| 1. |
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| 2. |
- Bergman, Kristina, et al.
(författare)
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Environmental and biodiversity performance of a novel single cell protein for rainbow trout feed
- 2024
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Ingår i: Science of the Total Environment. - : Elsevier B.V.. - 0048-9697 .- 1879-1026. ; 907
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Tidskriftsartikel (refereegranskat)abstract
- Seafood has an important role to play to achieve a sustainable food system that provides healthy food to a growing world population. Future seafood production will be increasingly reliant on aquaculture where feed innovation is essential to reduce environmental impacts and minimize feed and food competition. This study aimed to investigate whether a novel single cell protein feed ingredient based on Paecilomyces variotii grown on a side stream from the forest industry could improve environmental sustainability of farmed rainbow trout (Oncorhynchus mykiss) by replacing the soy protein concentrate used today. A Life Cycle Assessment including commonly addressed impacts but also the rarely assessed biodiversity impacts was performed. Furthermore, feeding trials were included for potential effects on fish growth, i.e., an assessment of the environmental impacts for the functional unit ‘kg feed required to produce 1 kg live-weight rainbow trout’. Results showed that the best experimental diet containing P. variotii performed 16–73 % better than the control diet containing soy protein concentrate in all impact categories except for energy demand (21 % higher impact). The largest environmental benefits from replacing soy protein with P. variotii in rainbow trout diets was a 73 % reduction of impact on biodiversity and halved greenhouse gas emissions. The findings have high relevance for the aquaculture industry as the production scale and feed composition was comparable to commercial operations and because the effect on fish growth from inclusion of the novel ingredient in a complete diet was evaluated. The results on biodiversity loss from land use change and exploitation through fishing suggest that fishery can dominate impacts and exclusion thereof can greatly underestimate biodiversity impact. Finally, a novel feed ingredient grown on side streams from the forest industry has potential to add to food security through decreasing the dependence on increasingly scarce agricultural land resources.
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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. |
- Hinchcliffe, James, 1992, et al.
(författare)
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Comparative survival and growth performance of European lobster Homarus gammarus post-larva reared on novel feeds
- 2020
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Ingår i: Aquaculture Research. - : Hindawi Limited. - 1355-557X .- 1365-2109. ; 51:1, s. 102-113
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Tidskriftsartikel (refereegranskat)abstract
- One approach to ongrow juvenile European lobster, Homarus gammarus, is to utilize land based rearing systems, incorporating automated feeding, individual culture and provision of stable pelleted feeds, preferably using sustainable ingredients. We initiated three feeding experiments to investigate the general suitability of ingredients produced from seafood by-products as novel feeds for H. gammarus, in terms of promoting survival, development and growth of post-larval lobsters from post-larvae (PL) stage IV to the first juvenile stage (stage V). The first experiment was designed to screen an array of candidate, locally produced, novel protein sources on growth performance parameters. This initial experiment revealed that PL reared on a raw (i.e. wet, unprocessed shrimp) feed used as a reference showed superior performance to those reared on experimental feeds containing fishmeal, herring protein isolate or mussel meal; however, a novel type of shrimp meal, produced by flocculation from waste water, promoted the best PL performance of any experimental feed. A second experiment was designed to test the effect of drying method and to optimize the form of a wet shrimp reference feed used by lobster hatcheries. This showed that the performance of PL reared on experimental freeze-dried shrimp feed was not significantly different to those reared on the wet, unprocessed shrimp used as a reference feed. However, lobsters offered experimental oven-dried shrimp feed (with or without an immune supplement) resulted in significantly lower survival or growth performance. A third and final experiment was designed in an attempt to improve a candidate herring-based protein source, by supplementing with nutrients found in shrimp. However, the results showed that PL reared on the wet reference shrimp feed still showed superior growth and survival than those reared on a herring feed alone, or supplemented with additives found in shrimp meal (either glucosamine, astaxanthin or both supplements combined). The high survival and growth, low incidence of moulting problems and high availability of waste shrimp material, suggest that non-heat-treated shrimp products are a promising feed ingredient for post-larval European lobsters.
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| 5. |
- Hultberg, Malin, et al.
(författare)
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Adding benefit to wetlands : valorization of harvested common reed through mushroom production
- 2018
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Ingår i: Science of the Total Environment. - 0048-9697 .- 1879-1026. ; 637-638, s. 1395-1399
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Tidskriftsartikel (refereegranskat)abstract
- Wetlands have been successfully implemented as water purification systems for removal of plant nutrients and can play a significant role in nutrient recycling, depending on use of the harvested biomass. In a constructed wetland in southern Sweden examined in this study, assimilation of plant nutrients in wetland biomass corresponded to 234 kg/ha nitrogen, 22.8 kg/ha phosphorus, and 158 kg/ha potassium in the study year (2016). The harvested biomass, composed exclusively of common reed, was evaluated as a substrate for production of oyster mushrooms, one of the most widely produced edible mushrooms in the world. The biological efficiency of the substrate was 138 ± 10%, corresponding to production of 1.4 kg mushrooms (fresh weight) based on 1 kg reed (dry weight). The fruiting bodies had high quality, with total protein concentration 18.3 ± 2.8% and very low levels of contaminating heavy metals. Thus, nutrient assimilation in wetland biomass not only decreases the risk of eutrophication in recipient waters, but can be utilized for direct production of high-quality food. The biomass remaining after mushroom production, composed of mycelium and partly degraded wetland biomass, has potential for use in ruminant feed, i.e., as roughage.
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| 6. |
- Hultberg, Malin, et al.
(författare)
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Adding benefit to wetlands - Valorization of harvested common reed through mushroom production
- 2018
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 637-638, s. 1395-1399
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Tidskriftsartikel (refereegranskat)abstract
- Wetlands have been successfully implemented as water purification systems for removal of plant nutrients and can play a significant role in nutrient recycling, depending on use of the harvested biomass. In a constructed wetland in southern Sweden examined in this study, assimilation of plant nutrients in wetland biomass corresponded to 234 kg/ha nitrogen, 22.8 kg/ha phosphorus, and 158 kg/ha potassium in the study year (2016). The harvested biomass, composed exclusively of common reed, was evaluated as a substrate for production of oyster mushrooms, one of the most widely produced edible mushrooms in the world. The biological efficiency of the substrate was 138 +/- 10%, corresponding to production of 1.4 kg mushrooms (fresh weight) based on 1 kg reed (dry weight). The fruiting bodies had high quality, with total protein concentration 18.3 +/- 2.8% and very low levels of contaminating heavy metals. Thus, nutrient assimilation in wetland biomass not only decreases the risk of eutrophication in recipient waters, but can be utilized for direct production of high-quality food. The biomass remaining after mushroom production, composed of mycelium and partly degraded wetland biomass, has potential for use in ruminant feed, i.e., as roughage. (C) 2018 Elsevier B.V. All rights reserved.
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| 7. |
- Huyben, David, et al.
(författare)
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Effects of dietary inclusion of the yeasts Saccharomyces cerevisiae and Wickerhamomyces anomalus on gut microbiota of rainbow trout
- 2017
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486 .- 1873-5622. ; 473, s. 528-537
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Tidskriftsartikel (refereegranskat)abstract
- Rainbow trout (Oncorhynchus mykiss) were fed for 10 weeks on a diet containing either 30% fish meal (FM) or with 20, 40 and 60% replacement of fish meal protein with Saccharomyces cerevisiae (SC) or a mixture of Wickerhamomyces anomalus and S. cerevisiae(WA). Luminal contents and mucosal tissue from the distal intestine were collected and analysed for yeast and bacterial loads by agar plating. Diversity and abundance were determined by sequencing of amplicons generated from the 26S rRNA (yeast) and 16S rRNA (bacteria) genes. In addition, the diets were analysed before and after feed extrusion to determine the viability and composition of the yeasts ingested by the fish. After extrusion, 9-10 log cells g(-1) of yeast were still intact in the SC and WA diets, but culturable yeast showed log-reductions of 5-7 CFU g(-1). For yeasts isolated from the gut contents, 81-96% of colonies consisted of Debaryomyces hansenii, with few or no colonies of S. cerevisiae or W. anomalus despite their high inclusion rate in the diets. Characterisation of gut bacteria using Illumina MiSeq showed that 70 and 19% of sequences were classified to the phyla Firmicutes and Proteobacteria, specifically sequences identified as Leuconostocaceae, Lactobacillaceae and Photobacterium. Compared with the FM diet, the WA40 diet reduced bacterial diversity, whereas the WA60 diet increased the abundance of the pathogenic yeast Candida albicans and reduced lactic acid bacteria in the gut. Overall, 40 and 60% replacement of fish meal protein with a mixture of W. anomalus and S. cerevisiae significantly altered the gut microbiota of rainbow trout, while 20% replacement and diets with only S. cerevisiae had little or no effect. (C) 2017 Elsevier B.V. All rights reserved.
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| 8. |
- Huyben, David, et al.
(författare)
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Effects of dietary yeast inclusion and acute stress on post-prandial whole blood profiles of dorsal aorta-cannulated rainbow trout
- 2017
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Ingår i: Fish Physiology and Biochemistry. - : Springer Science and Business Media LLC. - 0920-1742 .- 1573-5168. ; 43, s. 421-434
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Tidskriftsartikel (refereegranskat)abstract
- Yeast is a potential alternative to fish meal in diets for farmed fish, yet replacing more than 50 % of fish meal results in reduced fish growth. In a 4-week experiment, 15 rainbow trout (Oncorhynchus mykiss) were cannulated and fed three diets each week: 30 % fish meal as a control (FM); 60 % replacement of fish meal protein, on a digestible basis, with Saccharomyces cerevisiae (SC); and 60 % replacement with Wickerhamomyces anomalus and S. cerevisiae mix (WA). Blood was collected at 0, 3, 6, 12 and 24 h after feeding. In the final week, fish were exposed to a 1-min netting stressor to evaluate possible diet-stress interactions. Significant increases in pH, TCO2, HCO3 and base excess were found after fish were fed the SC and WA diets compared with FM, which elevated blood alkaline tides. Yeast ingredients had lower buffering capacity and ash content than fish meal, which explained the increase in alkaline tides. In addition, fish fed the WA diet had significantly reduced erythrocyte area and fish fed SC and WA diets had increased mean corpuscular haemoglobin levels, indicating haemolytic anaemia. Higher levels of nucleic acid in yeast-based diets and potentially higher production of reactive oxygen species were suspected of damaging haemoglobin, which require replacement by smaller immature erythrocytes. Acute stress caused the expected rise in cortisol and glucose levels, but no interaction with diet was found. These results show that replacing 60 % of fish meal protein with yeasts can induce haemolytic anaemia in rainbow trout, which may limit yeast inclusion in diets for farmed fish.
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| 9. |
- Huyben, David, et al.
(författare)
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Effects of dietary yeast inclusion and acute stress on postprandial plasma free amino acid profiles of dorsal aorta-cannulated rainbow trout
- 2018
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Ingår i: Aquaculture Nutrition. - : Hindawi Limited. - 1353-5773 .- 1365-2095. ; 24, s. 236-246
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Tidskriftsartikel (refereegranskat)abstract
- In a 4-week experiment, 15 cannulated rainbow trout were fed three diets based on fish meal (FM), Saccharomyces cerevisiae yeast (SC) and Wickerhamomyces anomalus and S.cerevisiae yeast mix (WA). Fish were fed daily, and blood samples were collected on day 7 of each week at 0, 3, 6, 12 and 24hr after feeding. In the final week, fish were exposed to a 1-min netting stressor. All essential and non-essential plasma amino acid levels except methionine were similar between fish fed diets FM, SC and WA. Plasma methionine and sarcosine were significantly higher in fish fed diets SC and WA, possibly due to the crystalline methionine level, form or feeding regime. Hydroxy-proline and 3-methyl-histidine were higher in fish fed diet FM, which can be explained by the higher levels present in fish meal compared with yeast. In stressed fish, there were no dietary effects on plasma amino acid levels, but significant increases in taurine and cystathionine were found in stressed compared with unstressed fish. These results demonstrate that yeast-based diets produce similar plasma amino acid profiles to fish meal and suggest that yeast may be a suitable fish meal replacement in diets for rainbow trout.
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| 10. |
- Huyben, David, et al.
(författare)
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Effects of feeding yeasts, Saccharomyces cerevisiae and Wickerhamomyces anomalus, on gut microbiota of rainbow trout
- 2016
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Introduction 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. Previous studies have fed live yeast, such asSaccharomyces cerevisiae, in cold pelleted diets to farmed fish in order to increase beneficial microbiota in the gut (Gatesoupe, 2007). However, commercial salmonid diets are typically extruded at high temperatures, which can inactivate yeasts and reduce their effects on gut microbiota. In addition, previous studies have used culture-based methods to determine gut microbiota, while the development of next generation sequencing has improved identification of unculturable microbiota. The objective of this study was to determine the effect of feeding yeasts,S. cerevisiae and Wickerhamomyces anomalus, on microbiota in the distal intestine of rainbow trout (Oncorhynchus mykiss). Materials and methods A diet of fish meal (FM) was used as a control against yeast diets that replaced 20, 40 and 60% of fish meal (digestible protein basis) with either S. cerevisiae(SC) orW.anomalus/S. cerevisiaemix (WA; Jästbolaget AB, Sweden). Diets were extruded at 120-130oC and later fed to triplicate tanks of 35 rainbow trout for 10 weeks. Afterwards, content and mucosa from the distal intestine of 3 fish per tank were collected. Ingredients, diets and gut samples were plated on yeast-peptone-D-glucose, then 26S rDNA were PCR-amplified and sequenced to determine live yeast counts and taxa. Diets and yeast ingredients were further examined microscopically to determine cell counts of yeast. For gut bacteria, 16S rDNA were PCR-amplified, barcoded and next generation sequenced using Illumina platform (SciLifeLab AB, Sweden). Significant differences (p<0.05) between diets were determined using ANOVA and ANOSIM methods. Results The yeast ingredients,S. cerevisiaeor W. anomalus/S. cerevisiae mix, contained between 9-10 log cfu g-1and SC and WA diets contained 7-8 log cfu g-1before extrusion. After extrusion, all diets had over 4-log reduction in cfu g-1(cultured yeast), however 7-8 log cells g-1of yeast were still viable. Diets of SC and WA contained between 96-100%S. cerevisiaeand 0-20%W. anomalus.After 10 weeks of feeding, the distal intestine contained between 84-96 Þbaryomyces hanseniiwith few colonies of S. cerevisiae and noW. anomalus. For bacteria, the distal intestine contained between 37-62 % ofLeuconostocaceae,Lactobacillaceae and Photobacteriumand significant differences in taxa abundance and similarity were found between fish fed SC60, WA40 and WA60 compared with the FM diet (Fig. 1). Discussion and conclusion This study is the first to analyse intestinal microbiota of rainbow trout fed yeast diets using next generation sequencing. In addition, few studies have investigated the viability and log reduction of yeast after feed extrusion. The low level of culturable yeast compared with the high level of intact yeast cells found after diet extrusion suggested that high temperature from extrusion inactivated yeasts, but did not disrupt the cells. Inactivated, non-disrupted yeast is not ideal because the yeast cannot cultivate the intestine or release nutrients for metabolic uptake. The lack of S. cerevisiaeandW. anomalusin the distal intestine despite the high level of yeast ingestion, suggests that large amounts of yeast were metabolised. However, higher levels of unculturable yeast cells may have been present in the intestinal content and mucosa. For gut bacteria, most were Lactic Acid Bacteria (Lactobacillales order), which includesCarnobacteriaceae, Leuconstocaceae, Leuconstocaceaeand Streptococcaceae families. In comparison, Ingerslev et al. (2014) found similar levels ofStreptococcus, Leuconostoc,Enterobacteriaceae and Lactobacillusin rainbow trout fed fish and plant-based diets.Significant differences in bacteria abundance for fish fed SC60, WA40 and WA60 diets indicated thatW. anomalushad a higher effect thanS. cerevisiaeand that more than 20% replacement of fish meal with yeast affected gut microbiota in rainbow trout. References Gatesoupe F.J. 2007. Live yeasts in the gut: Natural occurrence, dietary introduction, and their effects on fish health and development. Aquaculture 267: 20-30. Ingerslev H.C., L. von Gersdorff Jørgensen, M. Lenz Strube, N. Larsen, I. Dalsgaard, M. Boye, and L. Madsen. 2014. The development of the gut microbiota in rainbow trout (Oncorhynchus mykiss) is affected by first feeding and diet type. Aquaculture 424-425: 24-34.
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| 11. |
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| 12. |
- Huyben, David, et al.
(författare)
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Haematological and intestinal health parameters of rainbow trout are influenced by dietary live yeast and increased water temperature
- 2019
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Ingår i: Fish and Shellfish Immunology. - : Elsevier BV. - 1050-4648 .- 1095-9947. ; 89, s. 525-536
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Tidskriftsartikel (refereegranskat)abstract
- Live yeast may be a sustainable protein source in salmonid diets while exhibiting a probiotic effect to counteract environmental stressors, such as increased water temperature that is being exacerbated by climate change. The objective of this study was to evaluate the effects of feeding a high dietary inclusion of live yeast and increased water temperature on growth, haematological and intestinal physiology of rainbow trout. For six weeks, 129 g fish in 16 tanks (n = 4) were fed either a diet based on fishmeal or based on live yeast (214 g kg −1 of diet or 7.6 log CFU g −1 of Saccharomyces cerevisiae) that replaced 40% of fishmeal protein while fish were reared in water temperatures of either 11 °C (cold) or 18 °C (warm). Fish weights, caudal blood and proximal and distal intestines were collected and analysed. Fish fed live yeast resulted in reduced growth (SGR and WG) and higher FCR, while growth in cold and warm water was similar despite differences in TGC. However, increased mortality, plasma cortisol, and intestinal oedema and villous damage indicated fish reared in warm water were subjected to chronic stress. Temperature had a significant effect on haematocrit and red blood cell counts that resulted in significantly higher haemoglobin levels in fish kept in warm water attributed to an elevated oxygen demand. In the proximal intestine, increased temperature resulted in reduced expression of pro-inflammatory cytokines, e.g. TNFα and IL8, that were further reduced in fish fed live yeast. In addition, feeding live yeast reduced gene expression of CLD6 involved in gut barrier function, which suggests that the level of yeast was too high and masked any beneficial effects on fish health. In conclusion, feeding a high inclusion of live yeast reduced fish growth and expression of intestinal genes, while increasing the temperature from 11 to 18 °C subjected fish to chronic stress that restricted growth, suppressed innate immunity and induced intestinal damage. Replacing 40% of fishmeal protein with live yeast did not counteract negative effects caused by increased temperature, thus alternative strategies need to be explored and implemented to protect the growth and health of rainbow trout from seasonal and long-term rises in water temperature. © 2019
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| 13. |
- Huyben, David, et al.
(författare)
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High-throughput sequencing of gut microbiota in rainbow trout (Oncorhynchus mykiss) fed larval and pre-pupae stages of black soldier fly (Hermetia illucens)
- 2019
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486 .- 1873-5622. ; 500, s. 485-491
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Tidskriftsartikel (refereegranskat)abstract
- Black soldier fly (Hermetia illucens) meal is a potential alternative to fishmeal and plant proteins in diets for farmed fish since it can be produced on organic waste substrates, requires little energy and water inputs and contains high levels of essential amino acids. Recent studies have partially replaced fishmeal with black soldier fly meal, however, research on their impact on gut microbiota of fish is limited. In a five week experiment, juvenile rainbow trout (Oncorhynchus mykiss) were fed either a reference diet based on fishmeal or three diets with 30% inclusion of black soldier fly meals in the form of pre-pupae, larvae or defatted-larvae. The combined luminal content and mucosa were collected from the distal intestine of three fish per tank with four tanks per diet (n = 12) and 16S rRNA gene amplicons were sequenced using the Illumina MiSeq platform. Feeding the insect-based diets increased the alpha-diversity of bacteria and abundance of lactic acid bacteria, which may be due to the addition of dietary chitin. Compared with fishmeal, feeding insects resulted in higher abundance of phyla Firmicutes and Actinobacteria with lower abundance of Proteobacteria. Fish fed the full-fat meals had higher abundance of Corynebacterium that was attributed to its ability to produce lipase and the high content of dietary lipids as a substrate. Bacillaceae was increased in fish fed both larvae diets and unchanged in the pre-pupae diet, which indicated that life-cycle stage of the insect influenced the gut microbiota. Based on these results, we found that feeding black soldier flies increased diversity and altered the composition of gut bacteria of rainbow trout, which were further influenced by life-cycle stage and lipid content of the insect meal.
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| 14. |
- 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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| 15. |
- Kiessling, Anders, et al.
(författare)
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Alternative protein sources for fish, not competing with the human food demand evaluated by traditional and novel approaches
- 2016
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- At present, most alternative feed sources in fish is since long known in terrestrial animals. However, in a longer time frame this is questionable from a food security perspective, as these sources often are of human food quality. This is an argument rapidly growing in importance. Microbes, insects and products from other forms of extractive aquaculture are of major interest considering their growth potential, nutritional profile, probiotic qualities and ability to use simple resources as substrates. However, with a transition towards a circular economy, substrates that produce such feed ingredients will to a higher degree be based on waste and by-products. This development will demand novel approach in nutrition research in order to understand non-intuitive positive and negative effects in the fish gut biota, immune response, metabolism, welfare and product quality/safety. We will present our ongoing work, concerning physiological implications of alternative protein sources using in situ experimental technologies, such as cannulation and repeated tissue sampling. This work also combines advanced analytic methods of metabolomics and gut microbiota using amplicon next generation sequencing that targets 16S rDNA for bacterial identification. Data on post-prandial plasma AA profile, hematological parameters and erythrocyte indices will be presented together with data concerning the interaction between diet and stress in fish where fishmeal has been replaced by yeast up to 60%. Also, data concerning changes of the microbiota of fish given fungal mycelium-, yeast-, insect- (if ready) and mussel meal will be presented, including comparison between nutrient efficiency of feed given in clear or “green” water environments. Finally, experiments concerning yeast as biological barrier to prions, i.e. food safety, will be discussed. In all, an overall picture of one possible future development in fish nutrition will be painted with a focus on the use of novel feed stuffs in circular food production systems.
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| 16. |
- Kiessling, Anders, et al.
(författare)
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Musselodling i Östersjön som miljöåtgärd : nya positiva data från tre pågående EU-projekt
- 2019
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Rapport (populärvet., debatt m.m.)abstract
- Nya resultat visar att musselodlingar i Östersjön har en betydande potential att bidra till att minska övergödningen samtidigt som förutsättningar skapas för en cirkulär ekonomi/produktion. För att ta musselodling till nästa nivå krävs dels ytterligare förfining av den nya tekniken, men framförallt fler och i förlängningen också större odlingar samtidigt som vi måste vidareutveckla alla de initiativ som nu pågår hur näringen kan återanvändas i livsmedelssystemet på ett effektivt och ekonomiskt lönsamt sätt.
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| 17. |
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| 18. |
- Kotta, Jonne, et al.
(författare)
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Cleaning up seas using blue growth initiatives: Mussel farming for eutrophication control in the Baltic Sea
- 2020
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 709
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Tidskriftsartikel (refereegranskat)abstract
- © 2019 The Authors Eutrophication is a serious threat to aquatic ecosystems globally with pronounced negative effects in the Baltic and other semi-enclosed estuaries and regional seas, where algal growth associated with excess nutrients causes widespread oxygen free “dead zones” and other threats to sustainability. Decades of policy initiatives to reduce external (land-based and atmospheric) nutrient loads have so far failed to control Baltic Sea eutrophication, which is compounded by significant internal release of legacy phosphorus (P) and biological nitrogen (N) fixation. Farming and harvesting of the native mussel species (Mytilus edulis/trossulus) is a promising internal measure for eutrophication control in the brackish Baltic Sea. Mussels from the more saline outer Baltic had higher N and P content than those from either the inner or central Baltic. Despite their relatively low nutrient content, harvesting farmed mussels from the central Baltic can be a cost-effective complement to land-based measures needed to reach eutrophication status targets and is an important contributor to circularity. Cost effectiveness of nutrient removal is more dependent on farm type than mussel nutrient content, suggesting the need for additional development of farm technology. Furthermore, current regulations are not sufficiently conducive to implementation of internal measures, and may constitute a bottleneck for reaching eutrophication status targets in the Baltic Sea and elsewhere.
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| 19. |
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| 20. |
- Lalander, Cecilia, et al.
(författare)
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Processing and storage of mussels : mussels to feed through fly larvae
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The process line developed in the project is shown in Figure 1, which illustrates the different steps from harvest of Baltic Sea blue mussels to fish feed through fly larvae composting. This report describes the process line from Pre-process treatment (No 3.) to Post-process treatment (No 7.). The most crucial part of the process line is the fly larvae compost, as this involves living organisms that must be treated in certain ways to survive. SLU has long experiences of this and has operated fly larvae composting with municipal source separated organic waste since 2011. Several tests with blue mussels have been done in this project, where the experiences from the use of organic waste is used as a reference. Other parts of the process line - ensilage (optional); crushing of mussels before feeding them to the fly larvae; separation of fly larvae, shells and droppings and finally drying of fly larvae – are more straight forward and dependent on the technical equipment that are selected. Thus, other techniques, than those selected in this project, could be used depending on e.g. experiences, availability, local circumstances and economy.
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| 21. |
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| 22. |
- Langeland, Markus, et al.
(författare)
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Digestibility of microbial and mussel meal for Arctic charr (Salvelinus alpinus) and Eurasian perch (Perca fluviatilis)
- 2016
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Ingår i: Aquaculture Nutrition. - : Hindawi Limited. - 1353-5773 .- 1365-2095. ; 22, s. 485-495
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Tidskriftsartikel (refereegranskat)abstract
- Apparent digestibility coefficients (ADCs) for four protein-rich alternative feed ingredients, intact baker's yeast (Saccharomyces cerevisiae), extracted baker's yeast (S. cerevisiae), zygomycetes (Rhizopus oryzae) and blue mussel (Mytilus edulis), were determined for Arctic charr (Salvelinus alpinus) and Eurasian perch (Perca fluviatilis). Diets contained 30% of test ingredients, and ADCs were compared to a reference diet containing fish meal. For Arctic charr, ADCs for dry matter (DM, 71-99%), sum of amino acids (SAA, 84-99%) and gross energy (70-99%) were significantly lower for intact S. cerevisiae than for extracted S. cerevisiae, R. oryzae and M. edulis. The ADCs for the indispensable amino acids (IAA) in Arctic charr varied between 84% and 99%. Significant differences were found in ADCs for IAA between the test ingredients for Arctic charr, with higher values for extracted S. cerevisiae and M. edulis. The ADCs in Eurasian perch varied between 83% and 95% for DM, 89% and 98% for CP, 92% and 100% for SAA, 81% and 96% for gross energy. No significant differences were found for ADCs between the test ingredients in Eurasian perch, indicating a species effect on digestibility. Furthermore, the absence of intact cell walls had a positive effect on digestibility of S. cerevisiae for Arctic charr.
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| 23. |
- Lundh, Torbjörn, et al.
(författare)
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Nutrient digestibility and growth in Arctic charr fed microbial and mussel protein meal
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The content of marine based feed sources must be decreased in feed for fish. New production has to be built on sustainable practices and technologies which include production of aquafeeds with other ingredients which are not suitable as food for humans. We have investigated the nutrient digestibility and performed a short term growth study on Artic charr fed microbial biomass and blue mussel meal instead of fish meal. Analysis of feed show dif- ferent amino acid profiles with very low methionine content in especially R. oryaze (RHO) and extracted Saccha- romyces (ESC), whereas intact Saccharomyces (ISC) showed similar amino acid profile as fish meal but with slightly lower methionine content. The apparent digestibility coefficients of dry matter, crude protein, total amino acid and energy were highest for ESC, mussel meal (MYE) and RHO. No difference in weight gain was observed between fish fed the reference diet, diet ISC and diet MYE. Fish fed diet RHO and ESC showed 16 and 13% lower weight gain compared with fish fed diet REF. The conclusion of the results is that intact Saccharomyces and mussel meal are good alternatives as a protein source instead of marine fish meal for feeding Arctic charr. The results suggest that ISC togheter with MYE is the best choice for developing locally produced feed resources and closing the nutrient loop in the Baltic Sea region. The results will be followed up with further evaluation in long-term feeding experiments with Arctic charr
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| 24. |
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| 25. |
- Niyibizi, Leon, et al.
(författare)
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Growth performance, nutrient utilization and body indices of Nile tilapia (Oreochromis niloticus) fingerlings fed local feed ingredients
- 2023
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Ingår i: Livestock Research For Rural Development. - 0121-3784. ; 35
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Tidskriftsartikel (refereegranskat)abstract
- A 10-week trial was conducted to evaluate growth performance, feed utilization, and somatic indices of Nile tilapia (Oreochromis niloticus) fingerlings fed five diets based on local feed protein ingredients (kidney bean leaf meal (KBLM), spent brewer’s grain (SBG), spent brewer’s yeast (SBY), sweet potato leaf meal (SPLM), and wheat middlings (WM) and a fishmeal-based control diet (CD). The experimental diets were formulated to be iso-nitrogenous and iso-energetic, with 27-50% of fishmeal in CD replaced (‘as is’ basis) with test ingredient. Initial average body weight of individual fish was 28.9±1.88 g and final body weight (FBW) was 60.2±2.81 g. Weight gain (WG) and FBW were highest (p<0.05) for fish fed CD, followed by SPLM, SBY, SBG, WM, and KBLM in that order. Specific growth rate (SGR) was highest in fish fed CD and SPLM, followed by SBY and SBG, and lowest in fish fed WM and KBLM. Feed conversion ratio (FCR) was highest in fish fed KBLM and lowest in fish fed CD and SPLM. Survival was 75-87% and did not differ between the groups. Hepato-somatic index (HSI) and viscera-somatic index (VSI) also did not differ across dietary treatments. These results indicate that SPLM, SBY, and SBG protein can efficiently replace fishmeal in Nile tilapia diets without adverse effects on growth, feed utilization, or body indices, acting as a valuable protein source for sustainable tilapia production.
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