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Skedsmo FS, Løkka G, Chikwati E, Jacobsen JV, Espenes A, Kortner TM. Intestinal strangulation in farmed Atlantic cod (Gadus morhua): Pathological changes and possible predisposing anatomical features. J Fish Dis 2024:e13955. [PMID: 38587083 DOI: 10.1111/jfd.13955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 03/20/2024] [Accepted: 03/25/2024] [Indexed: 04/09/2024]
Abstract
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 provide the first in-depth description of this intestinal disorder, which is correctly denoted 'strangulating obstruction'. In affected fish, part of the intestine is permanently entrapped (incarcerated) under fibrous strands in the mesentery. The entrapment interferes with blood flow and physically blocks the intestine, causing a strangulating obstruction with severe venous congestion and ischemia of the intestinal wall. Furthermore, comparison of macroscopical and histological anatomy of farmed and wild Atlantic cod is presented and risk factors associated with the anatomical differences are discussed.
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Affiliation(s)
- Fredrik Strebel Skedsmo
- Pathology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), As, Norway
| | - Guro Løkka
- Nutrition and Health Unit, Faculty of Veterinary Medicine, NMBU, As, Norway
| | - Elvis Chikwati
- Nutrition and Health Unit, Faculty of Veterinary Medicine, NMBU, As, Norway
| | | | - Arild Espenes
- Pathology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), As, Norway
| | - Trond M Kortner
- Nutrition and Health Unit, Faculty of Veterinary Medicine, NMBU, As, Norway
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2
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Pasquariello R, Pavlovic R, Chacon MA, Camin F, Verdile N, Løkka G, Panseri S, Faustini M, Tandler A, Peggs D, Kortner TM, Bitan A, Brevini TAL, Gandolfi F. Development of a Rainbow Trout ( Oncorhynchus mykiss) Intestinal In Vitro Platform for Profiling Amino Acid Digestion and Absorption of a Complete Diet. Animals (Basel) 2023; 13:2278. [PMID: 37508055 PMCID: PMC10376269 DOI: 10.3390/ani13142278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 06/30/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2023] Open
Abstract
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 is time-consuming and expensive. Therefore, we are developing an in vitro platform that can provide a reliable evaluation of new ingredients. The main aim of this work was to combine an in vitro digestion protocol of extruded, commercially relevant aquafeeds with the exposure of intestinal epithelial cells to the extracted bio-available fraction (BAF). The results show that 250,000 cells/cm2 represents the optimal seeding density and that up to 50% BAF concentration for up to 24 h had no negative effects on the epithelial barrier morphology and function. It is possible to determine amino acid digestibility and bioavailability in all the experimental conditions (with and without BSA, at 25% and 50% dilution) and at all time points (0, 6, and 24 h). However, BAF concentration, the medium used for its dilution, and the length of exposure to the different epithelial cell lines can all influence the results and, therefore, must be selected according to the final aim of the experiment.
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Affiliation(s)
- Rolando Pasquariello
- Department of Agricultural and Environmental Sciences, University of Milan, 20133 Milan, Italy
| | - Radmila Pavlovic
- Department of Veterinary Medicine and Animal Sciences, University of Milan, 26900 Lodi, Italy
- Proteomics and Metabolomics Facility (ProMeFa), IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Marcelo A Chacon
- Israel Oceanographic and Limnological Research (IOLR), The National Center for Mariculture, Eilat 8800001, Israel
| | - Federica Camin
- Department of Agricultural and Environmental Sciences, University of Milan, 20133 Milan, Italy
| | - Nicole Verdile
- Department of Agricultural and Environmental Sciences, University of Milan, 20133 Milan, Italy
| | - Guro Løkka
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), 1433 Ås, Norway
| | - Sara Panseri
- Department of Veterinary Medicine and Animal Sciences, University of Milan, 26900 Lodi, Italy
| | - Massimo Faustini
- Department of Veterinary Medicine and Animal Sciences, University of Milan, 26900 Lodi, Italy
| | - Amos Tandler
- Israel Oceanographic and Limnological Research (IOLR), The National Center for Mariculture, Eilat 8800001, Israel
| | - David Peggs
- Skretting Aquaculture Research Centre, 4016 Stavanger, Norway
| | - Trond M Kortner
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), 1433 Ås, Norway
| | - Amir Bitan
- Israel Oceanographic and Limnological Research (IOLR), The National Center for Mariculture, Eilat 8800001, Israel
| | - Tiziana A L Brevini
- Department of Veterinary Medicine and Animal Sciences, University of Milan, 26900 Lodi, Italy
| | - Fulvio Gandolfi
- Department of Agricultural and Environmental Sciences, University of Milan, 20133 Milan, Italy
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Løkka G, Gamil AAA, Evensen Ø, Kortner TM. Establishment of an In Vitro Model to Study Viral Infections of the Fish Intestinal Epithelium. Cells 2023; 12:1531. [PMID: 37296652 PMCID: PMC10252704 DOI: 10.3390/cells12111531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/26/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023] Open
Abstract
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 for viruses into the fish is through mucosal surfaces including that of the gastrointestinal tract. The contradictory functions of this surface, both creating a barrier towards the external environment and at the same time being responsible for the uptake of nutrients and ion/water regulation make it particularly vulnerable. The connection between dietary components and viral infections in fish has been poorly investigated and until now, a fish intestinal in vitro model to investigate virus-host interactions has been lacking. Here, we established the permissiveness of the rainbow trout intestinal cell line RTgutGC towards the important salmonid viruses-infectious pancreatic necrosis virus (IPNV), salmonid alphavirus (subtype 3, SAV3) and infectious salmon anemia virus (ISAV)-and explored the infection mechanisms of the three different viruses in these cells at different virus to cell ratios. Cytopathic effect (CPE), virus replication in the RTgutGC cells, antiviral cell responses and viral effects on the barrier permeability of polarized cells were investigated. We found that all virus species infected and replicated in RTgutGC cells, although with different replication kinetics and ability to induce CPE and host responses. The onset and progression of CPE was more rapid at high multiplicity of infection (MOI) for IPNV and SAV3 while the opposite was true of ISAV. A positive correlation between the MOI used and the induction of antiviral responses was observed for IPNV while a negative correlation was detected for SAV3. Viral infections compromised barrier integrity at early time points prior to observations of CPE microscopically. Further, the replication of IPNV and ISAV had a more pronounced effect on barrier function than SAV3. The in vitro infection model established herein can thus provide a novel tool to generate knowledge about the infection pathways and mechanisms used to surpass the intestinal epithelium in salmonid fish, and to study how a virus can potentially compromise gut epithelial barrier functions.
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Affiliation(s)
- Guro Løkka
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway; (A.A.A.G.); (Ø.E.); (T.M.K.)
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Løkka G, Dhanasiri AKS, Krogdahl Å, Kortner TM. Bile components affect the functions and transcriptome of the rainbow trout intestinal epithelial cell line RTgutGC. Fish Shellfish Immunol 2022; 131:1144-1156. [PMID: 36444097 DOI: 10.1016/j.fsi.2022.10.049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 10/17/2022] [Accepted: 10/23/2022] [Indexed: 06/16/2023]
Abstract
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 down the broad range of ingredient options, to identify the most promising candidates before in vivo feeding trials are run. In vivo, differentiation of the various epithelial cells in the fish intestine, from the multipotent stem cells, takes place in the presence of a variety of substances from dietary and endogenous origin. Among these, bile salts have recently received attention as regulators of epithelial function in health and disease but have not, until now, been included in the medium when culturing fish gut epithelial cells in vitro. As bile salts are present at high levels in the chyme of the fish intestine, in particular in salmon and rainbow trout, mostly as taurocholate (>90%), their role for effects of diet ingredients on the in vitro gut cell model should be understood. With this study, we wanted to investigate whether inclusion of bile from rainbow trout or pure taurocholate in the culture media would modulate functions of the RTgutGC epithelial cells. Here, we demonstrated that the rainbow trout intestinal epithelial cell line RTgutGC responded significantly to the presence of bile components. Treatment with rainbow trout bile taken from the gall bladder (RTbile) or pure taurocholate (TC) at taurocholate concentrations of ≤0.5 mg/mL retained normal cell morphology, cell viability as in cell oxidation-reduction metabolic activity and membrane integrity, and barrier features, while high concentrations of bile salts (≥1 mg/mL) were cytotoxic to the cells. After long-term (4 days) bile treatment, transcriptome responses showed how bile salts play important roles in intestinal epithelial cell metabolism. qPCR data demonstrated that barrier function genes, brush border enzyme genes and immune genes were significantly affected. Although similar trends were seen, treatment with bile salt as a component of rainbow trout bile or pure taurocholate, induced somewhat different effects. In conclusion, this study clearly indicates that bile salts should be included in the cell medium when running in vitro studies of gut cell functions, not at least immune functions, preferably at the level of ∼0.5 mg/mL supplemented as pure taurocholate to ensure reproducibility.
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Affiliation(s)
- Guro Løkka
- Nutrition and Health Unit, Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway.
| | - Anusha K S Dhanasiri
- Nutrition and Health Unit, Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway
| | - Åshild Krogdahl
- Nutrition and Health Unit, Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway
| | - Trond M Kortner
- Nutrition and Health Unit, Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway
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Zhou W, Krogdahl Å, Sæle Ø, Chikwati E, Løkka G, Kortner TM. Digestive and immune functions in the intestine of wild Ballan wrasse (Labrus bergylta). Comp Biochem Physiol A Mol Integr Physiol 2021; 260:111011. [PMID: 34174428 DOI: 10.1016/j.cbpa.2021.111011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 11/25/2022]
Abstract
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. regarding mucosal fold height and branching, lamina propria and submucosal width and cellular composition and thickness of the muscle layers. Leucine aminopeptidase and maltase capacity decreased from IN1 to IN4, suggesting a predominant role of IN1 in digestion. Gene expression levels of vitamin C transporter (slc23a1) and fatty acid transporters (cd36 and fabp2) were higher in IN1 than in IN4, indicating a more important role of the proximal intestine regarding transport of vitamins and fatty acids. Higher expression of the gene coding for IgM heavy chain constant region (ighm) was found in IN4 than in IN1, suggesting an important immune function of the distal intestine. Other immune related genes il1b, il6, cd40, showed similar expression in the proximal and the distal part of the intestine. Parasite infection, especially the myxozoan parasite Enteromyxum leei, coincided with infiltration of lymphocytic and eosinophilic granular cells in the submucosa and lamina propria. The present study established reference information necessary for interpretation of results of studies of intestinal functions and health in cultured Ballan wrasse.
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Affiliation(s)
- Weiwen Zhou
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway.
| | - Åshild Krogdahl
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway.
| | - Øystein Sæle
- Feed and Nutrition, Institute of Marine Research, Bergen, Norway.
| | - Elvis Chikwati
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway.
| | - Guro Løkka
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway.
| | - Trond M Kortner
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway.
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Rajan B, Løkka G, Koppang EO, Austbø L. Passive Immunization of Farmed Fish. J I 2017; 198:4195-4202. [DOI: 10.4049/jimmunol.1700154] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 03/16/2017] [Indexed: 11/19/2022]
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Abstract
Antigen uptake in the gastrointestinal tract may induce tolerance, lead to an immune response and also to infection. In mammals, most pathogens gain access to the host though the gastrointestinal tract, and in fish as well, this route seems to be of significant importance. The epithelial surface faces a considerable challenge, functioning both as a barrier towards the external milieu but simultaneously being the site of absorption of nutrients and fluids. The mechanisms allowing antigen uptake over the epithelial barrier play a central role for maintaining the intestinal homeostasis and regulate appropriate immune responses. Such uptake has been widely studied in mammals, but also in fish, a number of experiments have been reported, seeking to reveal cells and mechanisms involved in antigen sampling. In this paper, we review these studies in addition to addressing our current knowledge of the intestinal barrier in fish and its anatomical construction.
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Affiliation(s)
- Guro Løkka
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Ullevålsveien 72, 0454 Oslo, Norway.
| | - Erling Olaf Koppang
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Ullevålsveien 72, 0454 Oslo, Norway.
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8
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Løkka G, Austbø L, Falk K, Bromage E, Fjelldal PG, Hansen T, Hordvik I, Koppang EO. Immune parameters in the intestine of wild and reared unvaccinated and vaccinated Atlantic salmon (Salmo salar L.). Dev Comp Immunol 2014; 47:6-16. [PMID: 24968078 DOI: 10.1016/j.dci.2014.06.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 06/13/2014] [Accepted: 06/16/2014] [Indexed: 06/03/2023]
Abstract
Forming a barrier to the outside world, the gut mucosa faces the challenge of absorbing nutrients and fluids while initiating immune reactions towards potential pathogens. As a continuation to our previous publication focusing on the regional intestinal morphology in wild caught post smolt and spawning Atlantic salmon, we here investigate selected immune parameters and compare wild, reared unvaccinated and vaccinated post smolts. We observed highest transcript levels for most immune-related genes in vaccinated post smolts followed by reared unvaccinated and finally wild post smolts, indicating that farming conditions like commercial feed and vaccination might contribute to a more alerted immune system in the gut. In all groups, higher levels of immune transcripts were observed in the second segment of mid-intestine and in the posterior segment. In the life stages and conditions investigated here, we found no indication of a previously suggested population of intestinal T cells expressing MHC class II nor RAG1 expression.
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Affiliation(s)
- Guro Løkka
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway.
| | - Lars Austbø
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway.
| | - Knut Falk
- Norwegian Veterinary Institute, Oslo, Norway.
| | - Erin Bromage
- Department of Biology, University of Massachusetts Dartmouth, MA, USA.
| | | | - Tom Hansen
- Institute of Marine Research, Matre Research Station, Matredal, Norway.
| | - Ivar Hordvik
- Department of Biology, University of Bergen, Bergen, Norway.
| | - Erling Olaf Koppang
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway.
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Løkka G, Falk K, Austbø L, Koppang EO. Uptake of yeast cells in the Atlantic salmon (Salmo salar L.) intestine. Dev Comp Immunol 2014; 47:77-80. [PMID: 25020196 DOI: 10.1016/j.dci.2014.07.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 07/04/2014] [Accepted: 07/06/2014] [Indexed: 06/03/2023]
Abstract
The intestinal mucosa is an important port of entry for many pathogens. Information of antigen uptake mechanisms is essential to understand and to possibly prevent infections. In teleosts, several studies have aimed at investigating particulate uptake in the gastrointestinal system that seems to vary dependent on fish species and antigen. In the present study, particulate uptake in the Atlantic salmon intestine by anal intubation of yeast cells has been investigated. In the anal intubated fish, yeast were found in the epithelium close to nuclei of macrophage-like cells and inside large mononuclear cells in the intestinal lumen, indicating uptake and possible transport of large antigen particles over the epithelium by macrophage-like cells.
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Affiliation(s)
- Guro Løkka
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, School of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway.
| | - Knut Falk
- Norwegian Veterinary Institute, Oslo, Norway.
| | - Lars Austbø
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, School of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway.
| | - Erling Olaf Koppang
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, School of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway.
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Moldal T, Løkka G, Wiik-Nielsen J, Austbø L, Torstensen BE, Rosenlund G, Dale OB, Kaldhusdal M, Koppang EO. Substitution of dietary fish oil with plant oils is associated with shortened mid intestinal folds in Atlantic salmon (Salmo salar). BMC Vet Res 2014; 10:60. [PMID: 24606841 PMCID: PMC3973862 DOI: 10.1186/1746-6148-10-60] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 02/25/2014] [Indexed: 02/06/2023] Open
Abstract
Background Fish meal and fish oil are increasingly replaced by ingredients from terrestrial sources in the feeds for farmed salmonids due to expanding production and reduced availability of marine feed raw material. Fish oil that is rich in n-3 polyunsaturated fatty acids is considered beneficial to human health in general and to prevent intestinal inflammation and carcinogenesis in particular. In contrast, n-6 fatty acids that are present in many vegetable oils have been associated with increased risk of colitis and colon cancer in rodents and humans, as well as lowered transcription levels of certain stress and antioxidant-related genes in Atlantic salmon. The aim of the present study was to investigate the intestinal health in Atlantic salmon fed with different vegetable oils as partial substitutes of fish oil in the diet. A feed trial lasting for 28 weeks included one reference diet containing fish oil as the sole lipid source and three diets where 80% of the fish oil was replaced by a plant oil blend with either olive oil, rapeseed oil or soybean oil as the main lipid source. These plant oils have intermediate or low n-3/n-6-ratios compared to fish oil having a high n-3/n-6-ratio. The protein and carbohydrate fractions were identical in all the feeds. Results Morphometric measurements showed significantly shorter folds in the mid intestine in all groups fed vegetable oils compared to the group fed fish oil. In the distal intestine, the complex folds were significantly shorter in the fish fed soybean oil compared to the fish fed rapeseed oil. Histological and immunohistochemical examination did not show clear difference in the degree of inflammation or proliferation of epithelial cells related to dietary groups, which was further confirmed by real-time RT-PCR which revealed only moderate alterations in the mRNA transcript levels of selected immune-related genes. Conclusions Shortened intestinal folds might be associated with reduced intestinal surface and impaired nutrient absorption and growth, but our results suggest that partial substitution of dietary fish oil with vegetable oils does not have any major negative impact on the intestinal health of Atlantic salmon.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Erling Olaf Koppang
- Norwegian School of Veterinary Science, Post Box 8146 Dep, 0033 Oslo, Norway.
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Rygh CB, Løkka G, Heljasvaara R, Taxt T, Pavlin T, Sormunen R, Pihlajaniemi T, Curry FR, Tenstad O, Reed RK. Image-based assessment of microvascular function and structure in collagen XV- and XVIII-deficient mice. J Physiol 2013; 592:325-36. [PMID: 24218547 DOI: 10.1113/jphysiol.2013.263574] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Collagen XV and XVIII are ubiquitous constituents of basement membranes. We aimed to study the physiological roles of these two components of the permeability barrier non-invasively in striated muscle in mice deficient in collagen XV or XVIII by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Structural information was obtained with transmission electron microscopy (TEM). MR data were analysed by two different analysis methods to quantify tissue perfusion and microcirculatory exchange parameters to rule out data analysis method-dependent results. Control mice (C57BL/6J Ola/Hsd strain) or mice lacking either collagen XV (Col15a1(-/-)) or XVIII (Col18a1(-/-)) were included in the study. MR images were acquired using a preclinical system using gadodiamide (Gd-DTPA-BMA, molecular weight 0.58 kDa) as a tracer. Exchange capacity (permeability (P)-surface area (S) product relative to blood flow (FB)) was increased in test mice compared to controls, but the contributions from P, S, and FB were different in these two phenotypes. FB was significantly increased in Col18a1(-/-), but slightly decreased in Col15a1(-/-). PS was significantly increased only in Col18a1(-/-) even though P was increased in both phenotypes suggesting S might also be reduced in Col15a1(-/-) mice. Immunohistochemistry and electron microscopy demonstrated alterations in capillary density and morphology in both knockout mouse strains in comparison to the control mice. Both collagen XV and XVIII are important for maintaining normal capillary permeability in the striated muscle. DCE-MRI and the perfusion analyses successfully determined microvascular haemodynamic parameters of genetically modified mice and gave results consistent with more invasive methods.
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Affiliation(s)
- C B Rygh
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway.
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Rygh CB, Thuen M, Poli A, Wang J, Løkka G, Huuse EM, Thorsen F, Enger PØ, Chekenya M. Early MRI findings of targeting the NG2 proteoglycan in GBM. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.858.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Marte Thuen
- Norwegian University of Technology and ScienceTrondheimNorway
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Totland GK, Fjelldal PG, Kryvi H, Løkka G, Wargelius A, Sagstad A, Hansen T, Grotmol S. Sustained swimming increases the mineral content and osteocyte density of salmon vertebral bone. J Anat 2011; 219:490-501. [PMID: 21615400 DOI: 10.1111/j.1469-7580.2011.01399.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
This study addresses the effects of increased mechanical load on the vertebral bone of post-smolt Atlantic salmon by forcing them to swim at controlled speeds. The fish swam continuously in four circular tanks for 9 weeks, two groups at 0.47 body lengths (bl) × s(-1) (non-exercised group) and two groups at 2 bl × s(-1) (exercised group), which is just below the limit for maximum sustained swimming speed in this species. Qualitative data concerning the vertebral structure were obtained from histology and electron microscopy, and quantitative data were based on histomorphometry, high-resolution X-ray micro-computed tomography images and analysis of bone mineral content, while the mechanical properties were tested by compression. Our key findings are that the bone matrix secreted during sustained swimming had significantly higher mineral content and mechanical strength, while no effect was detected on bone in vivo architecture. mRNA levels for two mineralization-related genes bgp and alp were significantly upregulated in the exercised fish, indicating promotion of mineralization. The osteocyte density of the lamellar bone of the amphicoel was also significantly higher in the exercised than non-exercised fish, while the osteocyte density in the cancellous bone was similar in the two groups. The vertebral osteocytes did not form a functional syncytium, which shows that salmon vertebral bone responds to mechanical loading in the absence of an extensive connecting syncytial network of osteocytic cell processes as found in mammals, indicating the existence of a different mechanosensing mechanism. The adaptive response to increased load is thus probably mediated by osteoblasts or bone lining cells, a system in which signal detection and response may be co-located. This study offers new insight into the teleost bone biology, and may have implications for maintaining acceptable welfare for farmed salmon.
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