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NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.

2022

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One part of aquaculture sustainability is reducing the environmental footprint of aquaculture feeds. For European aquaculture, this means finding feed ingredients that are produced within the economic community, and that are not in conflict with human consumption. This is especially challenging when formulating diets for carnivorous fish such as turbot with low tolerance to fishmeal replacement that are both nutritious and economically and environmentally sustainable. Therefore, we investigated the effects of two novel and innovative feed formulation concepts on growth and feed performance and the nutritional status of market-sized turbot in a recirculating aquaculture system. In a 16-week feeding trial, 440 turbot (300 ± 9 g) were fed twice a day with a control diet (CTRL), based on a commercial formulation, and four experimental diets. The experimental diets were designed to investigate the effects of two formulations concepts based on sustainable terrestrial plant proteins (NoPAP) or processed animal proteins (PAP) and of 30% and 60% fishmeal replacement with emerging feed ingredients (fisheries by-products, insect meal and fermentation biomass). Turbot from the CTRL group had a similar growth and feed performance than fish fed the NoPAP30 formulation, with a significant decline of performance in the fish fed both PAP formulations and the NoPAP60. Comparing the two formulation concepts with each other the voluntary feed intake and protein efficiency ratio on tank basis as well as the individual weight gain and relative growth rate was significantly higher in the fish from the NoPAP groups than PAP groups. Furthermore, the apparent digestibility of nutrients and minerals was significantly reduced in the fish fed with the diets with 30% and 60% fishmeal replacement level compared to the fish from the CTRL group. In conclusion, the performance of the fish fed the NoPAP30 formulation concept highlights the potential of the used combination of sustainable ingredients, such as fisheries by-products, insect meal, microbial biomass and plant protein for turbot. Furthermore, this study shows that turbot has a higher tolerance to the incorporation of plant and insect protein than of processed animal protein.

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Two Life-Cycle Assessments (LCAs) were conducted to evaluate the environmental performances of selected novel eco-intensification innovations for the treatment and valorisation of sludge and fish mortalities from finfish aquaculture. The first innovation is based on a new process for filtering and drying particles from the reject water from a Recirculating Aquaculture System (RAS), with end-of-life recovery of nutrients and biomass to be reused as organic fertiliser or as energy source. The second process is based on a new device for drying fish mortalities and reusing the end-product as ingredient in the pet food industry or as energy source. Innovations refer to a functional unit of 1 ton of farmed fish and of fish mortalities, respectively, and were tested with a RAS for smolt production within the physical system boundary of a Norwegian facility. A set of standard indicators was selected for the Life-Cycle Impact Assessment (LCIA). The results indicate that the new processes compare well with the established ones, showing a marked decrease in most impact categories: indicators decrease by −12% through to −67% when sludge treatment innovations are applied, and by more than −86% after novel changes about fish mortality, with water consumption instead increasing by +7% and up to +50%, respectively. Furthermore, the analysis provided insights which could lead to improve their environmental performances.

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In Europe, turbot aquaculture has a high potential for sustainable production, but the low tolerance to fishmeal replacement in the diet represents a big issue. Therefore, this study investigated the effects of more sustainable feed formulations on growth and feed performance, as well as nutritional status of juvenile turbot in recirculating aquaculture systems. In a 16-week feeding trial with 20 g juvenile turbot, one control diet containing traditional fishmeal, fish oil and soy products and two experimental diets where 20% of the fishmeal was replaced either with processed animal proteins (PAP) or with terrestrial plant proteins (PLANT) were tested. Irrespective of diets, growth performance was similar between groups, whereas the feed performance was significantly reduced in fish of the PAP group compared to the control. Comparing growth, feed utilisation and biochemical parameters, the results indicate that the fish fed on PAP diet had the lowest performance. Fish fed the PLANT diet had similar feed utilisation compared to the control, whereas parameters of the nutritional status, such as condition factor, hepato-somatic index and glycogen content showed reduced levels after 16 weeks. These effects in biochemical parameters are within the physiological range and therefore not the cause of negative performance. Since growth was unaffected, the lower feed performance of fish that were fed the PAP formulation might be balanced by the cost efficient formulation in comparison to the commercial and the PLANT formulations. Present study highlights the suitability of alternative food formulation for farmed fish.

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Chitin is one of the most diverse and naturally occurring biopolymers, and it is mainly present in crustaceans, insects, and fungi. Chitosan is derived from chitin by deacetylation process. It is important to note that the conventional chemical method of extracting chitin includes disadvantages and it poses various environmental issues. Recently, the green extraction techniques have perceived substantial development in the field of polymer chemistry. A variety of methods have been successfully developed using green extraction techniques for extracting chitin and chitosan from various resources. It includes the use of ionic liquids (ILs), deep eutectic solvents (DES), microbial fermentation, enzyme-assisted extraction (EAE), microwave-assisted extraction (MAE), ultrasonic-assisted extraction (UAE), subcritical water extraction (SWE), and electrochemical extraction (ECE). In this review, the extraction of chitin and chitosan using greener approaches were summarized. In addition, challenges, opportunities and future perspectives of green extraction methods have also been narrated.

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Aquaculture industry is one of the major food-producing sectors in the world that provide nutritional food security for mankind. Fish and crustacean farmers are facing various challenges in treating the rapid spread of infectious diseases in recent times. Numerous strategies, including antibiotics, disinfectants, and other antimicrobial agents, have been applied to protect the cultivable aquatic animals from infectious diseases. These applications lead to the development of antimicrobial resistance, toxicity, and the accumulation of antibiotic residues in cells and organelles of the cultivable edible organisms and the environment. The use of naturally derived compounds, polysaccharides, and functional metabolites has gained immense attention among aquaculturists. Mushrooms and their nutraceutical components have been widely used in various sectors, including food, pharmaceutical, poultry, and aquaculture industries, for their non-toxic and eco-friendly properties. To date, there are several reports available on edible and medicinal mushrooms as a dietary ingredient for fish and decapod crustacean culture. The mushroom products such as mycelia, stalk, dry powder, polysaccharides, and extracts have been utilized in aquaculture as growth promoters and immunostimulants, improving the digestive enzyme activity, antimicrobials, and improving the health status of cultivable aquatic animals. This present review elucidates the effectiveness of mushrooms and mushroom-derived compounds as prebiotics in aquaculture. The challenges and future perspectives of mushroom-derived bioactive molecules have been discussed in this review.

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Aquaculture industry is one of the world’s fastest and largest growing food producing sector. Most importantly, the usage of fish meal in aquaculture has been replaced with alternate protein sources due to their production cost, demand of raw materials and various environmental issues. The insect black soldier fly (Hermetia illucens) larval (BSFL) meal is being recognized as a feed ingredient in aquafeeds for their protein rich content similar to fish meal (FM). BSFL meal has been utilized as a fish meal or soy meal substitution in aquaculture to improve the nutrition. The culture of H. illucens larvae can be achieved using various biodegradable wastes and converted into a valuable biomass. In addition, the proximate analysis of H. illucens has been analyzed for its multifaceted role in poultry, cattle feed preparation and human consumption. The effectiveness of BSFL diet was analyzed for final body weight (FBW), specific growth rate (SGR), feed conversion ratio (FCR), feed intake (FI), feed efficiency (FE) and survival (SUR) of different fish and shrimp used as an experimental models with FM as the control diet. However, there is no comprehensive review available on the BSFL as an alternate protein source in aquaculture till date. Hence, the present review aimed to evaluate the feasible role of BSFL in feed, its sustainable production and challenges of BSFL meal in aquaculture sector along with their merits and demerits.

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Phototrophic microalgae use light to produce biomass and high-value compounds, such as pigments and polyunsaturated fatty acids (PUFA), for food and feed. These biomolecules can be induced by flashing light during the final growth stage. We tested different exposure times (1–6 days) of flashing light (f = 0.5, 5, 50 Hz; duty cycle = 0.05) on biomass, pigment and fatty acid productivity in Diacronema lutheri and Tetraselmis striata. A three-day exposure to low-frequency (5 Hz) flashing light successfully increased the production of fucoxanthin, diatoxanthin, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids in D. lutheri up to 4.6-fold and of lutein, zeaxanthin and EPA in T. striata up to 1.3-fold compared to that of continuous light. Biomass productivity declined 2-fold for D. lutheri and remained similar for T. striata compared to that of continuous light. Thus, short-term treatments of flashing light may be promising for industrial algal production to increase biomass value.

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Seaweed is considered a potentially sustainable source of protein for human consumption, and rapid, accurate methods for determining seaweed protein contents are needed. Seaweeds contain substances which interfere with common protein estimation methods however. The present study compares the Lowry and BCA protein assays and protein determination by N-ratios to more novel spectroscopic methods. Linear regression of the height or the integrated area under the Amide II band of diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used to predict seaweed protein with good prediction performance. Partial least squares regression (PLSR) was performed on both DRIFTS and near-infrared (NIR) spectra, with even higher prediction accuracy. Spectroscopy performed similar to or better than the calculated N-ratio of 4.14 for protein prediction. These spectral prediction methods require minimal sample preparation and chemical use, and are easy to perform, making them environmentally sustainable and economically viable for rapid estimation of seaweed protein.

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The large brown seaweeds (kelps) are potential sources of protein for animal feed. They have lower protein contents than most red and green algae, but due to potential for large-scale production, they may represent a significant future protein source. The impact of pH, temperature and polysaccharide-degrading enzymes on the solubility and extraction yields of protein from wet Saccharina latissima biomass was investigated. The protein solubility increased with increasing pH and reached maximum of 23% at pH 11, determined as total amino acids (TAA). The enzyme treatments increased the release of soluble compounds by 30–35%. The highest protein yield obtained was 19%, using a ratio of water to wet seaweed of 1:1 for extraction. Even if the yields can be increased by increasing the water amounts used for extraction, the majority of the protein would remain in the insoluble residue after separation. The strategy for production of a larger quantity of protein-enriched biomass was therefore to maintain the insoluble fraction as the product. A pilot scale production was carried out, also including the red algae Palmaria palmata. In total 750 kg S. latissima and 195 kg P. palmata were processed. The protein content in the product increased from 10 to 20% of dry weight (dw) for S. latissima and from 12 to 28% for P. palmata, with yields of 79 and 69%, respectively. The ash content was reduced from 44 to 26% and from 12 to 5% of dw, respectively, for the two species. The main protein loss was free amino acids, which constituted approximately 10% of TAA in the feedstocks. Less essential than non-essential amino acids were lost, thus, the essential amino acids were enriched in the product.