Plant extracts are an important alternative to antibiotics, which are ever more restricted because of their developing microbial resistance and some adverse effects that have been observed following frequent application. The aim of the present study was to determine the antifungal and antioxidant activity of the methanolic extracts of Acorus calamus, Chlorella vulgaris, Lemna minuta and Scenedesmus dimorphus. The antifungal activity of the extracts against strains of Aspergillus flavus, Aspergillus parasiticus, Aspergillus ochraceus, Aspergillus niger, Aspergillus carbonarius, Fusarium graminearum, Fusarium oxysporum, Penicillium chrysogenum and Alternaria alternata was evaluated via the agar well diffusion method. The antioxidant activity of the extracts was measured through the determination of three parameters—total phenolic content, total flavonoid content and radical scavenging potential (determined through UV/Vis analysis). A. calamus extracts had the highest antimicrobial activity against eight fungal strains, followed by the C. vulgaris, L. minuta and S. dimorphus extracts, which were inhibitory against two to three strains. Among the extracts from the species studied, the extract from S. dimorphus showed the highest antioxidant potential, as determined via the DPPH (1,1’-diphenyl-2-picrylhydrazil-radical) method. This correlated to its high total phenolic and flavonoid content. From A. calamus and L. minuta, methanolic extracts were obtained that exhibited similar values of the aforementioned parameters, followed by C. vulgaris extracts, which showed the lowest antioxidant activity. Based on the Pearson correlation coefficients, the impacts of the total phenolic content and the total flavonoid content on radical scavenging capacity are similar, and flavonoids were a significant part of the total phenolic compounds extracted from the plant materials studied.

The union of aquaculture and hydroponics is named aquaponics—a system where microorganisms, fish and plants coexist in a water environment. Bacteria are essential in processes which are fundamental for the functioning and equilibrium of aquaponic systems. Such processes are nitrification, extraction of various macro- and micronutrients from the feed leftovers and feces, etc. However, in aquaponics there are not only beneficial, but also potentially hazardous microorganisms of fish, human, and plant origin. It is important to establish the presence of human pathogens, their way of entering the aforementioned systems, and their control in order to assess the risk to human health when consuming plants and fish grown in aquaponics. Literature analysis shows that aquaponic bacteria and yeasts are mainly pathogenic to fish and humans but rarely to plants, while most of the molds are pathogenic to humans, plants, and fish. Since the various human pathogenic bacteria and fungi found in aquaponics enter the water when proper hygiene practices are not applied and followed, if these requirements are met, aquaponic systems are a good choice for growing healthy fish and plants safe for human consumption. However, many of the aquaponic pathogens are listed in the WHO list of drug-resistant bacteria for which new antibiotics are urgently needed, making disease control by antibiotics a real challenge. Because pathogen control by conventional physical methods, chemical methods, and antibiotic treatment is potentially harmful to humans, fish, plants, and beneficial microorganisms, a biological control with antagonistic microorganisms, phytotherapy, bacteriophage therapy, and nanomedicine are potential alternatives to these methods.

Aquaponics, defined as a sustainable technology combining aquaculture and hydroponics, integrates plant and fish production into one system. Aquaponics technology offers several major advantages over conventional methods of raising fish and/or plants. In this system, plants act as a natural biological filter, purifying the water so that the same amount can be used repeatedly. Fish, on the other hand, are a natural source of nutrients. This contributes to the aquaponics system’s substantial economic potential, thanks to its use of virtually free nutrients, dramatically reduced water consumption, and the elimination of filter systems, making this system innovative and sustainable. On the other hand, the use of medicinal plants for the needs of the pharmaceutical, cosmetics, and food industries is often associated with a decrease in their natural reserves. Utilizing aquaponics for the production of medicinal plants could reduce the pressure on these natural reserves. As a result, aquaponics has emerged as one of the most environmentally friendly methods of cultivating plant species. The concept of aquaponics, which evolved from traditional hydroponic systems, has gained worldwide recognition through the effective use of symbiosis. It refers to the coexistence and interaction of different organisms, facilitating their growth and life cycle processes. Unlike hydroponics, which requires the purification of nutrient solutions due to plant waste, aquaponics takes advantage of the natural cycle of waste and nutrient exchange between plants and fish. Fish waste serves as organic fertilizer for the plants, while the plants help purify the water for the fish. This symbiotic relationship not only reduces the environmental impact associated with aquaculture wastewater but also provides a sustainable method of food production. The integrated system reduces infrastructure costs, conserves water, and minimizes the potential for environmental pollution. Furthermore, it provides an opportunity for increased profitability from both crop and fish production. Cultivation of medicinal plants within aquaponic systems can be carried out year-round, offering a continuous supply of valuable pharmacological resources. This review examines suitable medicinal plants for aquaponic cultivation and evaluates their pharmacological benefits to humans.

The aim of this study was to determine the effect of the sweet flag (A. calamus L.) extract addition of growth performance, haematological (white blood cells, red blood cells, hemoglobin, hematocrit) and biochemical (glucose, urea, creatinine, total protein, albumin, ASAT, ALAT, Ca, P, Mg, triglycerides, cholesterol) blood parameters of common carp (Cyprinus carpio L.) cultivated in recirculation system. Carps were randomly selected and distributed into four concrete tanks for the growth trial (8 fish/tank). Fish were divided into experimental (E) and control groups (C), each of them with two replicates and mean initial weight 908.5±171.2 g and 913.8±147.4 g, respectively. They were fed with pelleted carp feed with 25% crude protein, produced by the "Top mix" company, having a granule size of 6 mm. To the fish feed on the experimental group (E) was added 1% aqueous extract of A. calamus root, as well as oiling the pellets with 5 mL of sunflower oil for every 100 g of feed. Carps from control group (C) were fed with feed only greased with the same amount of sunflower oil. The daily ration that the studied fish received was 1.8% of their live weight. The duration of the trial period was 45 days. At the end of the experiment with 5.2% was measured a higher average live weight in the fish receiving the sweet flag supplement compare to the value of this parameter of carps from control group, and the differences were statistically significant (P0.05). Better blood biochemical and haematological parameters were measured in carp fed with sweet flag supplement.

Aquafarms should reduce the use of fishmeal and fish oil in nutritional feed. One such accessible and relatively inexpensive food component that could successfully meet the challenge posed by aquaculture is algae. The objective of the present study was to evaluate the algae meal inclusion of Chlorella and Spirulina sp. in a diet for rainbow trout, evaluating its effects on fish growth, histological parameters and fillet quality. Experiments were carried out to replace 50% and 100% of fishmeal with Spirulina sp. and Chlorella vulgaris in feed for rainbow trout (Oncorhynchus mykiss W.) cultured in a recirculation system. At the end of the experimental period, the highest mean live weight was measured in rainbow trout fed a feed containing 50% algal meal in the feed. The absorptive vacuolization of cells was increased the most and lamina propria was average thickened when fed 50% algae diets. Fat droplets in the hepatocytes were larger in the 50% algae meal fed group, and their nuclei were replaced in the peripheral zone of the cells. Substitution of fishmeal with 50% algal meal in fish feed resulted in a 36.44% reduction in the lipid content of rainbow trout fillets compared to control fish.

One of the main challenges facing the development of aquaponics is disease control, due on one hand to the fact that plants cannot be treated with chemicals because they can lead to mortality in cultured fish. The aim of this study was to apply the visible–near-infrared spectroscopy and vegetation index approach to test aquaponically cultivated lettuce (Lactuca sativa L.) infected with different fungal pathogens (Aspergillus niger, Fusarium oxysporum, and Alternaria alternata). The lettuces on the third leaf formation were placed in tanks (with dimensions 1 m/0.50 m/0.35 m) filled up with water from the aquaponics system every second day. In this study, we included reference fungal strains Aspergillus niger NBIMCC 3252, Fusarium oxysporum NBIMCC 125, and Alternaria alternata NBIMCC 109. Diffuse reflectance spectra of the leaves of lettuce were measured directly on the plants using a USB4000 spectrometer in the 450–1100 nm wavelength range. In near-infrared spectral range, the reflectance values of infected leaves are lower than those of the control, which indicates that some changes in cell structures occurred as a result of the fungal infection. All three investigated pathogens had a statistically significant effect on leaf water content and water band index. Vegetative indices such as Chlorophyll Absorption in Reflectance Index (CARI), Modified chlorophyll absorption in reflectance index (MCARI), Plant Senescence Reflectance Index (PSRI), Red Edge Index (REI2), Red Edge Index (REI3), and Water band index (WBI) were found to be effective in distinguishing infected plants from healthy ones, with WBI demonstrating the greatest reliability.