Microaerobic fermentation (MF) is a process of controlled degradation of organic waste material that occurs in enclosed fermentors under micro-aerobic conditions at near-room temperature. MF processing of vegetal materials progresses to endpoints in about 2-5 weeks. During MF processing, an acidic leachate rich in organic acids and alcohols is produced. The research presented in this thesis focuses on the efficiency of MF pre-processing of feedstock containing fibrous lignocellulosic (FLC) materials; efficiency of microbial and insect larvae-based treatments of MF leachate; tolerance of the Black Soldier fly larvae (BSFL) to various biological inhibitors common in leachate; and effectiveness of using MF and BSFL solid and liquid processing products as agricultural fertilizers. Results indicate that MF is unsuitable for pre-processing of FLC materials. Enhanced MF leachate treatment may increase efficiency of FLC processing though. Leachate can be efficiently treated using BSFL which decrease overall leachate toxicity. BSFL are able to tolerate increased levels of many of the biological inhibitors within the leachate including ethanol, acetate, pH extremes and temperature. MF solid residues increased corn plant growth when amended into soil, but residues resulting from BSFL processing of solid organics stunted corn plant growth. Short-term phytotoxicity of MF leachate was eliminated by diluting it 10 - 10,000 times or through BSFL processing. It can be concluded that MF processing of organics is beneficial for producing solid soil amendments from non-FLC materials and that dilution or BSFL treatment of MF leachate leads to a beneficial liquid fertilizer.

Food waste in the waste stream is becoming an important aspect of integrated waste management systems. Current efforts are composting and animal feeding. However, these food waste disposal practices rely on slow thermodynamic processes of composting or finding farmers with domestic animals capable of consuming the food wastes. Bioconversion, a potential alternative, is a waste management practice that converts food waste to insect larval biomass and organic residue. This project uses a native and common non-pest insect in Texas, the black soldier fly, which processes large quantities of food wastes, as well as animal wastes and sewage in its larval stage. The goal of this research is to facilitate the identification and development of the practical parameters of bioconversion methods at a large cafeteria. Three major factors were selected to evaluate the practicality of a bioconversion system: (1) the biological constraints on the species; (2) the economic costs and benefits for the local community; (3) the perception of and interaction between the public and management agencies with respect to the bioconversion process. Results indicate that bioconversion is feasible on all levels. Larvae tolerate and consume food waste as well as used cooking grease, reducing the overall waste volume by 30-70% in a series of experiments, with an average reduction of 50%. The economical benefits are reduced collection costs and profit from the sale of pupae as a feedstuff, which could amount to as much as $1,200 per month under optimal conditions. Social acceptance is possible, but requires education of the public, specifically targeting school children. Potential impediments to social acceptance include historical attitudes and ignorance, which could be overcome through effective educational efforts.

Black Soldier Fly Larvae (BSFL) composting is a treatment procedure that generates two products: frass compost and BSFL. These products have different uses. BSFL can be used as animal feed and frass compost as soil fertiliser, and they need to be separated after the composting procedure has been finished. A separator of the vibrating sieve type, currently in use by a research group at SLU for separating BSFL from the frass compost generated by the composting process, was tested and evaluated in terms of fraction purity and separation time. It was found that the fraction purity was over 90% for the BSFL fraction, and that the separation time was approximately 1-1.5 minutes for 4 kg of material. Hotspots for improvement were identified and a new vibrating sieve was designed and built with the aim of providing flexibility for improving fraction purity, separation time and operator ergonomy for the end-customer. A CAD model of the new vibrating sieve was designed in SolidWorks with a complete set of technical drawings and purchasing components. These drawings were sent out for manufacturing at a workshop and the new vibrating sieve was built and tested. The new vibrating sieve was functioning properly, but its optimal mechanical settings need further research and testing. This separator design could be emulated by others, and also improved, and this research could be used for improving the process outcome for future BSFL separation processes.

<p dir="ltr">For this dissertation, two experiments were conducted to evaluate the effects of a multienzyme mix and partially defatted black soldier fly larvae meal on chicken coccidiosis, focusing on growth performance, intestinal health, and microbiota dynamics. Experiment 1 examined the growth performance, nutrient utilization, microbiota modulations, and other gut health-related indicators of broiler chickens under coccidia challenge, with dietary supplementation of multienzyme, including phytase, xylanase, β-glucanase, amylase, hemicellulase, and pectinase. Ross 308 broilers were assigned to 4 treatments in a 2×2 factorial arrangement comprising of 0 or 50 g·kg-1 multienzyme and oral challenge with PBS or mixed Eimeria spp. oocysts (250,000 E. acervulina, 50,000 E. maxima, and 50,000 E. tenella). Multienzyme reduced (P < 0.05) Eimeria-induced loss in feed efficiency and nutrient utilization, partially explained by reduced decrease of b0,+ amino acid transporter in jejunum. Multienzyme suppressed (P < 0.05) the overexpression of interleukin-8 in the duodenum and jejunum and ameliorated (P = 0.05) the decreased expression of antioxidant heme oxygenase 1 in ileum induced by Eimeria infections. Multienzyme facilitated (P < 0.01) the bloom of short-chain fatty acid-producing and fiber-degrading microbes. The study concluded that multienzyme supplementation partially alleviated the adverse effects of Eimeria infections through various mechanisms, including enhanced nutrient utilization, reduced local inflammations, and restoration of microbial homeostasis. Experiment 2 investigated the growth dynamics, nutrient assimilation, and gut health responses of broiler chickens under coccidia challenge, with dietary supplementation of partially defatted black soldier fly larvae meal (pBSFLM) with increasing concentrations of 0, 60, 120 g/kg. During the infection phase (from d 13 to 19), interactions between Eimeria and pBSFLM revealed significant associations with gain to feed ratio (G:F) (P < 0.05) and cecal interferon-γ (IFN-γ, P < 0.05), while showing tendencies for crypt depth (P = 0.088) and cecal acetate concentration (P = 0.06). The incremental inclusion of pBSFLM demonstrated a negative effect on the G:F and the generation of IFN-γ and acetate in the ceca during coccidia challenge. Conversely in the non-challenged birds, the impact of dietary pBSFLM varied from neutral (e.g. G:F) to potentially advantageous (e.g. acetate). Challenged broilers exhibited decreased (P < 0.01) BW, feed intake (FI), G:F, as well as the apparent ileal digestibility (AID) and total tract nutrient utilization (ATTU) of DM, gross energy (GE), and nitrogen (N). Eimeria challenge led to reduced (P < 0.01) serum carotenoid concentrations, increased (P < 0.01) ileal crypt depth (CD), and an increase in the generation of branched-chain fatty acids, specifically isobutyrate (P = 0.059) and isovalerate (P < 0.05) in the ceca. Dietary pBSFLM addition caused a linear reduction (P < 0.05) in BW, FI, G:F, and N utilization. Furthermore, a tendency (P < 0.06) was observed where pBSFLM linearly decreased the villi height: CD ratio and reduced goblet cell density in the villi. Results from this experiment reveal that higher levels of pBSFLM supplementation, especially at 12%, had detrimental effects on growth, ileal morphology, cecal acetate production, and downregulated the expression of key cytokines in response to coccidia infection. In summary, these studies shed light on the multifaceted effects of dietary interventions on Eimeria infections in broiler chickens, with a specific emphasis on growth, nutrient utilization, and indicators of gut health.</p>

Haematophagous parasites and disease vectors such as leeches, ticks, mites, lice, bed bugs, mosquitoes, and myiasis-causing fly larvae are common health problems in Lao Peoples Democratic Republic (Lao PDR). A main aim of my field work in Lao PDR in 2006-2010 was to document traditional knowledge among different ethnic groups about plants that people use to repel or to kill blood-feeding invertebrates. We carried out structured interviews in 66 villages comprising 17 ethnic groups, covering a range of ethnic group, throughout Lao PDR and recorded a total of 92 plant species - in 123 different plant-ectoparasite combinations - that are used as traditional repellents and/or as “pesticides” to kill "pest" invertebrates. Traditional use was confirmed in the scientific literature for 74 of these plant species, and for an additional 13 species based on literature on closely related species. We concluded that repellents and pesticides from many plant species are commonly used in the Lao countryside. We also investigated traditionally used Lao plants for their activity to repel or to kill certain disease vectors and parasites. Target organisms were mosquitoes (Diptera, Culicidae), fly larvae (Diptera, Cyclorrhapha) in fermented fish production, and terrestrial blood-sucking leeches (Hirudinea, Haemadipsidae). The potential mosquito repellent activities of essential oils of Croton roxburghii (Euphorbiaceae), Hyptis suaveolens (Lamiaceae), and Litsea cubeba (Lauraceae) were evaluated in the field near Vientiane. Oils at concentrations of 1.7-6.7 µg/cm2 were significantly repellent to Aedes, Armigeres and Culex attracted to human baits. The activities against fly larvae, infesting fermenting fish, of three plant species, Tadehagi triquetrum (Fabaceae), Uraria crinita (Fabaceae) and Bambusa multiplex (Poaceae) were investigated: When fresh material of the plants was added on top of fermenting fish infested with fly larvae significant proportions of the larvae were repelled or killed. The total protective effect, i.e., repellent and killing effect combined, of T. triquetrum, U. crinita, and B. multiplex was 60-83 %, 77-90 %, and 60-93 %, respectively. Field evaluation of the potential leech repellent activities of water extracts of Sapindus rarak (Sapindaceae), Catunaregam spathulifolia (Rubiaceae) and Vernonia elaeagnifolia, (Asteraceae) impregnated on stockings and worn by persons in two leech-infested biotopes revealed leech repellent activities of 82.6%, 62.6% and 63.0%, respectively. The corresponding repellencies of deltamethrin and diethyl-3-methyl-benzamide (DEET) were 73.1% and 88.4%, respectively. Identification of the active components in certain of the plants with the ultimate aim to develop more optimal, less costly repellents, insecticides, acaricides, and anti-leech compounds as alternatives to synthetic repellents and pesticides against blood-feeding insects, ticks, mites, and leeches is in progress.

Genom fluglarvskompostering erhålls biomassa från organiskt avfall samt en näringsrik behandlingsrest som kan användas som gödningsmedel eller för biogasutvinning. Larvbiomassan kan användas som djurfoder eller för att tillverka biodiesel. Eskilstuna Strängnäs Energi och Miljö AB planerar bygga en pilotanläggning för fluglarvskompostering med larver av den amerikanska vapenflugan (Hermetia illucens). Behandlingen ska ske i lådor staplade på varandra, avskilda med ett mellanrum för att tillåta luftning av materialet. Luftningsbehovet utgörs av larvernas syrebehov samt av att transportera bort fukt och värme från materialet. Syftet med det här projektet var att utvärdera luftningsbehovet under fluglarvskomposteringsbehandling av matavfall med staplade behandlingslådor. Först designades ett experimentskåp att utföra experimenten i och därefter ett ventilationssystem till skåpet. Två experiment utfördes där tre staplar med nio behandlingslådor vardera utvärderades. I experiment I användes totalt 15 kg matavfall och 15 000 larver per behandlingslåda, i experiment II användes 11 kg matavfall och 10 000 larver per behandlingslåda. Under experimenten togs prover för torrsubstans (TS) och glödförlust (VS), pH samt tillväxt av larverna. Sensorer mätte lufttemperatur, relativ luftfuktighet och materialtemperatur. I båda experimenten erhölls en behandlingsrest med betydligt lägre TS-halt än önskat, vilket troligtvis berodde på att luftflödet i experimentskåpet var lägre än beräknat. I experiment I evaporerade i genomsnitt 6,2 kg vatten per behandlingslåda och i experiment II 4,8 kg, vilket för båda experimenten motsvarade cirka 50 % av det med matavfallet tillsatta vattnet. Enligt resultaten av experimenten kan torrsubstansen av matavfallet reduceras med runt 60 %. Runt 32 % av torrsubstansen i matavfallet omvandlades till larvbiomassa. Materialtemperaturen var i genomsnitt 27–30 °C under experimenten. Lufttemperaturen i experimentskåpet var 27–28 °C och 31 °C i inluften. Den relativa luftfuktigheten i experimentskåpet var 59–67 % och 36 % i inluften. Baserat på resultaten krävs ett luftflöde på 8,4 m3/h per behandlingslåda för att nå en TS på 50 % i behandlingsresten om matavfallet har en TS-halt på 15 %. Baserat på resultaten är ett nedåtriktat luftflöde att föredra framför uppåtriktat i de fall ett vertikalt luftflöde används. Skillnader i temperaturer och luftfuktighet indikerade dock att det vertikala, nedåtriktade, luftflödet inte kunde förse alla behandlingslådor i staplarna med samma luftflöde. På grund av detta kan det vara lämpligt att överväga ett horisontellt luftflöde i containern i vilken behandlingen ska ske. Vidare kan det vara fördelaktigt att reglera vattenhalten i matavfallet så att stora variationer i luftningsbehov undviks eller reglera luftflödet efter vattenhalt i ingående matavfall. Inför val av ventilationsdesign rekommenderas fortsatta studier av hur höga luftflöden påverkar behandlingen. / Larvae of the Black Soldier Fly (Hermetia illucens) can convert organic waste into biomass. The residue is nutrient-rich and can be used as fertilizer or for biogas production. The aim of this study was to assess the aeration need for designing a ventilation system in a pilot plant for larvae composting in Sweden. First, a cabinet with required ventilation arrangement for performing the experiments was designed. Two experiments were performed, where three stacks each comprised of nine boxes with spacers were used. In the first experiment, a total of 15 kg of municipal food waste and 15 000 larvae were used per box. In the second experiment, a total of 11 kg food waste and 10 000 larvae were used per box. In the first experiment 6.2 kg of water evaporated per treatment box and in the second 4.8 kg, both corresponding to about 50 % of the water present in the substrate added. An average temperature of 31 °C in the inlet air resulted in temperatures of 27-30 °C in the material during the treatment. Based on the results, 8.4 m3/h of air is needed per treatment box to reach 50 % dry matter in the residue of food waste containing 15 % dry matter. The results also indicate that to reach the desired water content in the residue, there might be a need to adjust the initial water content in the food waste and use horizontal airflow in the treatment container. Before deciding on a ventilation design, further studies are necessary to assess how high airflows affect the treatment.

Förenta nationerna förutser en global befolkningsökning med 2 miljarder människor till 2050, vilket motsvara en total befolkningsmängd på nära 10 miljarder människor. Dessutom förväntas ökningen ske oproportionerligt över jorden och koncentreras i delar av världen där livsmedelssäkerheten är låg och produktionen otillräcklig. FN:s livsmedels- och jordbruksorganisation (FAO) uppskattar att det kommer krävas en produktionsökning med 70% för att möta livsmedelsbehovet för den globala populationen. Att odla fisk som alternativ till konventionellt fiske är en möjlighet att möta den ökande efterfrågan på animaliskt protein då de naturliga fiskbestånden minskar. Akvaponiska odling är ett kombinerat odlingssystem av hydroponisk odling och vattenbruk som möjliggör minskade risker kopplade till övergödning och smitning. Dock är fiskodlingarnas konsumtion av foderfisk problematisk. Insekter är ett av många foderalternativ som ofta nämns som en klimatsmart lösning då insekter är platseffektiva att odla och har en hög förmåga att omvandla biomassa till högvärdigt protein. En art som fått extra mycket uppmärksamhet inom detta område är den amerikanska vapenflugan (Hermetia illucens). Syftet med denna studie var att undersöka om implementeringen av ett insektsbaserat fiskfoder med vapenflugelarver kan sänka klimat- och miljöpåverkan från en fiskodling jämfört med att använda ett konventionellt fiskfoder baserat på ingredienser från vildfångad havsfisk. Detta har gjorts genom utförandet av en litteraturstudie av det konventionella fiskfodret och en livscykelanalys av larvproduktionens påverkan inom dessa fyra miljöpåverkansindikatorer: total energianvändning, klimatpåverkan (GWP), foderfiskkonsumtion (FIFO) och försurning. Resultatet av studien visade att det framförallt är lokalen för produktionen som konsumerar energi för uppvärmning, ventilation och belysning. Utöver detta visade sig bearbetning av larverna (torkning) vara en energiintensiv process. Från klimatperspektiv är det själva komposteringsprocessen som förorsakar de största enskilda utsläppen av växthusgaser. Resultatet visar vidare att produktionen av den amerikanska fluglarven presterar bättre för de studerade faktorerna än det konventionella fiskfodret och att den således har potential som foderkomponent. Fallstudien visar att den undersökta akvaponianläggningen kan minska sin påverkan inom samtliga effektkategorier jämfört med ett nyttjande av konventionellt foder. Dock är studiens utfall beroende av vilka förutsättningar som finns gällande produktionens geografiska placering och således vilken elmix som nyttjas samt vilken tillgången är på lämpliga substrat såsom matsvinn. / The United Nations foresees a global population increase of 2 billion people by 2050, corresponding to a total population of nearly 10 billion people. In addition, the increase is expected to be disproportionate over the earth and concentrated to parts of the world where food safety is low and production insufficient. The Food and agriculture organization of the United Nations (FAO) estimates that a production increase of 70% will be required to meet the food needs of the global population. Growing fish as an alternative to conventional fishing is an opportunity to meet the increasing demand for animal protein as the natural fish stocks decrease. Aquaponics is a combined cultivation system of hydroponic cultivation and aquaculture that reduces risks associated with eutrophication, invasive species and diffusion of antibiotics and chemicals. However, the consumption of feed fish is problematic in in both traditional aquaculture and in aquaponic cultivation. Insects are one of many feed alternatives that are often referred to as a climate-smart solution since they are effective to grow from a land use perspective and have a high ability to convert biomass into high-quality protein. One species that has received extra attention in this area is the black soldier fly (Hermetia illucens). The purpose of this study has been to investigate whether the implementation of an insect-based fish feed with black soldier fly larvae can reduce the environmental impacts of an aquaponic cultivation farm compared to using conventional fish feed based on ingredients from wild-caught sea fish. This has been done by carrying out a literature study of the conventional fish feed and a life cycle analysis of the influence of larva production within these four environmental impact indicators: total energy use, climate impact (GWP), feed fish consumption (FIFO) and acidification. The results of this study showed that the main energy use for the production of larvae is energy for heating, ventilation and lighting of the production location. In addition, the processing of the larvae (drying) was showed to be an energy intensive process as well. From a climate perspective, it is the composting process carried out by the larvae that causes the largest individual emissions of greenhouse gases. The result also shows that the production of the black soldier fly larvae performs better within the four environmental impact indicators than the conventional fish feed and thus it has the potential as a more sustainable feed component. The case study shows that the analyzed aquaponic farm can reduce its impact in all studied impact categories compared to using conventional feed. However, the study's outcome depends on the current circumstances regarding geographical location of the production, the electricity mix used as well as the availability suitable substrates such as food waste.

About one third of all edible food is wasted globally each year. This calls for improvements in resource and waste management. An interesting solution for organic waste is fly larvae composting, which both produces protein in the form of larvae and a nutrient rich residue. The larvae can be used as animal feed while the residue can be applied as an organic fertilizer, thus recycling the nutrients. Fly larvae composting with the black soldier fly (BSF), Hermetia illucens, is relatively new, but there is extensive research on how the treatment is affected by different parameters, e.g. temperature, moisture and type of organic waste that is treated. The role of bacteria has only been the topic of a few studies in recent years but has shown promising positive effects on larval growth. This study investigated the impact of bacteria isolated from BSF eggs on fly larvae composting of food waste by BSF larvae. The study was done in two experimental phases. In phase I, groups of three bacteria were added to each treatment together with the larvae and only single treatments were executed; in phase II triplicates of promising groups of three, two or single bacteria were evaluated. The results of phase I suggested that selected groupings of bacteria could either decrease or increase the bioconversion ratio and in general decrease the reduction ratio of the food waste, while the survival ratio did not seem to be impacted. However, in phase II no significant difference (p&lt;0.05) between the treatments with bacteria and the control were found for any evaluated variables. Interestingly, the variation in resulting bioconversion ratio and reduction ratio (on a VS basis) was found to be reduced when one or more bacteria were present. The coefficient of variation in bioconversion ratio was 9.5% for the control compared to between 2.5% and 6.1% for treatments with bacteria. For the reduction ratio the variation was reduced from 5.6% and to between 0.9% and 4.6% for the bacteria treatments. Hence, seeding with bacteria may improve stability of the process, which is especially interesting when scaling up the process. / Globalt slängs ungefär en tredjedel av all ätbar mat. Därmed finns ett stort behov av säker och hållbar avfallshantering. En intressant lösning för organiskt avfall är fluglarvskompostering, som både producerar protein i form av larver och en näringsrik behandlingsrest. Larverna kan exempelvis användas som djurfoder medan behandlings-resten kan användas som gödselmedel, vilket innebär att näring kan återvinnas. Fluglarvskompostering med amerikansk vapenfluga (BSF), Hermetia illucens, är en relativt ny teknik men det finns redan omfattande forskning på hur olika processparametrar, t.ex. temperatur och vattenhalt, påverkar processen. Bakteriers roll har studerats endast i ett fåtal studier men de indikerar att tillsats av bakterier kan ha en positiv inverkan på larvernas tillväxt. Den här studien har därför undersökt hur tillsats av bakterier isolerade från BSF ägg påverkar fluglarvskompostering av matavfall med BSF larver. Studien gjordes i två experimentella delar. I fas I undersöktes effekten av tillsats av bakteriegrupper om tre bakterier till matavfallet samtidigt med larverna; i fas II utfördes triplikat av lovande bakteriegrupper med tre, två eller enstaka bakterier. Resultaten från fas I indikerade att olika bakteriegrupper antingen kunde höja eller sänka bioomvandlingskvoten och generellt gav en minskning i materialreduktions-kvoten medan överlevnadsgraden inte verkade påverkas i samma utsträckning. I fas II observerades däremot ingen signifikant skillnad (p&lt;0,05) mellan någon av bakteriebehandlingarna och kontrollen för samtliga processvariabler. Variationen i resulterande bioomvandlingskvot och materialreduktionskvot (på VS basis) var dock lägre för bakteriebehandlingarna jämfört med kontrollen. Variationen i bioomvandlings-kvot var 9,5% för kontrollen jämfört med 2,5-6,1% för bakteriebehandlingarna. För materialreduktionskvoten minskade variationen från 5,6% till mellan 0,9% och 4,6%. Detta tyder på att tillsats av bakterier kan förbättra stabiliteten hos fluglarvskompostering, vilket är särskilt intressant vid uppskalning av processen.

Durch die Nutzung des fischfutterbedingten Nährstoffeintrags für die kombinierte Produktion von Fischen und Pflanzen können Aquaponiksysteme eine nachhaltige Erweiterung von Kreislaufanlagen der Aquakultur (RAS) darstellen. Herkömmliche Aquakulturfutter zielen jedoch auf Fischproduktion mit geringer Umweltbelastung ab und sind somit nicht für die Aquaponik optimiert. Daher weist RAS-Wasser häufig Mängel im Profil gelöster anorganischer Pflanzennährstoffe auf. So war es Ziel dieser Arbeit, die Auswirkungen unterschiedlicher Proteinquellen auf die Nährstoffdynamik in RAS durch Fütterungsversuche mit Afrikanischem Raubwels und Nil-Tilapia zu untersuchen, bei denen Wachstum, gelöste anorganische Nährstoffkonzentrationen im RAS-Wasser und die Ausscheidung von Nährstoffen über den Kot verfolgt wurden. Der Fokus lag auf nachhaltigen alternativen Proteinquellen zu marinem Fischmehl und terrestrischen Pflanzenproteinen: Larvenmehl der Schwarzen Soldatenfliege (BSFM), Welsschlachtabfallmehl (CM), Geflügelschlachtabfallmehl (PM) und Geflügelblutmehl (PBM). Experimentalfutter, die phosphorreiches PM und CM enthielten, förderten erhöhte Ausscheidung von löslichem reaktivem Phosphor, erzeugten die besten gelösten N:P-Verhältnisse im RAS-Wasser verglichen mit einer Hydroponik-Nährlösung und ermöglichten in Kombination mit PBM besseres Wachstum beim Wels als ein vergleichbares kommerzielles Futter. In Futtern basierend auf einer einzigen Proteinquelle führte PM bei Wels und insbesondere bei Tilapia zu ähnlichem Wachstum verglichen mit marinem Fischmehl, wohingegen BSFM und PBM bei beiden Arten Wachstumsleistung beeinträchtigte. Meta-Analysen aller Versuche legen nahe, dass höherer Phosphor-, Kalium- und Magnesiumgehalt im Futter erhöhte Ausscheidung dieser Elemente in gelöster Form bedingt, was sie zu Zielnährstoffen in Aquaponikfuttern macht, während die Optimierung des Protein zu Energie-Verhältnisses im Futter die gelösten N:P- und N:K-Verhältnisse im RAS-Wasser verbessern kann. / By using the nutrient input from fish feeds for the combined production of fish and plants, aquaponic systems can be a sustainable extension of recirculating aquaculture systems (RAS). However, conventional aquaculture feeds are optimized for fish production and reduced environmental impact rather than aquaponics. Hence, RAS water is often characterized by deficiencies regarding its dissolved inorganic plant nutrient profile. Therefore, this thesis aimed to explore the effect of purposeful dietary protein choice on nutrient dynamics in RAS through four systematic feeding trials involving African catfish and Nile tilapia in which growth performance, dissolved inorganic nutrient concentrations in RAS water and solid fecal nutrient excretion were tracked. Focus was on sustainable alternative protein sources to marine fish meal and terrestrial plant proteins: black soldier fly larvae meal (BSFM), catfish by-product meal (CM), poultry by-product meal (PM) and poultry blood meal (PBM). Experimental diets including phosphorus-rich PM and CM supported increased excretion of soluble reactive phosphorus, produced the most favorable dissolved N:P ratios in RAS water when compared to a renowned hydroponic nutrient solution, and, combined with PBM, enabled better growth performance in African catfish than a comparable commercial diet. In single protein source diets, PM produced similar growth performance in African catfish and particularly Nile tilapia versus marine fish meal, whereas BSFM and PBM impaired growth performance in both species. Meta-analyses covering all trials suggest that higher dietary phosphorus, potassium and magnesium content leads to their increased excretion in dissolved form, making them target nutrients for aquaponic feed formulation, while the optimization of the dietary protein to energy ratio can further improve dissolved N:P and N:K ratios in RAS water.