SuspensionFeeding Benthic Species’ Physiological and Microbiome Response to Salmon Farming and Associated Environmental Changes

Caged salmon farming is increasingly undertaken in water bodies with strong hydrodynamics where hard and mixed substrate habitats are more prevalent. Yet, these structurally complex and heterogeneous habitats support diverse benthic communities including several cnidarians and sponges that remain poorly characterized. This study used a combination of respirometry measurements, gas chromatography and 16S rRNA metabarcoding to define the respiration rate, stable carbon (δ13C) and nitrogen isotopes (δ15N), fatty acid (FA) and microbial profiles, and assess the impact of salmon farming on four important epibenthic suspension-feeders along the western Norwegian coast: the sponges Craniella and Weberella, the soft coral Duva florida and the anemone Hormathia digitata. Our results showed striking differences in fatty acid profiles and host microbiome communities in terms of identity, functional capabilities and genetic properties across the suspension-feeders. We found evidence of increased mortality rate in specimens located near fish farm activities and of a species-specific effect on respiration rate, with D. florida showing increased activity under the farm. Effects of fish farming on the suspension feeders were also species-specific and particularly evidenced by functional microbial turnover and by alteration of overall FA profiles in the soft coral and sea anemone. In particular, D. florida showed reduced level of FAs close to the farm (0-350 m), with significant difference in composition along a distance gradient. Only H. digitata showed evidence of incorporation of organic material from the fish farm waste via fatty acids trophic markers (FATM) and stable isotope analysis. Overall, our study demonstrates that suspension feeders have taxon-specific sensitivity towards the effect of salmon farming, and identified several potential molecular indicators that could be used as surrogate of impact gradient upon further research and validation. It also provides a wealth of ecological and physiological information on some of the most common sessile epibenthic organisms within Arctic and sub-Arctic regions, enabling us to better understand their response and evaluate their resilience to environmental changes.publishedVersio

Serum fatty acid and lipoprotein subclass concentrations and their associations in prepubertal healthy Norwegian children

Introduction The lipid metabolism is one of the most important and complex processes in the body. Serum concentrations of 18 fatty acids (FAs) and 24 lipoprotein features, i.e. concentrations of lipoprotein main and subclasses and average particle size in main classes, in 195 ethnic Norwegian children from the rural Fjord region were quantified by chromatography. Objectives To assess gender differences in prepubertal children and reveal predictive FA patterns for lipoprotein features. Methods Lipoprotein features were modelled from FA profiles using multivariate regression. Results Contrary to observations for adults from the same region, gender differences in prepubertal children were generally small. However, higher concentrations of C16–C18 FAs for girls compared to boys correlated to higher concentrations of triglycerides (TG) and very low density lipoprotein (VLDL) particles and larger average size of VLDL particles. Concentrations of high density lipoprotein (HDL) and its subclass of medium particle size were higher in boys than in girls. These findings are opposite to observations in adults from the same region, but reflect that prepubertal boys are more physically active than girls. Furthermore, children possessed only half the serum levels of eicosapentaenoic acid and docosahexaenoic acid measured in adults. Since sampling was done after 12 h of fasting, these differences may reflect higher rate of utilization of these crucial FAs in children. Conclusion Good predictive models were obtained for TGs, VLDL and chylomicrons with C14–C18 FAs as major contributors. Weak predictive associations were observed for HDL and Apolipoprotein A1 (ApoA1) with C20–C24 FAs as contributors.publishedVersio

Predictive associations between serum fatty acids and lipoproteins in healthy non-obese Norwegians: implications for cardiovascular health

A battery of methods for multivariate data analysis has been used to assess the associations between concentrations of fatty acids (FAs) and lipoprotein subclasses and particle size in serum for a normolipidemic population of ethnic Norwegians living in the rural Fjord region. Significant gender differences were found in the lipoprotein and FA patterns. Predictive FA patterns were revealed for lipoprotein features of importance for cardiovascular (CV) health. Thus, the subclasses of atherogenic small and very small low density lipoprotein (LDL) particles and the same subclasses of high density lipoprotein (HDL) particles were associated with a pattern of saturated FAs and mono-unsaturated C16-C18 FAs. Eicosapentaenoic acid (EPA) and the ratio of EPA to arachidonic acid (AA) had strongest associations to features that promotes CV health: (i) large average size of HDL and LDL particles, and, (ii) small average size of very low density lipoprotein (VLDL) particles. Total concentration of HDL in both genders correlated to EPA, but docosahexaenoic acid (DHA) correlated just as strongly for women. For men, docosapentaenoic acid (DPA) showed stronger association to HDL concentration than EPA. For both genders, concentration of large LDL particles showed associations to levels of EPA, but stronger to DHA and DPA. High values of EPA/AA seem to be the strongest single biomarker for good CV health in both men and women.publishedVersio

Intensive lifestyle intervention provides rapid reduction of serum fatty acid levels in women with severe obesity without lowering omega-3 to unhealthy levels

Serum fatty acid (FA) levels were monitored in women with severe obesity during intensive lifestyle intervention. At baseline, total FA levels and most individual FAs were elevated compared to a matching cohort of normal and overweight women (healthy controls). After 3 weeks of intensive lifestyle intervention, total level was only 11–12% higher than in the healthy controls and with almost all FAs being significantly lower than at baseline, but with levels of omega-3 being similar to the healthy controls. This is contrary to observations for patients subjected to bariatric surgery where omega-3 levels dropped to levels significantly lower than in the lifestyle patients and healthy controls. During the next 3 weeks of treatment, the FA levels in lifestyle patients were unchanged, while the weight loss continued at almost the same rate as in the first 3 weeks. Multivariate analysis revealed that weight loss and change of serum FA patterns were unrelated outcomes of the intervention for lifestyle patients. For bariatric patients, these processes were associated probably due to reduced dietary input and increased input from the patients’ own fat deposits, causing a higher rate of weight loss and simultaneous reduction of the ratio of serum eicosapentaenoic to arachidonic acid.publishedVersio

Comparing EPA production and fatty acid profiles of three Phaeodactylum tricornutum strains under western Norwegian climate conditions

Microalgae could provide a sustainable alternative to fish oil as a source for the omega-3 polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). However, growing microalgae on a large-scale is still more cost-intensive than fish oil production, and outdoor productivities vary greatly with reactor type, geographic location, climate conditions and microalgae species or even strains. The diatom Phaeodactylum tricornutum has been intensively investigated for its potential in large-scale production, due to its robustness and comparatively high growth rates and EPA content. Yet, most research have been performed in southern countries and with a single commercial P. tricornutum strain, while information about productivities at higher latitudes and of local strains is scarce. We examined the potential of the climate conditions in Bergen, western Norway for outdoor cultivation of P. tricornutum in flat panel photobioreactors and cultivated three different strains simultaneously, one commercial strain from Spain (Fito) and two local isolates (M28 and B58), to assess and compare their biomass and EPA productivities, and fatty acid (FA) profiles. The three strains possessed similar biomass productivities (average volumetric productivities of 0.20, 0.18, and 0.21 g L− 1 d− 1), that were lower compared to productivities reported from southern latitudes. However, EPA productivities differed between the strains (average volumetric productivities of 9.8, 5.7 and 6.9 mg L− 1 d− 1), due to differing EPA contents (average of 4.4, 3.2 and 3.1% of dry weight), and were comparable to results from Italy. The EPA content of strain Fito of 4.4% is higher than earlier reported for P. tricornutum (2.6–3.1%) and was only apparent under outdoor conditions. A principal component analysis (PCA) of the relative FA composition revealed strain-specific profiles. However, including data from laboratory experiments, revealed more significant differences between outdoor and laboratory-grown cultures than between the strains, and higher EPA contents in outdoor grown cultures.publishedVersio

Interpretation of chromatographic and mass spectrometric data from analyses of fatty acid methyl esters Application of multivariate methods

The purpose of this work has been to develop tools for fatty acid identification, with special emphasis on poly-unsaturated fatty acids and trans fatty acids. The work is based on application of gas chromatography with mass spectrometric detection and the fatty acids are analysed as fatty acid methyl esters (FAME). Various multivariate analytical techniques are applied as tools for interpretation of both chromatographic and spectral information. The ten papers are divided into five subsections with the following topics: Identification of FAME from shifts in retention indices: Papers I and II describe methods for partial identification of fatty acid structure from shifts in retention indices. These methods will basically provide information on the polarity (number of double bonds) and the chain lengths of the fatty acids. The procedure is not restricted to any particular class of fatty acids and may also be used to exclude compounds that are not fatty acids. Two-dimensional fatty acid retention indices (2D-FARI) are introduced in Paper II. Application to trans isomers: Papers III and IV are about trans isomers of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Paper III provides data about chromatographic properties of the trans isomers of EPA and DHA, which can be applied both for identification purposes and for optimisation of chromatographic parameters. A practical application of the data is shown in Paper IV. Prediction of equivalent chain lengths: Papers V and VI describe methods for prediction of equivalent chain lengths (ECL), which is the retention indices commonly applied for fatty acids. Paper V is restricted to polyunsaturated fatty acids with methylene-interrupted double bond systems. Paper VI is not restricted to a particular class of fatty acids, but 2D-FARI data must be available. Thus, the two procedures are complementary methods for ECL predictions. Identification of FAME from mass spectra: Paper VII and VIII are about multivariate analysis of mass spectra of FAME. In Paper VII it is shown that trans isomerism in certain positions has significant influence on the mass spectra of polyunsaturated fatty acids. In Paper VIIi it is shown that the number of double bonds in polyunsaturated fatty acids can be determined from selected ions in the mass spectra. Deconvolution of overlapping chromatographic peaks: Papers IX and X are about techniques for deconvolution of overlapping FAME peaks. Transformations for reduction of noise in the mass spectra were introduced in Paper IX. The transformations and the information from Paper VII about differences in the mass spectra caused by trans geometry were utilised for deconcvolution of overlapping chromatographic peaks of trans isomers in Paper X. Although the focus in this paper is basically on the quantification of the isomers, deconvolution of overlapping peaks has relevance also for the identification of the analytes because spectra and accurate retention times of the compounds are also provided

Rapport/Report 26/2007 English summary

Det er analysert for flyktige komponenter i 33 tørrfisker. Tørrfiskene ble inndelt i 4 del-forsøk. 1. Tørking på hjell kontra klimarom 2. Tørkeforsøk med referanse 3. Ulik kvalitet ved henging 4. Tørking stoppet ved frysing Det er kjørt PCA av alle del-forsøkene, men den forklarte variasjonen er så lav at der ikke er mulig på bakgrunn av flyktige komponenter å skille de ulike tørrfiskgruppene fra hverandre i del-forsøkene. Det er funnet mellom 76-88 flyktige komponenter i headspacen over tørrfisken hvor av ca 25 % ikke er identifisert.Flyktige komponenter i tørrfiskRapport/Report 26/2007 English summarypublishedVersio

Analyse av transfettsyrer i marine lipider – Risiko for falske positive

Transfettsyrer analyseres i dag nesten utelukkende ved hjelp av gasskromatografi på polare kapillærkolonner. Ved de betingelser som normalt anvendes for analyse av transfettsyrer vil fettsyrer som er naturlig tilstede i marine lipider kunne overlappe med C16 og C18 transfettsyrer. Dette kan lede til falske positive identifikasjoner. Elueringsmønsteret av transfettsyrer og fettsyrer i marine lipider ble studert ved å spore retensjonsindekser under varierende kromatografiske betingelser innenfor det området som normalt benyttes til analyse av transfettsyrer. Dette ble gjort på to forskjellige polare kapillærkolonner med cyanopropyl som den polare gruppen i stasjonærfasen. Totalt 17 mulige interferenter ble identifisert og mengdene av disse i utvalgte varer ble bestemt. De fleste av de kromatografiske overlappene som leder til falske positive kan unngås ved riktig optimalisering av de analytiske betingelsene, men det var ikke mulig å finne en enkelt tilstand som fullstendig eliminerer risikoen for falske positive. Fettsyrene som sannsynligvis vil bidra mest til for høye nivåer av transfettsyrer ved analyse med tradisjonelle metoder er 18:3 n–4 og 18:1 n–11.Rapport/Report 21/2011 English summaryAnalyse av transfettsyrer i marine lipider – Risiko for falske positivepublishedVersio