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Increasing dietary levels of the n-3 long-chain PUFA, EPA and DHA, improves the growth, welfare, robustness and fillet quality of Atlantic salmon in sea cages
Get PDFThe present study evaluated the effects of increasing the dietary levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in Atlantic salmon (Salmo salar) reared in sea cages, in terms of growth performance, welfare, robustness, and overall quality. Fish with an average starting weight of 275 g were fed one of four different diets containing 10, 13, 16, and 35 g/kg of EPA and DHA (designated as 1.0%, 1.3%, 1.6%, and 3.5% EPA and DHA) until they reached approximately 5 kg. The 3.5% EPA and DHA diet showed a significantly beneficial effect on growth performance and fillet quality compared with all other diets, particularly the 1% EPA and DHA diet. Fish fed the diet containing 3.5% EPA and DHA showed 400-600 g higher final weights, improved internal organ health scores and external welfare indicators, better fillet quality in terms of higher visual colour score and lower occurrence of dark spots, and higher EPA and DHA content in tissues at the end of the feeding trial. Moreover, fish fed the 3.5% EPA and DHA diet showed lower mortality during a naturally occurring cardiomyopathy syndrome outbreak, although this did not reach statistical significance. Altogether, our findings emphasise the importance of dietary EPA and DHA to maintain good growth, robustness, welfare, and fillet quality of Atlantic salmon reared in sea cages.Increasing dietary levels of the omega-3 long-chain polyunsaturated fatty acids, EPA and DHA, improves the growth, welfare, robustness, and fillet quality of Atlantic salmon in sea cagesacceptedVersionpublishedVersio
Whole-Genome Sequencing Analysis of Listeria monocytogenes from Rural, Urban, and Farm Environments in Norway: Genetic Diversity, Persistence, and Relation to Clinical and Food Isolates
Get PDFListeria monocytogenes is a ubiquitous environmental bacterium associated with a wide variety of natural and human-made environments, such as soil, vegetation, livestock, food processing environments, and urban areas. It is also among the deadliest foodborne pathogens, and knowledge about its presence and diversity in potential sources is crucial to effectively track and control it in the food chain. Isolation of L. monocytogenes from various rural and urban environments showed higher prevalence in agricultural and urban developments than in forest or mountain areas, and that detection was positively associated with rainfall. Whole-genome sequencing (WGS) was performed for the collected isolates and for L. monocytogenes from Norwegian dairy farms and slugs (218 isolates in total). The data were compared to available data sets from clinical and food-associated sources in Norway collected within the last decade. Multiple examples of clusters of isolates with 0 to 8 whole-genome multilocus sequence typing (wgMLST) allelic differences were collected over time in the same location, demonstrating persistence of L. monocytogenes in natural, urban, and farm environments. Furthermore, several clusters with 6 to 20 wgMLST allelic differences containing isolates collected across different locations, times, and habitats were identified, including nine clusters harboring clinical isolates. The most ubiquitous clones found in soil and other natural and animal ecosystems (CC91, CC11, and CC37) were distinct from clones predominating among both clinical (CC7, CC121, and CC1) and food (CC9, CC121, CC7, and CC8) isolates. The analyses indicated that ST91 was more prevalent in Norway than other countries and revealed a high proportion of the hypovirulent ST121 among Norwegian clinical cases.publishedVersio
Future feed resources in sustainable salmonid production: A review
Get PDFAquaculture is one of the most resource-efficient and sustainable ways to produce animal protein. The Food and Agriculture Organization predicts that cultivated aquatic species will provide around 53% of the world's seafood supply by 2030. Further growth of intensive farmed aquatic species may be limited by a shortage of feed resources. The aquaculture sector therefore needs to intensify its search for alternative ingredients based on renewable natural resources. A significant increase in production will require an accelerated transition in technology and production systems, better use of natural available resources, development of high-quality alternative feed resources and exploitation of available space. The present review discusses the urgent need to identify appropriate alternative ingredients for a sustainable future salmonid production. We describe and evaluate the most promising marine ingredients, including low-trophic species (mesopelagic fish, zooplankton, polychaetes, macroalgae and crustaceans), novel microbial ingredients (bacteria, yeast and microalgae), insects (black soldier fly, yellow meal worm and crickets), animal by-products (poultry meal, meat and bone meal, blood meal and hydrolysed feather meal) and by-products from other commercial productions (trimmings and blood). Furthermore, we discuss the available volumes and need for new processing technologies and refining methods to ensure commercial production of nutritionally healthy ingredients. The essential production steps and considerations for future development of sustainable and safe seafood production are also discussed.publishedVersio
Overcoming barriers to breeding for increased lice resistance in farmed Atlantic salmon: A case study from Norway
Get PDFThis article discusses whether there is an untapped potential in breeding for improved lice resistant salmon roe and fish, and if so, what factor may explain the gap. Three sets of factors that may impact the state of breeding are examined: market-based factors, regulation of breeding technologies, and policy instruments. Methodologically, our data material relies on the literature on breeding for lice resistance and in-depth interviews with key actors in salmon farming and salmon breeding programs. Market-based factors do not stimulate lice resistance in breeding and policy instruments has not targeted breeding measures. Meanwhile, delousing treatments leads to high mortality in fish. This could paradoxically lead to increased demand for fish that better endures harsh delousing treatments rather than demand for more lice resistant fish.Overcoming barriers to breeding for increased lice resistance in farmed Atlantic salmon: A case study from NorwaypublishedVersio
Drying of vegetable and root crops by solar, infrared, microwave, and radio frequency as energy efficient methods: A review
Get PDFFruits, vegetable, and root (FVR) crops are vital to achieve food and nutrition security (FNS), especially in Sub-Saharan Africa (SSA). However, their perishable nature results in losses across the value chain. The review discusses the application of dehydration technologies: solar, infrared (IR), microwave (MW), and radiofrequency (RF) to produce shelf-stable dried agricultural produce. Drying technologies for example IR, MW, and RF use radiation for heat transfer and are more energy efficient compared to traditional hot air drying. Due to shorter processing times and lower thermal load, the nutritional quality and functional properties of dried materials from IR/MW/RF are often superior compared to hot air convection ovens or solar drying. Combination methods with hot air, vacuum and ultrasonication, and pre-treatments are of great interest for higher efficiency and quality. There are, however, limited studies available on the use of IR/MW/RF dehydration technologies for FVR crops in SSA, albeit these technologies have potential and further investigations are required for adoption.publishedVersio
Guideline for harmonisation of measures and protocols related to consumer behaviour as an outcome. D4.4
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Meat replacer? No thanks! The clash between naturalness and processing: An explorative study of the perception of plant-based foods
Get PDFA shift towards a plant-based diet is desired to promote sustainability, improve health, and minimize animal suffering. However, many consumers are not willing to make such a transition, because of attachment to meat and unwillingness to change habits. The present work explored the perception of Norwegian and French consumers' attitudes, barriers and opportunities to increase the likelihood of a shift in diet. Three creative focus groups (CFGs), using interactive tasks such as photo-collage, projective mapping, story completion and third person technique, were run with omnivorous adult consumers in each country. CFGs gathers undirected feedback, providing less biased responses than other exploration methods, related to e.g. social norms. In both countries, results were in general lines comparable. Nutritional knowledge was low regarding vegetable proteins; familiar sources of protein were mostly animal. There is a strong gap between respondents’ desired behaviour (balancing nutrition, eating less meat) and their actual behaviour: meat is very important, and the menu is often organized around it. Consumers are curious about vegetable sources of protein, but major constraints were hedonics in France, and convenience in Norway. The main barrier to a shift in diet is the lack of knowledge on how to prepare plant-based meals. Many participants find a conflict between health & sustainability in industrial products, perceiving them as highly processed and suggesting that meat replacers might not be a straightforward way to drive omnivorous consumers to shift to a more plant-based diet.publishedVersio
Økonomiske og miljømessige effekter av superkjøling av laks
Get PDFDenne rapporten undersøker økonomiske og miljømessige effekter av superkjøling av laks. Effektene belyses gjennom eksempler på to viktige varestrømmer, laks til Europa med trailer og flyfraktet laks til Asia. Superkjøling av laks kan bidra til reduserte utslipp av klimagasser og betydelige kostnadsbesparelser ved at man reduserer bruk av is. Ved å eliminere behovet for is i kassene kan kassene fylles med inntil 20 % mer fisk. Utslippene og kostnadene til emballasje og transport kan dermed reduseres tilsvarende. I første omgang kan utslipp og kostnader reduseres for de store volumene som går til Europa med trailer og med fly til Asia og USA, men superkjøling kan også i fremtiden erstatte en større del av flyfrakten til USA, og muligens Asia, om holdbarheten forlenges tilstrekkelig. Økt kvalitet og økt holdbarhet styrker argumentene for superkjøling ytterligere.Økonomiske og miljømessige effekter av superkjøling av lakspublishedVersio
Valideringsrapport: Bestemming av Ca, Cu, Fe, K, Mg, Mn, Na, Y og Zn i fôr, fôringrediensar, fisk og feces ved bruk av ICP-OES og mikrobølgeomnsoppslutting
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Nanofiltration of intake water in RAS: Effect on fish performance, health and welfare
Get PDFThe experiment tested the effect of nanomembrane filtration in RAS on the salmon's physiology, welfare and growth. A specially designed membrane was used to remove sulphate from seawater and to adjust salinity from 32 to 12 ‰. A RAS where salinity was adjusted to 12 ‰ by mixing raw seawater and freshwater was used as control. The fish were kept in the two systems for 10 weeks before being transferred to tanks with seawater flow through for 4 weeks. Histology and measurements of gene expression in the gills, intestine, and skin were done and blood samples were taken to measure the content of cortisol and blood plasma ions after transfer to seawater. Post smolt in RAS with nanofiltered water grew slightly better compared to traditional RAS and the same tendency was maintained after transfer to seawater. There were no differences between systems in welfare indicators or skin morphology. In RAS with nanofiltration, some individuals showed an increase in the area of the gill lamella covered by mucus-producing cells and a lower number of chloride cells on the secondary lamellae in the gills. The effect of nanofiltration on gene expression in skin and gills was small, with only two genes that were differentially expressed in skin and 28 genes in gillsNanofiltration of intake water in RAS: Effect on fish performance, health and welfarepublishedVersio