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Tromsø, Norway

Schram E.,IMARES | Schelvis-Smit R.A.A.M.,IMARES | van der Heul J.W.,IMARES | Luten J.B.,Nofima Marine
Aquaculture Research | Year: 2010

We wanted to optimize the procedure for the selenium enrichment of farmed African catfish, using garlic as dietary selenium source. In the first experiment we established the relation between the length of the selenium enrichment period and the resulting total selenium level in the fillet of the fish. It was found that at a dietary level of 11.7 mg kg-1 Se, a total selenium level in the fillet of 0.7 mg kg-1 was reached in a relatively short enrichment period of 10 days before harvest. In the second experiment we studied the effect of depuration on the selenium level in the fillet and the sensory properties of selenium-enriched African catfish. It was found that total selenium levels in the fillet were not affected during a 7-day depuration period, while garlic odours and flavours in the raw and cooked fillets were significantly reduced after 2 days of depuration. We concluded that selenium enrichment of farmed African catfish can be obtained by selenium-enriched finishing diets, while garlic odours and flavours resulting from dietary garlic can be effectively reduced in the fillet during a short depuration period without negatively affecting fillet levels of total selenium. © 2009 The Authors. Journal Compilation © 2009 Blackwell Publishing Ltd. Source

Altintzoglou T.,Nofima Marine | Vanhonacker F.,Ghent University | Verbeke W.,Ghent University | Luten J.,NOFIMA Market
Aquaculture International | Year: 2011

Consumers in many European countries do not equally meet the recommended daily intake levels for fish consumption. Various factors that can influence fish consumption behaviour have been identified but limited research has been performed on fish consumption behaviour, discriminating between farmed and wild fish. The present survey study confirmed differences in total fish consumption, farmed fish and wild fish consumption behaviour in Belgium, Norway and Spain. Spanish consumers consumed more frequently fish of each category than Norwegian consumers. Belgian consumers reported the lowest consumption frequency of fish. Accordingly, health involvement and attitudes towards fish consumption decreased from Spain over Norway to Belgium, suggesting a positive association of health involvement and attitudes towards fish consumption with total fish consumption. Similar effects were found for farmed and wild fish consumption. In general, consumers in all countries were poorly aware of the origin of the fish they consume, despite the mandatory indication of origin on fish labels. Across countries, an increased awareness about fish origin was found with increased fish consumption. The findings of the study indicate that farmed and wild fish consumption should be further stimulated among Belgian, Norwegian and Spanish consumers in association with a healthy and positive meal. Additionally, given the limited awareness of the origin of fish, transparency on the issue of farmed origin will be important in order to anticipate potential adverse communication. © 2010 The Author(s). Source

Karlsson S.,Nofima Marine | Moen T.,Aqua Gen AS
BMC Research Notes | Year: 2010

Background. An increasing number of aquaculture species are subjected to artificial selection in systematic breeding programs. Rapid improvements of important commercial traits are reported, but little is known about the effects of the strong directional selection applied, on gene level variation. Large numbers of genetic markers are becoming available, making it feasible to detect and estimate these effects. Here a simulation tool was developed in order to explore the power by which single genetic loci subjected to uni-directional selection in parallel breeding populations may be detected. Findings. Two simulation models were pursued: 1) screening for loci displaying higher genetic differentiation than expected (high-FSToutliers), from neutral evolution between a pool of domesticated populations and a pool of wild populations; 2) screening for loci displaying lower genetic differentiation (low-FSToutliers) between domesticated strains than expected from neutral evolution. The premise for both approaches was that the isolated domesticated strains are subjected to the same breeding goals. The power to detect outlier loci was calculated under the following parameter values: number of populations, effective population size per population, number of generations since onset of selection, initial FST, and the selection coefficient acting on the locus. Among the parameters investigated, selection coefficient, the number of generation since onset of selection, and number of populations, had the largest impact on power. The power to detect loci subjected to directional in breeding programmes was high when applying the between farmed and wild population approach, and low for the between farmed populations approach. Conclusions. A simulation tool was developed for estimating the power to detect artificial selection acting directly on single loci. The simulation tool should be applicable to most species subject to domestication, as long as a reasonable high accuracy in input parameters such as effective population size, number of generations since the initiation of selection, and initial differentiation (FST) can be obtained. Identification of genetic loci under artificial selection would be highly valuable, since such loci could be used to monitor maintenance of genetic variation in the breeding populations and monitoring possible genetic changes in wild populations from genetic interaction between escapees and their wild counterpart. © 2010 Karlsson et al; licensee BioMed Central Ltd. Source

Karlsson S.,Nofima Marine | Moen T.,Aqua Gen AS | Moen T.,Norwegian University of Life Sciences | Lien S.,Norwegian University of Life Sciences | And 2 more authors.
Molecular Ecology Resources | Year: 2011

Genetic interactions between farmed and wild conspecifics are of special concern in fisheries where large numbers of domesticated individuals are released into the wild. In the Atlantic salmon (Salmo salar), selective breeding since the 1970's has resulted in rapid genetic changes in commercially important traits, such as a doubling of the growth rate. Each year, farmed salmon escape from net pens, enter rivers, and interbreed with wild salmon. Field experiments demonstrate that genetic introgression may weaken the viability of recipient populations. However, due to the lack of diagnostic genetic markers, little is known about actual rates of gene flow from farmed to wild populations. Here we present a panel of 60 single nucleotide polymorphisms (SNPs) that collectively are diagnostic in identifying individual salmon as being farmed or wild, regardless of their populations of origin. These were sourced from a pool of 7000 SNPs comparing historical wild and farmed salmon populations, and were distributed on all but two of the 29 chromosomes. We suggest that the generic differences between farmed and wild salmon at these SNPs have arisen due to domestication. The identified panel of SNPs will permit quantification of gene flow from farmed to wild salmon populations, elucidating one of the most controversial potential impacts of aquaculture. With increasing global interest in aquaculture and increasing pressure on wild populations, results from our study have implications for a wide range of species. © 2011 Blackwell Publishing Ltd. Source

Altintzoglou T.,Nofima Marine | Verbeke W.,Ghent University | Vanhonacker F.,Ghent University | Luten J.,NOFIMA Market
Journal of Aquatic Food Product Technology | Year: 2010

This study investigated the effect of balanced, nonpersuasive information related to safety, healthiness, and sustainability of aquaculture on the image of farmed fish among European consumers. It was demonstrated that there is neither positive nor negative influence of this type of information on the predominantly positive image of fish from aquaculture. Consumers who were exposed to information related to the EU origin and aquaculture related guarantee reported a more positive image of farmed fish. These results provide valuable input for transparent communication about fish farming practices which might increase consumer trust and will not harm the image of fish from aquaculture. Increasing consumers' knowledge about aquaculture and its positive effects on the image of farmed fish is also discussed as a pathway for maintaining and improving aquaculture's positive image in the future. Copyright © Taylor & Francis Group, LLC. Source

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