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Apschner A.,Hubrecht Institute KNAW and UMC Utrecht | Schulte-Merker S.,Hubrecht Institute KNAW and UMC Utrecht | Witten P.E.,Nutreco Aquaculture Research Center | Witten P.E.,Ghent University
Methods in Cell Biology | Year: 2011

Developmental osteogenesis and pathologies of mineralized tissues are areas of intense investigations in the mammalian field, but different from other areas of organ formation and developmental biology, zebrafish have been somewhat slow in joining the area of bone research. In recent years, however, genetic screens have provided a number of exciting mutants, and transgenic lines have been developed that permit visualization of osteoblasts and osteoclasts in vivo. We here review some of the recent literature and provide examples where insights from studies in zebrafish have complemented the information available from mammalian models or clinical studies. Furthermore, we provide a comparative overview about different forms of bone within the teleost lineage, and between teleosts and mammals. © 2011 Elsevier Inc.

Willems B.,National University of Singapore | Buttner A.,National University of Singapore | Huysseune A.,Ghent University | Renn J.,National University of Singapore | And 3 more authors.
Developmental Biology | Year: 2012

Different from tetrapods, teleost vertebral centra form without prior establishment of a cartilaginous scaffold, in two steps: First, mineralization of the notochord sheath establishes the vertebral centra. Second, sclerotome derived mesenchymal cells migrate around the notochord sheath. These cells differentiate into osteoblasts and deposit bone onto the mineralized notochord sheath in a process of intramembranous bone formation. In contrast, most skeletal elements of the cranial skeleton arise by chondral bone formation, with remarkably similar mechanisms in fish and tetrapods. To further investigate the role of osteoblasts during formation of the cranial and axial skeleton, we generated a transgenic osx:CFP-NTR medaka line which enables conditional ablation of osterix expressing osteoblasts. By expressing a bacterial nitroreductase (NTR) fused to Cyan Fluorescent Protein (CFP) under control of the osterix promoter these cells become sensitive towards Metronidazole (Mtz). Mtz treatment of stable osx:CFP-NTR transgenic medaka for several consecutive days led to significant loss of osteoblasts by apoptosis. Live staining of mineralized bone matrix revealed reduced ossification in head skeletal elements such as cleithrum and operculum, as well as in the vertebral arches. Interestingly in Mtz treated larvae, intervertebral spaces were missing and the notochord sheath was often continuously mineralized resulting in the fusion of centra. We therefore propose a dual role for osx-positive osteoblasts in fish. Besides a role in bone deposition, we suggest an additional border function during mineralization of the chordal centra. After termination of Mtz treatment, osteoblasts gradually reappeared, indicating regenerative properties in this cell lineage. Taken together, the osx:CFP-NTR medaka line represents a valuable tool to study osteoblast function and regeneration at different stages of development in whole vertebrate specimens in vivo. © 2012 Elsevier Inc.

Torstensen B.E.,National Institute of Nutrition And Seafood Research | Espe M.,National Institute of Nutrition And Seafood Research | Stubhaug I.,National Institute of Nutrition And Seafood Research | Stubhaug I.,Nutreco Aquaculture Research Center | Lie O.,National Institute of Nutrition And Seafood Research
British Journal of Nutrition | Year: 2011

In order to study whether lipid metabolism may be affected by maximum replacement of dietary fish oil and fish meal with vegetable oils (VO) and plant proteins (PP), Atlantic salmon (Salmo salar L.) smolts were fed a control diet containing fish oil and fish meal or one of three plant-based diets through the seawater production phase for 12 months. Diets were formulated to meet all known nutrient requirements. The whole-body lipid storage pattern was measured after 12 months, as well as post-absorptive plasma, VLDL and liver TAG. To further understand the effects on lipid metabolism, expression of genes encoding for proteins involved in VLDL assembly (apoB100), fatty acid uptake (FATP1, cd36, LPL and FABP3, FABP10 and FABP11) were measured in liver and visceral adipose tissue. Maximum dietary VO and PP increased visceral lipid stores, liver TAG, and plasma VLDL and TAG concentrations. Increased plasma TAG correlated with an increased expression of apoB100, indicating increased VLDL assembly in the liver of fish fed the high-plant protein-and VO-based diet. Atlantic salmon fed intermediate replacement levels of VO or PP did not have increased body fat or visceral mass. Overall, the present results demonstrate an interaction between dietary lipids and protein on lipid metabolism, increasing overall adiposity and TAG in the body when fish meal and fish oil are replaced concomitantly at maximised levels of VO and PP. © 2011 The Authors.

Agency: Cordis | Branch: H2020 | Program: RIA | Phase: SFS-10a-2014 | Award Amount: 8.10M | Year: 2015

European aquaculture production provides direct employment to 80,000 people and a 3-billion annual turnover. Parasites cause severe disease outbreaks and high economic losses in finfish aquaculture. The overarching goal of ParaFishControl is to increase the sustainability and competitiveness of European Aquaculture by improving understanding of fish-parasite interactions and by developing innovative solutions and tools for the prevention, control and mitigation of the major parasites affecting Atlantic salmon, rainbow trout, common carp, European sea bass, gilthead sea bream and turbot. To achieve these objectives, ParaFishControl brings together a multidisciplinary consortium comprising 30 partners possessing world-leading, complementary, cross-cutting expertise and drawn from public and private research organisations, and the aquaculture industry. The consortium has access to excellent research facilities, diverse biological resources including host-parasite models, and state-of-the-art vaccinology, genomic, proteomic and transcriptomic technologies. The project will: 1) generate new scientific knowledge on key fish parasites, including genomics, life-cycle, invasion strategy and host-parasite interaction data, with special emphasis on host immunity, pathogen virulence and immunomodulation, providing a scientific basis for improved prophylaxis; 2) determine the transfer of parasites between farmed and wild host populations; 3) develop a wide range of novel prophylactic measures, including vaccines and functional feeds; 4) provide a range of advanced or alternative treatments for parasitic diseases; 5) develop cost-effective, specific and sensitive diagnostic tools for key parasitic diseases; 6) assess the risk factors involved in the emergence, transmission and pathogenesis of parasitic diseases; 7) map the zoonotic risks due to fish helminths and; 8) provide a catalogue of good husbandry practices to obtain safe and high-quality fish products.

Agency: Cordis | Branch: FP7 | Program: MC-IAPP | Phase: FP7-PEOPLE-2011-IAPP | Award Amount: 611.95K | Year: 2012

Reduce the fish oil inclusion level in aquaculture feeds while maintaining high levels of marine omega 3 fatty acids (EPA and DHA) in fish products to meet consumer expectations is a major problem of modern aquaculture. Both of these conditions reflect the necessity to examine in depth nutritional strategies aimed to maximise EPA and DHA retention on fish tissues. Omega3max aims to optimise dietary fatty acid composition and antioxidant sources and concentration to limit in vivo oxidative stress in fish tissues helping to preserve EPA and DHA. In addition not only the quantity of EPA\DHA, but also the position of both fatty acids to conform triacyglycerols and phospholipids, is becoming an important aspect in terms of function and bioavailability for human consumers. Therefore, the present project also aims to study the regiospecificity of fatty acids which is a novel issue for fish nutritionist with important implications on the nutritive quality of the fish flesh. This programme aims to increase the EU aquaculture industry competitiveness being more cost-effective and improving the nutritional value and quality of aquaculture products but also to strengthen the research and educational potential on aquaculture of both sectors industry and academia. The proposed research group in this Consortium comprises four partners, including two national non-commercial organisations namely the Universidad Politcnica de Madrid (UPM-Spain) and the Christian-Albrechts University Kiel (CAU-Germany) as well as two commercial enterprises namely Skretting Aquaculture Research Center (Skretting ARC-Norway) and Lucta (Spain). Both the academic and industrial partners have a strong track record on research activities and already established successful research collaborations in the recent past. We propose to create a long-lasting consortium of leading researchers with complementary expertise that can synergize innovative research in the fields of fish nutrition and health.

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