combining different fertilizer treatments, substrate choices, plant species cultivated and water source provision. Life Cycle Assessment was performed using SimaPro v.9.4.0.2 software. Results: The results showcase that the optimal case studies include the cultivation of baby lettuce and rocket in perlite substrate using wastewater from fish and partial use of synthetic fertilizers. Indicatively, Global Warming Potential of these cases was calculated at 21.18 and 40.59 kg CO2-eq/kg of vegetable respectively. The parameter with the greatest impact on most of the environmental indicators was electricity consumption for the operation of the oxygen supply pump for the fish tanks, while greenhouse infrastructure had the greatest impact in Abiotic Depletion and Human Toxicity impact categories. In an alternative production scenario tested where renewable energy sources were used, system impacts were reduced by up to 50% for Global Warming Potential and 86% for Eutrophication impact. The results of this study aspire to constitute a significant milestone in environmental impact assessments of aquaponic production systems and the adoption of more sustainable farming practices. [ABSTRACT FROM AUTHOR]

As nutrient-rich water in aquaponic systems cannot supply growing plants with all the required trace elements, supplementation with specific fertilizers is performed to make up for this deficit. While chelated fertilizers such as ethylenediaminetetraacetic acid-zinc disodium complex (Zn-EDTA) are becoming more popular in this context for improving plant growth in aquaponic systems, little is known about their effects on fish. During two experiments, a total of 576 individuals of catfish fry (0.19 g) and fingerlings (220.01 g) of the African catfish (Clarias gariepinus; Burchell, 1822) were kept separately for 32 days under experimental aquarium conditions. The fry was exposed to 0.125 and 0.5 mg/L, while the fingerlings were exposed to 0.5 and 2.0 mg/L Zn-EDTA in a plantless aquaponic system. The third treatment group consisted of a control group without Zn-EDTA. The growth, mortality, and ethological indicators were assessed for all growth stages, while the leukocyte distribution and histopathological changes were additionally determined for the fingerlings. As the feed intake in the experiment was limited, the investigations were focused on the effects of Zn-EDTA and not on the growth process of a respective fish growth stage. While the growth, mortality, and behavior were not significantly different in both growing stages, the number of mature neutrophils changed significantly in all treatments in fingerlings. Zn was not detected in the histologically investigated organs at the tested concentrations using the staining method. However, morphological alterations of the gill epithelium were found on the secondary lamellae. Quantitative multiplex PCR was used to simultaneously evaluate the expression of 17 genes related to Zn metabolism and stress physiology in head kidney samples. The transcripts of several selected genes changed by up to 70-fold. Due to high individual variances, only the copy numbers of the KMT2A (lysinespecific methyltransferase 2a) gene were significantly different across treatment groups and sampling points. However, the present results indicate that the addition of Zn-EDTA at the tested concentrations can be considered relatively benign for the health and welfare of C. gariepinus, as no toxic effects of Zn-EDTAwere observed in moderately hard to hard water. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of starvation and refeeding on the growth and food intake of gilthead seabream (Sparus aurata) and seabass (Dicentrarchus labrax) and on the growth and nitrogen uptake of glasswort (Salicornia europaea) in a polyculture aquaponic system under 12 ppt salinity for 75 days. Nine small-scale autonomous aquaponic systems were used, each containing 10 gilthead seabreams (average weight of 6.33 ± 0.73 g and average length of 5.73 ± 0.72 cm) and 10 seabasses (5.82 ± 0.77 g and 6.35 ± 0.45 cm), as well as five glasswort plants. Three fish feeding treatments were performed, a control (A), in which fish were fed daily until satiation, and two fasting treatments for 4 (B) and 7 days (C). Fish growth performance was significantly lower (p < 0.05) in the C treatment for both species compared to treatments A and B. Food consumption (FC) and feed conversion ratio (FCR) were significantly higher (p < 0.05) in treatment C. Glasswort growth performance was significantly higher in treatment C (p < 0.05). The results showed that the 4-day food-deprived fish were similar to the control fish by achieving partial compensatory growth. The more extended fasting period (7 days) resulted in significantly lower growth performance. The lipid and nitrogen retention levels in both species were significantly lower in food-deprived fish than in the control fish both before and during compensatory growth. The results suggest that a feeding schedule involving starvation–refeeding cycles is a promising feed management option for these species in polyculture aquaponic systems. The effect of food deprivation was also significantly beneficial (p < 0.05) for the growth performance of glasswort compared to the control treatment. [ABSTRACT FROM AUTHOR]

The increasing population, its requirements for food, and the environmental impact of the excessive use of inputs make crop production a pressing challenge. Integrated nutrient management (INM) has emerged as a critical solution by maximizing nutrient availability and utilization for crops and vegetables. This review paper highlights the potential benefits of INM for various vegetables and field crops and explores the conceptual strategies, components, and principles underlying this approach. Studies have shown that a wide range of vegetables and field crops benefit from INM, in terms of increased yield and improvements in yield attributes, nutrient contents and uptake, growth parameters, and various physiological and biochemical characteristics. This paper discusses biostimulants, their categories, and their impact on plant propagation, growth, photosynthesis, seed germination, fruit set, and quality. Additionally, this review explores modern sustainable soilless production techniques such as hydroponics, aeroponics, and aquaponics. These cultivation methods highlight the advancements of controlled-environment agriculture (CEA) and its contribution to nutrient management, food security and minimizing the environmental footprint. The review concludes by proposing methods and fostering discussions on INM's future development, while acknowledging the challenges associated with its adoption. Finally, this review emphasizes the substantial evidence supporting INM as a novel and ecologically sound strategy for achieving sustainable agricultural production worldwide. [ABSTRACT FROM AUTHOR]

Indoor farming technologies, such as aquaponics and hydroponics, are crucial for advancing sustainable agriculture, especially in urban areas with limited land for conventional agriculture. As studies comparing these two systems are limited, this study explored the cultivation of five leafy vegetables--white leaf beets (Beta vulgaris var. cicla), hooker chives (Allium hookeri), basil (Ocimum basilicum), lemon balm (Melissa officinalis), and spearmint (Mentha spicata)--in an indoor greenhouse facility using two different food production platforms: an aquaponic system (AS) with catfish (Silurus asotus) and a conventional hydroponic system (HS). The results showed that the plant growth in AS outperformed that in HS, while the general growth patterns in AS were significantly affected by the different light sources. In addition, the leaf yield of the herbal plants (basil and lemon balm) in AS was 60%-70% more than that in HS. The leaf growth of hooker chives in AS also showed significant improvement (200%) compared with that in HS. It appears that the nutrient sources provided by fish were remarkable, as the average concentration of NO3-N (64 mg/L) was easily achieved in AS. The proposed AS, therefore, would be a promising alternative to the production and supply of supplement organic food, ultimately contributing to promoting sustainable agriculture in a changing climate. [ABSTRACT FROM AUTHOR]

A major challenge in agriculture, horticulture and aquaponics practices is the reduction of mineral fertilisers and peat to reduce CO2 emissions and increase sustainability. This study used a three-phase-natural fertiliser, the Humicacid Fiber-Substrate (HFS), made from natural regenerative organic and mineral-fractions (Humus-Mineral-Complex), to reduce the peat content in plant pots for aquaponics farming. Basil (Ocimum basilicum) growth was compared with i) 100% standard media substrate ("Einheitserde", white peat 80%, clay 20%), and ii) 85% "Einheitserde" and 15% of HFS under irrigation with aquaculture process waters from an extensive and intensive production of African catfish (Clarias gariepinus) under coupled aquaponic conditions. The substitution with 15% HFS and use of intensive fish water resulted in comparable plant growth to a fertiliser solution as control, and in higher leaf width and leaf green weight and lower root dry weight compared with the standard media substrate "Einheitserde". Basil leaf chlorophyll content from the aquaponics was higher compared with local market plants. This suggests the possible substitution of the peat substrate "Einheitserde" with at least 15% HFS to reduce the natural peat fraction. Further studies on crop-specific substrates are needed to reduce peat in aquaponics farming plant cultivation. [ABSTRACT FROM AUTHOR]

Aquaponics is the cultivation technique that integrates aquaculture with hydroponics. The present work compared two plant production cycles of a hydroponic component of an aquaponic system (tilapia-lettucecucumbers) vs. a hydroponic system. The tilapia growth trial lasted 22 weeks in the aquaponic system, during which two plant production cycles -lettuce-cucumber- (seven weeks) were performed. Water quality and environmental variables were recorded, evaluating weight growth and biomass produced in fish rearing. Leaf number, height, and weight were determined in lettuce plants. Stem length and fresh weight were measured in cucumber plants; length, fresh weight, and diameter were determined in cucumber fruit. The results showed that the average tilapia biomass per tank was 33.76 kg m-3 with an average final weight of 592.26 ± 25.45 g fish-1. Lettuce production (plants ha-1 ) was higher in aquaponics than hydroponics during the first cycle, while in the second one, it was greater in hydroponics. Significant differences (ANOVA, P < 0.05) resulted between treatments in both cucumber production cycles with larger biomass growth in hydroponics than in aquaponics. Cucumber fruit showed larger weight (212.52 ± 18.89 g) and length (14.15 ± 1.75 cm) in hydroponics, thus greater yield (4.97 t ha-1 ); hydroponics-grown cucumber plants had longer stem lengths (292.51 ± 8.73 cm). In conclusion, the hydroponic system had higher plant production. However, aquaponics provided a double benefit since it produced fish and plants, and the plants used waste from fish rearing without contaminating the environment. [ABSTRACT FROM AUTHOR]

During a suspension of a GIFT tilapia broodstock recirculating aquaculture system (RAS), a significant fish mortality event occurred. To determine the cause, four bacterial strains were isolated from affected fish and identified as Vibrio vulnificus through 16S rDNA sequencing. Virulence assays confirmed the pathogenicity of these strains, with the most virulent, CS-4, selected for a further analysis. Antimicrobial testing revealed CS-4's sensitivity to 19 antibiotics, including meloxicillin and Gentamicin. Challenge tests indicated varied 7-day Lethal Dose 50 (LD50) values for CS-4 depending on the infection route, with immersion after skin injury being the most lethal. Additionally, the effects of salinity, crowding with air exposure, and nitrite on tilapia mortality were evaluated. The results showed that salinity stress increased the mortality rate of tilapia infected with V. vulnificus through immersion, and that salinity stress and V. vulnificus infection had a synergistic effect. A 20 min crowding with air exposure stress reduced the mortality rate of Nile tilapia infected with V. vulnificus. Nitrite stress had little effect on the mortality rate of tilapia infected with V. vulnificus. The results of the risk factor analysis indicated that salinity was the main factor affecting tilapia mortality caused by V. vulnificus infection. This study will serve as a valuable reference for the future management of similar RAS. [ABSTRACT FROM AUTHOR]

ABSTRACTSaudi Arabia is the largest country in the Middle East with huge solar energy resources but has achieved minimal adoption of photovoltaic energy systems (PV). This study investigates the potential of PV systems to address pressing challenges, including water scarcity and agricultural unemployment. This study addresses the deployment of PV in contemporary agriculture such as aquaponics and hydroponics to promote sustainable water, energy, and agricultural practices. Scrutinising national goals for PV energy against ground realities. The buyback tariff, interest rates of loans, and potential future power price increases are simulated to find suitable rates to encourage PV adoption. The current government grid purchase price is 1.87 cents USD/kWh, while the national grid selling price is 4.8 cents USD/kWh. Small-scale PV plants offer local investors passive income streams if financial institutes can offer these projects at lower interest rates. Investigating the country’s educational sector reveals the need for an overhaul in technical education for solar energy systems. The simulation shows that PV use in agriculture is economically feasible for large loads even with buyback rates as low as 1.87 cents USD/kWh. This research contributes by emphasising local involvement and proposing financial mechanisms, government reforms, and sustainable agricultural development in the region.

Abstract Although food is produced in aquaponics systems worldwide, no information is available on the occurrence of insect pests and natural enemies in aquaponic lettuce, Lactuca sativa L. In this study, a survey was carried out in an aquaponic system combining lettuce with lambari, Astyanax altiparanae (Garutti & Briski), aiming to determine the insect pests and natural enemies associated with this system. We also determined the predominant insect species and the effect of meteorological factors on their populations. Insect abundance was estimated by visual sampling during 13 cultivation cycles, totaling 27 sampling dates. The meteorological factors considered were air temperature and relative humidity, and their effects were determined using the Pearson correlation. The thrips Frankliniella schultzei (Trybom) and Caliothrips phaseoli (Hood) and the aphid Aphis spiraecola (Patch) predominated. Ambient temperature and relative humidity were essential factors affecting C. phaseoli and F. schultzei. The natural enemies found on the lettuce plants were the thrips Franklinothrips vespiformis (Crawford) and Stomatothrips angustipennis (Hood) and the ladybugs Cycloneda sanguinea L., Eriopis connexa (Germar), and Hippodamia convergens (Guérin-Méneville). These results constitute the first step for a lettuce-integrated pest-management program in aquaponics systems.

Climate change, population expansion, water shortages, soil erosion, and food security are some of the primary concerns facing the world today. Hydroponic, aquaponic, and aquaculture systems may help to address these difficulties. Hydroponics is a closed-loop system for growing plants in nutrient-rich water rather than soil. Aquaponic systems combine hydroponics and the growing of fish or other aquaculture species in addition to plants. This review aims to evaluate the challenges encountered by aquaponic and aquaculture farming operations and identify which issues still need to be addressed. The review is organized as follows: recent previous studies on hydroponics, aquaponics, and aquaculture were collected and investigated; water quality and energy issues were addressed; technologies to improve water quality in these systems were discussed; and challenges to the implementation of large-scale aquaponics were discussed. The study found that a commercial reverse osmosis filtering system that provides excellent water quality control is a good method for removing harmful contaminants from water in small-scale aquaponics and aquaculture. Recirculation systems are more sustainable and effective in managing the volume of effluent in aquaculture units because only 10% of the total volume of water is refilled daily. Constructed wetland systems are a low-cost, high-efficiency treatment solution for nitrogen-containing wastewater, with removal efficiencies of up to 98% for NH4-N and above 98% for NO2-N. The use of aquaponics in desert settings with water constraints constraint is viewed as a possible sustainable food production approach.

In Germany, warm water Recirculating Aquaculture Systems (RAS) are generally integrated with biogas plants. The process sludge produced in aquaculture could be utilized to generate energy. This study investigates the potential of process sludge from commercial African catfish (Clarias gariepinus) warm water RAS, alongside associated plant production residues (whole plants and pruning residues) for energy generation through anaerobic digestion. Biogas tests, including batch, semi-Continuous Stirred Tank Reactor (CSTR), and Upflow Anaerobic Sludge Blanket Reactor (UASB) were conducted. In batch, methane yields were 229 L(N) / kg VS from the sludge and 173-184 L(N) / kg VS from the various plant substrates (cucumber, paprika, and tomato plants). During CSTR operation, mono-fermentation of sludge produced a methane yield of 265 L(N) / kg VS. Co-fermentation with 25% cucumber residues, based on VS, increased this value to 381 L(N) / kg VS. Mono-fermentation of sludge in the UASB reactor yielded a maximum of 329 L(N)/kg VS. The relatively low TS content and unfavorable C/N ratio in C. gariepinus sludge, along with the low energy density and occasional high sulfur content in the investigated plant substrates, present challenges for CSTR biogas production. These challenges can be partially mitigated through substrate combination. For mono-fermentation of African catfish RAS sludge, the UASB reactor is recommended. Improved solids separation, extraction, and concentration techniques at aquaculture operations are essential for the efficient utilization of aquaculture sludge, especially from African catfish, in biogas plants. [ABSTRACT FROM AUTHOR]

Seasonal factors such as temperature, solar UV-light intensity, and daylight length can induce changes in the water quality properties and, hence, the nutritional compositions of plants. This comparative study was carried out for the consecutive four (4) seasons (winter, spring, summer, and autumn) to determine the influence of seasonal variations on the 50% inhibitory concentration (IC50), total antioxidant capacity (TAC), total phenolics content (TPC), and total flavonoids content (TPC) of the red chili fruit (RCF), red tomato fruit (RTF), green leafy spinach (GLS), and green leafy lettuce (GLL) collected from a coupled commercial aquaponics system. The IC50, TAC, TPC, and TFC concentration levels indicated a significant (P<0.05) difference in the summer compared with the winter, spring, and autumn. The RCF extract indicated the lowest IC50, thus greater scavenging power in comparison to RTF, GLS, and GLL extracts. Similarly, the RCF showed the highest TAC and TPC, while the GLL showed the highest TFC. In this study, variations in seasons have induced changes in the IC50, TAC, TPC, and TFC concentration levels of the RCF, RTF, GLS, and GLL extracts. [ABSTRACT FROM AUTHOR]

The combined production of three varieties of lettuce (romaine, iceberg, and red leaf) with flathead grey mullet (Mugil cephalus) was tested in triplicate in three independent coupled aquaponic units with no thermal control. For this purpose, a total of 114 fish (2.5 kg/m3) were stocked in each fish tank (2 m3), and 92 lettuces were planted in the hydroponic unit (6 m2). As no thermal control was included in the design of the aquaponic system, water temperatures declined from maximum values of 20.4 °C to minimum values of 5.0 °C, which directly affected fish growth. However, the conditions imposed by the aquaponic system were suitable for promoting lettuce's growth and external appearance, as no pests or leaf discoloration were noticed. Lettuce survival was similar among the three tested varieties (98.5 ± 1.7%). The yields for the romaine and iceberg varieties were 384 ± 100 g/lettuce and 316 ± 70 g/lettuce, respectively, and that for the red leaf variety was lower, at 176 ± 75 g/lettuce. Yield values ranged between 3.6 and 4.4 kg/m2 depending on the replicate considered (4.0 ± 0.4 kg/m2). According to present results, each aquaponic unit required ca. 2.6–2.7 L of water per unit of lettuce produced. [ABSTRACT FROM AUTHOR]

The article discusses the importance of the Lamiaceae family of plants, which includes species like thyme, mint, oregano, basil, and sage. These plants are known for their aromatic properties and are widely used in various industries such as food, cosmetics, and pharmaceuticals. The article also highlights recent research on topics such as plant cultivation methods, extraction techniques for essential oils, and the preservation of fresh produce using natural compounds. The collection of scientific papers aims to explore the potential of these plants and their extracts in various applications while optimizing growth conditions and extraction methods. [Extracted from the article]

Lactic acid bacteria have been widely used as feed additives in aquaculture to improve the absorption of nutrients, as well as the immunity and growth performance of fish. According to the lactic acid bacteria to decompose organic matter, this study aims to improve the utilization efficiency of solid waste resources with high nutrients in aquaponics systems. Fishderived bacteria were screened with strong resistance and better mineralization function, in order to enhance the fermentation and mineralization of fish waste. The experiments were conducted to take the biofilter media and fish from the aquaponics system as the source of lactic acid bacteria. A series of tests were then performed on the high-temperature tolerance, acid and alkali tolerance, high salt tolerance, and the mineralization performance of various nutrients in fish waste. Two strains were obtained with mineralization function and application potential, which were identified as Lactococcus lactis L1 and Lactobacillus dextrinicus L2, respectively. A comparison was also made on the growth performance of the strains at 10, 20, 30 and 40 °C. The results revealed that the growth of L1 and L2 was inhibited at 10 and 20 °C, while they proliferated normally at 30 and 40 °C. The survival rate of L1 and L2 after 30 min of heating at 50, 60, and 70 °C was examined to verify the high-temperature tolerance of the strains. It was found that the L1 was achieved the better high-temperature tolerance. The survival rate of L1 was 96.60% at 50 °C, which was significantly higher than that of L2 (80.35%). According to the range of water acidity and alkalinity in the environment of aquaculture, the tolerance of the two strains was examined at pH 5.0-9.0. The results showed that the survival rates of L1 (65.43% and 71.25%) were higher than those of L2 (31.10% and 52.22%) at both pH 5.0 and 9.0 (P<0.05). The tolerance of the strains was examined at 15, 30, and 60 g/L salinity, where the mariculture and salinity were considered after the thickening of mariculture sludge. The survival rate of the strains gradually decreased with the increase of salinity. Once the salt concentration was 60 g/L, the survival rate of L1 was 37.33%, while there was no L2 survival. In terms of tolerance to temperature, acid, and alkali, L1 was selected as the subsequent experimental object for the fish waste fermentation mineralization experiment. The control group (no lactic acid bacteria added) and the L group (with Lactococcus lactis added) were divided to last for seven days. A comparison was made on the contents of nitrogen, phosphorus and various mineral elements in the fermentation broth at days 0, 1, 3, 5 and 7. The results showed that better degradation and mineralization of organic matter were achieved in the L group. The highest concentrations of total ammonia nitrogen (TAN) and total nitrogen (TN) in the fermentation broth of the L group were 192.82 and 342.00 mg/L, respectively, which were much higher than the control group (30.29 and 79.00 mg/L, respectively). Potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), and zinc (Zn) in the fermentation broth of the L group were significantly higher than those of the control group, except for sulfur (S) and all reached the highest values (27.59%-94.67%) in the 3d. In conclusion, Lactococcus lactis presented the better resistance to heat, salt, acid, and alkali, indicating better fermentation and mineralization of fish waste. Furthermore, 3 d was the optimal cycle of fermentation and mineralization. The finding can provide a strong reference to apply the lactic acid bacteria to the mineralization of solid wastes, in order to improve the nutrient utilization efficiency in aquaponics systems. [ABSTRACT FROM AUTHOR]

The expansion of food production is becoming more important due to a rising world population, which is relying on food security on regional and local scales. Intensive food production systems exert a negative impact on the regional ecosystem because of agrochemical pollution and nutrient-rich water discharging into nearby rivers. Furthermore, these systems highly depend on regional water resources, causing water scarcity and soil erosion due to the overexploitation of natural resources in general. The objective of this article is to review the water usage in the two most water-intensive food production systems, agriculture and aquaculture, showing lacking areas like system management and climate change, which must be considered in the implementation of a sustainable water footprint. In addition, the review includes an analysis of the combination of both production systems in aquaponic food production and the possibilities of water saving. There are a variety of analyses related to water usage for crop and aquatic animal production, but in these analyses, there is a lack of information about system management in general, which includes cleaning processes, water substitution, pond removal, water evaporation, and, especially in aquaculture, the water usage required for industrially elaborated fish feed. [ABSTRACT FROM AUTHOR]

Conventional aquaponics conserve water used in aquaponics whereas the literature suggests a certain level of freshwater replenishment or freshwater exchange for good water quality, fish and plant wellbeing, and the overall productivity of the system. This paper deals with the determination of an optimal freshwater replenishment rate for a standard aquaponics system. IoT devices and sensors were used for this project data collection. This paper used linear regressions and ensemble methods to determine the optimal rate of periodic water replenishment to maintain the water quality parameters that determine the yield and productivity of aquaponics systems. Cubic spline and Lagrange interpolation were applied to raw and simulated data. Results were evaluated and compared using statistical error estimation approaches. The bestmodel amongst the investigated machine learning models was gradient boost with an optimal replenishment rate of 19L per week and a water quality of 4.86 for an aquaponic tank of 100 L capacity. The error estimations were a Mean Squared Error of 0.0224, Mean Absolute Error of 0.1137, Root Mean Squared Error of 0.1499, and R2 of 0.7208. This was within 1% of the value obtained fromraw and interpolated data using a polynomial regression. These findings suggest that the water quality of an aquaponics system can be maintained at the desired optimal level with a weekly 19% water replenishment, thereby contributing to the improvement of productivity and resource efficiency. [ABSTRACT FROM AUTHOR]

The European Union's (EU) agricultural self-sufficiency is challenged by its reliance on imported plant proteins, particularly soy from the Americas, contributing to deforestation and greenhouse gas emissions. Addressing the EU's protein deficit, this study evaluates alternative protein sources for aquaculture, focusing on their nutritional value, elemental content, and polycyclic aromatic hydrocarbons (PAHs). Protein flours from gastropods (Helix pomatia, Arion lusitanicus, Arion vulgaris) and their hepatopancreas, along with plant-based proteins from food industry by-products (oilcakes, coffee grounds, spent brewer's yeast), were analyzed. Results revealed that snail flour contained the highest protein content at 59.09%, significantly outperforming hepatopancreas flour at 42.26%. Plant-based proteins demonstrated substantial nutritional value, with coffee grounds flour exhibiting a remarkable protein content of 71.8% and spent brewer's yeast flour at 57.9%. Elemental analysis indicated high levels of essential minerals such as magnesium in hepatopancreas flour (5719.10 mg/kg) and calcium in slug flour (48,640.11 mg/kg). However, cadmium levels in hepatopancreas flour (11.45 mg/kg) necessitate caution due to potential health risks. PAH concentrations were low across all samples, with the highest total PAH content observed in hepatopancreas flour at 0.0353 µg/kg, suggesting minimal risk of PAH-related toxicity. The analysis of plant-based protein sources, particularly oilcakes derived from sunflower, hemp, flax, and pumpkin seeds, revealed that these by-products not only exhibit high protein contents but present a promising avenue for enhancing the nutritional quality of feed. This study underscores the potential of utilizing gastropod and plant-based by-products as sustainable and nutritionally adequate alternatives to conventional feeds in aquaculture, contributing to the EU's environmental sustainability goals. [ABSTRACT FROM AUTHOR]

Many studies provide ways to monitor and manage the aquaponics system, a closed-loop ecosystem that combines hydroponics—growing plants without soil—and aquaculture—raising fish—using cloud computing, the Internet of Things (IoT), and smart sensing technologies. A system operating at peak efficiency yields organic, healthful food with little water and no chemical fertilizer usage, therefore contributing to food security and sustainability. In order to develop our proposed aquaponic system based on Internet of Things technologies, this paper will centralize our endeavor to integrate big data tools, namely Apache Spark and Kafka, into the previous architecture for data collection and processing, as well as for the prediction of any anomalies in the system. [ABSTRACT FROM AUTHOR]

Interest in aquaponics (AP) is increasing due to its ability to minimize sewage and maximize feed efficiency in fish farming. However, owing to limitations of intensive cultures and a lack of nutrients such as NO3 for growing crops, AP requires the use of artificial nutrients. Therefore, novel approaches are required to develop AP-intensive culturing methods. An AP system based on biofloc technology (BFT) called FLOCponics (FP) has been recommended. Here, the productivity of the weather loach (Misgurnus anguillicaudatus) in the FP system, BFT system, and flow-through systems (FTSs), as well as these systems' effect on Caipira lettuce (Lactuca sativa) growth, was analyzed. To compare crop productivity, a hydroponic (HP) bed was installed. The growth rate of M. anguillicaudatus showed significant differences, at 51.1 ± 3.69% in the FP system, followed by 24.0 ± 4.16% in the BFT system and −14.3 ± 1.4% in the FTS. Its survival rates were better in the FP system (91.1 ± 2.64%) than in the BFT system (82.1 ± 10.98%) or the FTS (66.8 ± 2.75%) (p < 0.05). Total ammonia nitrogen and NO2−-N concentrations were stabilized in every plot during the experimental period. However, the NO3−-N concentration continuously increased in the BFT system but decreased in the FP system and was maintained. The shoot weight of the Caipira lettuce was 163.6 ± 8.65 g in the FP system and 149.6 ± 9.05 g in the HP system. In conclusion, FP system can provide a large amount of nutrients and improve the growth performance of both fish and crops in the FP system. [ABSTRACT FROM AUTHOR]

In this study, we investigated the effects of swimming activity and feed restriction on juvenile rainbow trout (Oncorhynchus mykiss) in decoupled aquaponic systems. Our focus was on assessing their impact on water quality parameters within the aquaponic setup and evaluating the growth performance of the fish, including final weight (FW), condition factor (K), coefficient of variation (c.v.) in weight, specific growth rate (SGR), total feed intake (g/fish), feed conversion rate (FCR), hepatosomatic index (HSI), and viscerosomatic index (VSI), as well as the growth of lettuce (Lactuca sativa L. var. elmaria). The study involved 108 juvenile rainbow trout with an average initial weight of 26.54 ± 0.36 g and 60 ten‐day‐old lettuce seedlings, over a period of 42 days. We designed four treatment groups, each with three fish tanks: static ad libitum (SA), where fish were in static water conditions and fed to satiation; static restriction (SR), with fish in static water and a 25% feed restriction; current ad libitum (CA), where fish experienced forced swimming at 1 BL s−1; and current restriction (CR), with swimming exercise at 1 BL s−1 and a 25% feed restriction. Using a flow rate of 1 BL s−1 in the tanks for rainbow trout yielded several benefits. Notably, the fish in the CA group exhibited increased feed intake (60 ± 1.78 g fish−1) and enhanced fish growth with an FW of 91.72 ± 0.91 g, compared to the SA group (55.88 ± 0.88 g fish−1 for feed intake and 89.26 ± 0.81 g for FW). In contrast, the CR group showed a reduced feed intake (39.02 ± 2.78 g fish−1) and a lower FW (67.85 ± 1.49 g) compared to the CA group. In addition, the CA group demonstrated positive contributions to fish development with a reduced HSI (1.26 ± 0.02) in comparison to the SA group (1.56 ± 0.14). Inadequate nutrient provisioning in the SR and CR groups negatively impacted fish growth and system efficiency. Our findings suggest that optimizing water flow and feed benefits fish and plants and enhances system sustainability. [ABSTRACT FROM AUTHOR]

The effects of nutrient flows on tilapia fish (Oreochromis niloticus) and plant crops in three model aquaponic systems (deep water culture system, nutrient film technique and substrate beds) placed under identical conditions were evaluated. Quantitative analysis of ammonia, nitrite, nitrate concentrations and the factors on which they depend (air and fish water temperature, air humidity, pH and dissolved oxygen) was performed. The nutrient solutions affecting the yield and quality of the produce and the efficiency of the resources used were assessed. Monitoring and good management of aquaponics are necessary and mandatory requirements to ensure optimal conditions for the symbiosis between fish, beneficial bacteria and plants. [ABSTRACT FROM AUTHOR]

Zero-discharge and low-input aquaponics systems are a promising alternative to the intensive agricultural and aquacultural production systems currently used, ensuring high environmental sustainability. However, new approaches and management practices are needed to increase their productivity to reach the yields of classic production systems. In this context, the present study investigated for the first time the potential of two biostimulants to improve lettuce performance in aquaponics, whether coupled or decoupled, with hydroponics serving as a control. A comprehensive evaluation was conducted to assess the plant functional (focusing on the photosynthetic process evaluation) and growth responses at the whole-plant level. In addition, the nutritional state of the leaves was determined and metabolomic analysis was performed at the cellular level, the latter also for the first time in aquaponics research. The results demonstrated the limitations that coupled aquaponics poses in relation to lettuce growth, function and metabolism, which were already obvious from the 12th day of the experiment. Indicatively, the plants grown under coupled aquaponics exhibited a notable decrease in the leaf fresh weight, potassium content and nitrogen content, with reductions of 80%, 60%, and 30%, respectively, in comparison to the hydroponics control. However, the combined physiological and metabolomic data indicate that these plants down-regulate processes and metabolism to acclimate to low nutrient levels in lettuce leaves rather than experiencing damage. The application of biostimulants did not significantly optimize the plants' performance, though one of them appeared to be effective in improving some aspects of the photochemical efficiency. The decoupled and hydroponics systems resulted in similarly high yields and efficiency in terms of plant function, without any marked contribution from the biostimulants. We conclude that the decoupled aquaponics system has been successful in achieving yields comparable to those of hydroponics, with lower chemical inputs. Future studies should focus on examining other biostimulants in this system to further improve its performance while maintaining its environmental benefits within a circular economy framework. [ABSTRACT FROM AUTHOR]

Sedimentable solids generated in aquaponic systems are mainly composed of organic waste, presenting molecules such as phytate, which can be a potential source of inorganic nutrients through mineralization. This work aimed to isolate and identify phytase-producing bacteria and evaluate the inoculation effects of pure strains on mineralization and nutrient release from solid waste generated in aquaponic systems at different oxygen and temperature conditions. The bacteria were isolated from the settleable solids of a commercial aquaponic system and molecularly identified by amplifying the 16S rRNA gene. Subsequently, two tests were carried out: 1. Test for the biochemical identification of phytase-producing bacteria; 2. In vitro mineralization test, where the ability to mineralize phytate and release nutrients under different oxygen conditions [0 rpm (2.1 mg L−1) and 200 rpm (7.8 mg L−1)] and temperatures (24 and 37 °C) were evaluated. Our findings show that two pure strains of Lysinibacillus mangiferihumi can mineralize phytate under conditions of 200 rpm and 24 °C, mainly increasing the mineralization of PO4- and Ca, a property that has not yet been reported for this species. On the other hand, at 0 rpm and 24 °C, an increase in K was observed (control conditions), while the conditions of 200 rpm and 24 °C, regardless of bacterial inoculation, favored a rise in S, Mg, and Fe. The Lysinibacillus strains obtained in this investigation are of great importance due to their application in agriculture and the optimization of mineralization in aquaponic systems. A proper combination of oxygen and temperature will lead to a greater availability of nutrients for the growth and development of vegetables. [ABSTRACT FROM AUTHOR]

AI plays a pivotal role in predicting plant growth in agricultural contexts and in creating optimized environments for cultivation. However, unlike agriculture, the application of AI in aquaculture is predominantly focused on diagnosing animal conditions and monitoring them for users. This paper introduces an Automated Fish-feeding System (AFS) based on Convolutional Neural Networks (CNNs) and Gated Recurrent Units (GRUs), aiming to establish an automated system akin to smart farming in the aquaculture sector. The AFS operates by precisely calculating feed rations through two main modules. The Fish Growth Measurement Module (FGMM) utilizes fish data to assess the current growth status of the fish and transmits this information to the Feed Ration Prediction Module (FRPM). The FRPM integrates sensor data from the fish farm, fish growth data, and current feed ration status as time-series data, calculating the increase or decrease rate of ration based on the present fish conditions. This paper automates feed distribution within fish farms through these two modules and verifies the efficiency of automated feed distribution. Simulation results indicate that the FGMM neural network model effectively identifies fish body length with a minor deviation of less than 0.1%, while the FRPM neural network model demonstrates proficiency in predicting ration using a GRU cell with a structured layout of 64 × 48. [ABSTRACT FROM AUTHOR]

Carbon source addition is an important way improving the carbon and nitrogen transformation in aquaculture system; however, its effectiveness of algal–bacterial-based aquaponics (AA) through carbon source addition is still vague. In this study, the influences of organic carbon (OC-AA system) and inorganic carbon (IC-AA system) addition and without carbon source addition (C-AA system) on the operational performance of AA system were investigated. Results showed that 10.1–19.5% increase of algal–bacterial biomass enhanced the purifying effect of ammonia nitrogen in OC-AA system and IC-AA system relative to C-AA system. Moreover, extra electron donor supply in the OC-AA system obtained the lowest NO3−-N concentration. However, that was at the cost of aggravated N2O conversion ratio, which increased by more than 2.0-folds than other systems, attributing to 2.9-folds increase of nirS gene abundance. In addition, carbon source addition increased the pH and then decreased the fish biomass production of AA system. The results of this study would provide theoretical supports of carbon source addition on the performance of nutrient transformation and greenhouse gas effect in AA system. [ABSTRACT FROM AUTHOR]

The increasing demand on water resources, reduced land for agriculture, and concerns over food and nutrition security have prompted the evolution of innovative and complex food production systems. In this context, efficient and sustainable food production systems such as aquaponics are viewed as an important and environmentally friendly technology for adaptation under resource-limited environments. Producing food in soilless systems is a promising strategy, as this method utilizes significantly less water than traditional agriculture. However, optimizing growing conditions to enhance crop and fish yields in aquaponics is frequently ambiguous and is often not economically feasible. One of the strategies to improve plant yields and supply of nutrients in aquaponics is the application of probiotics. With this strategy, the crop yields in aquaponics are improved via a variety of mechanisms, including nitrogen fixation, solubilization of mineral nutrients, organic matter mineralization, plant hormone modulation, and biocontrol. As a result, incorporating probiotics in aquaponic systems is a strategy for mitigating environmental effects and advancing sustainable agriculture. This review paper provides the current knowledge of the use of probiotics in aquaponics. Suggestions for further studies on the effects of probiotics in aquaponic systems are proposed. Through literature review, integrating probiotics into aquaponic systems has the potential to improve nutrient supply, modulation of water quality parameters, and microbial communities, which are key processes in enhancing the productivity of aquaponic systems. [ABSTRACT FROM AUTHOR]

Aquaculture activities often lead to environmental deterioration due to discharges of nutrient-rich wastewater without treatments. The present study aimed to develop a bio-green floating system (BFAS) to utilize excess nutrients, improve water quality, enhance plant and fish production, and minimize threats of aquaculture effluents. The floating raft system was constructed using water spinach integrated with a substrate (lava rock) to allow the development of biofilm communities, which together with the plants, improved the water quality by nutrient sequestration. Three treatments were employed for 105 days: (1) zero water exchange without BFAS (T1-NCT); (2) water exchange at 5-day intervals without BFAS (T2-PCT); (3) zero water exchange with BFAS (T3-BFAS). Total ammonia removal was significantly (p < 0.05) higher (92.4 ± 1.2%) in T3-BFAS compared to T2-PCT (89.2 ± 0.5%). The percent removal of other nutrients such as unionized ammonia, nitrite, and soluble reactive phosphorus was significantly (p < 0.05) higher in T3-BFAS compared to T2-PCT and the control. The T3-BFAS showed a significantly (p < 0.05) lower feed conversion ratio (FCR, 1.16 ± 0.05), higher (p < 0.05) specific growth rate (SGR, 3.58 ± 0.03), and better health indicators (hemato-biochemistry characteristics) compared to the other treatments. Heavy metals in T3-BFAS were significantly lower (p < 0.05) than the control and were significantly higher in roots than in the water. The findings suggested that the simple newly developed energy-free BFAS could enhance water quality, improve fish health, and optimize fish production in an aquaculture system without water exchange. [ABSTRACT FROM AUTHOR]

This research aimed to standardize the growth of two commonly cultivated herbs in the United Arab Emirates, basil (Ocimum basilicum L.) and coriander (Coriandrum sativum L.), within an aquaponic system. The study compared a recirculatory aquaponic system (RAS) with static aquaculture systems (for fish performance) and irrigated greenhouse cultivation systems (for herb performance). The project assessed growth, element composition, and aquaponic efficacy to determine the viability of aquaponics for these herbs. In the soilless (aquaponic) system, both herbs exhibited significantly enhanced growth parameters, including plant height, root length, leaf count, and fresh and dry weights, compared to conventional soil‐based cultivation. This growth enhancement was attributed to the additional nutrients derived from fish waste in the aquaponic system. Furthermore, plants displayed significantly higher element levels, highlighting the effectiveness of aquaponics in nutrient delivery. Notably, the aquaponic system demonstrated superior antioxidant activity in both herbs. The study also revealed remarkable water use efficiency in the aquaponic system, with water savings exceeding 90% compared to conventional methods. These findings establish the efficiency and sustainability of aquaponic systems over traditional food production approaches, particularly in arid regions such as the United Arab Emirates. Utilizing an aquaponic system for these commonly cultivated herbs resulted in improved growth and resource efficiency, affirming its viability as an environmentally sustainable and efficient method of food production in desert climates. [ABSTRACT FROM AUTHOR]