Reports

Þróun á nýju bleikjufóðri // Novel enhancement of soy meal for Arctic charr diets

Published:

01/08/2020

Authors:

Alexandra Leeper, Clara Sauphar, Margareth Øverland, Wolfgang Koppe, Jón Árnason, Gunnar Örn Kristjánsson, Stephen Knobloch, Sigurlaug Skírnisdottir, David Benhaïm

Supported by:

AVS funding

Fiskeldi er í hröðum vexti um allan heim og gegnir sífellt mikilvægara hlutverki í að tryggja fæðuöryggi. Ísland er stærsti framleiðandi á bleikju í heiminum, en bleikja hefur mikla próteinþörf sem hefur að mestu verið mætt með fóðri sem er ríkt af fiskimjöli. Fiskimjöl er hins vegar dýr próteingjafi og því er fóðurkostnaður í bleikjueldi um 50% af framleiðslukostaði, auk þess sem fiskimjöl er takmörkuð auðlind. Það er því mikilvægt að leita nýrra próteingjafa fyrir bleikju-framleiðiendur. Einn slíkur kostur er að nota soyamjöl, sem hefur verið notað með góðum árangri í laxeldi. Það er hins vegar rannsóknir sem benda til að soyamjöl geti haft neikvæð áhrif á vöxt, þarmaflóru og almenna velferð laxfiska.

This report discusses the main results of the AVS project "Development of new charr feed", the aim of which was to reduce feed costs and increase sustainability in charr farming by replacing fishmeal with soybean meal in feed. The project also sought to gain an understanding of the effects of different "treatment" soybean meal on the growth, intestinal flora and welfare of char.

Fjórar mismunandi tegundir fóðurs voru rannsakaðar þ.e. hefðbundið fóður með fiskimjöli (FM), með ómeðhöndluðu soyamjöli (US), með Ensím-meðhöndluðu soyamjöli (ES), og með ómeðhöndluðu soyamjöli með viðbættu góðgerlum (USP). Lifun, vöxtur, atferli og þarmaflóra bleikju sem fóðruð var í 10 vikur á áðurnefndum fjórum fóðurtegundum var síðan borin saman. Bleikjan sem gerð var tilraun á var smáfiskur á því stigi þar sem vöxtur er mikill og þarmaflóran er í mótun; og því eru áhrif fóðursins sérlega mikilvæg.

Helstu niðurstöður verkefnisins voru að fóður sem innihélt Hypro soyamjöl með viðbættum FOS góðgerlum dró verulega úr vexti, í samanburði við hinar fóðurtegundirnar. Ensím-meðhöndlaða soyamjölið, sem innihélt niðurbrotið NSPs sem virka sem góðgerlar, sem og ómeðhöndlaða soyamjölið með viðbættum góðgerlum stuðlaði að fjölbreyttari þarmaflóru og jók magn mjólkursýru baktería (LABs) sem tengt hefur verið við ónæmi gagnvart sjúkdómum og sýkingum, sem og bættri upptöku og vexti. Niðurstöður sýndu einnig að atferli fiskanna gagnvart ómeðhöndlaða soyamjölinu var umtalsvert öðruvísi en gagnvart hinum fóðurtegundunum, á þann hátt að þeir sýndu því fóðri minni áhuga.

Niðurstöðurnar benda til að viðætur á góðgerlum á þessu vaxtarstigi stuðli að jákvæðum breytingum á þarmaflóru, og geti því leitt til aukins þols við stressi og sjúkdómum síðar meir á lífsferlinum. En Þetta virðist hins vegar koma niður á vexti fiskanna. Þörf er því á frekari rannsóknum til að skera úr um hvort vöxturinn muni skila sér á seinni vaxtarstigum bleikjunnar og þá hvort lifun og aðrir jákvæðir eiginleikar aukist. Vera má að FOS góðgerlar séu ekki hentugir fyrir fiska svo snemma í þroskastigi, en svo virðist sem FOS hafi áhrif á efnaskipti og örfi þarma og ónæmiskerfið. En frekari rannsókna er þörf til að draga frekari ályktanir þar um. Ensím-meðhöndlaða soyamjölið hafði ekki sömu neikvæðu áhrif á vöxt, en breytileiki var meiri var hins vegar meiri. LABs í þarmaflóru bendir til þess að meðhöndlunin stuðli að hættri heilsu og þoli gagnvart sýkingum, án þess að það komi niður á vexti. Niðurstöðurnar benda því til þess að ensím-meðhöndlun á soyamjöli í fóður stuðli að bættri heilsu og lifun bleikju. Mikilvægt er að framtíðar rannsóknir skoði niðurstöður þessa verkefnis og beri saman við ástand þarmavefja. Einnig er mikilvægt að rannsaka frekar hvernig efnaskipti, atferli og þarmaflóra verka saman við mismunandi fóðrun á fyrri lífskeiðum, sem og hver áhrifin eru á langtíma vöxt og velferð.

Skýrslan er lokuð / This report is closed


Aquaculture is globally growing in importance as part of the solution for future food security. In Iceland one of the most important farmed species is the salmonid, Arctic Charr, and Iceland is the world´s leading producers of this cold-water, carnivorous species. Arctic Charr has a high dietary protein requirement which is traditionally provided by diets high in fish meal protein. This drives feed costs that are 50% of the total production costs and puts pressure on wild capture fisheries from which fish meal species are sourced. To facilitate the further expansion of Arctic charr aquaculture it is necessary to find less expensive and more environmentally sustainable feed ingredients. One potential alternative that is widely used in Atlantic Salmon aquaculture is soybean meal, however increasing evidence suggests that for some salmonids, untreated soybean meal can have negative consequences for the growth, gut health and welfare.

The overall aim of this study was to decrease Arctic Charr feed costs and improve the long-term sustainability of salmonid aquaculture in Iceland by replacing fish meal with untreated and treated soybean meal. This study also aimed to understand the wider consequences of untreated and treated soybean meal on the growth, gut health and welfare of Arctic Charr.

Four different diets were assessed, a fish meal control (FM), an untreated soybean meal (US), an enzyme pre-treated soybean meal (ES) and an untreated soybean meal with an added prebiotic (USP). The survival, growth performance, gut microbiome assemblage, and behaviour were of juvenile Arctic Charr fed each of these diets during a 10-week feeding trial were compared. The juvenile life stage was selected since it is a period of crucial developmental, when growth rates a very rapid, and the gut microbiome is colonising, so impact of differing diets can be obtained quickly.

The key findings of this report were that the addition of FOS prebiotic to untreated Hypro soybean meal feed treatment significantly reduced growth compared to the fish meal control when all other feed treatments including the enzyme treated soybean meal performed significantly the same as the fish meal control. The enzyme treatment of soybean meal which aimed to have a secondary benefit of the broken down NSPs acting as prebiotics, as well as the untreated soybean meal with prebiotic had higher gut microbiome diversity as well as a greater presence of Lactic Acid Bacteria (LABs) which are both associated with positive benefits such as more immune robustness and resilience to disease and infection as well as benefits for nutritional uptake and growth. There was also a notable different in behaviour where the fish fed the untreated soybean meal with added prebiotic were both shyer and less active than the fish fed any other feed treatment, indicating that they were more reactive individuals.

When the results of these different tests are viewed together this suggests that the addition of pure prebiotics at such an early developmental stage does promote beneficial changes to the gut microbiome which suggest that the fish will be more resilient to stress and disease later in life and may receive other benefits of prebiotic addition too, however at this early stage the combination with low growth performance suggests that the immune system and gut development may be stimulated but at the cost of energy being drawn away from growth. Salmonids given FOS should be followed from early development through to harvest to see if growth can be compensated and if survival or performance is in fact improved. Otherwise these results may indicate that FOS may not be suitable to apply to diets during such early stages of development, when growth curves are steep naturally. The observation that these fish were also had more reactive coping strategies suggests that the prebiotic application may also effect metabolic rate which could be linked to the stimulation of the gut and immune system, but further experimentation will be need to elucidate this and also to investigate the consequence of this altered behaviour, which could potential reduce the welfare of a intensively farmed fish. On the other hand, the enzymatic treatment of soybean meal did not show the same negative impact to early growth performance but did influence a higher diversity and LABs presence in the gut microbiome suggesting this method of threating soybean meal may bring benefits to health and resilience without as much trade-off. These enzyme-soy treated fish groups were also slightly more reactive than the control treatments, but the impact was not as pre-announced as for the prebiotic added treatment. Overall the results suggest that the best potential benefit to long term health and survival of charr when soybean meal is pre-treated with enzymes when used in the diet.

It will be extremely important in the future to combine these results with gut histology data to clarify the impact of differing treatments to internal gut morphology and health. It will also be important to further study how metabolism, behaviour and the gut microbiome interact with dietary treatments at this early development stage and what the long-term consequences for production and welfare will be.

Reports

Drug residues in the Icelandic environment

Published:

31/01/2019

Authors:

Sophie Jensen, Helga Gunnlaugsdóttir, Hrönn Ólína Jörundsdóttir

Supported by:

Ministry of the Environment and Natural Resources

contact

Sophie Jensen

Project Manager

sophie.jensen@matis.is

Drug residues in the Icelandic environment

The aim of the audit was to assess the theoretical release of drugs into the environment (receptors) in Iceland, with an emphasis on coastal waters, rivers and lakes. For medicinal products used for humans, an assessment was made of the concentration of these medicinal products in the sewerage system in the capital area and in two selected locations outside the capital area. For medicinal products used in agriculture and aquaculture, a theoretical assessment was made of the release of medicinal products from production units where the emissions could be the highest. The potential concentration of the drugs in the receptors was assessed and these values were compared with the expected risk, as there are environmental limits. The drugs that were examined and evaluated were determined on the basis of Icelandic sales figures and the priority list of the European Union's Water Framework Directive, together with the results of previous research. The following human medicinal products were examined: estradiol, ethinyl estradiol, amoxicillin, azithromycin, fluconazole, paracetamol, ibuprofen, diclofenac, metoprolol, fluoxetine, sertraline and the veterinary medicinal products emamectin benzoate (laxalucalicylphenyl). Theoretical evaluation suggests that the levels of ibuprofen, amoxicillin, fluoxetine, paracetamol, diclofenac, azithromycin and sertraline need to be further investigated in sewage treatment plant receptors. The results for the veterinary medicinal product do not indicate a risk of procaine benzylpenicillin used in pig farming or emamectin benzoate used in aquaculture.

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Reports

Method development to estimate infection load in aquaculture

Published:

15/12/2016

Authors:

René Groben, Viggó Þór Marteinsson

Supported by:

AVS (S 15 006-15)

contact

René Groben

Project Manager

rene.groben@matis.is

Method development to estimate infection load in aquaculture

The aim of the pilot project was to create a DNA probe that binds to the genetic material of the fish-causing bacteria Flavobacterium psychrophilum and Aeromonas salmonicida, a subspecies of achromogenes, which can be detected using microscopy (FISH) and flow cytometry. One selective DNA probe for the bacterium F. psychrophilum was created with a combination of two and used with great success to screen for the bacterium using microbial and FISH technology. Specific DNA sensors could not be generated for A. Salmonicida, a subspecies of achromogenes, as its identification gene (16S rDNA) is too similar to other non-infectious Aeromans species. It will be necessary to develop new tentacles that are unique to A. Salmonicida, a subspecies of achromogenes. The flow cytometry is a very fast tool for detecting the binding of specific DNA sensors to microorganisms, which makes the device very suitable for detecting pathogenic bacteria in water. Quantitative analysis of bacteria with such technology is subject to various shortcomings, but it still gives a very good indication of the condition of the water in the fire so that the infection burden can be assessed. The results of this preliminary project show that it is possible to assess the infection burden in aquaculture quickly, but it is necessary to further develop and verify the methodology in real conditions in aquaculture. This was assumed at the beginning of this preliminary project and the participants have applied for a continuation grant to AVS based on the current results and the methodology will be tested under real conditions in charr farming.

The aim of this proof-of-concept study was the development and application of molecular probes for the fish pathogens Flavobacterium psychrophilum and Aeromonas salmonicida subsp. achromogenes, and their detection through Fluorescence In Situ Hybridization (FISH) and flow cytometry. A combination of two species-specific FISH probes was successfully used in combination with flow cytometry to identify and detected F. psychrophilum strains. It was not possible to find specific FISH probes for A. salmonicida subsp. achromogenes. The bacterium is too similar to other Aeromonas species in its 16S rRNA gene sequence and does not contain suitably unique regions that could have been used to develop a species-specific FISH probe. Flow cytometry offers a fast detection system for FISH probes, although technological limitations make reliable quantification difficult. The system is therefore best suited as a semi-quantitative early warning system for emerging fish pathogens in water samples from aquaculture tanks. The results of this preliminary project show that it is possible to estimate the infection load for certain pathogens in aquaculture rapidly but it is necessary to develop the methodology further and test it under real aquaculture conditions. The participants have applied to AVS for new funding based on these results; to develop our rapid methodology further, expand it to more pathogens and test it under real aquaculture conditions.

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Reports

Testing different types of impregnations and its effect on bio fouling

Published:

01/10/2013

Authors:

Ólafur Ögmundarson, Þorleifur Eiríksson, Böðvar Þórðarson, Gunnar Þórðarson

Supported by:

Tækniþróunarsjóður, AVS

contact

Gunnar Þórðarson

Regional Manager

gunnar.thordarson@matis.is

Testing different types of impregnations and its effect on bio fouling

The use of copper oxide in the treatment paint of cow bags is highly criticized and has been banned in many places due to its negative effects on the environment. Within the European Union, the use has been grayed out due to these negative effects of the substance on the environment, but it has been difficult to ban it as no substances have been found that repel sediments as well from the sacs as copper oxide. In the Norðurkví project, there has been a project where an attempt has been made to find a substance that could replace the copper oxide, but no permanent solution has been found. The results of this experiment are presented in this report.

Usage of copper oxide in treating net ‐ bags in aquaculture is a controversial and has been banned in many countries due to its negative environmental impact. Within the EU, use of copper oxide has been put on a gray list but not banned because no substitute treating material has been found which has the same effect in keeping algae away from the nets ‐ bags. The North Cage project has been looking into finding alternative solutions to copper oxide, and the conclusion of this research is drafted in this report.

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Reports

Utilization of raw materials from the plant and animal kingdom in fish feed

Published:

10/07/2011

Authors:

Ásbjörn Jónsson, Jón Árnason, Ragnheiður Þórarinsdóttir, Sjöfn Sigurgísladóttir

Supported by:

Vocational Training Fund of the Ministry of Social Affairs and Social Security

Utilization of raw materials from the plant and animal kingdom in fish feed

Feed costs in aquaculture are generally around 50‐70% of operating costs and a large proportion of raw materials in feed are imported. The purpose of this report is to compile information on the possibility of utilizing domestic raw materials used in agriculture and fisheries for aquaculture feed. It is considered that the raw materials are generally used for aquaculture and the summary is not limited to individual species. It is possible to use by-products from the fisheries sector as feed in aquaculture, but by-products from the plant kingdom need to be treated in order to reduce / eliminate a high proportion of fiber and increase the protein content. By-products of the plant kingdom may be used as food for invertebrates, bacteria and fungi, thus producing a protein-rich product suitable for fish feed.

Feed cost in aquaculture is about 50‐70% of the total cost, and most of the feed is imported. The aim of this report is to gather information about utilizing by-products from agriculture and fishing industry as a feed in aquaculture. By-products from the fishing industry can be used as feed in aquaculture but it is necessary to lower the level of fiber and increase protein in by-products from agriculture. This can possibly be done by using the by-products as feed for invertebrates, bacteria and mushrooms and produce protein rich feed for aquaculture.

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Reports

Affinity of benthic communities in Ísafjarðardjúpur

Published:

01/12/2010

Authors:

Þorleifur Eiríksson, Ólafur Ögmundarson, Guðmundur V. Helgason, Böðvar Þórisson

Supported by:

Fisheries Project Fund

Affinity of benthic communities in Ísafjarðardjúpur

Knowledge of benthic life in the shallow waters off Iceland is low, both in terms of natural conditions and under stress from, for example, aquaculture. There is also a lack of knowledge about how benthic communities react to stress from aquaculture, but one study has tried to answer this regarding low stress. In order to understand which benthic community types exist under natural conditions and which are present in the case of pollution from pollution, the relationship between benthic life inside and outside the area must be examined. In this way, it is possible to understand which animal groups are predominant in similar situations. This study uses data on benthic life in Ísafjarðardjúpur, which is mostly due to fish farming in the fjords. A benthic study is also being carried out in fjords that may be suitable for aquaculture, but are still only under pressure from natural conditions. The project is part of a larger project "Icelandic fjords: The natural ecosystem of Ísfjarðardjúp and the limits of pollution" and is funded by the Fisheries Project Fund.

Knowledge about the benthic live in shallow waters around Iceland is poor, both regarding natural circumstances and when there is pressure from aquaculture. Knowledge is also poor about how benthic communities respond to pollution from aquaculture. This study shows the relationships between research stations with regards to kinship between found indicative species.

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