Triploid Atlantic salmon and triploid Atlantic salmon × brown trout hybrids have better freshwater and early seawater growth than diploid counterparts

The use of reproductively sterile triploid salmonids would enhance the environmental sustainability of the aquaculture industry by preventing genetic exchange between escapees and wild conspecifics. To this end, we assessed smoltification and early seawater performance (241 days) following a yearling production cycle (i.e. spring smolts) in diploid and triploid female Atlantic salmon (Salmo salar) × male brown trout (Salmo trutta) hybrids compared to purebred diploid and triploid salmon. During freshwater rearing (n = 180/group), hybrids demonstrated a degree of bimodality in body size, significantly (p < 0.05) more so in diploid than triploid hybrids (11 and 37% in the lower mode, respectively) that was not seen in purebred salmon of either ploidy. This resulted in diploid hybrids being 66% smaller on average at sea transfer, whereas no hybridisation effect was seen in triploids, and both triploid groups were significantly heavier (16–43%) than diploid salmon. Irrespective of ploidy, lower mode hybrids grew poorly and showed low survival in seawater, suggesting they had failed to undergo smoltification. However, the upper mode diploid hybrids showed a similar Na+/K+-ATPase (NKA) enzyme activity surge during the spring as in diploid and triploid salmon, despite a higher ratio of the freshwater to seawater mRNA abundance of the NKA subunits (nkaα1a and nkaα1b) and a reduced plasma cortisol surge. At the end of the experimental period, both hybrids weighed significantly less than their salmon counterparts although the hybrid effect was again greater in diploids (71% smaller) than triploids (6% smaller). In addition, both triploid groups were on average heavier (15–22%) than diploid salmon. As such, both triploid Atlantic salmon and triploid hybrids can show enhanced growth performance from juveniles up to post-smolts compared to diploid salmon in an aquaculture setting.publishedVersio

Annual report on health monitoring of wild anadromous salmonids in Norway 2017

Svært få funn av virus i tilbakevandrende laks selv om de samme virusene er vanlige i oppdrett Havforskningsinstituttet har undersøkt forekomsten av flere virus som er prevalent i oppdrett i tilbakevandrende laks fra Etneelva 2015-2016. Laksen stammer fra kultivert smolt som ble snutemerket og satt ut i Etne 2013 og 2014. Forekomsten av SAV-, PRV-, ILAV- og PMCV-infeksjoner ble testet ved å bruke sanntids RT-PCR metoden. Disse virusene kan forårsake sykdommene pankreassykdom (PD) og hjerte- og skjelettmuskelbetennelse (HSMB), Infeksiøs lakseanemi og kardiomyopatisyndrom (CMS, hjertesprekk) hos oppdrettslaks. SAV ble ikke påvist i den tilbakevandrende laksen. Derimot ble PRV1-, ILAV- og PMCV-infeksjoner påvist hhv. i 5 %, 1% og 3% av fisken. Infeksjoner med disse virusene er vanlig i opprett. Disse resultatene indikerer at villaksen ikke blir smittet i særlig grad, selv om de kan ha blitt utsatt for smitte fra oppdrett når de vandret ut eller på veien tilbake til elven. Samtidig kan vi ikke utelukke at syk villfisk ikke blir fanget fordi den er svekket og ikke går opp i elv, eller at den dørpublishedVersio

The Norwegian PraksisNett: a nationwide practice-based research network with a novel IT infrastructure

Clinical research in primary care is relatively scarce. Practice-based research networks (PBRNs) are research infrastructures to overcome hurdles associated with conducting studies in primary care. In Norway, almost all 5.4 million inhabitants have access to a general practitioner (GP) through a patient-list system. This gives opportunity for a PBRN with reliable information about the general population. The aim of the current paper is to describe the establishment, organization and function of PraksisNett (the Norwegian Primary Care Research Network). Materials and Methods We describe the development, funding and logistics of PraksisNett as a nationwide PBRN. Results PraksisNett received funding from the Research Council of Norway for an establishment period of five years (2018–2022). It is comprised of two parts; a human infrastructure (employees, including academic GPs) organized as four regional nodes and a coordinating node and an IT infrastructure comprised by the Snow system in conjunction with the Medrave M4 system. The core of the infrastructure is the 92 general practices that are contractually linked to PraksisNett. These include 492 GPs, serving almost 520,000 patients. Practices were recruited during 2019–2020 and comprise a representative mix of rural and urban settings spread throughout all regions of Norway. Conclusion Norway has established a nationwide PBRN to reduce hurdles for conducting clinical studies in primary care. Improved infrastructure for clinical studies in primary care is expected to increase the attractiveness for studies on the management of disorders and diseases in primary care and facilitate international research collaboration. This will benefit both patients, GPs and society in terms of improved quality of care.publishedVersio

Attraction of cod Gadus morhua from coastal spawning grounds to salmon farms

Wild fish aggregate at aquaculture net-pens, but the underlying mechanisms are not fully understood. This study examined how salmon farms attract coastal Atlantic cod Gadus morhua from their inshore spawning grounds. Acoustic receivers were deployed at 5 known cod spawning grounds and 6 salmon Salmo salar farms located at varying distances from these grounds in a mid-Norway study site. Cod were caught at each spawning ground annually from 2017-2019, fitted with acoustic transmitters and released (n = 535). A total of 289 tagged cod (54%) were detected at the salmon farms, with more cod detected at farms closest to the focal spawning grounds and at operational farms. The latter result is likely linked to the availability of feeding opportunities at farm locations. Those cod that were detected by the receivers spent less time at farms farther from their release locations. For the farm-associated cod, 70% were detected for 1 mo close to the farms, with 1 individual staying 720 d underneath the farm. A total of 135 cod visited 2 or more farms, with farms in proximity more connected in terms of inter-farm movement. Some of the cod utilizing these local spawning grounds likely have considerable dietary input from salmon feed.publishedVersio

Attraction of cod Gadus morhua from coastal spawning grounds to salmon farms

Wild fish aggregate at aquaculture net-pens, but the underlying mechanisms are not fully understood. This study examined how salmon farms attract coastal Atlantic cod Gadus morhua from their inshore spawning grounds. Acoustic receivers were deployed at 5 known cod spawning grounds and 6 salmon Salmo salar farms located at varying distances from these grounds in a mid-Norway study site. Cod were caught at each spawning ground annually from 2017-2019, fitted with acoustic transmitters and released (n = 535). A total of 289 tagged cod (54%) were detected at the salmon farms, with more cod detected at farms closest to the focal spawning grounds and at operational farms. The latter result is likely linked to the availability of feeding opportunities at farm locations. Those cod that were detected by the receivers spent less time at farms farther from their release locations. For the farm-associated cod, 70% were detected for 1 mo close to the farms, with 1 individual staying 720 d underneath the farm. A total of 135 cod visited 2 or more farms, with farms in proximity more connected in terms of inter-farm movement. Some of the cod utilizing these local spawning grounds likely have considerable dietary input from salmon feed.publishedVersionpublishedVersio

Attraction of cod Gadus morhua from coastal spawning grounds to salmon farms

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Image quality of list-mode proton imaging without front trackers

List mode proton imaging relies on accurate reconstruction of the proton most likely path (MLP) through the patient. This typically requires two sets of position sensitive detector systems, one upstream (front) and one downstream (rear) of the patient. However, for a clinical implementation it can be preferable to omit the front trackers (single-sided proton imaging). For such a system, the MLP can be computed from information available through the beam delivery system and the remaining rear tracker set. In this work, we use Monte Carlo simulations to compare a conventional double-sided (using both front and rear detector systems) with a single-sided system (only rear detector system) by evaluating the spatial resolution of proton radiographs (pRad) and proton CT images (pCT) acquired with these set-ups. Both the pencil beam spot size, as well as the spacing between spots was also adjusted to identify the impact of these beam parameters on the image quality. Relying only on the pencil beam central position for computing the MLP resulted in severe image artifacts both in pRad and pCT. Using the recently extended-MLP formalism that incorporate pencil beam uncertainty removed these image artifacts. However, using a more focused pencil beam with this algorithm induced image artifacts when the spot spacing was the same as the beam spot size. The spatial resolution tested with a sharp edge gradient technique was reduced by 40% for single-sided (MTF10% = 3.0 lp/cm) compared to double-sided (MTF10% = 4.9 lp/cm) pRad with ideal tracking detectors. Using realistic trackers the difference decreased to 30%, with MTF10% of 4.0 lp/cm for the realistic double-sided and 2.7 lp/cm for the realistic single-sided setup. When studying an anthropomorphic paediatric head phantom both single- and double-sided set-ups performed similarly where the difference in water equivalent thickness (WET) between the two set-ups were less than 0.01 mm in homogeneous areas of the head. Larger discrepancies between the two set-ups were visible in high density gradients like the facial structures. A complete CT reconstruction of a Catphan$^{\circledR}$ module was performed. Assuming ideal detectors, the obtained spatial resolution was 5.1 lp/cm for double-sided and 3.8 lp/cm for the single-sided setup. Double- and single-sided pRad with realistic tracker properties returned a spatial resolution of 3.8 lp/cm and 3.2 lp/cm, respectively. Future studies should investigate the development of dedicated reconstruction algorithms targeted for single-sided particle imaging.publishedVersio

The salmon louse genome: Copepod features and parasitic adaptations

Copepods encompass numerous ecological roles including parasites, detrivores and phytoplankton grazers. Nonetheless, copepod genome assemblies remain scarce. Lepeophtheirus salmonis is an economically and ecologically important ectoparasitic copepod found on salmonid fish. We present the 695.4 Mbp L. salmonis genome assembly containing ≈60% repetitive regions and 13,081 annotated protein-coding genes. The genome comprises 14 autosomes and a ZZ-ZW sex chromosome system. Assembly assessment identified 92.4% of the expected arthropod genes. Transcriptomics supported annotation and indicated a marked shift in gene expression after host attachment, including apparent downregulation of genes related to circadian rhythm coinciding with abandoning diurnal migration. The genome shows evolutionary signatures including loss of genes needed for peroxisome biogenesis, presence of numerous FNII domains, and an incomplete heme homeostasis pathway suggesting heme proteins to be obtained from the host. Despite repeated development of resistance against chemical treatments L. salmonis exhibits low numbers of many genes involved in detoxification.publishedVersio

Infeksjoner med parasitten Nucleospora cyclopteri (Microsporidia) i rognkjeks, Cyclopterus lumpus

Source at https://www.vetinst.no/rapporter-og-publikasjoner/rapporter/2019/infeksjoner-med-parasitten-nucleospora-cyclopteri-microsporidia-i-rognkjeks-cyclopterus-lumpus.Nucleospora cyclopteri (Microsporidia) is one of many parasites infecting lumpfish, Cyclopterus lumpus, and has been shown to cause disease and mortality in lumpfish. Infections in fish are often multifactorial and the impact of one agent on the development of disease can be difficult to elucidate. In addition to mortality, infections in lumpfish can lead to diseases with subsequently lowered appetite. This is of particular importance since lumpfish are used as a biological control agent, eating salmon lice, Lepeophtherius salmonis, off the salmon. Knowledge on the different disease agents of lumpfish is therefore of utmost importance. The main aim of this project was to identify how to obtain an infection-free lumpfish in land-based hatcheries and to study the impact that N. cyclopteri has on the health of the lumpfish and thereby its effect as a biological control agent. The project therefore aimed to map the presence of N. cyclopteri and other disease agents in wild caught lumpfish and in eggs/sperm, in fry and in farmed lumpfish stocked in the sea. In addition, we wanted to study the transmission pathways and clinical significance of the parasite. Unfortunately, we were not able to obtain a group of lumpfish fry infected with N. cyclopteri that we intended to follow through the land phase. The study of pathogenesis, infection dynamics, or whether an infection with N. cyclopteri pre-disposes for secondary infections, was therefore abandoned. We studied the presence of co-infections, methods for optimal sampling and tissue tropism in wild caught lumpfish in this project. Nucleospora cyclopteri was present in 60% of the sampled individuals from the waters around Averøy, in county Møre og Romsdal. The fish were analysed with regard to a range of infectious agents (viruses, bacteria and parasites) commonly found in other fish species, or previously recorded in lumpfish. No viral agents or other important pathogens were detected, but supposedly nonpathogenic microparasites, like Kudoa islandica (Myxozoa) in the muscle tissue and coccidians in the intestine, were frequently found. Nucleospora cyclopteri was detected in all tissues examined: anterior, mid and posterior kidney, spleen, heart, gills, brain, muscle liver and blood, thus indicating that the infection is systemic. The density of N. cyclopteri was highest in the anterior kidney, followed by mid and posterior kidney, spleen and gills, while the prevalence was highest in the ventricle of the heart. Observations from this study indicate that the parasite is released through urine and bile. We also show that N. cyclopteri can be detected using swabs from the skin, gill and vent, and by blood samples and gill biopsies, thus demonstrating the possibility of non-lethal detection of N. cyclopteri in lumpfish. Amongst these, the most promising non-lethal samples for detection were gill biopsies and leukocyte fractions from blood samples. Images normal histology and pathological agents from this project is included in an openly available online image database. This image database can be accessed by diagnosticians and researchers and used when evaluating pathological findings in lumpfish. While vertical transmission cannot be excluded, the results from this project indicate that this is not the dominant route. It is in any case advisable to routinely screen broodfish for N. cyclopteri to avoid using positive individuals for the production of eggs and fry. Given that N. cyclopteri undoubtedly destroys leukocytes in high numbers and over large areas of tissue, it is reasonable to assume that the parasite has an effect on the immune competence of the fish

Nationwide, population-based observational study of the molecular epidemiology and temporal trend of carbapenemase-producing Enterobacterales in Norway, 2015 to 2021

National and regional carbapenemaseproducing Enterobacterales (CPE) surveillance is essential to understand the burden of antimicrobial resistance, elucidate outbreaks, and develop infection-control or antimicrobial-treatment recommendations. Aim: This study aimed to describe CPE and their epidemiology in Norway from 2015 to 2021. Methods: A nationwide, population-based observational study of all verified clinical and carriage CPE isolates submitted to the national reference laboratory was conducted. Isolates were characterised by antimicrobial susceptibility testing, whole genome sequencing (WGS) and basic metadata. Annual CPE incidences were also estimated. Results: A total of 389 CPE isolates were identified from 332 patients of 63years median age (range:0–98). These corresponded to 341 cases, 184 (54%) being male. Between 2015 and 2021, the annual incidence of CPE cases increased from 0.6 to 1.1per 100,000person-years. For CPEisolates with available data on colonisation/infection, 58% (226/389)were associated with colonisation and 38% (149/389) with clinical infections. WGS revealed a predominance of OXA-48-like (51%; 198/389) and NDM (34%; 134/389) carbapenemases in a diversified population of Escherichia coli and Klebsiella pneumoniae, including high-risk clones also detected globally. Most CPE isolates were travel-related (63%;245/389). Although local outbreaks and healthcare-associated transmission occurred, no interregional spread was detected. Nevertheless, 18% (70/389) of isolates not directly related to import points towards potentially unidentified transmission routes. A decline in travelassociated cases was observed during the COVID-19 pandemic. Conclusions: The close-to-doubling of CPE case incidence between 2015 and 2021 was associated with foreign travel and genomic diversity. To limit further transmission and outbreaks, continued screening and monitoring is essential