Use of crystalline methionine to optimize amino acid profiles in feeds for Atlantic salmon (Salmo salar L.) was studied in three experiments. A basic experimental diet with 25% of dietary protein from marine origin and the remaining 75%... more
Use of crystalline methionine to optimize amino acid profiles in feeds for Atlantic salmon (Salmo salar L.) was studied in three experiments. A basic experimental diet with 25% of dietary protein from marine origin and the remaining 75% from soya protein concentrate was used either with or without supplementation of L-methionine, D-methionine or DL-methionine. A fishmeal-based diet was used as control. In experiment 1, growth performance of 100 g salmon in seawater was improved by supplementation with the different methionine products. Growth performance was, however, inferior to that of fish fed the control. Feed conversion ratios (FCR) exhibited similar trends to specific growth rate (SGR) with methionine supplementation, but again not as the control. Protein retention, measured as productive protein value (PPV), was significantly better in the control and D-methionine groups as compared with either L-methionine or the nonsupplemented group. These trends were confirmed in experiment 2, using fish of the same size, where an absorption and digestibility study of D- and L-methionine clearly indicated that D-methionine was absorbed as well as L-methionine. Results indicated that racemization of D- into L-methionine occurs in liver and kidney in Atlantic salmon. Ornithine decarboxylase (ODC) activity in liver was significantly affected by dietary treatment and there was a good correlation with growth and feed utilization data. In experiment 3, a growth study with large salmon (1 kg) was performed using increasing supplementation of DL-methionine to the basic diet. Results indicated a methionine requirement for maximum growth of 9.2 g kg–1 feed dry matter (DM) kg–1 growth. This is slightly higher than that reported in the literature. The present study clearly shows that optimizing the amino acid profile by inclusion of a single crystalline amino acid (crystalline methionine) does not give the same protein utilization as that of a diet in which the amino acids are mainly protein bound. D-methionine was found to result in better protein utilization than L-methionine when measured as PPV.
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Abstract The effects of different hatching systems on the timing of first feeding in Atlantic salmon alevins has been investigated. One alevin group was reared in traditional flatscreen incubators and first fed when two thirds of yolk... more
Abstract The effects of different hatching systems on the timing of first feeding in Atlantic salmon alevins has been investigated. One alevin group was reared in traditional flatscreen incubators and first fed when two thirds of yolk mass was resorbed. The other alevin group was reared in astroturf incubators and first fed at swim-up. The outlet of the incubators was constructed in such a way that the alevins could swim directly into the first-feeding tanks. The astroturf-reared alevins showed better growth and had higher contents of RNA and DNA. Moreover, for this group the timing for first feeding was less critical compared to the flatscreen-reared alevins. By letting the salmon alevins have first feeding at swim-up, our sampling system provides a method for optimal timing for feeding which does not depend on the hatching conditions.
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Research Interests: Zoology, Biology, Aquaculture, Telemetry, Crowding, and 4 moreFisheries Sciences, Fishery, Salmo, and Salmonidae
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ABSTRACT
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Research Interests: Biology, Fish Diseases, Aquaculture, Medicine, Animals, and 5 moreCataract, Salmon, Fishery, Veterinary Sciences, and Salmo
There has been an increasing number of reports on cataracts in Norwegian and international salmon farming. The present study was undertaken to examine physiological and nutritional conditions during an outbreak of cataracts observed in... more
There has been an increasing number of reports on cataracts in Norwegian and international salmon farming. The present study was undertaken to examine physiological and nutritional conditions during an outbreak of cataracts observed in rapidly growing Atlantic salmon, Salmo salar L., smolt with emphasis on zinc status. During this study, the cataracts were classified as irreversible. The outbreak of cataracts was positively related to fish growth and negatively related to the condition factor of the fish. Zinc concentrations in liver, eye and plasma were recorded in fish with cataract and in healthy fish from December to May. Lower zinc status (around 20%) was found in fish with cataracts compared to healthy fish, both over time and with regard to severity of the cataract. The decline in organ zinc concentrations seems to be explained by increased relative liver size, lower dry matters in liver and eye, and lower plasma protein. From the present data, the incidence of cataracts could not be directly related to zinc or any of the other nutrients (vitamin A, iron) examined, although relative deficiencies caused by other unknown rearing factors cannot be excluded. The lower condition factor and differences in organ water composition in fish with cataracts indicate that the cataracts may be related to the smoltification processes. Smoltification in the fish population was most probably accelerated by elevated water temperatures.
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The aim of the study was to investigate the presence, distribution and density of major histocompatibility complex (MHC) class II+ cells in the ocular tissues of the Atlantic salmon, Salmo salar, prior to and following vaccination. Eyes... more
The aim of the study was to investigate the presence, distribution and density of major histocompatibility complex (MHC) class II+ cells in the ocular tissues of the Atlantic salmon, Salmo salar, prior to and following vaccination. Eyes were collected 14 days prior to and at 4, 11, 25 and 39 days and 4 months subsequent to vaccination with a commercial fish vaccine. A quantitative analysis was performed in sections on the number of immunopositive cells in the retinal layers. In all groups, MHC class II+ cells were detected in the area of the limbus but not in the central parts of the cornea. In the uvea, immunopositive cells were present in unvaccinated and vaccinated fish. Abundant immunopositive cells were identified in the choroid rete (or choroid gland) in all groups as well as in the ventral ciliary cleft, where macrophage-like MHC class II+ cells were seen. Quantitative histology of the retina revealed a significant increase in MHC class II+ cells in the outer plexiform layer (OPL) and the inner nuclear layer (INL) 4 days following vaccination. Positive cells were detected in all layers of the retina with the exception of the photoreceptor layer.
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Research Interests: Zoology, Animal Science, Biology, Aquaculture, Osmoregulation, and 7 moreSalinity, Temperature, Fisheries Sciences, Fishery, Eye, Sea Water, and Salmo
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Environmental challenges related to open sea cage production of Atlantic salmon have sparked interest in developing commercial-scale semi-closed sea systems for post-smolt Atlantic salmon (100–1000 g). Determining the mass-specific water... more
Environmental challenges related to open sea cage production of Atlantic salmon have sparked interest in developing commercial-scale semi-closed sea systems for post-smolt Atlantic salmon (100–1000 g). Determining the mass-specific water flow required by post-smolts will largely influence the design and dimensioning of such systems. In this experiment, post-smolts were exposed to four levels of specific water flow: 0.2, 0.3, 0.4, and 0.5 L kg fish−1 min−1. All treatments involved flow-through seawater with full oxygenation, a salinity of 34‰, and a mean temperature of 9.3 °C. The stocking density was kept stable at 75 kg m−3. Water pH decreased with reduced flow, while partial pressure of carbon dioxide (pCO2) and total ammonia nitrogen (TAN) in the water increased. The increase in water CO2 was reflected in the blood with increased pCO2, HCO3−, and decreased Cl− in the lowest water flow treatment (0.2 L kg fish−1 min−1), indicating a typical regulatory response to increased water C...
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Animals and their associated microbiota share long evolutionary histories. Both host genotype and associated microbiota influence phenotypes such as growth and disease resilience. We applied a hologenomic approach to explore the... more
Animals and their associated microbiota share long evolutionary histories. Both host genotype and associated microbiota influence phenotypes such as growth and disease resilience. We applied a hologenomic approach to explore the relationship between host and microbiota in shaping lifetime growth and parasitic cestode infection in farmed Atlantic salmon. Genomes, transcriptomes, metabolomes and metagenomes were generated from the guts of 460 harvest-aged salmon, 82% of which were naturally infected with an intestinal cestode. One salmonid-specificMycoplasmadominated the gut microbiota of uninfected salmon. However, the microbiota was perturbed in smaller, parasitised fish, with increased abundance ofVibrionaceaeand otherMycoplasmaspecies previously linked to the cestode microbiota. The cestode-associatedMycoplasmacarry more virulence-associated genes than the salmonidMycoplasma. Colonisation by one cestode-associatedMycoplasmawas associated with a region of the salmon genome encoding...
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Alternative feed ingredients for farmed salmon are warranted due to increasing pressure on wild fish stocks. As locally farmed blue mussels may represent an environmentally sustainable substitute with a lower carbon footprint, we aimed to... more
Alternative feed ingredients for farmed salmon are warranted due to increasing pressure on wild fish stocks. As locally farmed blue mussels may represent an environmentally sustainable substitute with a lower carbon footprint, we aimed to test the potential and safety of substituting fish meal with blue mussel meal in feed for Atlantic salmon. Salmon were fed diets in which fish meal was partially replaced with blue mussel meal in increments, accounting for up to 13.1 % of the ingredients. Fillets from the salmon were subsequently used to prepare obesity-promoting western diets for a 13-weeks mouse feeding trial. In a second mouse trial, we tested the effects of inclusion of up to 8% blue mussel meal directly in a meat-based western diet. Partial replacement of fish meal with blue mussel meal in fish feed preserved the n-3 polyunsaturated fatty acid (PUFA) content in salmon fillets. The observed blue mussel-induced changes in the fatty acid profiles in salmon fillets did not translate into similar changes in the livers of mice that consumed the salmon, and no clear dose-dependent responses were found. The relative levels of the marine n-3 fatty acids, EPA, and DHA were not reduced, and the n-3/n-6 PUFA ratios in livers from all salmon-fed mice were unchanged. The inclusion of blue mussel meal in a meat-based western diet led to a small, but dose-dependent increase in the n-3/n-6 PUFA ratios in mice livers. Diet-induced obesity, glucose intolerance, and hepatic steatosis were unaffected in both mice trials and no blue mussel-induced adverse effects were observed. In conclusion, our results suggest that replacing fish meal with blue mussel meal in salmon feed will not cause adverse effects in those who consume the salmon fillets.
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The importance of the parasite microbiome is gaining recognition. Of particular concern is understanding how these parasite microbiomes influence host-parasite interactions and parasite interactions with the vertebrate host microbiome as... more
The importance of the parasite microbiome is gaining recognition. Of particular concern is understanding how these parasite microbiomes influence host-parasite interactions and parasite interactions with the vertebrate host microbiome as part of a system of nested holobionts.
Research Interests: Microbiology, Biology, Salmonids, Gut Microbiome, Holobiont, and 12 moreHost-parasite interactions, Cestodes, Atlantic Salmon, Salmon, Host Parasite Interaction, Microbiome, Intestinal microbiota and gut pathology, Mbio, Metagenomics and microbiome identification, Dysbiosis, Intestinal Microbiota, and Gut dysbiosis
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Light cues vary along the axis of periodicity, intensity and spectrum and perception of light is dependent on the photoreceptive capacity encoded within the genome and the opsins expressed. A global approach was taken to analyze the... more
Light cues vary along the axis of periodicity, intensity and spectrum and perception of light is dependent on the photoreceptive capacity encoded within the genome and the opsins expressed. A global approach was taken to analyze the photoreceptive capacity and the effect of differing light conditions on a developing teleost prior to first feeding. The transcriptomes of embryos and alevins of Atlantic salmon (Salmo salar) exposed to different light conditions were analyzed, including a developmental series and a circadian profile. The results showed that genes mediating nonvisual photoreception are present prior to hatching when the retina is poorly differentiated. The clock genes were expressed early, but the circadian profile showed that only two clock genes were significantly cycling before first feeding. Few genes were differentially expressed between day and night within a light condition; however, many genes were significantly different between light conditions, indicating that...
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Additional File 2. Lipidomic dataset containing lipid features found to distinguish FG and GS fish. Compounds found to significantly drive the separation were identified using OPLS-DA analysis (w [1] score > +/− 0.04 and a p (corr) [1]... more
Additional File 2. Lipidomic dataset containing lipid features found to distinguish FG and GS fish. Compounds found to significantly drive the separation were identified using OPLS-DA analysis (w [1] score > +/− 0.04 and a p (corr) [1] score > +/− 0.6).
To measure the effect of physical feed quality on gut evacuation, Atlantic salmon with mean weight 1047 g (measured after finishing the sampling) was fed two extruded feeds with different physical quality to satiation. Each feed quality... more
To measure the effect of physical feed quality on gut evacuation, Atlantic salmon with mean weight 1047 g (measured after finishing the sampling) was fed two extruded feeds with different physical quality to satiation. Each feed quality was produced in three batches to contain three different markers (La, Yb and Y). The measured hardness for Diet 1 was 128.5, 140.5 and 152.1 N for the batches added La, Yb and Y, respectively. For Diet 2, the corresponding figures were 148.2, 172.0 and 153.3 N, respectively. The mean water stability, given as % of dry matter remaining after 2 hours shaking in water bath, was 78.6, 76.9 and 77.9 % for Diet 1 added La, Yb and Y, respectively. For Diet 2, the corresponding figures were 84.9, 85.2 and 81.8, respectively. The durability, given as remaining intact pellets in the DORIS test, was 64.6, 65.9 and 81.6 for Diet 1, and 80.1, 81.4 and 78.3 for Diet 2, respectively, in the batches added La, Yb and Y. The pellet size was 10 mm. The salmon was fed one meal daily. The feeds added La was fed for a period of 26 days. On day 27, feeds containing Yb was given, and on day 28 and thereafter, the salmon was fed feeds with Y added. Faeces were collected from the outlet water during 30 minutes intervals at 8, 16, 24, 32, 40 and 48 hours after the feeding on day 27, and analyzed for La, Yb and Y. The ratio of the markers was calculated as concentration of each marker divided by concentration of sum of markers. For both feed groups, some Yb appeared in faeces 8 h after feeding diets containing this marker, and amount of Yb peaked around 24 h and almost no Yb was left after 48 h. Sixteen hours after feeding, at the time when the change in marker concentrations had happened fastest, the relative concentration was lowest for La, and highest for Yb, in faeces from fish fed Diet 1, indicating a higher gastrointestinal transit rate for this feed in this period. The apparent digestibility of fat was approximately 2 % higher in Diet 1 than in Diet 2. The data indicate that even small differences in the physical quality of feeds may have an impact on the gut evacuation rate in Atlantic salmon. This may affect how well the genetically inherent growth capacity of the fish is expressed (and utilized)
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PurposeTo explore whether high intake of cod or salmon would affect gut microbiota profile, faecal output and serum concentrations of lipids and bile acids.MethodsSeventy-six adults with overweight/obesity with no reported... more
PurposeTo explore whether high intake of cod or salmon would affect gut microbiota profile, faecal output and serum concentrations of lipids and bile acids.MethodsSeventy-six adults with overweight/obesity with no reported gastrointestinal disease were randomly assigned to consume 750 g/week of either cod or salmon, or to avoid fish intake (Control group) for 8 weeks. Fifteen participants from each group were randomly selected for 72 h faeces collection at baseline and end point for gut microbiota profile analyses using 54 bacterial DNA probes. Food intake was registered, and fasting serum and morning urine were collected at baseline and end point.ResultsSixty-five participants were included in serum and urine analyses, and gut microbiota profile was analysed for 33 participants. Principal component analysis of gut microbiota showed an almost complete separation of the Salmon group from the Control group, with lower counts for bacteria in theBacteroidetesphylum and theClostridialeso...
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Abstract An association between infections with the ubiquitous microsporidian Desmozoon lepeophtherii (D. lepeophtherii) and pancreas disease (PD) outbreaks has previously been suggested. We followed infections with D. lepeophtherii and... more
Abstract An association between infections with the ubiquitous microsporidian Desmozoon lepeophtherii (D. lepeophtherii) and pancreas disease (PD) outbreaks has previously been suggested. We followed infections with D. lepeophtherii and salmonid alpha virus (SAV) in thirteen Atlantic salmon farms in western Norway during the first production year at sea. The purpose of the survey was to examine if the presence and density of infection with the microsporidian could be linked to severity of PD-infection. Since the microsporidian develops both in salmon and in salmon lice (Lepeophtheirus salmonis) and louse abundance varies geographically, we also examined the spatial and temporal distribution and density of D. lepeophtherii infections in farmed Atlantic salmon. The prevalence of D. lepeophtherii was 100% in all samples from all farms. D. lepeophtherii densities varied with season, peaking in autumn followed by a marked decrease in winter. Geographical differences between areas were observed in August, between the outer coast (salinity 23.5 ppt.) and the Hardangerfjord (inner area) (16.1 ppt.) with higher infection rates in the outer coastal areas. We likewise found that D. lepeophtherii density was significantly associated with the host condition factors; D. lepeophtherii density being significantly higher in salmon with low status. SAV infections occurred in six farms. Five of these developed — and were diagnosed with PD. No relationship was detected between D. lepeophtherii density, the detection of SAV or PD outbreaks over time. Statement of relevance This is an epizootiological study of Atlantic salmon, P. theridion and SAV. There is much known about the pathogen in connection with disease outbreaks, but less is known about the occurrence of potential pathogen in healthy farmed salmon or how such infections develop over time. P. theridion has been connected to SAV infection and PD outbreak. The result from this study does not support such connection. It appears that the SAV virus can persist in a farmed population at least 10 months prior to a PD outbreak. There is a connection between the salmon condition and density of P. theridion where salmon with low condition has elevated density. This could identify P. theridion as the agent possibly causing this condition.
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Growth of haddock (Melanogrammus aeglefinus) was assessed in onshore tanks in West Scotland. Fish were stocked at a mean weight of 15 g in July 2002, with a second stocking in October 2002 at 25 g. Fish had a mean weight of 755 ± 150... more
Growth of haddock (Melanogrammus aeglefinus) was assessed in onshore tanks in West Scotland. Fish were stocked at a mean weight of 15 g in July 2002, with a second stocking in October 2002 at 25 g. Fish had a mean weight of 755 ± 150 (s.d.) g at 20 months after stocking and were harvested. The specific growth rate of haddock was similar to Atlantic cod (Gadus morhua) during the first year but decreased by 20% after that. Liver biomass was 17.6% of the whole body weight, suggesting haddock had difficulty in utilizing dietary lipid. Reduced lipid levels in the diet had only a short-term effect on hepatosomatic index (HSI). Haddock that were held under 24-h light from the first summer solstice did not mature at an age of two years when compared with complete maturation of fish reared under ambient light. Mortality during the on-growing stage was high (28% of stock) and was attributed to Vibrio anguillarum infection, and possibly to enlarged livers. An assessment of quality found taste ...
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... SOLBERG, C., WILLUMSEN, L., AMBLE, S., JOHANESSEN, T. and SVEIER, H. (2006), The effects of feeding frequencies on seasonal changes in ... access to feed, feed composition, temperature in the water, light conditions and sexual... more
... SOLBERG, C., WILLUMSEN, L., AMBLE, S., JOHANESSEN, T. and SVEIER, H. (2006), The effects of feeding frequencies on seasonal changes in ... access to feed, feed composition, temperature in the water, light conditions and sexual maturation are factors that will have large ...
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Abstract The effects of different hatching systems on the timing of first feeding in Atlantic salmon alevins has been investigated. One alevin group was reared in traditional flatscreen incubators and first fed when two thirds of yolk... more
Abstract The effects of different hatching systems on the timing of first feeding in Atlantic salmon alevins has been investigated. One alevin group was reared in traditional flatscreen incubators and first fed when two thirds of yolk mass was resorbed. The other alevin group was reared in astroturf incubators and first fed at swim-up. The outlet of the incubators was constructed in such a way that the alevins could swim directly into the first-feeding tanks. The astroturf-reared alevins showed better growth and had higher contents of RNA and DNA. Moreover, for this group the timing for first feeding was less critical compared to the flatscreen-reared alevins. By letting the salmon alevins have first feeding at swim-up, our sampling system provides a method for optimal timing for feeding which does not depend on the hatching conditions.
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Additional file 2. Metadata file. File containing all the metadata associated with the samples.
Additional file 7. OTU taxonomy file. Taxonomic classification of each OTU.
Additional file 4. PCR info file. File containing the information on the number of PCR cycles and dilution used for each sample.
Additional file 5. qPCR Ct values file. File containing the qPCR Ct value for each sample.
Additional file 9. Table with the p-values for all the mean Ct values comparison.
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The aim of the study was to investigate the presence, distribution and density of major histocompatibility complex (MHC) class II+ cells in the ocular tissues of the Atlantic salmon, Salmo salar, prior to and following vaccination. Eyes... more
The aim of the study was to investigate the presence, distribution and density of major histocompatibility complex (MHC) class II+ cells in the ocular tissues of the Atlantic salmon, Salmo salar, prior to and following vaccination. Eyes were collected 14 days prior to and at 4, 11, 25 and 39 days and 4 months subsequent to vaccination with a commercial fish vaccine. A quantitative analysis was performed in sections on the number of immunopositive cells in the retinal layers. In all groups, MHC class II+ cells were detected in the area of the limbus but not in the central parts of the cornea. In the uvea, immunopositive cells were present in unvaccinated and vaccinated fish. Abundant immunopositive cells were identified in the choroid rete (or choroid gland) in all groups as well as in the ventral ciliary cleft, where macrophage-like MHC class II+ cells were seen. Quantitative histology of the retina revealed a significant increase in MHC class II+ cells in the outer plexiform layer (OPL) and the inner nuclear layer (INL) 4 days following vaccination. Positive cells were detected in all layers of the retina with the exception of the photoreceptor layer.
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ABSTRACT
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ABSTRACT
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ABSTRACT
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Three feeds with different physical pellet quality but the same formulation were fed to Atlantic salmon for 97 days. Pellet quality was measured as bulk density, durability, fat leakage, hardness, water stability and porosity. The largest... more
Three feeds with different physical pellet quality but the same formulation were fed to Atlantic salmon for 97 days. Pellet quality was measured as bulk density, durability, fat leakage, hardness, water stability and porosity. The largest difference among the feeds was measured in hardness (201, 236 and 86 Newton for Diet 1, Diet 2 and Diet 3 respectively). The relative feed intake was highest in salmon fed Diet 2 and Diet 3 with no effects of pellet hardness. Growth and feed efficiency ratio were similar among all fish. The apparent digestibility of energy, dry matter, nitrogen and lipid was similar for all feeds, whereas the apparent digestibility of phosphorus and zinc was the lowest in Diet 3. Retention of energy, lipid and nitrogen was also similar for all feeds. Salmon fed Diet 1 and Diet 3 retained more phosphorus than those fed Diet 2. An increased retention of the digested zinc was found in salmon fed Diet 3. This study concludes that physical pellet quality affects feed in...
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Salmonids are important sources of protein for a large proportion of the human population. Mycoplasma species are a major constituent of the gut microbiota of salmonids, often representing the majority of microbiota. Despite the frequent... more
Salmonids are important sources of protein for a large proportion of the human population. Mycoplasma species are a major constituent of the gut microbiota of salmonids, often representing the majority of microbiota. Despite the frequent reported dominance of salmonid-related Mycoplasma species, little is known about the phylogenomic placement, functions and potential evolutionary relationships with their salmonid hosts. In this study, we utilise 2.9 billion metagenomic reads generated from 12 samples from three different salmonid host species to I) characterise and curate the first metagenome-assembled genomes (MAGs) of Mycoplasma dominating the intestines of three different salmonid species, II) establish the phylogeny of these salmonid candidate Mycoplasma species, III) perform a comprehensive pangenomic analysis of Mycoplasma, IV) decipher the putative functionalities of the salmonid MAGs and reveal specific functions expected to benefit the host. Our data provide a basis for fu...
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Background: Rainbow trout (Oncorhynchus mykiss) is a salmonid species with a complex life-history. Wild populations are naturally divided into freshwater residents and sea-run migrants. Migrants undergo an energy-demanding adaptation for... more
Background: Rainbow trout (Oncorhynchus mykiss) is a salmonid species with a complex life-history. Wild populations are naturally divided into freshwater residents and sea-run migrants. Migrants undergo an energy-demanding adaptation for life in seawater, known as smoltification, while freshwater residents display these changes in an attenuated magnitude and rate. Despite this, in seawater rainbow trout farming all animals are transferred to seawater. Under these circumstances, weeks after seawater transfer, a significant portion of the fish die (around 10%) or experience growth stunting (GS; around 10%), which represents an important profitability and welfare issue. The underlying causes leading to GS in seawater-transferred rainbow trout remain unknown. In this study, we aimed at characterising the GS phenotype in seawater-transferred rainbow trout using untargeted and targeted approaches. To this end, the liver proteome (LC-MS/MS) and lipidome (LC-MS) of GS and fast-growing pheno...