In recirculating aquaculture systems (RAS), the water exchange rate influences the removal of waste compounds. However, the inappropriate exchange rate favors the presence of stress factors, causing alterations in the cultured organisms. Therefore, the aim was to determine the effect of the water exchange rate in the different productive stages (fingerling, juvenile, and adult) of Nile tilapia (Oreochromis niloticus). Three exchange rates were used: rates of 1.2 (T1), 2.8 (T2), and 5.3 (T3) tank volume h-1. The following were established as response variables: growth rate (GR), survival rate (SR), feed conversion rate, protein efficiency, and condition factor. Likewise, cortisol and glucose concentrations were established as explanatory variables. The results suggest that in the fingerling stage, the T2 treatment contributes most to the productive performance (GR = 40.24 g and SR = 95%), keeping low levels of cortisol and glucose (6.76 ng mL-1 and 33.73 mg dL-1). In the juvenile stage, T3 treatment shows the best result both in productive performance (GR = 117.69 g and SR = 90%) and in cortisol and glucose concentrations (35.13 ng mL-1 and 70.67 mg dL-1). Finally, all treatments present cortisol and glucose levels above the normal range in the adult stage, T1, where the highest productive performance is presented (GR = 90.06 g and SR = 95%). The information leads us to consider the variation in the exchange rate in a RAS through the different stages of the Nile tilapia to maintain the favorable conditions that lead to the highest performance.

In this research, the effect of different productive stages of tilapia (Oreochromis niloticus) in a hyper-intensive aquaculture system on the growth of tomatoes was evaluated. Fish were cultivated in a final density of 80 kg m3 considering three development stages (an average of fingerling of 1.487 g, juvenile of 62 g, and adult of 203.75 g, respectively). The quality of water was measured by determining temperature, pH, electric conductivity, and dissolved oxygen. Biometric data were registered throughout the growth of fish and tomatoes. Results showed that the survival, growth, and health of fish are not affected by the hyper density of culture; as well as the quality water was maintained under acceptable conditions for the development of organisms. Besides, it was obtained that the early productive stages (fingerlings and juveniles) gave the best results for tomato growth. These results suggest using the wastewater from fingerlings and juveniles of a hyper intensive recirculation aquaculture system to produce hydroponic tomato; to achieve sustainable production systems with maximum use of the resources.

In aquaponics, a limitation in productive performance is the concentration of nutrients for plant development. So, the intensity of fish in the culture could be an internal variant that favors the presence of nutrients, thus avoiding their external supply. Therefore, the aim was to determine the effect of intensive fish density during its three biological stages (fingerling, juvenile, and adult) on the yield, quality, and safety of tomato (Solanum lycopersicum) and tilapia (Oreochromis niloticus) in an aquaponic system. The study was conducted using a randomized block design, having as an experimental unit an intensive aquaponic system and as a control, an aquaculture module and a hydroponic module, each with three replications. The response variables for plant yield were dry weight, relative growth rate, crop growth rate, survival rate, and production per plant, and for fish, there were growth rate, feed conversion factor, protein efficiency ratio, and survival rate. For fruit quality, the variables were pH, total soluble solids (TSS), titratable acidity (TA), TSS/TA ratio, and lycopene content; for fillet quality, the following were considered: percentage of protein, lipids, ash, and nitrogen-free extract. Finally, in the safety evaluation of both products, the variables were the presence of total coliforms, Salmonella, and Escherichia coli. Intensive fish density (40 kg/m³) significantly improves tilapia biomass and fillet quality, while tomato yield remains comparable to that of hydroponics, with some quality variables even higher, without showing significant differences in the microbiological safety of the fillet or the fruit.

Accelerated population growth has driven the search for efficient food production systems such as aquaponics, which integrates aquaculture and hydroponics in a closed-loop configuration. In conventional aquaculture and hydroponic systems, intensification often causes physiological stress, nutrient imbalances, and resource inefficiencies. This study tested the hypothesis that, in an intensive aquaponic configuration, the synergy between aquaculture and hydroponic modules helps mitigate stress, improve nutrient and water use efficiency, and sustain overall performance compared to stand-alone hydroponic and aquaculture systems. The experiment was conducted under greenhouse conditions over three consecutive 180-day cycles, comparing an intensive aquaponic system with aquaculture and hydroponic modules. Tilapia in aquaponics showed 30% lower cortisol and 22% lower glucose (p < 0.05) than in aquaculture, indicating reduced stress. Tomatoes showed 25% higher catalase activity and 18% higher phenolic content (p < 0.05), reflecting moderate oxidative stress. Tilapia productivity reached 38.4 kg m⁻³ (+11.7%), tomato yield was 22.7% lower than in hydroponic conditions, and N–P use efficiencies were 23.3% and 20.7% (p < 0.05). Water use efficiency improved by 17.4%. Despite reduced plant growth, aquaponics decreased fish stress and enhanced nutrient recovery, supporting its potential as a sustainable, resource-efficient alternative for integrated food production under intensive conditions.

This study evaluates the bioeconomic performance index of an experimental intensive aquaponic system (IAS) integrating Nile tilapia (Oreochromis niloticus) and tomato (Solanum lycopersicum), in comparison with standalone aquaculture (AM) and hydroponic (HM) systems operated under identical greenhouse conditions. The systems were assessed at experimental scale over a 180-day production cycle using productive, environmental, and economic indicators integrated through a normalized Bioeconomic Performance Index (BPI) formulated as a benefit-to-resource ratio. Tilapia growth and feed conversion efficiency were comparable between IAS and AM, while water quality stability and nutrient use efficiencies were significantly higher in the integrated system (P < 0.05). Tomato yield was highest in the hydroponic system; however, crop production in the aquaponic system was achieved without synthetic fertilizers, relying exclusively on recycled aquaculture-derived nutrients. Although the IAS exhibited higher operating costs, mainly due to energy consumption associated with continuous water circulation and filtration, the combined production of fish and crops resulted in the highest net profit among the evaluated systems. The BPI indicated that the intensive aquaponic system achieved superior overall bioeconomic performance by balancing higher resource demand with gains in combined output and resource-use efficiency. Sensitivity analysis identified energy consumption as the dominant factor influencing bioeconomic performance, without altering system ranking. These results suggest that intensive aquaponics can represent a competitive alternative to conventional aquaculture and hydroponics when evaluated through an integrated bioeconomic framework, particularly in contexts prioritizing water conservation and nutrient recycling, while acknowledging trade-offs related to energy use and system complexity.