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.

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>

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.