| 1. |
- Lundh, Torbjörn, et al.
(författare)
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In search for protein sources: Evaluating an alternative to the traditional fish feed for Arctic charr (Salvelinus alpinus L.)
- 2018
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486 .- 1873-5622. ; 486, s. 253-260
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Tidskriftsartikel (refereegranskat)abstract
- Traditional sources of protein in fish feed for salmonids, such as fishmeal, face sustainability problems. Therefore, ingredients not attractive for human consumption are increasingly being considered for the development of future feeds. However, it is uncertain how this alternative range of ingredients will affect fish growth, quality and consumer opinion. In this experimental study, we tested a new fish feed on Arctic charr, containing a protein mixture from the Baltic Sea and yeast, all ingredients unattractive for human consumption. This feed comprised of sprat (Sprattus sprattus) and herring (Clupea harengus), blue mussels (Mytilus edulis) and baker's yeast (Saccharomyces cerevisiae), in a ratio of three parts to the whole. Fish fed with this feed grew 11.5% less than the control group. The digestibility and microscopy analysis of the faeces suggested a lower digestibility of the test feed, presumably caused by the fish's inability to utilize the nutrients from the yeast cells. Consumers' perceptions of the final product were evaluated through a sensory evaluation, indicating no differences in scores of fillet quality between the two treatments. Potential implications of these results are discussed in context of feed composition, quality and other factors including species biology and season, which are relevant topics in the discussions on feed sustainability. Statement of relevance: Evaluating a feed mix unattractive for human consumption.
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| 2. |
- Vidakovic, Aleksandar, et al.
(författare)
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Evaluation of growth performance and intestinal barrier function in Arctic Charr (Salvelinus alpinus) fed yeast (Saccharomyces cerevisiae), fungi (Rhizopus oryzae) and blue mussel (Mytilus edulis)
- 2016
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Ingår i: Aquaculture Nutrition. - : Hindawi Limited. - 1353-5773 .- 1365-2095. ; 22:6, s. 1348-1360
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Tidskriftsartikel (refereegranskat)abstract
- Arctic charr (Salvelinus alpinus) were fed for 99 days on experimental diets with 40% of fish meal replaced, on a crude protein basis, with intact yeast (Saccharomyces cerevisiae) (ISC), extracted yeast (ESC), Rhizopus oryzae fungus (RHO) or de-shelled blue mussels (Mytilus edulis) (MYE). The fish were evaluated for growth performance, nutrient digestibility and fish intestinal function. Growth performance, retention of crude protein and sum of amino acids were not affected in fish fed diets ISC or MYE compared with those fed the reference (REF) diet. However, fish fed diet ISC displayed decreased digestibility of crude protein and indispensable amino acids and decreased intestinal barrier function compared with fish fed the REF diet. Fish fed diet ESC exhibited decreased growth performance and protein retention, but had comparable digestibility to fish fed the REF diet. Fish fed diets MYE and RHO showed similar performance in terms of growth, nutrient digestibility and intestinal barrier function. Overall, the results indicated that blue mussel and intact S. cerevisiae yeast are promising protein sources for Arctic charr.
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| 3. |
- 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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| 4. |
- Huyben, David, et al.
(författare)
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Dietary live yeast and increased water temperature influence the gut microbiota of rainbow trout
- 2018
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Ingår i: Journal of Applied Microbiology. - : Oxford University Press (OUP). - 1364-5072 .- 1365-2672. ; 124, s. 1377-1392
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Tidskriftsartikel (refereegranskat)abstract
- Aims: The objective was to determine the effects of dietary substitution of fishmeal (FM) with live yeast and increasing water temperature on the diversity and composition of gut microbiota in rainbow trout.Methods and Results: Fish were fed either FM or yeast (Saccharomyces cerevisiae) and reared in water temperatures of either 11 degrees C (cold) or 18 degrees C (warm) for 6 weeks. Luminal content and mucosa were collected from the distal gut and the load, diversity and species abundance of yeast and bacteria were analysed using agar plating, MALDI-TOF and rRNA gene amplicon sequencing. Yeast in the gut of fish fed FM were represented by S. cerevisiae, Rhodotorula spp. and Debaryomyces hansenii, while fish fed yeast contained 4-5 log higher CFU per g of yeast that were entirely represented by S. cerevisiae. For gut bacteria, sequencing of 16S rRNA gene amplicons using Illumina MiSeq showed lower bacterial diversity and abundance of lactic acid bacteria, especially Lactobacillus, in fish reared in warm rather than cold water. Fish fed yeast had similar bacterial diversity and lower abundance of Leuconostocaceae and Photobacterium compared with fish fed FM.Conclusions: Feeding live yeast mainly increased yeast load in the gut, while increased water temperature significantly altered the gut microbiota of rainbow trout in terms of bacterial diversity and abundance.Significance and Impact of the Study: Live yeast can replace 40% of FM without disrupting bacteria communities in the gut of rainbow trout, while increased water temperature due to seasonal fluctuations and/or climate change may result in a gut dysbiosis that may jeopardize the health of farmed fish.
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| 5. |
- Huyben, David, et al.
(författare)
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Post-prandial changes of unstressed and stressed dorsal aorta cannulated rainbow trout (Oncorhynchus mykiss) fed yeasts
- 2015
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Introduction Feeding experiments can demonstrate long-term effects of test diets on fish growth and feed digestibility, however, they cannot determine short-term effects on nutrient uptake and stress response. Blood sampling during feeding experiments requires sedation and handling that can stress and affect blood parameters of fish (Djordjevic et al., 2011). Dorsal aorta (DA) cannulation of fish allows for serial blood sampling without inflicting stress. Single cell proteins, such as yeasts, are an ideal feed alternative to plant and fish meals as they do not compete as food for humans. In addition, yeasts, such as Saccharomyces cerevisiae, contain beta-glucans in their cell walls that can induce an immunostimulant effect on fish that increases disease resistance (Siwicki et al., 1994). The objective of this study was to determine the post-prandial changes of unstressed and stressed DA cannulated rainbow trout fed two different yeast diets. Materials and methods Rainbow trout were DA cannulated according to Kiessling et al (1995) with modifications. Briefly, fish were sedated with 1mg L-1 metomidate, anesthetised with 80mg L-1 tricaine methane sulfonate (MS222) and then placed in a recirculating surgery bath of 60mg L-1 MS222. Lidocain was used as a local anaesthetic at the incision sites where 180 polyethylene (PE) tubing was inserted in the snout of the fish and 90 PE tubing was inserted into the DA via guide wire. The 1m long cannula was injected with heparinised saline and sealed and the fish was given 3-5 days to recover while being fed a commercial diet. In total, 15 cannulated fish that weighed 849 ± 199g (±SD) were fed three iso-nitrogenous diets: fish meal control (FM), 60% replacement of fish meal with S. cerevisiae (YS) and 60% replacement with a 70:30 mix of W. anomalus and S. cerevisiae (YW). Fish were fed at 1% body weight (BW) via automated feeders with collectors in 200L tanks equipped with individual water flow (15C), shadow and light. For the diet test, 5 random fish were fed each diet for 1 week and then fed a different diet for weeks 2 and 3 (cross over design). For the stress test, fish were fed for a 4th week and then stressed via netting for 1min after feeding. Blood samples of 0.35mL were taken at 0 (before feeding), 3, 6, 12 and 24 hours on day 7 of every week. Blood was analysed for sodium, potassium, glucose, pH, PCO2, TCO2, HCO3, base excess and hemoglobin using an i-STAT analyser and haematocrit and leucocrit were measured after centrifugation. Red blood cells (RBC) were diluted and counted in a Burker chamber. Results Fish consumed diets at a rate of 0.83 ± 0.22% BW over 4 weeks. Samples from fish that consumed less than 0.20% BW were excluded from analyses. There were no mortalities, but 5 fish were replaced due to non-functioning cannulas. For the diet test, YS and YW diets were both significantly different (P<0.05) than FM diet for sodium, potassium, pH, TCO2, HCO3 and base excess. Hemaglobin of diet YW was different from diet FM. For the stress test, no significant differences existed between diets. In comparison, only glucose (YS and YW diets) and potassium (YW diet) were significantly different between diet and stress tests, although hematocrit and hemaglobin significantly increased and pH and blood gases significantly decreased after stress (i.e. 0 to 3 hr). Discussion and conclusion This study is one of the first to analyse blood samples from DA cannulated rainbow trout that voluntarily consumed feed after surgery. In the diet test, differences in blood potassium and sodium between diets are likely due to feed composition as yeast diets contained higher levels of potassium and lower levels of sodium compared to the FM diet. Increased levels of pH and blood gases in the yeast diets may be due to an immunostimulant effect from yeast beta-glucans (Siwicki et al., 1994), but more research is needed. In the stress test, increased levels of haematocrit, haemoglobin and glucose as well as reduced pH and blood gases have been previously reported as a result of increased catecholamine release and ventilation to cope with stress (Djordjevic et al., 2011). In conclusion, replacing fish meal with yeasts can significantly impact blood parameters of rainbow trout, however, yeasts diets had no significant effect on acute stress response. References Djordjevic B., T. Kristensen, Ø. Øverli, B. Rosseland, and A. Kiessling. 2011. Effect of nutritional status and sampling intensity on recovery after dorsal aorta cannulation in free-swimming Atlantic salmon. Fish Physiology and Biochemistry 38: 259-272. Kiessling A., B. Dosanjh, D. Higgs, G. Deacon, and N. Rowshandeli. 1995. Dorsal aorta cannulation: a method to monitor changes in blood levels of astaxanthin in voluntarily feeding Atlantic salmon. Aquaculture Nutrition 1(1): 43-50. Siwicki A., D. Anderson, and G. Rumsey. 1994. Dietary intake of immunostimulants by rainbow trout affects non-specific immunity and protection against furunculosis. Veterinary lmmunology and lmmunopathology 41: 125-139.
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| 6. |
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| 7. |
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| 8. |
- Olstorpe, Matilda, et al.
(författare)
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Strain-and temperature-dependent changes of fatty acid composition in Wickerhamomyces anomalus and Blastobotrys adeninivorans
- 2014
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Ingår i: Biotechnology and Applied Biochemistry. - : Wiley. - 0885-4513 .- 1470-8744. ; 61, s. 45-50
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Tidskriftsartikel (refereegranskat)abstract
- The fatty acid (FA) profiles of two strains of the yeasts Wickerhamomyces anomalus and Blastobotrys (Arxula) adeninivorans at cultivation temperatures from 15 to 30 degrees C were characterized. Besides the common even-numbered C16 and C18 FAs, substantial proportions of the uneven-numbered C17:1 were found in both species. C18:3(n-3) (alpha linolenic acid) made up to 3% of the total FAs in all strains. Considerable strain differences occurred, with regard to both the presence of single FAs and parameters like the double binding index (DBI) and C16:C18 ratio. W. anomalus J121 formed C18:1(n-5) (up to 10.9% of the total FAs) but no C18:1(n-7), whereas in W. anomalusVKM160, no C18:1(n-5) was found but up to 14.6% C18:1(n-7). Similarly, B. adeninivoransCBS 8244 formed exclusively C18:1(n-7) (maximum 9%) and CBS 7377 C18:1(n-5) (maximum 12.6%). W. anomalus J121 had the lowest DBI (0.72) at 15 degrees C and the highest (0.92) at 20 degrees C, at which point the values decreased with increasing temperatures. In W. anomalusVKM160 and both B. adeninivorans strains, DBI was highest at 15 degrees C and decreased with increasing temperature. In J121, the C16:C18 ratio was highest at 15 degrees C, decreasing at higher temperatures, whereas in the other strains, the opposite trend was observed.
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| 9. |
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| 10. |
- Bankefors, Johan, et al.
(författare)
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A comparison of the metabolic profile on intact tissue and extracts of muscle and liver of juvenile Atlantic salmon (Salmo salar L.) - Application to a short feeding study
- 2011
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Ingår i: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 129, s. 1397-1405
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Tidskriftsartikel (refereegranskat)abstract
- The metabolite profiles from muscles and livers of Atlantic salmon were investigated using high resolution nuclear magnetic resonance (HR-NMR) spectroscopy of aqueous extracts and magic angle spinning (MAS) NMR spectroscopy of intact tissues. Comparison of the data showed that most small metabolites present in the aqueous extracts were also identified in the Carr-Purcell-Meiboom-Gill (CPMG) MAS NMR spectra of the intact tissues. Not only the total omega-3 fatty acid content, but also the EPA and DHA content, in the muscle and liver tissues could be calculated directly from the diffusion-edited MAS NMR spectra without the need for lipophilic extraction. The effect of replacing a normal fish meal during a period of 3 months with a diet containing 20% zygomycete was also investigated by multivariate analysis of the NMR spectra. Principal component analysis (PCA) was used to study the small metabolites distribution in the aqueous extracts of liver and muscles, and revealed that the feed containing zygomycete could have an influence on the metabolites profiles of juvenile Atlantic salmon. (C) 2011 Elsevier Ltd. All rights reserved.
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