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| Registros recuperados: 41 | |
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| Normand, Julien; Boudry, Pierre; Cornette, Florence; Ledu, Christophe. |
| Reproduction was studied in triploid Crassostrea gigas, by crossing gametes from diploid and triploid parents.Triploids are able to produce viable gametes and their resulting progeny consisted in diploids, aneuploids and polyploids. Gametes from triploid parents frequently led to abnormal polar body formation, even before caryogamy occurred. A high frequency of aneuploids was observed, related to the missegregation of chromosomes during meiosis in triploids. This might be due to the observed incomplete synapsis in triploid eggs during Prophase I. The proportion of aneuploids decreased during larval development, reflecting differential mortality between ploidy levels. Due to limited gonadic development and high larval mortality rates, the reproductive... |
| Tipo: Text |
Palavras-chave: Triploid; Genetic; Oysters; Crassostrea gigas. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/acte-3319.pdf |
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| Boudry, Pierre; Degremont, Lionel; Bedier, Edouard; Pouvreau, Stephane; Normand, Julien; Ernande, Bruno. |
| To date, the most significant method to genetically reduce reproductive effort in the Pacific oyster (Crassostrea gigas) has been through the production of triploids, especially since the development of tetraploid lines allowing the breeding of 'natural' triploids. Gametogenesis of triploid oysters is strongly reduced compared with diploids, although they are not fully sterile and can produce viable gametes and some progenies when crossed with diploids. Reduced reproductive allocation and higher heterozygocity are commonly proposed as the main reasons why triploids often present superior yield compared with diploids. Temperature and food availability are known to favour gametogenesis in triploids, but the existence of genetic variation for this trait... |
| Tipo: Text |
Palavras-chave: Selective breeding; Reproduction; Genetic variation; Crassostrea gigas; Pacific oyster; Genetic. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/acte-3445.pdf |
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| De Decker, Sophie; Normand, Julien; Duperthuy, Marylise; Boudry, Pierre; Saulnier, Denis. |
| Rearing of Crassostrea gigas is the most economically important aquaculture activity in France. Bacteria belonging to Vibrio genus constitute one of the most abundant bacterial group in marine ecosystems. Two Vibrio species, V. splendidus and V. aestuarianus, were associated with many cases of mortality events in reared C. gigas spat and juvenile oysters, commonly during summer. This summer mortality syndrome has been extensively documented as the result of complex interactions between pathogens, host and environmental conditions. This work aims to study the Vibrio-host interactions and their modulations according to the virulence of pathogens and the genetic and/or physiological parameters of the host. These factors will be characterized by in vitro and... |
| Tipo: Text |
Palavras-chave: Genetic; Pathogens; Interaction; Vibrio; Crassostrea gigas; Oyster. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/acte-3430.pdf |
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| Normand, Julien; Huvet, Arnaud; Fabioux, Caroline; Raguenes, Morgane; Boudry, Pierre. |
| Genetic improvement of the Pacific oyster, Crassostrea gigas, can be achieved through triploidisation, which leads to partially sterility, allowing higher growth and survival together with improved meat quality during the reproductive period. Most triploids are not fully sterile and the genetic and environmental factors involved in their partial fertility remained to be investigated. We examined gametogenesis by image analysis of histological cross sections in diploid (2n) and triploid oysters obtained either by crossing tetraploids and diploid broodstock (« natural » triploids: 3nn) or from second polar body retention (« chemical » triploids: 3nc). 5-month old triploid spat reared in a standard intensive nursery system only showed a reduction of 50% of... |
| Tipo: Text |
Palavras-chave: Gametogenesis; Triploid; Crassostrea gigas; Genetic; Oysters. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/acte-3327.pdf |
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| Normand, Julien. |
| L’amélioration génétique de l’huître creuse par l’induction de la triploïdie consiste en l’adjonction d’un jeu haploïde de 10 chromosomes au génome diploïde (n= 20 chromosomes) de l’huître. Cette modification du génome entraîne chez Crassostrea gigas des remaniements physiologiques avantageux pour son aquaculture, dus notamment à la réduction de l’effort reproducteur. Les huîtres triploïdes ne sont pourtant pas complètement stériles et peuvent présenter dans certains cas une gamétogenèse assez avancée. Nous étudions les bases génétiques et environnementales de l’allocation à la reproduction chez les huîtres creuses triploïdes par une approche mixte inspirée par la génétique quantitative et l’écophysiologie, afin d’estimer la faisabilité d’une sélection, ou... |
| Tipo: Text |
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| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/00442/55335/56827.pdf |
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| Normand, Julien; Ernande, Bruno; Boudry, Pierre. |
| Today, triploidy is the most common method used to genetically improve marine bivalve aquaculture production. In the Pacific oyster Crassostrea gigas, triploidy affects many traits. The most proeminent one is reproductive effort, which is greatly reduced compared to diploids. The combined effects of physiological trade-offs between survival, growth and reproduction together with the reduction of reproductive effort in triploids explains the global enhancement of yield observed. However, the sterility of triploid oysters is only partial and some triploid individuals can show normal gametogenesis (i.e. similar to diploids), especially under warm conditions. In diploid oysters, the heritability of reproductive effort has been shown to be relatively low, but a... |
| Tipo: Text |
Palavras-chave: Parentage analysis; Triploidy; Oyster; Quantitative genetics; Gametogenesis. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/acte-4525.pdf |
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| Normand, Julien; Le Pennec, Marcel; Boudry, Pierre. |
| We compared the temporal dynamics of gametogenesis in diploid and triploid Pacific oysters (Crassostrea gigas) using histology. Oysters were reared in an estuarine farming site in Brittany over 3 years and their gametogenesis was monitored over the exceptionally hot summer of 2003. Both diploids and triploids showed active gametogenesis, but a high proportion of triploids remained at early stages of gonad development. Gametogenesis of triploids was characterized by the simultaneous occurrence of gonias and immature cytes together with mature gametes rather than overall retardation, though some triploids showed complete gonad maturation. Evidence of spawning was seen in both groups, and the quantity of germinal products emitted appeared to be similar in... |
| Tipo: Text |
Palavras-chave: Triploidy; Crassostrea gigas; Oyster; Gametogenesis. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4152.pdf |
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| Normand, Julien; Ernande, Bruno; Haure, Joel; Mccombie, Helen; Boudry, Pierre. |
| Early reproductive effort and growth were measured in 3 groups of the Pacific oyster Crassostrea gigas: 1 diploid group and 2 triploid groups resulting from either chemical induction (3nCB) or crosses between tetraploid and diploid parents (3nDT). Oysters were reared under intensive nursery conditions and sampled when 5 mo old. Reproductive effort was estimated by cross-sectional area measurements of the visceral mass (i.e. gonadic occupation) and maturation stage was assessed by qualitative histology. As expected, comparison of the reproductive patterns of these 3 groups revealed a lower reproductive effort in triploid individuals relative to diploid. However, gonadic occupation in triploid oysters was higher than expected in both 3nCB and 3nDT groups, as... |
| Tipo: Text |
Palavras-chave: Triploidy; Oyster; Gametogenesis; Crassostrea gigas. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6978.pdf |
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| Pernet, Fabrice; Barret, Jean; Le Gall, Patrik; Malet, Nathalie; Pastoureaud, Annie; Munaron, Dominique; De Lorgeril, Julien; Bachere, Evelyne; Vaquer, Andre; Huvet, Arnaud; Corporeau, Charlotte; Normand, Julien; Boudry, Pierre; Moal, Jeanne; Quere, Claudie; Quilien, Virgile; Daniel, Jean-yves; Pepin, Jean-francois; Saulnier, Denis; Gonzalez, Jean-louis. |
| This study was conducted in the Mediterranean area during a mass mortality event of Pacific oyster Crassostrea gigas. The objectives of this work were to increase our understanding of the mass mortality phenomena in Pacific oysters, to identify risky cultivation practises and to propose mitigation strategies. In the first part of this work, we followed environmental parameters of the Thau lagoon in relation with mortality events. Then, we compared mortality and growth parameters of oysters as a function of their origins, their development stages and cultivation sites in relation with energetic, reproduction and pathogens. Finally, we conducted transfer experiments where oysters maintained free of mortality in open sea were transferred in the Thau lagoon... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00002/11354/7927.pdf |
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| Huvet, Arnaud; Normand, Julien; Fleury, Elodie; Quillien, Virgile; Fabioux, Caroline; Boudry, Pierre. |
| Summer mortality of the Pacific oyster Crassostrea gigas is the result of a complex interaction between oysters, their environment and their pathogens. The physiological status of an oyster, especially its reproductive status, is suspected to play a significant role in the outcome of this interaction. As genetic variability exists for susceptibility to summer mortality, resistant (R) and susceptible (S) oyster lines were produced using a divergent selection scheme. The present paper reports a histological study on gonad area, which is representative of reproductive effort, in randomly chosen five R and five S oyster lines. The R lines showed a significantly lower gonad area than the S lines (P<0.001). with an estimated mean difference of 12.5%, whereas,... |
| Tipo: Text |
Palavras-chave: Bivalve mollusc; Crassostrea gigas; Reproduction; Selected lines; Summer mortality. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00006/11766/8502.pdf |
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| Degremont, Lionel; Maurouard, Elise; Nourry, Max; Seugnet, Jean-luc; Bedier, Edouard; Fleury, Elodie; Langlade, Aime; Pernet, Fabrice; Pouvreau, Stephane; Le Souchu, Pierrick; Normand, Julien; D'Amico, Florence; Rumebe, Myriam; Cantin, Christian; Barret, Jean; Le Gall, Patrik; Baud, Jean-pierre; Cochennec-laureau, Nathalie; Gervasoni, Erika; Pelissier, Pablo. |
| Ce rapport présente la comparaison des mortalités de deux lots de naissains de Crassostrea gigas dans plusieurs bassins conchylicoles et déterminer le gain de survie obtenu par la sélection pour des huîtres diploïdes |
| Tipo: Text |
Palavras-chave: Mortalités; Huître creuse; Crassostrea gigas; Sélection génétique; Naissain. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00065/17644/15180.pdf |
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| Fleury, Elodie; D'Amico, Florence; Annezo, Jean-pierre; Barret, Jean; Blin, Jean Louis; Bouget, Jean-francois; Claude, Serge; Guilpain, Patrice; Grizon, James; Hitier, Benoist; Langlade, Aime; Le Gall, Patrik; Le Souchu, Pierrick; Martin, Anne-genevieve; Mary, Charlotte; Normand, Julien; Parrad, Sophie; Penot, Julia; Pernet, Fabrice; Pien, Sebastien. |
| Depuis 2009, l'Observatoire Conchylicole assure le suivi, sur des sites ateliers disposés sur l'ensemble du littoral français, de lots sentinelles d'huîtres creuses Crassostrea gigas représentatifs de la production française. Leur suivi permet d'acquérir des données nationales de croissance et de mortalité, de traduire la dynamique spatio-temporelle des performances d’élevage et ainsi de participer à la compréhension des phénomènes observés. Pour ce faire, des lots sentinelles d’huîtres correspondant à différentes origines (captage ou écloserie, diploïdes ou triploïdes) et à différents stades d’élevage (naissain ou adultes 18 mois) sont déployés simultanément sur 13 sites ateliers représentant les grandes régions conchylicoles du littoral français. En... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00083/19433/17047.pdf |
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| De Decker, Sophie; Normand, Julien; Saulnier, Denis; Pernet, Fabrice; Castagnet, Sophie; Boudry, Pierre. |
| Several Vibrio species are known to be pathogenic to the Pacific oyster Crassostrea gigas. Survival varies according to pathogen exposure and high mortality events usually occur in summer during gametogenesis. In order to study the effects of gametogenetic status and ploidy (a factor known to affect reproduction allocation in oysters) on vibriosis survival, we conducted two successive experiments. Our results demonstrate that a common bath challenge with pathogenic Vibrio splendidus and Vibrio aestuarianus on a mixture of mature, spawning and non-mature oysters can lead to significant mortality. Previous bath challenges, which were done using only non-mature oysters, had not produced mortality. Immunohisto-chemical analyses showed the affinity of Vibrio... |
| Tipo: Text |
Palavras-chave: Experimental vibriosis; Crassostrea gigas; Vibrio; Survival distribution function; Triploidy; Reproductive effort. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00030/14108/11368.pdf |
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| Mary, Charlotte; Pien, Sebastien; Normand, Julien. |
| Comme les deux dernières années, cette année 2011 se caractérise par des niveaux de mortalités de juvéniles estivales très élevés. Les adultes quant à eux n’ont pas subi de fortes mortalités.. Les poids moyens observés en fin de printemps et début d’été sont faibles pour les 2 classes d’âge et pour l’ensemble des stations. Ce déficit apparent en croissance pourrait être dû au faible poids initial à la mise à l’eau ou à des conditions environnementales moins propices à la croissance qu’au cours des années précédentes. |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00055/16641/14136.pdf |
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| Normand, Julien; Li, Ronghua; Quillien, Virgile; Nicolas, Jean-louis; Boudry, Pierre; Pernet, Fabrice; Huvet, Arnaud. |
| Pacific oyster Crassostrea gigas suffers from chronic or sporadic mortality outbreaks worldwide, resulting from infectious diseases and/or physiological disorders triggered by environmental factors. Since 2008, ostreid herpesvirus OsHV-1 μVar has been identified as the main agent responsible for mass mortality of juvenile oysters in Europe. Previous studies of genome-wide expression profiling have provided candidate genes that potentially contribute to genetically-based resistance to summer mortality. To assess their value in determining resistance to the juvenile mass mortality that has occurred in France since 2008, we analyzed the expression of 17 candidate genes in an experimental infection by OsHV-1 μVar, and in an in vivo field experiment. Individual... |
| Tipo: Text |
Palavras-chave: Molluscs; Gene expression profiling; Inhibitor of kappa B; Summer mortality; Ostreid herpesvirus. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00177/28823/27325.pdf |
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| Pien, Sebastien; Mary, Charlotte; Normand, Julien. |
| Le réseau régional REMONOR est un dispositif d’observation des performances annuelles de mortalité, croissance et qualité des huîtres creuses. Le protocole s’attache à surveiller des individus de deux classes d’âge (« adultes » = 2 ans et « juvéniles » = 1 an) réparties entre différentes stations dans les principaux secteurs ostréicoles normands. Ce réseau est mené conjointement par le LERN (Laboratoire Environnement Ressources de Normandie) et le SMEL (Synergie Mer Et Littoral) qui mettent en commun leurs moyens humains et techniques de façon à suivre les 10 stations du réseau sur l’ensemble de la côte Bas-Normande. Une nouvelle fois, la mortalité estivale du naissain est très importante, plus particulièrement sur la côte Ouest du Cotentin. Sur ce... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Huître creuse; REMONOR; Basse-Normandie; Mortalité; Croissance; Qualité; REMORA. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00181/29268/27677.pdf |
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| Normand, Julien; Parrad, Sophie; Fontaine, Bruno; Le Gagneur, Eric; Simon, Benjamin; Louis, Wilfried; Mary, Charlotte. |
| Les mortalités massives de naissain d’huître creuse, apparues en France en 2008, font peser de lourdes contraintes sur les entreprises conchylicoles. Le projet EVILS s’est explicitement inscrit comme une première étape dans l’application d’une démarche d’amélioration de la survie du naissain d’huître creuse. L’objectif visé était de proposer une méthodologie permettant aux éleveurs d’identifier des critères d’approvisionnement en naissain, dans le but de sélectionner les lots les plus à mêmes de présenter les plus faibles taux de mortalité en élevage. Les protocoles déployés ont d’abord permis de caractériser la variation inter-lots des taux de survie, qui restait jusque là peu explorée. Par ailleurs, les analyses réalisées mettent en évidence l’effet de... |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00180/29139/27553.pdf |
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| Normand, Julien; Blin, Jean-louis; Jouaux, Aude. |
| Early detection of Pacific oyster spat infected with ostreid herpesvirus 1 (OsHV-1) could prevent introduction of OsHV-1-infected individuals into farming areas or onshore rearing facilities, thus reducing the risk of infection of naïve oysters in such production systems. Experiments were conducted on several hundred oyster spat provided by producers in order to examine whether early rearing practices could be considered as potential risk factors for (1) OsHV-1 infection as detected by molecular methods and (2) spat mortality experimentally induced through thermal challenge. Spat groups collected on oyster beds and hatchery spat reared in growout areas during summer exhibited higher viral DNA contamination and mortalities during the trial than spat kept in... |
| Tipo: Text |
Palavras-chave: Oyster spat; Epidemiology; OsHV-1; QPCR; Thermal challenge. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00203/31407/29797.pdf |
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| Gangnery, Aline; Cugier, Philippe; Le Gendre, Romain; Legendre, Aurelie; Maheux, Frank; Mary, Charlotte; Normand, Julien; Parrad, Sophie; Pierre-duplessix, Olivier; Picoche, Coralie; Pien, Sebastien; Rabiller, Emilie; Simon, Benjamin. |
| L’objectif général du projet OGIVE est d’acquérir des connaissances sur le fonctionnement des écosystèmes conchylicoles de Basse-Normandie dans le but d’établir une plateforme de données communes à l’ensemble des partenaires du projet. Ces connaissances sont ensuite utilisées pour développer des outils permettant de fournir des avis et expertises aux gestionnaires du Domaine Public Maritime. Le projet a ainsi pour objectif de contribuer au développement durable de la filière conchylicole en Basse-Normandie en optimisant la production conchylicole et en préservant la qualité environnementale des écosystèmes qui supportent cette activité. Le projet OGIVE a été structuré initialement autour de trois actions : 1) Acquisition de données : cette action a le... |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00253/36468/35010.pdf |
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| Registros recuperados: 41 | |
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