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Vibriosis is a bacterial disease in fish caused by the Gram negative bacterium Vibrio anguillarum with severe impact on rainbow trout (Oncorhynchus mykiss) farming. Sustainable control methods should be developed and we here show that marker assisted selective breeding of fish naturally resistant to the disease is feasible. We have validated the use of a single nucleotide polymorphism (SNP) marker SNP AX-89,945,921 (QTL on chromosome 21). The QTL was previously found associated with resistance to vibriosis and described following a genome wide association analysis (GWAS) of trout exposed to the bacterium. For this validation spawners were genotyped by use of the 57 K Axiom®Trout Microarray (Affymetrix) and homozygous male fish carrying the allele with the SNP AX-89,945,921 were then selected and used to fertilize eggs from outbred female trout resulting in fish all carrying the SNP (QTL-fish). Control fish (non-QTL fish) were produced by fertilizing the same batch of eggs by use of male parents negative for the SNP. The fish were exposed in freshwater to V. anguillarum (water bath infection) at 19 ºC. A total of 900 fish were challenged in a common garden set-up in triplicate. A bacterial solution of V. anguillarum (serotype O1) was added to each of three freshwater fish tanks, each with 150 QTL and 150 non-QTL fish. Fish were tagged by tail fin cut (upper/lower) to discern the two groups, whereafter fish were monitored around the clock to detect disease signs and remove moribund fish. Clinical vibriosis developed within two days in non-QTL-fish (overall morbidity of 70%). QTL fish developed clinical signs later and the morbidity was significantly lower and did not reach 50%. Rainbow trout farming may benefit from using the QTL associated with higher resistance towards vibriosis. The effect may be optimized in the future by use of both male and female parents homozygous for the marker allele.

“Just because you're paranoid doesn't mean they aren't after you.”(Joseph Heller, Catch-22, 1961) Thomas Pynchon’s earliest novels – V. (1963) The Crying of Lot 49 (1966) and Gravity’s Rainbow (1973) – were fictions which overtly addressed ideas of plot and history. Paranoid characters encounter multiple possible conspiracies, complots and possibilities of sinister networks in control of the world in which they live. At a time where conspiracy theorists were still considered part of a subculture, initial literary criticism of Pynchon’s conspiracy literature was successful in pursuing narratological and philosophical readings which interpreted those novels as postmodern lessons in paranoid reading styles, author schizophrenia, subjective erasure and ontological doubt. On this basis, for many, Pynchon was enshrined as one of the great postmodernist writers of the USA. Pynchon’s critique of late capitalism and the conspiracies in politics and history which continued to be central to his later literature – Vineland (1990), Mason & Dixon (1997), Against The Day (2006) – was long overlooked, I would argue, because conspiracy theory itself could not be taken seriously within academia. Plot is a respectable object of literary study; complots are more problematic and in Pynchon’s case would be subsumed by the former, especially because he was taught for the narrative style rather than the content of his writing.In the 21st century, marked by 9/11, a number of things have changed, however. On the one hand, Pynchon studies has taken a turn towards history and politics and while conspiracy theory methods or topics have not become respectable to academics, they now reside in the mainstream of American culture and politics: A good story seems to carry more weight than facts in a post-truth society. Academic readers are starting to recognize the extent to which Pynchon’s fiction has always been fact-based and reflected historical, social and political contexts. What is troublesome about this new angle is the fact that paranoia, conspiracies and sinister plotting are no less prevalent in Pynchon’s latest novels – Inherent Vice (2009) and Bleeding Edge (2013).A conspiracy theorist is a person who claims to be an authority in possession of (alternative) facts: an author of an unwelcome truth. At one end of the spectrum is Donald Trump’s Twitter feed, at the other end is March Kelleher’s “Tabloid of the Damned” blog. In the current climate, the dilemma for respectable academic analysis has now become what perspective to put on a paranoid authorship at a time where our culture at large seems to be losing its grip on reality.

Additional file 1: Table S1. Allocation of the fish at the start of the experiment. Table S2. Analysis of the composition of the β-glucan used in this study. Figure S3. Principal component analysis showing the microbiota of the fish at week 6. Figure S4. Heatmap showing the 10 most abundant bacterial phyla in the intestine of the fish for the two control groups and the groups receiving the three different concentration of β-glucan. Table S5. Performance of the fish over the course of the experiment. Figure S6. Average weight of the fish per treatment over the course of the experiment. Figure S7. Average Fulton's condition factor (K) of the fish per treatment over the course of the experiment. Table S8. All metabolites measured in the serum of the fish for all investigated groups. Table S9. Metabolites measured at significantly different levels between treated fish and the control. Arrows indicate if the metabolite were upregulated (↑) or downregulated (↓) relative to the control without β-glucan treatment. Lack of significant change is indicated by “No”. Figure S10. Survival curves of the fish following 9 h bath exposure to 1.6 × 107 CFU∙mL−1 of live Y. ruckeri O1 biotype 2 (100415-1/4).

The fish pathogen Flavobacterium psychrophilum infects farmed salmonids worldwide, and application of bacteriophages has been suggested for controlling disease outbreaks in aquaculture. Successful application of phages requires detailed knowledge about the variability in phage susceptibility of the host communities. In this study we analyzed the genetic diversity of F. psychrophilum hosts and phages from the Baltic Sea area, to identify genetic determinants of phage-host interaction patterns. A host range analysis of 103 phages tested against 177 F. psychrophilum strains (18,231 phage-host interactions) identified 9 phage clusters, infecting from 10% to 91% of the strain collection. The core genome-based comparison of 35 F. psychrophilum isolates revealed an extremely low overall genomic diversity (>99.5% similarity). However, a small subset of 16 ORFs, including genes involved in the type IX secretion system (T9SS), gliding motility and hypothetical cell-surface related proteins, exhibited a highly elevated genetic diversity. These specific genetic variations were linked to variability in phage infection patterns obtained from experimental studies, indicating that these genes are key determinants of phage susceptibility. These findings provide novel insights on the molecular mechanisms determining phage susceptibility in F. psychrophilum and emphasizes the importance of phages as drivers of core genomic diversity in this pathogen. This article is protected by copyright. All rights reserved.

”Just remember, what you’re seeing and what you’re reading is not what’s happening”Donald J. Trump, Veterans of Foreign Wars National Convention in Kansas City, Missouri. 24 July 2018” If there is something comforting—religious, if you want—about paranoia, there is still also anti-paranoia, where nothing is connected to anything, a condition not many of us can bear for long.” Thomas Pynchon, Gravity’s Rainbow, 1973.Donald Trumps forkærlighed for nogle af konspirationens retoriske greb - når han i kryptiske, vage eller ”sladrende” vendinger stipulerer viden om dette og hint – undergraver de usikre ”læseres” tiltro til én, verificerbar sandhed. Én reaktion har været at forstærke informationssøgning og meningsdannelse indenfor snævre epistemiske ”bobler” som styrker ofte ekstreme fortolkninger af selektiv viden til et næsten kultisk niveau. Trumps held med at fremelske denne effekt forekommer derfor ikke blot at være en politisk men også en epistemologisk krise. Jeg vil ikke desto mindre argumentere for at USA's 45. præsident ikke er ophav til, end ikke katalysatoren for, en stærkt forhøjet konspirationskultur i USA i de seneste år. Han er blot velplaceret og usædvanlig dygtig til at praktisere og til en vis grad forny en genre som landet har været prædisponeret for siden puritanere grundlagde kolonier i New England og som moderne medier, internetbaseret kommunikation og sociale medier har accelereret og udbredt eksponentielt i det 21. århundrede.Argumentet for konspirationskulturens rod i puritanismen har at gøre med deres fokus på individuel nærlæsning og fortolkning både af Skriften og af Tegn. Både bibelsk tekst og hændelser observeret i naturen kunne fungere som symbolsk kommunikation mellem en øvre autoritet og den enkelte troende i en udsat, belejret ny verden hvor man søgte at finde en dybere mening. Menneskets iboende drift mod mønstergenkendelse blev i Amerika bundet til både en stærk individualistisk tradition og et ambivalent forhold til (verdslige) autoriteter, hvilket i nogen grad forklarer hvorfor Trumps antagonisme mod eliten, ”the swamp” ”the deep state” og de falske profeter i pressen er så velmodtaget. Hans antydning af privilegeret adgang til en alternativ sandhed er så troværdig i en konspirationstankegang at radikaliserede grupper som ”QAnon” decideret modlæser Trump i en sådan grad at dét at han selv spreder ”fake news” og signalforvirring i virkeligheden fortolkes som udtryk for hans ophøjede kontrol og altomfattende plan for USA. Paranoia er, ironisk nok, mere beroligende end det modsatte.Ifølge litterære kritikere har litteraturen selv forholdt sig til og trænet postmoderne læsere til at genkende både paranoia og antiparanoia (en tilstand hvor intet er forbundet, som ingen kan udholde i længden) i måden at forholde sig til både teksten og verden. Dette har tilsyneladende været et tilbagevendende projekt for en forfatter som Thomas Pynchon, hvis encyclopædiske romaner inviterer til konspiratorisk nærlæsning af tekstbåret evidens om fiktionens rette sammenhæng og mening men også til refleksion over denne aktivitets grundlag. Brian McHale har ligeledes beskrevet Pynchon’s genrepasticher (”genre poaching” eller appropriering af lavkulturel genrelitteratur til et højere formål) som medieret historiografi. Mit argument er man i konspirationsteorier ser en tilsvarende appropriering af metode, men med omvendt værdi. I nyere tid har konspirationer været popkulturelle aktiviteter, som i forsøget på at afdække omverdenens rette sammenhæng har plagieret legitime læsnings- og fortolkningsmetoder. Bibelsk exegese gav først modellen for udlægning af encyclopædisk materiale, mens historiografisk metode senere gav et skin af videnskabelighed over kognitivt forudindtaget indsamling og udlægning af beviser for hypoteser. Konspirationsteori er en underkultur, et læsefællesskab, en epistemisk boble som legitimeres ved at maskere sine aktiviteter som anerkendte litterære og videnskabelige metoder.Det der gør Trumps evne til at fremelske konspirationstankegang blandt prædisponerede amerikanske tilhørere specielt interessant i denne kontekst er to ting: På den ene side burde konspirationsteoriens antiautoritære logik arbejde imod ideen om en elitær magthaverfigur som den der kan afsløre konspirationer (som ellers udgår fra højere magter). På den anden side forekommer hans vage hentydninger om mulige rænker samt indlysende kontrafaktuelle påstande langt fra detaljerede og overbevisende nok til at generere konspirationsteorier i den grad tilfældet er. Trump har ikke skabt mistroen til autoriseret viden, men skaber nye legitimiseringsstrategier for konspirationslogik som i en allerede destabiliseret informationskultur, hvor Internettet, som forskningsarkiv og kommunikationsværkstøj, i samspil med sociale og traditionelle medier har demokratiseret en tidligere suspekt, subkulturel aktivitet.

Puritan ideas of close reading of the Good Book to interpret the greater divine plan for their lives in the new American colonies are the foundations of a conspiratorial mindset in the USA. Personal biblical exegesis was in essence an antiestablishment activity, where personal interpretation could supersede dogmatic readings. At the same time, pursuing signs and patterns fostered a paranoid reading strategy in which “everything is connected” and confirmed a (sinister) establishment.Conspiracy has never seemed more central to the ontological understanding of the USA than now. This paper reviews the way Pynchon has handled this particular worldview in his novels, practically and historically, before arguing that our acts of interpretation of his work may themselves actually use the epistemological tools of conspiracy theory.The qualitative analysis of “elite” academic readers adjoins the quasi-scientific practices of conspiracy theorists: thorough research filtered by subjective insights. Both groups pursue textual traces and connections to reveal unseen truths. Puritan readers sifted information for God’s true plan rather than that established of Roman clergy; QAnon activists look for the veiled plan Trump has mounted against a “they”-system of the hidden “Deep State” establishment. In both cases signs and interpretations proliferate around an author(itarian) figure.Early Pynchon novels arguably invited this sort of paranoid reading activity as a postmodern insight. In a post-factual world, where conspiracy theory approaches the main stream, I question whether recent novels can work this way without changing our role as readers and Pynchon’s as the author of our pursuit.

This paper considers the subjunctive implications of three relations in Thomas Pynchon’s Bleeding Edge (2013) structured along the lines of inside/outside, real/virtual and now/then. Critics have applied the idea of the subjunctive and questions of Pynchon’s experiments with time and space relations in earlier works to investigate ambiguity or multiple realities in his fiction. This analysis of his latest novel focuses on how Other figurations of New York commute between hopeful, subjunctive and pessimistic, indicative readings. The first of three relations identifies the way in which urban planning has been a locus for discussions of dispossession and colonization in Pynchon’s work. In this text exemplified by the loss of diversity effected by Rudy Giuliani’s sanitizing of Time’s Square in the 1980s and the different outcomes projected for the bird sanctuary, Isle of Meadows, and for the landfill site containing it, Fresh Kills, before and after 9/11 in 2001. The second relation focuses on how different character remember the architectural past of New York city or rebuild it in a virtual and virtuous alternative form, though the Internet is a highly contested space in Bleeding Edge. The final relation overlays the two first spatial and virtual relations with the complicated temporal and modal relationship between the 2001 setting of the 2013 text and the present-day reader. Pynchon has often worked with the historically inevitable, deterministic closing down of subjunctive possibilities by the forward march of indicative, possessive, indexed world. Some elements of this this text, and not least the position of the reader in the flow of time between the historical facts presented in the text and the as-of-yet unknown outcomes of these in present-day real life, keeps some ambiguity about projected (negative) outcomes alive.

Profilartikel: Amerikas nyeste førstedame, Melania Trump, er en fåmælt dame men hendes fremtoning er blevet anklaget for at være både højtråbende og tonedøv hvad enten der er tale om den Dolce & Gabbana jakke til over 300.000 kr hun var iklædt til et G7 møde eller det par Manolo Blahnik-stiletter hun iførte sig på rejsen til et katastroferamt Texas. Med en fortid som fotomodel var Melanias personlig interesse for stil og couture forventelig og samtidig har medierne i stigende grad beskæftiget sig med indgående analyser af førstedamers tøjvalg i de seneste årtier. Men hvorfor har det overhovedet nogen betydning hvad en velhavende kvinde, der ikke er folkevalgt til et officielt embede, iklæder sig?

Indexación: Scopus. Flavobacterium psychrophilum, the etiological agent of rainbow trout fry syndrome and bacterial cold-water disease in salmonid fish, is currently one of the main bacterial pathogens hampering the productivity of salmonid farming worldwide. In this study, the genomic diversity of the F. psychrophilum species is analyzed using a set of 41 genomes, including 30 newly sequenced isolates. These were selected on the basis of available MLST data with the two-fold objective of maximizing the coverage of the species diversity and of allowing a focus on the main clonal complex (CC-ST10) infecting farmed rainbow trout (Oncorhynchus mykiss) worldwide. The results reveal a bacterial species harboring a limited genomic diversity both in terms of nucleotide diversity, with ~0.3% nucleotide divergence inside CDSs in pairwise genome comparisons, and in terms of gene repertoire, with the core genome accounting for ~80% of the genes in each genome. The pan-genome seems nevertheless "open" according to the scaling exponent of a power-law fitted on the rate of new gene discovery when genomes are added one-by-one. Recombination is a key component of the evolutionary process of the species as seen in the high level of apparent homoplasy in the core genome. Using a Hidden Markov Model to delineate recombination tracts in pairs of closely related genomes, the average recombination tract length was estimated to ~4.0 Kbp and the typical ratio of the contributions of recombination and mutations to nucleotide-level differentiation (r/m) was estimated to ~13. Within CC-ST10, evolutionary distances computed on non-recombined regions and comparisons between 22 isolates sampled up to 27 years apart suggest a most recent common ancestor in the second half of the nineteenth century in North America with subsequent diversification and transmission of this clonal complex coinciding with the worldwide expansion of rainbow trout farming. With the goal to promote the development of tools for the genetic manipulation of F. psychrophilum, a particular attention was also paid to plasmids. Their extraction and sequencing to completion revealed plasmid diversity that remained hidden to classical plasmid profiling due to size similarities. https://www.frontiersin.org/articles/10.3389/fmicb.2018.00138/full

Flavobacterium psychrophilum, the etiological agent of rainbow trout fry syndrome and bacterial cold-water disease in salmonid fish, is currently one of the main bacterial pathogens hampering the productivity of salmonid farming worldwide. In this study, the genomic diversity of the F. psychrophilum species is analyzed using a set of 41 genomes, including 30 newly sequenced isolates. These were selected on the basis of available MLST data with the two-fold objective of maximizing the coverage of the species diversity and of allowing a focus on the main clonal complex (CC-ST10) infecting farmed rainbow trout (Oncorhynchus mykiss) worldwide. The results reveal a bacterial species harboring a limited genomic diversity both in terms of nucleotide diversity, with similar to 0.3% nucleotide divergence inside CDSs in pairwise genome comparisons, and in terms of gene repertoire, with the core genome accounting for similar to 80% of the genes in each genome. The pan-genome seems nevertheless "open" according to the scaling exponent of a power-law fitted on the rate of new gene discovery when genomes are added one-by-one. Recombination is a key component of the evolutionary process of the species as seen in the high level of apparent homoplasy in the core genome. Using a Hidden Markov Model to delineate recombination tracts in pairs of closely related genomes, the average recombination tract length was estimated to similar to 4.0 Kbp and the typical ratio of the contributions of recombination and mutations to nucleotide-level differentiation (r/m) was estimated to similar to 13. Within CC-ST10, evolutionary distances computed on non-recombined regions and comparisons between 22 isolates sampled up to 27 years apart suggest a most recent common ancestor in the second half of the nineteenth century in North America with subsequent diversification and transmission of this clonal complex coinciding with the worldwide expansion of rainbow trout farming. With the goal to promote the development of tools for the genetic manipulation of F. psychrophilum, a particular attention was also paid to plasmids. Their extraction and sequencing to completion revealed plasmid diversity that remained hidden to classical plasmid profiling due to size similarities.

Flavobacterium psychrophilum, the etiological agent of rainbow trout fry syndrome and bacterial cold-water disease in salmonid fish, is currently one of the main bacterial pathogens hampering the productivity of salmonid farming worldwide. In this study

High mortalities among rainbow trout (Oncorhynchus mykiss) fry are often the result of infections caused by Flavobacterium psychrophilum, and in Denmark this pathogen can be found in nearly all freshwater fish farms. The infection can be treated with antibiotics, but lower sensitivity against the infection is an increasing problem for some of the used drugs, wherefore alternative treatment methods (e.g. bacteriophages) are investigated. Prophylactic measures (e.g. feed additives) are another approach, so infections with the bacterium can be avoided, before they become a problem. No matter if the focus is on prophylactic or alternative treatment, reliable infection models are needed to evaluate the treatments as well as to get more knowledge about infections with F. psychrophilum. Experimental infection models will be presented, among them a reproducible intraperitoneal injection model as well as different bath models, and the potential for using the models will be discussed.

Background Flavobacterium psychrophilum causes serious fish diseases such RTFS and BCWD, affecting the aquaculture industry worldwide. Commercial vaccines are not available and control of the disease depends on the use of antibiotics. Reliable methods for detection and identification of different isolates of this bacterium could play an important role in the development of good management strategies. The aim of this study was to identify genetic markers for discrimination between isolates. A selection of eight VNTRs from 53 F. psychrophilum isolates from Norway, Chile, Denmark and Scotland were analyzed. The results were compared with previous work on the same pathogen using MLST for genetic differentiation. Results The VNTR analysis gave a separation between the F. psychrophilum isolates supporting the results of previous MLST work. A higher diversity was found among the Chilean isolates compared to those from Norway, which suggests a more homogenous reservoir in Norway. Transgenerational transmission of F. psychrophilum from other countries, exporting salmon embryos to Chile, may explain the differences in diversity. The same transmission mechanisms could also explain the wide geographical distribution of identical isolates in Norway. But, this could also be a result of movement of smolts and embryos. The selected VNTRs are stable genetic markers and no variation was observed after several passages on agar plates at different temperatures. Conclusions These VNTRs are important additions for genotyping of F. psychrophilum isolates. Future studies on VNTRs of F. psychrophilum should include isolates from more host species from a wider geographical area. To get a more robust genotyping the VNTRs should be used in concert with MLST. Future studies of isolates with high and low virulence should focus on identifying virulence markers using VTNRs and MLST. Electronic supplementary material The online version of this article (doi:10.1186/s12917-015-0469-7) contains supplementary material, which is available to authorized users.

Aquaculture in brackish and marine water is growing worldwide. New cultured species are introduced, and types of aquaculture vary from outdoor to indoor and from flow through to recirculated water, at various temperature. In these types of aquaculture various Vibrio species play and important role, as causative agents of fish, crustacean and shellfish diseases. In this workshop experts on vibriosis are giving short lectures. After that there is time for a discussion, to work jointly towards a list of the current most important problems on vibriosis in aquaculture production with definition of gaps in knowledge and recommendations on future research. Discussion points:1. Which are the most important vibriosis problems in fish culture, crustcean culture and shellfish culture? 2. Diagnostic methods up to date, and are the used therapies effective? 3. Are prevention methods effective, and are specific vaccines futher needed. Which recommendation can be made for adequate prevention and control of vibriosis in aquaculture?

Feed for rainbow trout aquaculture has traditionally been based on marine resources such as fish meal and fish oil. Because of a shortage of marine resources as well as the growing production of farmed fish, the feed industry has been forced to partially exchange fish meal protein with proteins derived from plants, like soy bean meal. This has been shown to affect the salmonid intestinal mucosa, and in addition, plant-based dietary proteins have been associated with changes in disease susceptibility in salmon and it has been suggested that these special diet types weakens the immune status of the fish. One major cause for losses in Danish freshwater fish farms is the fry disease rainbow trout fry syndrome (RTFS), caused by the bacterium Flavobacterium psychrophilum, and experiences of the fish farmers suggest that the diet type is an important factor for disease development. Enteric redmouth disease caused by Yersinia ruckeri is also an economically important disease which causes problems in rainbow trout fry as well as larger fish. Rainbow trout were fed from first-feeding with five different diets; diet A with marine fish oil (conventional fry diet), diet B (an organic version of A), diet C with rape seed oil (like B but with rape seed oil exchanging marine fish oil), diet C with pea protein (like B but added pea protein) and diet E with rape seed oil and pea protein. When the fry had reached sizes 1.5 g and 4 g, groups of fish from the five diet groups were infected with Flavobacterium psychrophilum and Yersinia ruckeri, respectively. An intraperitoneal injection model was used for F. psychrophilum, whereas a bath challenge was used for Y ruckeri. Before and after infection, samples were taken from internal organs including the intestine for traditional bacteriology and only intestinal samples for next generation sequencing. The cumulative mortalities among the diet groups did not differ between groups in either of the two infection trials, suggesting that the diets did not have different effects on the immune status of the fish, when it comes to survival after infection, meaning that plant content did not seem to weaken the immune status of the rainbow trout fry. Results of the trial as well as the bacteriological examinations and the next generation sequencing results will be presented.

In warm-blooded animals such as humans and pigs the intestinal microbial composition is dependent on the type of ingested diet. It is known that it also influences the immune system and prevent colonization of pathogenic bacteria. The question is if the gut microbiota has the same impact in lower vertebrates such as fish? To examine this rainbow trout fry were fed two different diets of either a marine or vegetable origin. At a size of about four gram a subset of the fish was bath challenged by Yersinia ruckeri serotype O1 and intestines were then sampled 5 days post challenge from challenged fish (n = 40) and non-challenged control fish (n = 40). Subsequent metagenomic examination based on the 16S rDNA gene was then performed using the Illumina HiSeq 2000 platform. Obtained sequences were paired, sorted, filtered, checked for chimeras and finally mapped against the Greengene database using the open-source package Bion-meta. Analysis of the microbial communities when then made for the non-infected control fish and Yersinia ruckeri challenged fish. For the non-infected control fish, the results showed two distinctly different microbial patterns in the intestines dependent on the administered diet type. Fish fed a marine based diet overall had a significantly higher amount of the class β-proteobacteria, while phylum Firmicutes was significantly higher abundant in the intestines of vegetable fed fish. The genera within phylum Firmicutes present in significantly higher amounts in vegetable fed fish were Weissella, Leuconostoc and Streptococcus. Genus Aeromonas from the γ-proteobacteria class was also present in significantly higher amounts in the vegetable fed fish.The microbial community was different in the fish that were challenged by Yersinia ruckeri. Challenged fish clustered into two groups according to the load of Yersinia ruckeri specific reads in their intestine; the main part of challenged fish (n = 34) had a low amount of Yersinia specific reads (≤ 1.2 % of total amount of reads), while a minor group (n = 6) had a high load ranging between 13.9 and 23.2 % of all reads. These ‘high Yersinia level’ fish had a significantly lower amount of reads from the order Burkholderiales relative to the ‘low Yersinia level’ fish and non-infected control fish. Further, the ‘high Yersinia level’ fish further clustered separately when analyzing the bacterial community on a PCA plot. The immunological examinations were performed by RT-qPCR in order to measure the expression of selected immune genes. The results showed a similar expression pattern between the two diet groups of non-infected fish, but the response differed between the two diet groups in challenged fish. Overall, the results indicate that the gut microbiota in rainbow trout, like in warm-blooded animals, is highly plastic according to the type of diet and does also seem to be involved in the immunological response in connection to pathogenic challenge.

The portal of entrance of either formalin inactivated or live Yersinia ruckeri organism in rainbow trout fish was studied by applying immunohistochemistry and in-situ hybridization. The sequential study involved a specific monoclonal antibody and a specific oligonucleotide probe binding to Yersinia ruckeri. It demonstrated the differential and regional uptake of both formalin inactivated and live bacterial organism in rainbow trout. The uptake dynamics in various organs/tissues demonstrated a site specific propensity between formalin inactivated and live bacteria. The possibility that lateral lines, dorsal fins and the gastro-intestinal tract could act as an active avenue to bacterial entrance was shown by both immunohistochemistry and in situ hybridization. The translocations of systemically absorbed formalin inactivated and live bacteria within different host body compartments were elucidated.

In recent years it has become more and more evident that the bacterial flora in the gut of warm-blooded animals modulates physiological processes and the immunological status of the host. Besides effects on growth parameters, commensal intestinal bacteria balance the immune system and prevent colonization of pathogenic bacteria. The question is if the gut microbiota is also important in lower vertebrates such as fish? Is the microbiota related to the diet type and does it play a protective role in connection to pathogenic challenge? To examine these questions rainbow trout fry were fed two different diets of either a marine or vegetable origin from first feeding and onwards. At a size of about four gram the fish were bath challenged by Yersinia ruckeri serotype O1 and intestines were then sampled 5 days post challenge for subsequent metagenomic examination. Next-generation sequencing was applied for the metagenomic studies using the Illumina HiSeq 2000 platform. The results showed two distinctly different microbial patterns in the intestines dependent on the diet type. Fish fed a marine based diet overall had a significantly higher amount of the class β-proteobacteria, while the amount of reads belonging to phylum Firmicutes were significantly higher in the intestines of vegetable fed fish. The genera within phylum Firmicutes present in significantly higher amounts in vegetable fed fish were Weissella, Leuconostoc and Streptococcus. Genus Aeromonas from the γ-proteobacteria class was also present in significantly higher amounts in the vegetable fed fish. When challenged with Yersinia ruckeri, fish with a high amount of sequence reads belonging to genus Yersinia had a significantly lower amount of reads from the order Burkholderiales relative to non-infected control fish and fish with a low amount of Yersinia specific sequences. Further, these infected fish further clustered separately when analyzing the bacterial community on a PCA plot. The immunological examinations using RT-qPCR showed similar constitutive expression between the two diet groups, but the response differed between the two diet groups in challenged fish. Here, the general pattern was a pro-inflammatory response in the intestine of marine fed fish challenged with Yersinia ruckeri relative to non-infected control fish, while several immune genes were down-regulated in vegetable fed fish relative to non-infected control fish. Overall, the results indicate that the gut microbiota in rainbow trout is highly plastic according to the type of diet and does further seem to be involved in the immunological response in connection to pathogenic challenge.

In recent years it has become more and more evident that the bacterial flora in the gut of warm-blooded animals modulates physiological processes and the immunological status of the host. Besides effects on growth parameters, commensal intestinal bacteria balance the immune system and prevent colonization of pathogenic bacteria. The question is if the gut microbiota is also important in lower vertebrates such as fish? And does it play a role in connection to pathogenic challenge? To examine these questions rainbow trout fry were fed two different diets of either a marine or vegetable origin directly after first feeding. At a size of about four gram the fish were bath challenged by Yersinia ruckeri and intestines were then sampled 5 and 18 days post challenge for subsequent metagenomic and immunological examinations. Next-generation sequencing was applied for the metagenomic studies using the Illumina HiSeq platform. The results clearly showed two different microbial patterns in the intestines dependent on the diet type. Control fish fed a marine based diet overall had a higher amount of proteobacteria, while high amount of reads belonging to phylum Firmicutes dominated in the intestines of vegetable fed fish. Several genera within the order Lactobacillales belonged to the many reads from Firmicutes. In challenged fish with a high load of reads from genus Yersinia there was a significantly lower amount of reads from the order Burkholderiales. Further, these fish further clustered separately when analyzing the bacterial community on a PCA plot. The immunological examinations using RT-qPCR showed no different expression patterns between the diet groups in control fish, but the response was very different in connection to challenge. Here, the general pattern was a pro-inflammatory response in the intestine of marine fed fish challenged with Yersinia ruckeri, while several immune genes were down-regulated in vegetable fed fish. Overall, the results indicate that the gut microbiota in rainbow trout is highly plastic according to the type of diet and does further seem to be involved in the immunological response in connection to pathogenic challenge.

The preparation of samples of bacteria and other very small organisms (

Figures from classical mythology which can be identified broadly as “technologists” are transformed and live on in later works of literature. Mythic characters like Daedalus, Hephaistos and Prometheus have survived through the years by a process of adaptation. Their significance either changes as they reappear in later works of fiction, as is the case with Mary Shelley’s Frankenstein, or, the New Prometheus (1818), or their characteristics inform later technologist figures as part of the critical fictional strategies of authors like Herman Melville or Thomas Pynchon.

The fish pathogen Flavobacterium psychrophilum is one of the main causes of mortality in farmed rainbow trout and other salmonid fish. The disease following infection is often called bacterial coldwater disease (BCWD) in USA or rainbow trout fry syndrome (RTFS) in Europe. An infected farm can expect mortality rates around 50-60% in fry and 2-10% in juvenile fish within few weeks, which causes significant economical losses worldwide. Presently no commercial vaccine exists, and fish farmers control the disease with antibiotics. The project is currently in its preliminary phase but the overall goal is to examine gene expression and location of transcription products in rainbow trout fry, in order to optimize vaccination or immune-stimulation. The presentation will focus on the future plans for the project, since no data have yet been obtained.

Furunculosis, caused by Aeromonas salmonicida, continues to be a health problem for the growing salmonid aquaculture. Despite effective vaccination programs regular outbreaks occur at Danish trout farms calling for repeated antibiotic treatment. We hypothesized that a difference in natural susceptibility to this disease might exist between Baltic salmon and the widely used rainbow trout. Hence, a cohabitation challenge model was applied to investigate the relative susceptibility to infection with Aeromonas salmonicida in rainbow trout and Baltic salmon. The course of infection was monitored daily over a 30-day period post challenge and the results were summarized in mortality curves. A. salmonicida was recovered from mortalities during the entire test period. At day 30 the survival was 6.2 % and 34.0 % for rainbow trout and Baltic salmon, respectively. Significant differences in susceptibility to A. salmonicida were demonstrated between the two salmonids and hazard ratio estimation between rainbow trout and Baltic salmon showed a 3.36 higher risk of dying from the infection in the former. The finding that Baltic salmon carries a high level of natural resistance to furunculosis might raise new possibilities for salmonid aquaculture in terms of minimizing disease outbreaks and the use of antibiotics.

Udgivelsesdato: Summer

Udgivelsesdato: 2008

Udgivelsesdato: 2008

Dansk Akvakultur's målsætning for udviklingen inden for økologisk fiskeopdræt frem mod år 2015 er, at 1. Mindst 10% (10.000 tons) af produktionen skal være økologisk 2. Eksportandelen heraf skal være på mindst 50% 3. Der opdrættes mindst tre forskellige økologiske arter 4. Den samlede forskningsindsats i økologi er på mindst 3% af primæromsætningen 5. Senest i 2007 er der etableret et fælles europæisk regelsæt 6. Danmark er EU's førende producent af økologisk fiskefoder Formålet med denne vidensyntese er at identificere de væsentligste indsatsområder af betydning for den målsatte udvikling af økologisk fiskeopdræt i Danmark, herunder en sammenfatning af den eksisterende viden om økologisk fiskeopdræt såvel nationalt som i det øvrige Europa. Den årlige globale produktion inden for akvakultur udgør ca. 45 mio. tons, hvoraf mere end 90 % foregår i Asien, mens europæisk akvakultur tegner sig for ca. 4% af produktionen. Til sammenligning udgør den økologiske produktion ca. 25.000 tons, der primært foregår i Europa. Den danske produktion i akvakultur udgør ca. 32.000 tons regnbueørreder i ferskvand, ca. 8.000 regnbueørreder i saltvand og ca. 2.000 tons ål. Produktion af fisk i Danmark efter økologiske principper startede i 2001. Da et egentligt regelsæt for økologisk fiskeproduktion først forelå i 2004 kom den første danske regnbueørred med det røde Ø-mærke på markedet i 2005. Den økologiske produktion udgør ca. 150 tons ørreder i ferskvand (regnbueørred og kildeørred). Der er p.t. ingen produktion af økologiske ål i Danmark. Førstehåndsværdien af den danske økologiske fiskeproduktion ligger i størrelsesordenen 2,5 - 3 mio. kr. om året. Til sammenligning udgjorde salget af økologiske produkter i Danmark i 2005 ca. 2,3 mia. kr., hvilket er en stigning på 12% fra året før. I forhold til det totale danske fødevareforbrug udgjorde salget af økologiske fødevarer ca. 4%, hvilket på globalt plan er blandt de højeste markedsandele. Ideologien bag økologisk opdræt er at skabe en mere etisk produktionsform, hvor produktionen foregår ved naturlige processer og primært skal være baseret på opretholdelse af naturens kredsløb og ved anvendelse af lokale ressourcer, d.v.s. bevare naturens balance. Det røde økologimærke garanterer, at producenten efterlever veldefinerede og kontrollerbare produktionsbetingelser (opvækstforhold, fodersammensætning m.m.), som i forhold til konventionel produktion er mere vidtgående. Den økologiske fisk forventes således at repræsentere en reel forskel i forhold til produkter uden Ø-mærket. Økologien er således drevet af en forbrugertillid til, at man gennem køb af økologiske produkter bidrager til et bedre miljø, lavere ressourceforbrug og højere dyrevelfærd og sundere mad (miljø, etik og kvalitet). Fiskevelfærd tilgodeses gennem passende besætningstæthed, gode og stabile interne miljøforhold (ilt mv.), skånsom håndtering, sikring mod smittekilder (afskærmning) samt sundhedsovervågning og – rådgivning. Idet økologibegrebet udelukkende er knyttet til produktionen, hvor alle led er dokumenterbare, kan vildfisk ikke betegnes som økologiske. Det danske økologiske opdræt skiller sig særligt ud ved restriktive krav til anvendelse af medicin og hjælpestoffer (fødevaresikkerhed); toleranceområder for specifikke vandmiljøparametre (dyrevelfærd), mens bæredygtighedskonceptet indgår i foderbekendtgørelsen. Den danske bekendtgørelse om økologisk akvakulturbrug stiller imidlertid ingen krav med hensyn til vand-/ressourceforbrug i forhold til den anvendte mængde energi på et økologisk dambrug. Trods hensynet til faunapassage, forekommer det imidlertid som et paradoks, at der nedlægges en bæredygtig energiform som vandkraft (stemmeværk) til fordel for el-kraft (pumpeenergi) baseret på afbrænding af fossile brændstoffer med følgelig større energiforbrug og udledning af væsentlige mængder af CO2 til atmosfæren. I modsætning til Danmark, hvor den økologiske fiskeproduktion er underlagt statsligt kontrol (Fødevarestyrelsen og Plantedirektoratet), er det private certificeringsorganer, der forestår omlægning og godkendelse i de øvrige europæiske lande. Der er imidlertid væsentlige forskelle i indholdet af de enkelte landes regelsæt, ligesom der ikke er en fælles forståelse af en række centrale forhold indenfor økologisk opdræt, f.eks.: Fiskevelfærd, produktionsetik, miljø, økologisk fiskefoder, antibiotika behandling, vanddesinfektion m.v.. Et fælles EU-regelsæt for økologiske fisk vil være en absolut fordel for hele kæden fra vand til bord, idet den kan bidrage til at reducere eller harmonisere produktions-omkostningerne og dermed også styrke den økonomiske bæredygtighed i den økologiske produktion af opdrætsfisk. I forhold til det danske regelsæt knytter den vigtigste problemstilling sig til økologisk fiskefoder i henseender til restriktioner i fodersammensætning, pris, tilstrækkeligt kvantum og udbud af produkter. I mangel af et fælles europæisk regelsæt udelukker det restriktive danske regelsæt reelt produktion og eksport af økologisk fiskefoder og hæmmer derved udviklingen af økologisk fiskeopdræt i Danmark. Under de danske regelsæt er foderet således den mest følsomme parameter i forhold til bæredygtig økologisk produktion. Foderet alene påvirker p.t. produktions-omkostningerne med ca. 6 kr./kg fisk. En bæredygtig produktion af økologiske fisk i Danmark er således betinget af et større udbud af egnede økologiske råvarer til fiskefoder (d.v.s. vegetabilske råvare med et højt fordøjeligt proteinindhold og en relevant sammensætning af aminosyrer) til en konkurrencedygtig pris. Hertil kommer usikkerheden og driftsrisikoen i forbindelse med bestemmelsen i økologibekendtgørelsen om, at der kun må behandles med antibiotika en gang under den økologiske produktionscyklus. Bliver en ekstra behandling nødvendig kan fiskene ifølge bekendtgørelsen herefter kun sælges som konventionelle og følgelig til en lavere pris. En så restriktiv bestemmelse findes ikke i andre europæiske økologiske standarder for fisk. I forhold til fiskesundhed og velfærd i økologisk fiskeopdræt er der bl.a. behov for belysning af følgende problemstillinger: • Kontrol af parasit- og svampesygdomme med de hjælpestoffer, der er til rådighed ved økologisk fiskeopdræt. • Sammenhæng mellem indhold af vegetabilske råvarer i ørredfoder og evt. effekt på fiskenes immunstatus. • Furunkulose vaccine til bækørred, kildeørred og rødding. • Undersøgelse af mulighederne for alternativer til kuldioxid. Det er ikke klarlagt hvorvidt der er forskelle i spisekvalitet mellem økologisk opdrættede fisk sammenlignet med fisk fra konventionelt opdræt. Der er således behov for videnopbygning om spisekvalitet, herunder lagring og oxidativ stabilitet, i forhold til: • Fodertyper med højt indhold af vegetabilsk protein (over 30 %) og vegetabilsk olie • Sammenhænge med længde af fodringsperiode med vegetabilsk baserede fodertyper • Minimeret stresspåvirkning af økologisk opdrættede fisk • Ændringer af protein- og fedtsammensætning hos fisk, der er fodret med vegetabilsk baserede fodertyper. De vigtigste problemstillinger i forhold til videre udvikling af et bæredygtigt økologisk fiskeopdræt i Danmark knytter sig dels til økologisk fiskefoder og dels til konkurrenceforvridende forskelle mellem det danske økologiske regelsæt og de tilsvarende regelsæt i andre europæiske lande. Det er især behovet for konkurrencedygtige vegetabilske proteinkilder med et højt proteinindhold (gerne op ± 70% protein) med relevant aminosyresammensætning i forhold til fiskemel (72% protein) som er centralt for udviklingen af den økologiske fiskeproduktion i Danmark. I planteavls- og grovvaresektoren er der et generelt stærkt ønske og behov for vegetabilske råvarer med et betydeligt højere proteinindhold end i de eksisterende vegetabilske foderstoffer uden at egentlige initiativer på området kan spores. Der bør derfor indledes et samarbejde med landbrugssektoren på dette område, herunder producenter af økologiske foderingredienser. Denne indsats foreslås indledningsvist udmøntet i et målrettet ”forskningsforum”, hvor der knyttes yderligere kontakter mellem erhverv og forskning i form af en ”tænketank”, med det overordnede mål, at øge anvendelsen af økologiske vegetabilier i fiskefoder. Gennem denne fremad rettede og innovative indsats aktiveres de viden- og teknologi ressourcer, der findes i landbrugs- og grovvaresektoren samt akvakultur sektoren. Med foderproblematikken som det centrale omdrejningspunkt er en fremad rettet udvikling af økologisk fiskeopdræt i Danmark således betinget af en indsats på følgende områder: • Tilgængelighed af relevante økologisk producerede vegetabilier med højt proteinindhold, herunder mulighederne for opkoncentrering (under hensyn til økologiske principper) af eksisterende proteinkilder med relevant aminosyreprofil i forhold til fiskemel samt høj fordøjelighed og konkurrencedygtig pris • De respektive økologiske proteinkilders effekt på vækst og fordøjelighed undersøges ved vækstforsøg med regnbueørred • Evt. effekt af økologisk vegetabilsk protein og - olie på spisekvalitet • Evt. effekter af økologiske vegetabilier på fisk’s sundhed og velfærd • Optimering af produktionen ved case studier af økologiske produktionssystemer. • Harmonisering af europæiske regelsæt for økologisk akvakultur

Udgivelsesdato: Søndag, 10. juli