| 1. |
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| 2. |
- Blomqvist, Johanna, et al.
(författare)
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Oleaginous yeast as a component in fish feed
- 2018
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the replacement of vegetable oil (VO) in aquaculture feed for Arctic char (Salvelinus alpinus) with oil produced by the oleaginous yeast Lipomyces starkeyi grown in lignocellulose (wheat straw) hydrolysate. VO is extensively used to partially replace fish oil in aquaculture feed, which can be seen as non-sustainable. VO itself is becoming a limited resource. Plant oils are used in many different applications, including food, feed and biodiesel. Its replacement in non-food applications is desirable. For this purpose, yeast cells containing 43% lipids per g dry weight were mechanically disrupted and incorporated into the fish feed. There were no significant differences in this pilot study, regarding weight and length gain, feed conversion ratio, specific growth rate, condition factor and hepatosomatic index between the control and the yeast oil fed group. Fatty and amino acid composition of diet from both groups was comparable. Our results in fish demonstrate that it is possible to replace VO by yeast oil produced from lignocellulose, which may broaden the range of raw materials for food production and add value to residual products of agriculture and forestry.
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| 3. |
- Brandenburg, Jule, et al.
(författare)
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Oleaginous yeasts respond differently to carbon sources present in lignocellulose hydrolysate
- 2021
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Ingår i: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Background Microbial oils, generated from lignocellulosic material, have great potential as renewable and sustainable alternatives to fossil-based fuels and chemicals. By unravelling the diversity of lipid accumulation physiology in different oleaginous yeasts grown on the various carbon sources present in lignocellulose hydrolysate (LH), new targets for optimisation of lipid accumulation can be identified. Monitoring lipid formation over time is essential for understanding lipid accumulation physiology. This study investigated lipid accumulation in a variety of oleaginous ascomycetous and basidiomycetous strains grown in glucose and xylose and followed lipid formation kinetics of selected strains in wheat straw hydrolysate (WSH). Results Twenty-nine oleaginous yeast strains were tested for their ability to utilise glucose and xylose, the main sugars present in WSH. Evaluation of sugar consumption and lipid accumulation revealed marked differences in xylose utilisation capacity between the yeast strains, even between those belonging to the same species. Five different promising strains, belonging to the species Lipomyces starkeyi, Rhodotorula glutinis, Rhodotorula babjevae and Rhodotorula toruloides, were grown on undiluted wheat straw hydrolysate and lipid accumulation was followed over time, using Fourier transform-infrared (FTIR) spectroscopy. All five strains were able to grow on undiluted WSH and to accumulate lipids, but to different extents and with different productivities. R. babjevae DVBPG 8058 was the best-performing strain, accumulating 64.8% of cell dry weight (CDW) as lipids. It reached a culture density of 28 g/L CDW in batch cultivation, resulting in a lipid content of 18.1 g/L and yield of 0.24 g lipids per g carbon source. This strain formed lipids from the major carbon sources in hydrolysate, glucose, acetate and xylose. R. glutinis CBS 2367 also consumed these carbon sources, but when assimilating xylose it consumed intracellular lipids simultaneously. Rhodotorula strains contained a higher proportion of polyunsaturated fatty acids than the two tested Lipomyces starkeyi strains. Conclusions There is considerable metabolic diversity among oleaginous yeasts, even between closely related species and strains, especially when converting xylose to biomass and lipids. Monitoring the kinetics of lipid accumulation and identifying the molecular basis of this diversity are keys to selecting suitable strains for high lipid production from lignocellulose.
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| 4. |
- Brunel, Mathilde, et al.
(författare)
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Oleaginous yeast Rhodotorula toruloides biomass effect on the metabolism of Arctic char (Salvelinus alpinus)
- 2022
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Ingår i: Frontiers in Molecular Biosciences. - : Frontiers Media SA. - 2296-889X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Sustainability issues arise when using fish oil and vegetable oils in fish feed production for aquaculture purposes. Microbial production of single cell oil is a potential alternative as a lipid ingredient in the production of fish feed. In this study, we replaced the vegetable oils with the oleaginous yeast R. toruloides biomass in the diet of Arctic char (S. alpinus) and investigated the effects on health and composition. Measurement of fish growth parameters showed a higher liver weight and hepatosomatic index in the experimental group of fish fed partly with yeast biomass compared to a control group fed a diet with vegetable oils. No significant differences in the lipid content of muscle and liver tissues were found. The fatty acid profiles in the muscle of both fish groups were similar while the experimental fish group had a higher amount of monounsaturated fatty acids in the liver. Histology of livers showed no significant difference in the number of lipid droplets. The size of hepatic lipid droplets seemed to be related to liver fat content. Quantification of metabolites in the liver revealed no differences between the fish groups while plasma metabolites involved in energy pathways such as alanine, 3-hydroxybutyrate, creatinine, serine, betaine, and choline were significantly higher in the experimental fish group.
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| 5. |
- Cerveny, Daniel, et al.
(författare)
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Insect Meal as a Partial Replacement for Fish Meal in a Formulated Diet for Perch Perca fluviatilis
- 2020
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Ingår i: Turkish Journal Of Fisheries And Aquatic Sciences. - : Central Fisheries Research Institute (SUMAE). - 1303-2712. ; 20, s. 867-878
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Tidskriftsartikel (refereegranskat)abstract
- The growing importance of aquaculture products for human health also raises the question of product sustainability and decreasing its costs. Insects are considered as novel feed ingredients and source of proteins. In this study, a twelve-week feeding trial with replacement of 25% fishmeal by a mixture of house cricket (Acheta domesticus) and superworm (Zophobas morio) in the fish feed was conducted with perch (Perca fluviatilis). There were no significant differences in this feeding trial, regarding survival, but decreased fish growth and increased feed conversion between the control and the experimental fed groups. Hepatic cytochrome P450 (CYP1A and CYP3A-like) activity and fatty acid (FA) composition were assessed in perch also. No significant effects were observed on cytochrome P450 activity associated with presence of toxic compounds in fish. Feeding with insect pellets resulted in significant increasing of linoleic FA and an increase of the total content of n-6 FA in fish fillets, compared to the fish fillets from control group. However, changes in FA composition were only minor and did not affect the nutritional value of the fish with insect-based diet for human consumption. Further evaluation should be conducted with different ratios or different insect species.
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| 6. |
- Chmielarz, Mikolaj, et al.
(författare)
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FT-NIR: a tool for rapid intracellular lipid quantification in oleaginous yeasts
- 2019
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Ingår i: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundLipid extraction for quantification of fat content in oleaginous yeasts often requires strong acids and harmful organic solvents; it is laborious and time-consuming. Therefore, in most cases just endpoint measurements of lipid accumulation are performed and kinetics of intracellular lipid accumulation is difficult to follow. To address this, we created a prediction model using Fourier-transform near-infrared (FT-NIR) spectroscopy. This method allows to measure lipid content in yeast.MethodsThe FT-NIR calibration sets were constructed from spectra of freeze-dried cells of the oleaginous yeasts Rhodotorula toruloides CBS 14, Lipomyces starkeyi CBS 1807 and Yarrowia lipolytica CBS 6114. The yeast cells were obtained from different cultivation conditions. Freeze-dried cell pellets were scanned using FT-NIR in the Multi Purpose Analyser (MPA) from Bruker. The obtained spectra were assigned corresponding to total fat content, obtained from lipid extraction using a modified Folch method. Quantification models using partial least squares (PLS) regression were built, and the calibration sets were validated on independently cultivated samples. The R. toruloides model was additionally tested on Rhodotorula babjevae DBVPG 8058 and Rhodotorula glutinis CBS 2387.ResultsThe R-2 of the FT-NIR model for R. toruloides was 98%, and the root mean square error of cross-validation (RMSECV) was 1.53. The model was validated using a separate set of R. toruloides samples with a root mean square error of prediction (RMSEP) of 3.21. The R-2 of the Lipomyces model was 96%, with RMSECV 2.4 and RMSEP 3.8. The R-2 of the mixed model, including all tested yeast strains, was 90.5%, with RMSECV 2.76 and RMSEP 3.22, respectively. The models were verified by predicting the total fat content in newly cultivated and freeze-dried samples. Additionally, the kinetics of lipid accumulation of a culture were followed and compared with standard lipid extraction methods.ConclusionsUsing FT-NIR spectroscopy, we have developed a faster, less laborious and non-destructive quantification of yeast intracellular lipid content compared to methods using lipid extraction.
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| 7. |
- Chmielarz, Mikolaj, et al.
(författare)
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Microbial lipid production from crude glycerol and hemicellulosic hydrolysate with oleaginous yeasts
- 2021
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Ingår i: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Background Crude glycerol (CG) and hemicellulose hydrolysate (HH) are low-value side-products of biodiesel transesterification and pulp-and paper industry or lignocellulosic ethanol production, respectively, which can be converted to microbial lipids by oleaginous yeasts. This study aimed to test the ability of oleaginous yeasts to utilise CG and HH and mixtures of them as carbon source. Results Eleven out of 27 tested strains of oleaginous yeast species were able to grow in plate tests on CG as sole carbon source. Among them, only one ascomycetous strain, belonging to Lipomyces starkeyi, was identified, the other 10 strains were Rhodotorula spec. When yeasts were cultivated in mixed CG/ HH medium, we observed an activation of glycerol conversion in the Rhodotorula strains, but not in L. starkeyi. Two strains-Rhodotorula toruloides CBS 14 and Rhodotorula glutinis CBS 3044 were further tested in controlled fermentations in bioreactors in different mixtures of CG and HH. The highest measured average biomass and lipid concentration were achieved with R. toruloides in 10% HH medium mixed with 55 g/L CG-19.4 g/L and 10.6 g/L, respectively, with a lipid yield of 0.25 g lipids per consumed g of carbon source. Fatty acid composition was similar to other R. toruloides strains and comparable to that of vegetable oils. Conclusions There were big strain differences in the ability to convert CG to lipids, as only few of the tested strains were able to grow. Lipid production rates and yields showed that mixing GC and HH have a stimulating effect on lipid accumulation in R. toruloides and R. glutinis resulting in shortened fermentation time to reach maximum lipid concentration, which provides a new perspective on converting these low-value compounds to microbial lipids.
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| 8. |
- Ewald, Nils, et al.
(författare)
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Fatty acid composition of black soldier fly larvae (Hermetia illucens) - Possibilities and limitations for modification through diet
- 2020
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 102, s. 40-47
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Tidskriftsartikel (refereegranskat)abstract
- Black soldier fly larvae (Hermetia illucens; BSFL) can convert organic wastes into a nutrient-rich biomass suitable in animal feed, which could be a way to achieve more sustainable production of food. However, little is known about how the diet fed to BSFL affects their nutritional value, especially their fatty acid composition. In this study, BSFL were fed 11 diets based on four different organic waste sources (mussels, bread, fish and food waste). Fatty acid and proximate composition (dry matter, crude fat, crude protein and ash) were analysed in the diets, in two-week-old larvae and substrate residues. Larval weight, survival and feed conversion were also recorded. The diet was found to affect all parameters investigated. Irrespective of diet, the larval fat consisted mainly of lauric acid and other saturated fatty acids and these were found to be synthesised by the larvae. However, both the fatty acid composition of the substrate, and the larval weight were found to affect the fatty acid profile of the larvae. In general, larvae with a higher weight contained a higher percentage of saturated fatty acids and a lower percentage of unsaturated fatty acids, such as eicosapentaenoic (EPA) and docosahexaenoic acid (DHA). It was concluded that the possibilities to tailor the fatty acid composition of the BSFL through the diet are limited; thus, the BSFL fat may not be suitable to replace fish oil, but has potential of inclusion in other food, feed and fuel products. (C) 2019 The Authors. Published by Elsevier Ltd.
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| 9. |
- Lindahl, Gunilla, et al.
(författare)
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Ageing of large cuts of beef loin in vacuum or high oxygen modified atmosphere - Effect on shear force, calpain activity, desmin degradation and protein oxidation
- 2010
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Ingår i: Meat Science. - : Elsevier BV. - 0309-1740 .- 1873-4138. ; 85, s. 160-166
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to investigate the effect of ageing large beef cuts directly in high oxygen modified atmosphere (MA) and how ageing time in vacuum influence meat quality when followed by retail packaging in high oxygen MA. Large cuts (10 cm long) of beef loin (LD) were aged for up to 25 days postmortem in different ageing systems at 4 degrees C. Ageing solely in high oxygen modified atmosphere (MA, 80% O(2) + 20% CO(2)) for 5 or 10 days and ageing in vacuum for 5 or 15 days followed by high oxygen MA for 5 or 10 days were compared with ageing in vacuum for 5, 15 and 25 days. Warner-Bratzler shear force, purge and cooking losses, calpain activity and desmin and carbonyl contents were measured. Shear force decreased to the same level when ageing this large beef cut solely in high oxygen MA for 5 or 10 days as when ageing in vacuum. The activity of mu-calpain disappeared, the activity of m-calpain decreased and purge loss increased between 5 and 10 days, but cooking loss and the contents of desmin and carbonyls were unaffected. The ageing time in vacuum before packaging of this large beef cut in high oxygen MA did not affect the ultimate shear force. The m-calpain activity decreased and the content of carbonyls increased compared with solely in vacuum after 15 days of total ageing, but there was no difference in the content of desmin or cooking loss between these ageing systems at the same ageing time. (C) 2009 Elsevier Ltd. All rights reserved.
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| 10. |
- Lu, Jing, et al.
(författare)
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Lipolysis and Oxidation in Ultra-High Temperature Milk Depend on Sampling Month, Storage Duration, and Temperature
- 2019
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Ingår i: Journal of Food Science. - : Wiley. - 0022-1147 .- 1750-3841. ; 84, s. 1045-1053
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Tidskriftsartikel (refereegranskat)abstract
- During storage, some factors (for example, storage duration and temperature) can affect milk stability and consumer acceptability. Thiobarbituric acid reactive substances (TBARSs), lipid classes, and fatty acid profiles in stored ultra-high temperature (UHT) milk were analyzed to assess the effects of storage time and temperature on lipid oxidation and lipolysis. With storage duration up to 12 months, the milk fat phase was separated and showed high levels of oxidation and lipolysis, manifested as increased levels of TBARS and free fatty acids. High oxidation levels decreased the percentage of unsaturated fatty acids (UFAs) in triacylglycerol and phospholipids. Higher storage temperatures (20, 30, and 37 degrees C) resulted in a higher degree of fat aggregation, oxidation, and lipolysis compared with refrigerated storage (4 degrees C). Additionally, sampling month of raw milk (May, July, and November) affected the lipid profiles of UHT milk during storage, with more UFA oxidized in July than in the other 2 months.
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| 11. |
- Nagavara Nagaraj, Yashaswini, et al.
(författare)
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Identification, Quantification and Kinetic Study of Carotenoids and Lipids in Rhodotorula toruloides CBS 14 Cultivated on Wheat Straw Hydrolysate
- 2022
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Ingår i: Fermentation. - : MDPI AG. - 2311-5637. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Production of carotenoids and lipids by Rhodotorula toruloides CBS 14 cultivated on wheat straw hydrolysate was investigated. An ultra-high-performance liquid chromatography (UHPLC) method for carotenoid quantification was developed and validated. Saponification effects on individual carotenoid quantification were identified, and lipid and carotenoid kinetics during cultivation were determined. The carotenoids beta-carotene, gamma-carotene, torularhodin, and torulene were identified; beta-carotene was the major carotenoid, reaching a maximum of 1.48 mg/100 g dry weight. Recoveries of the carotenoids were between 66% and 76%, except torulene and torularhodin, which had lower recoveries due to saponification effects. Total carotenoid content in saponified and unsaponified yeast extract, respectively, determined by UHPLC or photometer, respectively, was 1.99 mg/100 g and 4.02 mg beta-EQ/100 g dry weight. Growth kinetics showed a positive correlation between carotenoid content and lipid accumulation. beta-carotene was the major carotenoid at all time points. At the end of the cultivation, triacylglycerols (TAGs) were the major lipid class, with 58.1% +/- 3.32% of total lipids. There was also a high proportion of free fatty acids, reaching from 20.5% to 41.8% of total lipids. Oleic acid (C18:1) was the major fatty acid. The lipid yield at the end of the cultivation was 0.13 g/g of sugar consumed.
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| 12. |
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| 13. |
- Priyashantha, Hasitha, et al.
(författare)
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Composition and Properties Has Little Impact on Cheese Ripening: Insights from a Traditional Swedish Long-Ripening Cheese
- 2021
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Ingår i: Dairy. - : MDPI AG. - 2624-862X. ; 2, s. 336-355
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Tidskriftsartikel (refereegranskat)abstract
- The monthly variation in raw dairy silo milk was investigated and related to the ripening time of the resulting cheese during an industrial cheese-making trial. Milk composition varied with month, fat and protein content being lowest in August (4.19 and 3.44 g/100 g, respectively). Casein micelle size was largest (192–200 nm) in December–February and smallest (80 nm) in August. In addition, SCC, total bacteria count, proteolytic activities, gel strength, and milk fatty acid composition were significantly varied with month. Overall sensory and texture scores of resulting cheese were mainly influenced by plasmin and plasminogen activity, indicating the importance of native proteolytic systems. Recently, concepts based on the differentiated use of milk in dairy products have been suggested. For the investigated cheese type, there might be little to gain from such an approach. The variation in the investigated quality characteristics of the dairy milk used for cheese making had little effect on cheese ripening in our study. In contrast to our hypothesis, we conclude that as long as the quality of the milk meets certain minimum criteria, there are only weak associations between cheese milk characteristics and the time required for the development of aroma and texture in the cheese. To find answers behind the observed variation in cheese ripening time, studies on the effects of process parameters are needed.
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| 14. |
- Sampels, Sabine
(författare)
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Alteration of mRNA abundance, oxidation products and antioxidant enzyme activities during oocyte ageing in common carp Cyprinus carpio
- 2019
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Oocyte ageing is the most important factor affecting egg quality of several fish species after ovulation. Oxidative stress has been proposed as the initiator of the oocyte ageing process in other vertebrates. To identify the role of oxidative stress and apoptosis on the progress of oocyte ageing in the common carp Cyprinus carpio, changes in the relative mRNA abundance of selected transcripts were examined. The possible alteration in the oxidation status of the oocytes during ageing was also studied. In addition, the activity of antioxidant enzymes during oocyte ageing was evaluated. Oocytes from 6 females were incubated in vivo for 14 hours post-ovulation (HPO) and in vitro for 10 hours post-stripping (HPS) at 20 degrees C before fertilization. Hatching rates were over 65% up to 4-6 HPO, finally dropping to 1.3% at 12-14 HPO. Hatching rates were over 65% up to 4-6 HPO, finally dropping to 1.3% at 1214 HPO. Hatching rates were more than 70% for the eggs stored in vitro up to 6 HPS and then decreased to 21.3% at 10 HPS. The results demonstrated no significant changes in the relative mRNA levels of oxidative stress-related genes or genes involved in the cell cycle during the progress of oocyte ageing in common carp. Additionally, the amount of TBARS and carbonyls did not change as time elapsed following ovulation. The apoptosis-related genes however, were significantly altered following the prolonged time interval between ovulation and fertilization. The lack of response of both activities of antioxidant enzymes and oxidation products during oocyte ageing strengthens the conclusion that oxidative stress is unlikely to be a main factor determining the progress of oocyte ageing in common carp. However, an increase in the mRNA abundance of apoptosis-related genes demonstrates that apoptotic pathway might be involved in the progress of oocyte ageing.
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| 15. |
- Sampels, Sabine
(författare)
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Berry Marinades Enhance Oxidative Stability of Herring Fillets
- 2010
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 58, s. 12230–12237-
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Tidskriftsartikel (refereegranskat)abstract
- Marinating herring fillets in a 50 g/L powder of elderberry, cranberry, or black currant inhibited the oxidation of lipids and proteins and also the degradation of tocopherol. Cranberry and black currant appeared to be more efficient than elderberry in inhibiting the degradation of tocopherol and the formation of ammonium. Elderberry marinades provided the most significant color changes. The injection of fillets with a 5% salt solution resulted in significantly increased levels of carbonyls, ammonium, and biogenic amines, whereas formation of the volatile lipid compounds propanal, hexanal, 2-penten-1-ol, and 1-penten-3-ol was lowest in fillets marinated in black currant following injection of the salt solution. All marinade treatments resulted in a significantly decreased liquid holding ability, coinciding with a lower muscle pH. It is concluded that marinating herring fillets in solutions containing berry powder can enhance the quality and shelf life of the fillets and simultaneously provide the fillets with natural antioxidants beneficial for consumers.
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| 16. |
- Sampels, Sabine, et al.
(författare)
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Biomarker response, health indicators, and intestinal microbiome composition in wild brown trout (Salmo trutta m. fario L.) exposed to a sewage treatment plant effluent-dominated stream
- 2018
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 625, s. 1494-1509
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Tidskriftsartikel (refereegranskat)abstract
- Concerns about the effect of sewage treatment plant (STP) effluent on he health of freshwater ecosystems have increased. In this sludy, a unique approach was designed to show the effect of an STP effluent-dominaled stream on naive wild brown Luna (Sohn trultu L.) exposed under fully natural conditions. Zivny stream is located in South Bohemia, Czech Republic. The downstream site of Zivny stream is an STP-affecled sire, which receives 25% of is wafer from Prachalice STP effluent.. Upsffeam, however, is a minimally polluted water site and i is considered Lo be the control sire. Native fish were collected from the upstream site, Lagged, and distributed W both upstream and downstream sites. After 30, 90, and 180 days, fish were recaptured from both sites to determine whether the downstream site of the Zivny stream is associated with the effects of environmental pollution. Several biomarkers indicating the oxidative stress and antioxidant enzyme activities, cytochrome P450 activity, xenoestrogenic effects, bacterial composition, and lipid composition were investigated. Additionally, polar chemical contaminants (pharmaceuticals and personal care products (PPCPs)) were quantified using polar organic chemical integrative samplers (POCIS). Fifty-three PPCPs were detected in the downstream site; 36 of those were constantly present during the 180-day investigation period. Elevated hepatic 7-benzyloxy-4trifluoromethylcoumarin-0-debenzyloxylase (BFCOD) (alter 90 days) and blood plasma vitellogenin concentrations in males were detected in fish downstream of the SIP effluent during all sampling events. An increase in the fishes' total fat content was also observed, but with low levels of omega-3 fatty acid in muscle tissue. Two bacterial taxa related to activated sludge were found in the intestines of fish from downstream. Our results show that Prachatice STP is a major source of PPCPs in the Zivny stream, which has biological consequences on fish physiology. (C) 2018 Elsevier B.V. All rights reserved.
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| 17. |
- Sampels, Sabine
(författare)
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Comparison between lipid and protein oxidation progress in the tail and claw muscles of signal crayfish (Pacifastacus leniusculus)
- 2020
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Ingår i: International Journal of Food Science and Technology. - : Wiley. - 0950-5423 .- 1365-2621. ; 55, s. 3622-3629
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Tidskriftsartikel (refereegranskat)abstract
- Microbial activity and then oxidation progress are the most important freshness indicators during post-mortem. In this study, we monitored proteomic and microbial changes, as well as biochemical degradation, in the tail and claw muscles of crayfish stored for 12 days at +4 degrees C. One specified protein band at 107 kDa in the claw muscle and two specified protein bands in the tail muscle at 140 and 36-40 kDa were identified. Western blotting indicated a higher amount of oxidised proteins in the tail compared to the claw muscle. Tail muscle showed higher oxidation progress and calpain activity than claw one. Both muscles were spoiled after 12 days with respect to total viable counts. In the first days, calpain activity is the main reason for protein degradation, while protein oxidation dominates for the rest of the time. Lipid-protein oxidation progress showed probably, protein oxidation started earlier than lipid oxidation in both muscles.
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| 18. |
- Sampels, Sabine
(författare)
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Comparison of Quality Changes in Eurasian Perch (Perca fluviatilis L.) Fillets Originated from Two Different Rearing Systems during Frozen and Refrigerated Storage
- 2021
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Ingår i: Foods. - : MDPI AG. - 2304-8158. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- The current knowledge on how different Eurasian perch rearing systems impact the final fillet quality is scant. Therefore, two domestic storage conditions were investigated-10 months frozen (-20 degrees C) and 12 days refrigerated (+4 degrees C) storage conditions-in order to determine (i) how the choice of rearing system affects fillets quality during different processing conditions and (ii) if oxidative changes and other quality parameters were interactive. For the proposed idea, proteome analysis, oxidative changes, and some quality parameters were considered in this study. Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) indicated a higher loss of protein in the frozen fillets from ponds (PF) than the fillets from recirculating aquaculture systems (RAS) (RF). Western blot showed a higher protein carbonyls level in RF compared to PF, which was confirmed by the total protein carbonyls during frozen storage. PF indicated less liquid loss, hardness, and oxidation progress than RF in both storage conditions. The biogenic amines index (BAI) in the fillets from either origin showed acceptable levels during storage at +4 degrees C. Furthermore, the n-3/n-6 ratio was similar for both fillets. The deterioration of fillets during frozen storage was mainly caused by formation of ice crystals followed by protein oxidation, while protein oxidation was the main concern during refrigerated storage confirmed by principal component analysis (PCA) analysis.
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| 19. |
- Sampels, Sabine, et al.
(författare)
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Comparison of two different methods for the separation of lipid classes and fatty acid methylation in reindeer and fish muscle
- 2011
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Ingår i: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 128, s. 811-819
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Tidskriftsartikel (refereegranskat)abstract
- In the present study different methods for the separation of lipid classes and methylation were compared and evaluated for method optimisation in muscle tissue. Fish and reindeer muscle were tested as fish represents a high proportion of polyunsaturated FA (PUFA) and reindeer a moderate amount of PUFA. Lipids were separated either by solid phase extraction (SPE) into neutral (NL) and polar lipids (PL) or by thin layer chromatography into triacylglycerols (TAG) and phospholipids. All fractions were methylated with or without boron trifluoride (BF3). The two different separation methods showed differences between PL and phospholipids, while TAG and NL were largely similar. Methylation method did not lead to important differences when comparing within the different separation methods, though methylation with BF3 generally resulted in similar or higher values of methylated FA, indicating a more complete methylation. The content of PUFA in the muscle tissue did not affect these outcomes. Separation of lipids by SPE, followed by methylation with BF3 was judged to be the best overall method, though not suitable for analysis of samples with labile fatty acids. (C) 2011 Elsevier Ltd. All rights reserved.
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| 20. |
- Sampels, Sabine
(författare)
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Effect of cadmium on uptake of iron, zinc and copper and mRNA expression of metallothioneins in HepG2 cells in vitro
- 2017
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Ingår i: Toxicology in Vitro. - : Elsevier BV. - 0887-2333 .- 1879-3177. ; 44, s. 372-376
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Tidskriftsartikel (refereegranskat)abstract
- The intake of cadmium contaminated fish was mimicked by incubating human hepatoblastoma cells (Cell line HepG2) with a combination of different levels of cadmium (0-5 mu M) plus the n-3 fatty acids docosahexaenoic acid and eicosapentaenoic acid, which are typical for fish. Uptake of cadmium, iron, copper and zinc was measured by ICP-MS. In addition mRNA expression of two metallothioneins (mt1 g and mt1 m) was evaluated by real-time PCR.The obtained data shows that the presence of cadmium increases the uptake of iron and zinc into the HepG2 cells while the uptake of copper remains unaffected. The presence of the chosen fatty acids did not affect the uptake of either cadmium or iron, zinc and copper. The presence of already 1 mu M cadmium increased the mRNA expression of mt1 g and mt1 m significantly, while the fatty acids did not interfere with the effect of cadmium.
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| 21. |
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| 22. |
- Sampels, Sabine, et al.
(författare)
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Effect of genetic background, pen size and outdoor access on meat quality in two slow growing broiler hybrids
- 2021
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Ingår i: Acta Agriculturae Scandinavica, Section A - Animal Science. - : Informa UK Limited. - 0906-4702 .- 1651-1972. ; 70, s. 13-22
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to evaluate the effect of two different rearing systems, indoor small pens (S) and big pens with outdoor access (B), on meat quality and fatty acid (FA) composition of two slow growing broiler hybrids (Rowan Ranger [RR] and Hubbard CYJA57 [H]). In addition, changes in the phospholipid FA composition, due to the possibility of more movement, were investigated. The results regarding meat quality were exclusively influenced by genotype, where RR chickens had higher breast weight, higher Warner-Bratzler shear force and higher pH than H chickens. Differences in lipid composition were found both due to hybrid and to the rearing system. The H birds were slightly leaner and had, therefore, higher proportions of phospholipids. Rearing in a big pen resulted in lower concentrations of 16:0 and higher concentrations of both total n-3 and n-6 fatty acids and of individual long chain polyunsaturated FA.
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| 23. |
- Sampels, Sabine, et al.
(författare)
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Effects of -linolenic acid and eicosapentaenoic acid from linseed and algae, respectively, on reindeer (Rangifer tarandus tarandus L.) muscle fatty acid composition
- 2010
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Ingår i: Acta agriculturae Scandinavica. Section A, Animal science. - : Informa UK Limited. - 0906-4702 .- 1651-1972. ; 60:3, s. 175-186
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Tidskriftsartikel (refereegranskat)abstract
- In an earlier study, we concluded that pellet-fed reindeer could not elongate 18:3n - 3 (-linolenic acid - ALA) sufficiently towards long-chain polyunsaturated fatty acids (LC PUFA) and need supplementation of LC PUFA. The present work investigated that the addition of n - 3 LC PUFA to feed in combination with ALA would increase the LC PUFA in the meat. Two groups of reindeer were fed pellets containing either linseed cake or linseed cake combined with algae (Nannochloropsis oculata) for 6 weeks before slaughter. Dietary n - 6/n - 3 ratio had a distinct influence on meat fatty acid (FA) composition when comparing linseed and linseed algae-fed animals with animals fed a conventional diet. Increased dietary proportions of ALA and eicosapentaenoic acid (EPA) increased these FA in muscle and docosapentaenoic acid (DPA) and docosahexaenoic acid in the polar lipid fraction compared to the conventional-fed animals. We concluded that an increased proportion of dietary EPA might lead to an increased elongation towards DPA in muscle. Algae and linseed are possible additives to reindeer feed in order to assure a similar valuable FA composition as in pasturing animals.
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| 24. |
- Sampels, Sabine, et al.
(författare)
-
Egg oxidation status, antioxidant enzyme activities, lipid classes, fatty acid composition profile and embryo survival rates during in vitro oocyte ageing in tench Tinca tinca (Linnaeus, 1758)
- 2018
-
Ingår i: Aquaculture Research. - : Hindawi Limited. - 1355-557X .- 1365-2109. ; 49, s. 2305-2316
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Tidskriftsartikel (refereegranskat)abstract
- The effect of invitro storage of oocytes on embryos survival rate, egg oxidation status, antioxidant enzyme activities, lipid classes and fatty acid composition profile was investigated in common tench Tinca tinca. In order to identify the role of oxidative stress in the progress of oocyte ageing the levels of thiobarbituric acid reactive substances (TBARS) and carbonyls as indicators of lipid and protein oxidation were measured and the activity of antioxidant enzymes were examined. Stripped ova from six females were stored in cell culture plates at 20 degrees C for up to 10 hr post-stripping (HPS). The stored ova were fertilized and the embryo survival rates were assessed. The results indicated that tench eggs could be successfully stored invitro for 4 hr after stripping at 20 degrees C. Superoxide dismutase enzyme activity increased at 6 HPS, whereas glutathione peroxidase and glutathione reductase activities decreased in oocytes during in vitro storage (p < .05) at 4 and 8 HPSs, respectively. The level of malondialdehyde did not show any significant changes during the progress of oocyte ageing. Carbonyls increased up to 2 HPS and thereafter decreased significantly. However, ova ageing did not affect the main lipid class composition and the fatty acid composition of the eggs. Lower quality eggs exhibited lower levels of cholesterol but higher levels of triacylglycerol.
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| 25. |
- Sampels, Sabine
(författare)
-
Essential fatty acids composition and oxidative stability of frozen minced carp meat
- 2022
-
Ingår i: International Journal of Food Properties. - : Informa UK Limited. - 1094-2912 .- 1532-2386. ; 25, s. 204-213
-
Tidskriftsartikel (refereegranskat)abstract
- This study aimed to introduce minced common carp (Cyprinus caprio L.) meat as a nutritional valuable by-product from carp filleting. This research was focused on fatty acid composition and considered its sensitivity to oxidation during frozen storage (-20 degrees C). Additionally, copper chloride was used to magnify possible oxidation reactions. A better understanding of minced carp meat quality and deterioration during frozen storage could help to promote the usage of this underestimated by-product. The utilization of this by-product for human consumption could be a useful way to increase the carp aquaculture economy and sustainability. The fatty acid profile showed a favorable content of essential fatty acids, as well as a beneficial ratio of omega-3/omega-6 polyunsaturated fatty acids. Furthermore, during 4 months of frozen storage (-20 degrees C), no significant changes were detected in fatty acid composition. Negligible changes were observed in the oxidation of lipids and proteins. The nutritional value and storage stability of minced carp meat was shown.
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| 26. |
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| 27. |
- Sampels, Sabine
(författare)
-
Insects in the feed of rainbow trout (Oncorhynchus mykiss): Effect on growth, fatty acid composition and sensory attributes
- 2020
-
Ingår i: Acta Ichthyologica et Piscatoria. - 0137-1592 .- 1734-1515. ; 50, s. 171–181-
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Tidskriftsartikel (refereegranskat)abstract
- Background. An ongoing quest for alternative feed sources in global aquaculture includes insect breeding for feed and food production. The aim of this study was to evaluate the effect of partial to full replacement of commercial diets with live insects on growth and health parameters of rainbow trout, as well as on sensory and texture attributes and fatty acid composition of fish muscle. Material and methods. Five isocaloric diets containing commercial pellets and live insects were evaluated in rainbow trout, Oncorhynchus mykiss (Walbaum, 1792), in a 60-day feeding trial. Control Group (K) was fed commercial pellets only. In other groups, 25% gross energy of pellets was replaced by live adult house cricket, Acheta domestica (Group C), live superworm, Zophobas morio larvae (Group L), or a combination of 12.5% crude energy of each (group LC). The insect-only group (I) was fed live cricket and superworm only (50% by 50% crude energy). Results. No significant differences were found in growth, survival, feed conversion ratio (dry basis), or energy utilization between groups. The protein efficiency ratio was highest in Group K and decreased with increasing cricket proportion. Insect inclusion was associated with lower content of nutritionally valuable n-3 fatty acid in fish muscle. Subjective sensory evaluation of cooked fillets revealed significantly less acceptable taste, aroma, and aftertaste in Group I than for Groups K, L, and LC. Some differences were found in the whiteness and redness of fillets between groups. The control group had significantly lower hardness compared to those receiving insect diets. No gross morphological or histopathological anomalies of viscera in any group and no significant differences in 7-ethoxyresorufin-O-deethylase activity were observed.Conclusions. Live insects replaced the commercial diet of the equivalent caloric level without negative effects on the growth or health of rainbow trout. The lower content of n-3 fatty acids and differences in color and texture of fillets from fish fed insects may influence acceptability to consumers. The high cost of insects compared to commercial feed currently limits their widespread use in trout production.
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| 28. |
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| 29. |
- Sampels, Sabine
(författare)
-
mRNA abundance changes during invitro oocyte ageing in African catfish Clarias gariepinus (Burchell, 1822)
- 2018
-
Ingår i: Aquaculture Research. - : Hindawi Limited. - 1355-557X .- 1365-2109. ; 49, s. 1037-1045
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Tidskriftsartikel (refereegranskat)abstract
- Delayed fertilization following ovulation leads to the oocyte ageing which has been identified as the most important factor affecting egg quality after ovulation. Very little is known about the molecular changes associated with the progress of oocyte ageing. The present study monitored the egg viability rates during post-stripping oocyte ageing in African catfish Clarias gariepinus. In addition the mRNA abundance of selected genes were studied during the progress of oocyte ageing by real time quantitative PCR. To study how maternal transcripts influence egg quality, expression levels were correlated with egg hatching rates. The highest embryo survival and hatching rates (88% and 81%, respectively) were obtained from eggs that were fertilized immediately after stripping. Complete loss of egg viability occurred at 16 and 24 hr Post Stripping (HPS) when eggs were stored at 25 degrees C and 4 degrees C respectively. Under both storage temperatures, the embryo mortality and larval malformation rates increased significantly over time and were the highest in the most aged oocytes. Genes indicating an upward trend in expression during ova ageing were determined to be related to oxidative injury and the stress response (hsp70), mitochondrial function (calmodulin), apoptosis (cathepsin D) and germ line speciation (vasa and sox9a). The results suggest that oxidative stress and mitochondrial dysfunction might be associated with post-stripping ova ageing and the consequent induction of egg quality defects. The examined genes may be considered as candidate markers of egg quality associated with oocyte ageing in African catfish.
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| 30. |
- Sampels, Sabine
(författare)
-
Nutritional Value of Fish: Lipids, Proteins, Vitamins, and Minerals
- 2018
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Ingår i: Reviews in Fisheries Science & Aquaculture. - : Informa UK Limited. - 2330-8249 .- 2330-8257. ; 26, s. 243-253
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Tidskriftsartikel (refereegranskat)abstract
- The present review aims to give a concise review about important nutrients from fish and their impact on human health. In addition, possible effects of rearing system and feeding on the most vulnerable group of nutrients, the lipids, are summarized.Fish are considered as nutritionally valuable part of the human diet and consumption two times a week is recommended, mostly due to the content of long chain polyunsaturated n-3 fatty acids. These fatty acids are essential in human nutrition and have proven to be involved in many metabolic functions. Among others, they have anti-inflammatory effects, decrease platelet aggregation and are essential parts in the cell membranes, cardiovascular system, brain, and nervous tissue.In addition the proteins, peptides and amino acids from fish became more recently known for having positive health effects. Furthermore fish is also a rich source of certain vitamins and minerals as Vitamin D, selenium, phosphorus, and calcium.It should be highlighted that, when considering nutrition and related health aspects, it is impossible to focus one group of nutrients separately. Most probably the discussed effects of fish on human health are due to the consumption of the fish as a whole and hence the combination of all present nutrients.
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| 31. |
- Sampels, Sabine, et al.
(författare)
-
Nutritional value of several commercially important river fish species from the Czech Republic
- 2018
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Ingår i: PeerJ. - : PeerJ. - 2167-8359. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Proximate and fatty acid (FA) composition of seven freshwater fish species from the Czech Republic were examined. Moreover, the index of atherogenicity (IA) and the index of thrombogenicity (IT) were calculated from the obtained data. These two indices along with the total content of the essential n-3 FAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) as well as the ratio of n-6/n3 FAs, provide good indicators for the nutritional value of the fish. The species had been selected owing to the limited amount of information about their nutritional composition available. Furthermore, they are not typically subject to aquaculture, being almost exclusively obtained by angling. The protein content was relatively stable in all species (17.1 +/- 1.55 to 19.2 +/- 2.20 g/100 g). The content of carbohydrates ranged from 0.02 +/- 0.1 to 0.99 +/- 0.0 g/100 g and ash from 1.08 +/- 0.20 to 2.54 +/- 1.57 g/100 g. As expected, a high variability was observed in the fat content (0.74 +/- 0.04 to 4.04 +/- 0.81 g/100 g) and the FA composition, as well as the contents of EPA and DHA. IA and IT were close to the values stated for the Eskimo diet, indicating a high nutritional value with a positive effect for human health.
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| 32. |
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| 33. |
- Sampels, Sabine
(författare)
-
Relationship between lipid and protein oxidation in fish
- 2019
-
Ingår i: Aquaculture Research. - : Hindawi Limited. - 1355-557X .- 1365-2109. ; 50, s. 1393-1403
-
Forskningsöversikt (refereegranskat)abstract
- Reactive oxygen species (ROS) are generated in all aerobic organisms. Free radicals are highly reactive ROS that cause damage to biological materials. Fish is rich in polyunsaturated fatty acids, and hence, very prone to lipid peroxidation. Both lipid and protein oxidations are important for quality loss during storage of fish, with high impact on taste and texture. Also, there are interactions between protein and secondary lipid oxidation products (aldehydes) that occur in foods because the oxidation products from one reaction can further react with both lipids and proteins respectively. This review focuses on the mechanisms and pathways of the lipid and protein oxidation and their possible relationship. Additionally, the target amino acids and final impacts of this relationship were considered. We propose that the products of lipid oxidation promote protein oxidation in fish rather than the other way around specially, during frozen storage, while during postmortem changes protein oxidation dominates. Finally, it seems that, secondary products of lipid oxidation might have more impact on the functionality of proteins from both Michael addition and Schiff base reaction rather than lipid hydroperoxides and lipid radical transfer.
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| 34. |
- Sampels, Sabine
(författare)
-
Relationship of Motility Activation to Lipid Composition, Protein Profile, and Swelling Rate of Burbot Lota lota Spermatozoon Following Change of Temperature and Osmolality
- 2021
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Ingår i: Frontiers in marine science. - : Frontiers Media SA. - 2296-7745. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Despite available information on the roles of osmotic pressure, potassium (K+), and calcium (Ca2+) in activation of Eurasian burbot spermatozoon motility, the changes in milt biochemical composition and mechanisms underlying their activation at temperatures above optimal spawning temperature is still unclear. We explored spermatozoon swelling, lipid composition and proteome in relation to osmolality and temperature of swimming medium. The result revealed that temperature increment from 4 to 30 degrees C increases burbot spermatozoa vulnerability to osmotic pressure, decreasing motility in extremely hypotonic media, and the presence of Ca2+ decreases swelling of spermatozoa. No spermatozoon swelling was observed in non-ionic isotonic media at all studied temperatures. A role of swelling in activation of spermatozoa motility at 30 degrees C was rejected. No differences were found in protein profile and lipid composition with respect to activation of burbot spermatozoa at 30 degrees C. Burbot spermatozoon activation occurs at 30 degrees C without modification of the spermatozoon membrane. Elucidation of the intrinsic signaling pathway of burbot spermatozoon spontaneous activation requires further study.
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| 35. |
- Sampels, Sabine
(författare)
-
Sperm motility and lipid composition in internally fertilizing ocellate river stingray Potamotrygon motoro
- 2019
-
Ingår i: Theriogenology. - : Elsevier BV. - 0093-691X .- 1879-3231. ; 130, s. 26-35
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Tidskriftsartikel (refereegranskat)abstract
- All extant groups of Elasmobranches have internal fertilization and the structure of the male reproductive organs is very specific: sperm passes from the internal organs via the cloaca, but the male copulating organ (clasper) is distant from the cloaca. This suggests that sperm can contact the surrounding medium before fertilization. Because of this involvement with the environment, external signaling in sperm motility activation could occur in these species even though their fertilization mode is internal. In this case, spermatozoa of Elasmobranches should hypothetically possess a specific structure and membrane lipid composition which supports physiological functions of the sperm associated with environmental tonicity changes occurring at fertilization. Additionally, sperm motility properties in these taxa are poorly understood. The current study examined sperm lipid composition and motility under different environmental conditions for the ocellate river stingray, Potamotrygon motoro, an endemic South America freshwater species. Sperm samples were collected from six mature males during the natural spawning period. Sperm motility was examined in seminal fluid and fresh water by light video microscopy. Helical flagellar motion was observed in seminal fluid and resulted in spermatozoon progression; however, when diluted in fresh water, spermatozoa were immotile and had compromised structure. Lipid class and fatty acid (FA) composition of spermatozoa was analyzed by thin layer and gas chromatography. Spermatozoa FAs consisted of 33 +/- 1% saturated FAs, 28 +/- 1% monounsaturated FAs (MUFAs), and 41 +/- 1% polyunsaturated FAs (PUFAs), and a high content of n-6 FAs (32 +/- 2%) was measured. These results allowed us to conclude that sperm transfer from P. motoro male into female should occur without coming into contact with the hypotonic environment so as to preserve potent motility. In addition, this unusual reproductive strategy is associated with specific spermatozoa structure and lipid composition. Low level of docosahexaenoic acid and relatively low PUFA/MUFA ratio probably account for the relatively low fluidity of freshwater stingray membrane and can be the main reason for its low tolerance to hypotonicity. (C) 2019 Elsevier Inc. All rights reserved.
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| 36. |
- Sampels, Sabine
(författare)
-
Spermatozoa quality and sperm lipid composition in intensively cultured and wild burbot (Lota iota)
- 2018
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Ingår i: Animal Reproduction Science. - : Elsevier BV. - 0378-4320 .- 1873-2232. ; 198, s. 129-136
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to compare the spermatozoa quality parameters in spermatozoa of RAS (Recirculating Aquaculture System; RAS group) cultured (commercial pellets) and natural condition cultured (WILD group) burbot Lota lota (live prey, Pseudorasbora parva). Seven of nine fish of the RAS group produced sperm, with sperm from only four of the fish having a motility of > 5%. Sperm were collected from all nine fish of the WILD group, and sperm of six of the fish from the WILD group had motility of about 100% and three had sperm with 50% to 60% motility. Spermatozoa from the RAS group had a delay in activation compared to the WILD group. Fish from the RAS group also had a lesser volume of sperm (1.8 +/- 1.2 mL) collected compared to the WILD group (3.6 +/- 1.2 mL). Compared to the RAS group, sperm of the WILD group had a greater proportion of saturated fatty acids (SFA), as well as the phospholipid, phosphatidylethanolamine. The findings indicate that fish grown in natural conditions may be more suitable as broodstock. Ongoing research to develop methods of enhancing reproductive performance of burbot broodstock cultured in RAS is needed to investigate whether the quality of sperm can be improved by adjusting environmental conditions, diet, or combination of these factors.
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| 37. |
- Sampels, Sabine, et al.
(författare)
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Sustainable Delicacy: Variation in Quality and Sensory Aspects in Wild Boar (Sus scrofa) Meat and Comparison to Pork Meat—A Case Study
- 2023
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Ingår i: Foods. - 2304-8158. ; 12
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate quality and sensory variation in wild boar meat in comparison to pork. Meat quality in wild boar is expected to vary more compared to pork due to different feeding environment, age and gender. In order to be able to promote wild boar meat as a sustainable high-quality product, there is a need to evaluate the variation in meat quality attributes, including technological, compositional and sensory/texture aspects. We evaluated carcass characteristics, pH, colour, lipid profile and sensory aspects of wild boar meat of different age and gender and compared them with pork. Wild boars had lower carcass weight (p = <0.0001) and higher ultimate pH (p = 0.0063) compared to domestic pigs. Intramuscular fat content had a tendency to be higher in wild boar meat (p = 0.1010), as well as the proportion of nutritional valuable n-3 FA (p = 0.0029). The colour of pork was more pink (p = 0.0276) and pale (p = <0.0001) compared to meat from wild boar. Meat from wild boar gilts received the highest sensory scores. Based on these findings, we suggest that meat from younger animals could be sold in different cuts directly while meat from older animals might be more suitable for the production of sausage.
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| 38. |
- Sampels, Sabine
(författare)
-
Swimming at different temperatures: The lipid composition of sperm from three freshwater fish species determined by mass spectrometry and nuclear magnetic resonance spectroscopy
- 2019
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Ingår i: Chemistry and Physics of Lipids. - : Elsevier BV. - 0009-3084 .- 1873-2941. ; 221, s. 65-72
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Tidskriftsartikel (refereegranskat)abstract
- The spawning behavior of different fish species is as diverse as their habitats. A lot of factors influence the (phospho)lipid composition of fish sperm, including the water temperature at which spawning takes place. Therefore, this study aimed on the elucidation of the phospholipid composition of sperm from three fish species from different orders (common carp - Cyprinus carpio, northern pike - Esox lucius and burbot - Lota lota) with different spawning temperatures by nuclear magnetic resonance spectroscopy (NMR), matrix-assisted laser desorption/ionization mass spectrometry and thin-layer chromatography (TLC) coupled to electrospray ionization mass spectrometry as well as gas chromatography.Next to the lipid composition that was different for carp, northern pike and burbot, regarding the moieties of the different (phospho)lipid classes (particularly sphingomyelin and acidic phospholipids) and the saturation degree of the fatty acyl residues, there were differences observed depending on the analytical method that was used. The results from TLC and NMR investigations differed regarding the amounts of the different phospholipids. Reasons for these discrepancies are discussed in detail.
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| 39. |
- Tiukova, Ievgeniia, 1987, et al.
(författare)
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Proteome analysis of xylose metabolism in Rhodotorula toruloides during lipid production
- 2019
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Ingår i: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834 .- 1754-6834. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Rhodotorula toruloides is a promising platform organism for production of lipids from lignocellulosic substrates. Little is known about the metabolic aspects of lipid production from the lignocellolosic sugar xylose by oleaginous yeasts in general and R. toruloides in particular. This study presents the first proteome analysis of the metabolism of R. toruloides during conversion of xylose to lipids. Results: Rhodotorula toruloides cultivated on either glucose or xylose was subjected to comparative analysis of its growth dynamics, lipid composition, fatty acid profiles and proteome. The maximum growth and sugar uptake rate of glucose-grown R. toruloides cells were almost twice that of xylose-grown cells. Cultivation on xylose medium resulted in a lower final biomass yield although final cellular lipid content was similar between glucose- and xylose-grown cells. Analysis of lipid classes revealed the presence of monoacylglycerol in the early exponential growth phase as well as a high proportion of free fatty acids. Carbon source-specific changes in lipid profiles were only observed at early exponential growth phase, where C18 fatty acids were more saturated in xylose-grown cells. Proteins involved in sugar transport, initial steps of xylose assimilation and NADPH regeneration were among the proteins whose levels increased the most in xylose-grown cells across all time points. The levels of enzymes involved in the mevalonate pathway, phospholipid biosynthesis and amino acids biosynthesis differed in response to carbon source. In addition, xylose-grown cells contained higher levels of enzymes involved in peroxisomal beta-oxidation and oxidative stress response compared to cells cultivated on glucose. Conclusions: The results obtained in the present study suggest that sugar import is the limiting step during xylose conversion by R. toruloides into lipids. NADPH appeared to be regenerated primarily through pentose phosphate pathway although it may also involve malic enzyme as well as alcohol and aldehyde dehydrogenases. Increases in enzyme levels of both fatty acid biosynthesis and beta-oxidation in xylose-grown cells was predicted to result in a futile cycle. The results presented here are valuable for the development of lipid production processes employing R. toruloides on xylose-containing substrates.
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| 40. |
- Zajic, Tomas, et al.
(författare)
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Fillet quality changes as a result of purging of common carp (Cyprinus carpio L.) with special regard to weight loss and lipid profile
- 2013
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486 .- 1873-5622. ; 400, s. 111-119
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Tidskriftsartikel (refereegranskat)abstract
- Purging is a very important part of the rearing process for common carp (Cyprinus carpio L.) in Central Europe and is commonly conducted between October and December. Fish are kept in clear water without feeding in order to empty the gut, decrease the entrail proportion and eliminate possible tainted flavour. This leads to weight loss and stored fat mobilisation. This study investigated the effect of a purging period of up to 70 days on lipid content and quality of common carp flesh. Four-year-old, market-size carp (weight 1700-2600 g) from three different production systems (C: cereal supplemented; P: linseed/rapeseed pellet supplemented; N: natural feed) were sampled every 14 days for weight, fillet yield and lipid analysis. Fillet yield was highest after 14 days and decreased thereafter. Throughout the experiment, fillet fat content decreased continuously in groups C and P, but remained stable in group N. Initially, carp from groups C and P mainly metabolised monounsaturated fatty acids (MUFAs), but with prolonged starvation fish from all groups started to metabolise more polyunsaturated fatty acids (PUFAs). After 70 days of purging, all groups showed almost identical saturated FA (SFA), MUFA and PUFA values. Our conclusion is that carp are able to metabolise selected FA for their energy needs when they are in good condition and have surplus fat stores. However, when body fat content is low, they may metabolise all FA types equally to sustain metabolic functions. (C) 2013 Elsevier B. V. All rights reserved.
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| 41. |
- Zajic, Tomas, et al.
(författare)
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Finishing feeding strategy as an instrument for modification of fatty acid composition of brook char (Salvelinus fontinalis)
- 2016
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Ingår i: Aquaculture International. - : Springer Science and Business Media LLC. - 0967-6120 .- 1573-143X. ; 24, s. 1641-1656
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the possibility of using a finishing feeding strategy and to apply a dilution model for the calculation of the content of fatty acids (FA) in farmed brook char (Salvelinus fontinalis). Four duplicate groups of fish with an initial weight 153.3 +/- 4.9 g(-1) were kept in a flow-through system for 135 days, during which they more than triplicated their weight. Control groups were fed the same unmodified commercial diet with 100 % fish oil (FO) or with 60 % fish oil and 40 % rapeseed oil (RO) mixture. Two groups were fed by RO diet followed by 45 (RO:45FO) and 90 (RO:90FO) days of FO diet, respectively, at the end of the growing period. The fillet FA composition at the end of the experiment corresponded with the FA composition of the lipid source in the diet for the tested groups. A significant (p < 0.05) impact on FA composition with a decreasing tendency in the representation of n-3 HUFA with a prolonged feeding period with the RO diet was observed. The application of a dilution model enabling the prediction of the content of a given fatty acid in a given time was successfully performed.
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| 42. |
- Zamaratskaia, Galia, et al.
(författare)
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The effects of sewage treatment plant effluents on hepatic and intestinal biomarkers in common carp (Cyprinus carpio)
- 2018
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 635, s. 1160-1169
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Tidskriftsartikel (refereegranskat)abstract
- Sewage treatment plants (STPs) are one of the major source of pharmaceuticals and personal care products in the aquatic environment. Generally, the effects of individual chemicals on fish are studied under laboratory conditions, which leads to results that are potentially not realistic regarding the effects of these chemicals under environmental conditions. Therefore, in this study, common carps were held in exposed pond that receive water from STP effluents for 360 days under natural conditions. Elimination of xenobiotics starts in the fish intestine, in which the microbial community strongly influences its function. Moreover, the fish intestine functions as crucial organ for absorbing lipids and fatty acids (FA), with consequent transport to the liver where their metabolism occurs. The liver is the primary organ performing xenobiotic metabolism in fish, and therefore, the presence of pollutants may interact with the metabolism of FA. The catalytic activity of CYP1A and CYP3A-like enzymes, their gene expression, FA composition and intestinal microbiome consortia were measured. The catalytic activity of enzymes and their gene and protein expression, were induced in hepatic and intestinal tissues of fish from the exposed pond. Also, fish from the exposed pond had different compositions of FA than those from the control pond: concentration of 18: 1 n-9 and 18: 2 n-6 were significantly elevated and the longer chain n-3 FA 20: 5 n-3, 22: 5 n-3 and 22: 6 n-3 were significantly lowered. There were clear differences among microbiome consortia in fish intestines across control and exposed groups. Microbiome taxa measured in exposed fish were also associated with those found in STP activated sludge. This study reveals that treated STP water, which is assumed to be clean, affected measured biomarkers in common carp. (C) 2018 Elsevier B.V. All rights reserved.
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