Trond M Kortner

Trond M Kortner
Norwegian University of Life Sciences · Department of Basic Sciences and Aquatic Medicine

Associate Professor

About

109
Publications
33,237
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
3,617
Citations
Additional affiliations
November 2013 - present
Norwegian University of Life Sciences
Position
  • Researcher
November 2009 - October 2013
Norwegian School of Veterinary Science
Position
  • Post Doctor
June 2008 - November 2009
Norwegian University of Science and Technology
Position
  • Post Doctor
Education
May 2005 - June 2008
Norwegian University of Science and Technology
Field of study
  • Fish reproductive physiology

Publications

Publications (109)
Article
Full-text available
Background Antibiotic use has undesirable side-effects on the host, including perturbations of gut microbiota, immunity, and health. Mammalian studies have demonstrated that concomitant/post antibiotic use of pro-, pre-, and synbiotics could re-establish gut microbiota and prevent detrimental host effects. However, studies evaluating similar effect...
Article
Full-text available
Choline is now recognized as an essential nutrient to ensure lipid transport in Atlantic salmon. Its deficiencyleads to excessive lipid accumulation in the enterocytes, a condition known as steatosis. The knowledge of lipidmetabolism and steatosis in fish remains limited, motivating the use of in vitro intestinal models to performdeeper exploration...
Article
Full-text available
Choline is recognized as an essential nutrient for Atlantic salmon at all developmental stages. However, its dietary requirement is not well defined. Choline plays a critical role in lipid transport, and the clearest deficiency sign is intestinal steatosis. The present work, aiming to find whether lipid source and fish size may affect steatosis sym...
Article
During recent years, there has been a renewed interest in establishing farming of Atlantic cod ( Gadus morhua ) in Norway. However, a fatal abdominal disorder compromises animal welfare and causes economic losses. A similar problem was present during a previous attempt to establish Atlantic cod farming more than a decade ago. In this paper, we prov...
Article
Full-text available
An earlier study of ours investigating the effect of dietary lipid levels on the choline requirement of Atlantic salmon showed increasing severity of intestinal steatosis with increasing lipid levels. As choline is involved in epigenetic regulation by being the key methyl donor, pyloric caeca samples from the study were analysed for epigenetic effe...
Article
Full-text available
Background The importance of the gut microbiota for physiological processes in mammals is well established, but the knowledge of their functional roles in fish is still limited. The aims of this study were to investigate associations between variation in taxonomical composition of the gut microbiota and gut health status in Atlantic salmon and to e...
Article
Full-text available
Reliable and predictive in vitro models would support the search for new raw materials that can improve current fish diets. We recently developed some rainbow trout (RT) intestinal cell-based organotypic platforms demonstrating that the platform type modulates the degree of cell differentiation achieved in vitro and here we studied whether such dif...
Article
Full-text available
The ever-increasing number and variation of raw materials utilized to provide alternative feed formulations continues to allow for a more sustainable and flexible approach. Testing all these options in vivo is still the most robust and reliable manner to pick the best raw material candidates, but it requires the use of large numbers of animals and...
Article
Full-text available
Viral infections are still a major concern for the aquaculture industry. For salmonid fish, even though breeding strategies and vaccine development have reduced disease outbreaks, viral diseases remain among the main challenges having a negative impact on the welfare of fish and causing massive economic losses for the industry. The main entry port...
Article
Full-text available
Choline was recently established as an essential nutrient for Atlantic salmon at all life stages. Choline deficiency is manifested as an excessive accumulation of dietary fat within the intestinal enterocytes, a condition known as steatosis. Most of today's plant-based salmon feeds will be choline-deficient unless choline is supplemented. Choline's...
Article
Full-text available
Background Given the importance of gut microbiota for health, growth and performance of the host, the aquaculture industry has taken measures to develop functional fish feeds aiming at modulating gut microbiota and inducing the anticipated beneficial effects. However, present understanding of the impact of such functional feeds on the fish is limit...
Article
Full-text available
Intestinal steatosis, called lipid malabsorption syndrome (LMS) in severe cases, is a common condition in farmed Atlantic salmon, associated with choline deficiency causing low lipid transport in enterocytes, excessive lipid accumulation, and increased mucosal weight. A previous dose-response study supplying a plant-based diet with choline chloride...
Article
Full-text available
Functional feed ingredients are frequently used in feeds for Atlantic salmon, often claimed to improve immune functions in the intestine and reduce severity of gut inflammation. However, documentation of such effects is, in most cases, only indicative. In the present study effects of two packages of functional feed ingredients commonly used in salm...
Article
Full-text available
A 5-week feeding trial was conducted in the cleaner fish Ballan wrasse (Labrus bergylta) for a better understanding of the basic biology of the intestinal functions and health in this stomach less species. During the trial, Ballan wrasse was fed either a reference diet, the reference diet supplemented with i) a commercial prebiotic (Aquate™ SG, 0.4...
Article
Full-text available
Steatosis and inflammation have been common gut symptoms in Atlantic salmon fed plant rich diets. Choline has recently been identified as essential for salmon in seawater, and β-glucan and nucleotides are frequently used to prevent inflammation. The study is aimed at documenting whether increased fishmeal (FM) levels (8 levels from 0 to 40%) and su...
Article
Full-text available
Lumpfish (Cyclopterus lumpus) aquaculture has expanded greatly in recent years due to demands for sea lice cleanerfish from the salmon industry. There are knowledge gaps in lumpfish digestive physiology, nutrient requirement and implications of nutrition for health and disease susceptibility. The present study, conducted to follow up our recent scr...
Article
Gallbladders with mucosal outpouchings (diverticula) were found in a population of Atlantic salmon farmed in sea water. Soft tissue calcification affected the skin, skeletal muscle and gut, as identified by histological observations. In addition, inflammation of muscle and intestinal tissue and lymphocytic and fibrous reaction were present in the l...
Article
Full-text available
The concomitant increase in cultivation of fish and decrease in supply of marine ingredients, have greatly increased the demand for new nutrient sources. This also regards so-called functional ingredients which may benefit health and welfare of the fish. In vitro cell line-based intestinal epithelial barrier models may serve as tools for narrowing...
Article
Full-text available
Cultivation of lumpfish (Cyclopterus lumpus) as lice cleaner fish for salmon is now expanding. For successful cultivation of a new species, understanding the basic biology of digestive functions is vital to facilitate and optimize diet formulation. This paper presents results from two experiments conducted to deepen our knowledge on lumpfish intest...
Article
Full-text available
A meta-analytic approach was used to determine factors associated with the severity of enteritis in distal intestine of Atlantic salmon fed soybean meal (SBM)-based diets. Dataset from 26 fish studies were extracted and standardized for use in the meta-analysis. After standardization, the data were analyzed with ordinal logistic regression model by...
Article
Full-text available
Atlantic salmon (Salmo salar L.) undergo great alterations in physiology and gut microbiota composition throughout their life stages. This study assessed gut health and microbiota in out-of-season smolts before and after seawater transfer and modulatory effects of functional feed ingredients under commercial Arctic conditions. The fish were fed two...
Article
Full-text available
The interest for krill-based ingredients for aquaculture feed applications has increased steadily in recent years. For decades, there has been a heavy reliance on the limited sources of fishmeal and fish oil in the salmonid aquaculture industry. Further growth in farming of carnivorous fish is dependent on new feed resources becoming available. The...
Article
Full-text available
Background: Being part of fish's natural diets, insects have become a practical alternative feed ingredient for aquaculture. While nutritional values of insects have been extensively studied in various fish species, their impact on the fish microbiota remains to be fully explored. In an 8-week freshwater feeding trial, Atlantic salmon (Salmo salar)...
Chapter
In this chapter, the potentially harmful compounds, which may be found in ingredients used in fish feed, are gathered in two groups, the antinutritional factors (ANFs) and the adventitious toxins (ATs). The ANFs are naturally occurring constituents of feed ingredients, whereas the ATs come from other sources than the plant. The function of an ANF i...
Preprint
Full-text available
Background Given the importance of gut microbiota for health, growth and performance of the host, the aquaculture industry has taken measures to develop functional fish feeds aiming at modulating gut microbiota and inducing the anticipated beneficial effects. However, present understanding of the impact of such functional feeds on the fish is limit...
Preprint
Full-text available
Background Given the importance of gut microbiota for health, growth and performance of the host, the aquaculture industry has taken measures to develop functional fish feeds aiming at modulating gut microbiota and inducing the anticipated beneficial effects. However, present understanding of the impact of such functional feeds on the fish is limit...
Preprint
Full-text available
Background: Being part of fish's natural diets, insects have become a realistic, sustainable feed ingredient for aquaculture. While nutritional values of insects have been extensively studied in various fish species, their impact on the fish microbiota remains to be fully explored. In an 8-week freshwater feeding trial, Atlantic salmon ( Salmo sala...
Preprint
Full-text available
Being part of fish's natural diets, insects have become a realistic, sustainable feed ingredient for aquaculture. While nutritional values of insects have been extensively studied in various fish species, their impact on the fish microbiota remains to be fully explored. In an 8-week freshwater feeding trial, Atlantic salmon (Salmo salar) were fed e...
Article
Full-text available
IntroductionMetabolomics applications to the aquaculture research are increasing steadily. The use of standardized proton nuclear magnetic resonance (1H NMR) spectroscopy can provide the aquaculture industry with an unbiased, reproducible, and high-throughput screening tool, which can help to diagnose nutritional and disease-related metabolic disor...
Article
This study was carried out to profile key characteristics of intestinal functions and health in wild-caught Ballan wrasse. To describe functional variation along the intestine, samples were collected from four intestinal segments, named from the proximal to the distal segment: IN1, IN2, IN3 and IN4. The sections showed quite similar structure, i.e....
Article
The aim of the present work was to evaluate the protein value of products from the two seaweeds Saccharina latissima and Palmaria palmata grown in Norwegian waters and to characterize possible beneficial or detrimental effects in the intestine and other organs. Mink, a well-established model for comparison of nutrient digestibility in monogastric a...
Article
Full-text available
Background The importance of the gut microbiota for health and wellbeing is well established for humans and some land animals. The gut microbiota is supposedly as important for fish, but existing knowledge has many gaps, in particular for fish in the Arctic areas. This study addressed the dynamics of Atlantic salmon digesta-associated gut microbiot...
Article
Full-text available
Farmed ballan wrasse (Labrus bergylta) is an efficient cleaner fish used for non-medicinal delicing of Atlantic salmon in sea cages replacing to an increasing degree wild wrasse due to considerations for biodiversity and risk of overfishing local wrasse populations. Farming of ballan wrasse has been hampered by low growth rates, high prevalence of...
Article
Full-text available
Background Intestinal digesta is commonly used for studying responses of microbiota to dietary shifts, yet evidence is accumulating that it represents an incomplete view of the intestinal microbiota. The present work aims to investigate the differences between digesta- and mucosa-associated intestinal microbiota in Atlantic salmon ( Salmo salar ) a...
Article
Full-text available
Increased industrialized production of salmonids challenges aspects concerning available feed resources and animal welfare. The immune system plays a key component in this respect. Novel feed ingredients may trigger unwarranted immune responses again affecting the well-being of the fish. Here we review our current knowledge concerning salmon intest...
Article
Full-text available
The present study was conducted to strengthen the knowledge on gut immune functions and health in Atlantic salmon under large scale, commercial conditions in the Arctic region of Norway. Two groups of fish were monitored, one fed a series of diets without functional ingredients (Ref) and the other diets with functional ingredients (Test). The nutri...
Preprint
Full-text available
Background: Intestinal digesta is commonly used for studying responses of microbiota to dietary shifts, yet evidence is accumulating that it represents an incomplete view of the intestinal microbiota. The present work aims to investigate the differences between digesta- and mucosa-associated intestinal microbiota in Atlantic salmon ( Salmo salar )...
Preprint
Full-text available
Background: Intestinal digesta is commonly used for studying responses of microbiota to dietary shifts, yet evidence is accumulating that it represents an incomplete view of the intestinal microbiota. The present work aims to investigate the differences between digesta- and mucosa-associated intestinal microbiota in Atlantic salmon (Salmo salar) an...
Preprint
Full-text available
Background: Intestinal digesta is commonly used for studying responses of microbiota to dietary shifts, yet evidence is accumulating that it represents an incomplete view of the intestinal microbiota. The present work aims to investigate the differences between digesta- and mucosa-associated intestinal microbiota in Atlantic salmon (Salmo salar) an...
Article
Full-text available
Excessive enterocyte lipid accumulation, with the suggested term lipid malabsorption syndrome (LMS), is frequently observed in Atlantic salmon (Salmo salar L), in small fish in fresh water as well as in large fish in seawater. The symptoms indicate insufficient supply of components involved in lipid assimilation. The questions addressed in the pres...
Preprint
Full-text available
Intestinal digesta is commonly used for studying responses of microbiota to dietary shifts, yet evidence is accumulating that it represents an incomplete view of the intestinal microbiota. In a 16-week seawater feeding trial, Atlantic salmon (Salmo salar) were fed either a commercially-relevant reference diet or an insect meal diet containing ~15%...
Article
Foamy, whitish appearance of the pyloric caeca, reflecting elevated lipid content, histologically visible as hypervacuolation, is frequently observed in Atlantic salmon fed high plant diets. Lipid malabsorption syndrome (LMS) is suggested as term for the phenomenon. Earlier studies have shown that insufficient supply of phospholipids may cause simi...
Article
Full-text available
Background: Various intestinal morphological alterations have been reported in cultured fish fed diets with high contents of plant ingredients. Since 2000, salmon farmers have reported symptoms indicating an intestinal problem, which we suggest calling lipid malabsorption syndrome (LMS), characterized by pale and foamy appearance of the enterocyte...
Poster
Full-text available
Field survey of gut health status of farmed Atlantic salmon in Norway
Article
A new non-GM cultivar of soybean, named Triple Null (TN), devoid of Kunitz trypsin inhibitor, lectin and the allergen P34/Gly m Bd 30 k has been developed from a commercial cultivar. Use of standard soybean meals in diets for Atlantic salmon most often induces distal intestinal inflammation whereas soy protein concentrate (SPC), in which several an...
Article
Full-text available
Little is known about the digestion of nutrients in stomachless (agastric) fishes with short intestines, such as wrasse. This study describes the digestion, absorption and evacuation rates in ballan wrasse (Labrus bergylta) fed either dry or pre-soaked diets. Ballan wrasse juveniles received either dry or pre-soaked diets containing inert markers t...
Article
The fish intestine comprises an important environment-organism interface that is vital to fish growth, health and pathogen defense. Yet, knowledge about the physiology and defense mechanisms toward environmental stressors, such as bacterial or viral cues, is limited and depends largely on in vivo experiments with fish. On this background, we here e...
Article
Full-text available
The objective of this study was to evaluate the suitability of the rainbow trout intestinal epithelial cell line (RTgutGC) as an in vitro model for studies of gut immune function and effects of functional feed ingredients. Effects of lipopolysaccharide (LPS) and three functional feed ingredients [nucleotides, mannanoligosaccharides (MOS), and beta-...
Article
Limited availability of sustainable feed ingredients is a serious concern in salmon aquaculture. Insects may become an important, sustainable resource for expanding the raw material repertoire. Herein, we present data from an 8-week feeding trial with pre-smolt Atlantic salmon (initial body weight 49 ± 1.5 g) fed either a reference diet containing...
Article
The essential trace element selenium (Se) unfolds its physiological activity through selenoproteins. Almost half of these proteins have antioxidant properties, which are essential to minimize perturbations, as i.e. lipid peroxidation, damage to proteins and nucleic acids, caused by reactive oxygen species. Lack of Se and the resulting decrease in a...
Article
Full-text available
Importance: The intestine of cultivated Atlantic salmon shows symptoms of compromised function, which are most likely caused by imbalances related to the use of new feed ingredients. Intestinal microbiota profiling may become in the future a valuable endpoint measurement in order to assess fish intestinal health status and effects of diet. The pre...
Article
Full-text available
In Atlantic salmon (Salmo salar L.), and also in other fish species, certain plant protein ingredients can increase fecal water content creating a diarrhea-like condition which may impair gut function and reduce fish growth. The present study aimed to strengthen understanding of the underlying mechanisms by observing effects of various alternative...
Article
Inclusion of plant ingredients in carnivorous fish feeds is often associated with decreased lipid digestibility, reduced bile acid levels and hypocholesterolaemia, which may result in lower growth performance and feed utilization. The present study aimed at evaluating the effects of dietary taurocholate supplementation in turbot (Scophthalmus maxim...
Article
Full-text available
Background The present study was undertaken to gain knowledge on the role of bile components and lecithin on development of aberrations in digestive functions which seemingly have increased in Atlantic salmon in parallel with the increased use of plant ingredients in fish feed. Post smolt Atlantic salmon were fed for 77 days one of three basal diet...