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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2023

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Abstract

Chlorella vulgaris is a freshwater microalga that synthesises large amounts of saturated lipids, which makes it suitable for production of bioenergy and biofuels. Since its cultivation usually requires freshwater, it competes with agriculture, economic development and ecological conservation for this limited natural resource. This study investigated the possibility of the partial replacement of freshwater by seawater (50 %) in the growth medium for a more sustainable biomass and lipid production. Chlorella vulgaris 211-11b was cultivated as shake-flask cultures in Bold's Basal Medium (BBM) formulated with 50 % freshwater and 50 % seawater under photoautotrophic, mixotrophic and heterotrophic conditions for eight days with glucose as organic carbon source in the latter two cases. The alga's best growth performance and highest lipid contents (49 % DW−1), dominated by palmitioleic and oleic acid, occurred under mixotrophic rather than photoautotrophic and heterotrophic conditions. This study demonstrates a more economic and ecologically sustainable biomass and lipid production of C. vulgaris by saving 50 % freshwater, which is available for other purposes.

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Abstract

The Norwegian Scientific Committee for food an Environment (VKM) has assessed an application for authorisation of refined oilseed rape oil (Aquaterra®) derived from genetically modified oilseed rape line NS-B50027-4 for exclusive use as an ingredient in fish feed in Norway. NS-B50027-4 is also named DHA-canola. This report uses the term oilseed rape. NS-B50027-4 produces omega-3 long-chain (≥C20) polyunsaturated fatty acids (omega-3 LC-PUFAs) in its seeds, with a high level of docosahexaenoic acid (DHA) and a small amount of eicosapentaenoic acid (EPA) and docosapentaenoic acid (DPA). Aquaterra® also contains a significant level of alpha-Linolenic acid (ALA). Whereas ALA can be derived from plants, the primary producers of EPA and DHA are mainly marine microalgae. EPA and DHA are concentrated in the food chain to fish in the oceans and are often referred to as marine omega-3 fatty acids. NS-B50027-4 was developed as an alternative land-based source of marine fatty acids, mainly DHA. NS-B50027-4 was genetically modified to express seven transgenes derived from yeasts and marine microalgae that encode the enzymes necessary for the biosynthesis of omega-3 long chain polyunsaturated fatty acids. In addition, an eighth gene, pat, was inserted as a marker for selection purposes during development. The pat gene encodes the enzyme phosphinothricin N-acetyltransferase (PAT) conferring tolerance to glufosinate-ammonium herbicides. Equally to conventional refined oilseed rape oils any residues levels of proteins, including the introduced enzymes, will be negligible in the Aquaterra® oil. The risk assessment of Aquaterra® was conducted in accordance with the guidance for risk assessment of derived food and feed from genetically modified plants as described by the European Food Safety Authority (EFSA, 2011a). The risk assessment is based primarily on scientific documentation provided in the application EFSA-GMO-NL-2019-160, which seeks approval for NS-B50027-4 for all applicable food and feed uses in the European Union (EU). VKM concludes that the provided scientific documentation fulfills the criteria of the EFSA guidance and is adequate for risk assessment. VKM concludes that the molecular characterisation, comparative, nutritional, toxicological and allergenicity assessments of NS-B50027-4 do not indicate increased risks to animal or human health compared to its conventional counterpart (comparator) or commercial reference varieties. Based on this together with specific analyses of the seed oil fraction and studies, e.g., in fish, VKM therefore concludes that the refined oil Aquaterra®, is equal to conventional oils from oilseed rape except for the altered composition in fatty acids. VKM concludes there is no increased health risk to fish fed Aquaterra® in feed compared to conventional feeds with oils from other sources, nor is there an indication of increased risk to the environment. Since Aquaterra® is equal to conventional oils from oilseed rape except for the marine omega-3 fatty acids already present in fish feeds, VKM concludes there is no greater need for health or environmental monitoring of feeds containing Aquaterra® than conventional feeds.

Abstract

Since the world’s population is increasing, alternative food sources must be tapped. Although algae have a high potential to become a part of our diets due to their favorable nutritional properties, there is a little information on the willingness of consumers in Norway to try algae-made foods. In this paper we used a Norwegian survey to address this question. We constructed an order logistic regression model and predicted conditional probabilities to try algae food. The results show that among the most important aspect for willingness to try food with algae is age, health conscientiousness, and environmental attitudes.

2022

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Abstract

Phycoerythrin (PE) is a photosensitive red pigment from phycobiliprotein family predominantly present in the red algae. The concentration of PE depends on photon flux density (PFD) and the quality of light absorbed by the algae tissue. This necessitates robust techniques to extract PE from the embedded cell-wall matrix of the algal frond. Similarly, PE is sensitive to various factors which influence its stability and purity of PE. The PE is extracted from Red algae through different extraction techniques. This review explores an integrative approach of fractionating PE for the scaling-up process and commercialization. The mechanism for stabilizing PE pigment in food was critically evaluated for further retaining this pigment within the food system. The challenges and possibilities of employing efficient extraction for industrial adoption are meticulously estimated. The techniques involved in the sustainable way of extracting PE pigments improved at a laboratory scale in the past decade. Although, the complexity of industrial-scale biorefining was found to be a bottleneck. The extraction of PE using benign chemicals would be safe for food applications to promote health benefits. The precise selection of encapsulation technique with enhanced sensitivity and selectivity of the membrane would bring better stability of PE in the food matrix.

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Abstract

There is an increasing need in the aquaculture industry for more sustainable and functional feed concepts for marine finfish. This study provides results for the effect of alternative feed formulations on health status, welfare parameters, sensory analysis, and growth performance in European seabass (Dicentrarchus labrax) over an 83-day feeding trial. Fish were fed twice a day with five experimental diets. A control diet (control) and four different alternative feed concepts rich in processed animal proteins (PAP), other alternative ingredients (NOPAP), and a positive (NOPAP+) and negative (PAP−) formulation were tested. All alternative formulations contained hydrolysates from aquaculture by-products and macroalgae. The results indicate that the alternative feed concepts are more sustainable alternatives compared with the commercial diet. Equally interesting, the alternative formulations did not affect the sensory analysis of the fillet quality or the animal welfare. These are increasingly important factors in aquaculture products and, accordingly, also in the formulation of new feeds. Feed concepts that are not only more sustainable in their production, have shorter transportation distances, recycle the resources (usage of by-products), and have no adverse effect on growth or welfare parameters are highly needed. Therefore, the experimental diets tested in this study are a win-win concept for future seabass aquaculture production.

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Abstract

The hypothesis of the present study was that increased growth in spring, stimulated by increasing temperature and daylength, leads to oxidative stress in Atlantic salmon with accumulation of oxidation products in the tissues and increased utilization of antioxidants. The drop in fillet pigmentation and astaxanthin, often observed in spring by the industry, could be explained by oxidative stress. Furthermore, oxidative stress may cause production related diseases such as development of cataracts and melanin spots in the fillet. We sampled Atlantic salmon from two cages in a commercial scale experiment in Northern Norway (67°N), every month from April until August and then every second month until December (510 ± 160–3060 ± 510 g, mean weight ± std). The specific growth rate (SGR) increased with increasing temperature until midsummer and decreased thereafter. We found that vitamin E in the fillet and vitamin C in the liver were depleted in the spring and were restored in the autumn, even though the dietary concentrations were stable. Astaxanthin concentration in the muscle was constant during the spring and summer and increased in the autumn, concomitant with an increase in astaxanthin supplementation. Cataract increased from zero in May until July, when 90% of the fish were affected. The glutathione based redox-potential in the lenses became more reduced from June, indicating a protective mechanism against oxidative stress and cataract. The number of fish with melanin spots was high in June and decreased in August and October, but the size and intensity of the remaining spots increased in the same period. The change in vitamin C and E concentrations, cataract and glutathione metabolism during spring and early summer, indicate that the fish became oxidized in this period, while malon-di-aldehyde (MDA) and astaxanthin concentrations did not support the hypothesis. There are too few data to draw conclusions on possible effects of oxidative stress on melanin spots.

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Abstract

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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Abstract

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.