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| Registros recuperados: 85 | |
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| Degremont, Lionel; Bedier, Edouard; Soletchnik, Patrick; Ropert, Michel; Huvet, Arnaud; Moal, Jeanne; Samain, Jean-francois; Boudry, Pierre. |
| Summer mortality has been reported in the Pacific oyster, Crassostrea gigas, for many years in different parts of the world. The causes of this phenomenon are complex. The multidisciplinary program "MOREST", coordinated by IFREMER, was initiated to understand the causes of summer mortality of Crassostrea gigas juveniles in France and to reduce its impact on oyster production. Within this program, three successive groups of bi-parental families were bred in a hatchery in 2001 and placed in the field during summer in three sites (Ronce, Riviere d'Auray, and Baie des Veys). This paper reports the relative importance of family, site and field placement timing for three characters of major importance for oyster production: survival, growth, and yield. At the... |
| Tipo: Text |
Palavras-chave: Juvenile; Crassostrea gigas; Oysters; Yield; Growth; Survival. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-1693.pdf |
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| Gagnaire, Pierre-alexandre; Lamy, Jean-baptiste; Cornette, Florence; Heurtebise, Serge; Degremont, Lionel; Flahauw, Emilie; Boudry, Pierre; Bierne, Nicolas; Lapegue, Sylvie. |
| The Pacific cupped oyster is genetically subdivided into two sister taxa, Crassostrea gigas and C. angulata, which are in contact in the north-western Pacific. The nature and origin of their genetic and taxonomic differentiation remains controversial due the lack of known reproductive barriers and the high degree of morphologic similarity. In particular, whether the presence of ecological and/or intrinsic isolating mechanisms contributes to species divergence is unknown. The recent co-introduction of both taxa into Europe offers a unique opportunity to test how genetic differentiation is maintained under new environmental and demographic conditions. We generated a pseudo-chromosome assembly of the Pacific oyster genome using a combination of BAC-end... |
| Tipo: Text |
Palavras-chave: Cupped oysters; Genome assembly; Species divergence; Reproductive barriers; Recombination rate. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00455/56622/58337.pdf |
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| Bernard, Ismael; Lapegue, Sylvie; Dumas, Franck; Talarmain, Eric; Cornette, Florence; Degremont, Lionel; Chavanne, Herve; Pouvreau, Stephane; Auby, Isabelle; Maurer, Daniele; Plus, Martin; Le Moine, Olivier; Boudry, Pierre. |
| La forte augmentation des mortalités de juvéniles d’huître creuse depuis 2008 a relancé la problématique de l’approvisionnement en naissains de l’ostréiculture française. Dans ce contexte, cette étude a pour objectif d’étudier la faisabilité d’opérations de repeuplement en huîtres génétiquement plus résistantes, afin d’améliorer les performances de survie du naissain capté dans le milieu naturel. Cette étude s’est ainsi focalisée sur les deux bassins naisseurs historiques, Marennes-Oléron et Arcachon. Nous avons donc cherché à établir (1) une hiérarchie des bancs en fonction de l’expulsion de larves d’huître dans le bassin d’Arcachon, (2) une cartographie des liens en termes de connectivité entre les bancs des pertuis charentais et (3) la faisabilité du... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00083/19410/17013.pdf |
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| Flahauw, Emilie; Davenel, Armel; Quellec, Stéphane; Quillien, Virgile; Degremont, Lionel; Lapegue, Sylvie; Hatt, Philippe-jacques. |
| Biological parameters of the cupped oyster Crassostrea gigas such as growth, reproductive effort (duration of the gametogenesis, date of spawning, and fecundity) differ widely among oysters in the same location. Furthermore, most of the traditional methods, like histological observations, could lead to large variability on the observations and the measurements ofthese traits, and large uncertainties on their changes over time. These can be drastically reduced by using Magnetic Resonance Imaging (MRI) which is a non invasive method allowing to measure the same individual during its development. Forty oysters were assessed using MRI for the volume of whole soft body, the intra valves space, the adductor muscle, and the gonad, which also include the digestive... |
| Tipo: Text |
Palavras-chave: Molluscs; Crassostrea gigas; Gonad; Histology; MRI. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00107/21784/19370.pdf |
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| Pernet, Fabrice; Barret, Jean; Le Gall, Patrik; Lagarde, Franck; Fiandrino, Annie; Huvet, Arnaud; Corporeau, Charlotte; Boudry, Pierre; Quere, Claudie; Degremont, Lionel; Pepin, Jean-francois; Saulnier, Denis; Boulet, Hélène; Keck, Nicolas. |
| The objectives of this study are to increase our understanding of the mass mortality phenomena in Pacific oysters Crassostrea gigas in the Thau lagoon and to examine the effect of cultivation practises. Mortality events in 2009 and 2010 always coincide with simple or dual infections involving primarily the Herpes virus OsHV-I and secondarily the bacteria Vibrio splendidus, when seawater temperature is between 17°C and 24°C. In the Thau lagoon, mortality starts early May and last until fall with an interruption period when seawater temperature is higher than 24°C in July and August. Mortality of oysters varies as a function of zootechnical life-history, hydrodynamics and cultivation practises. First, mortality depends on whether or not oysters have been... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00043/15404/12764.pdf |
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| David, Elise; Boudry, Pierre; Degremont, Lionel; Tanguy, Amelie; Quere, N; Samain, Jean-francois; Moraga, D. |
| Large-scale mortality events have been observed in Pacific oyster Crassostrea gigas on the west coast of France since the early 1980s, particularly during summer. In order to understand the causes of this mortality, two generations of oysters from single-pair matings were studied in three sites on the French Atlantic coast (Baie-des-Veys, Auray and Ronce-les-Bains). The present paper examines the role of two candidate genes in the susceptibility of oysters to summer mortality, and the selective pressure exerted by such mortality on their polymorphism. Glutamine synthetase (amino-acid metabolism) and delta-9 desaturase (lipid metabolism) genes were studied in the successive generations, using polymerase chain reaction single-strand conformation polymorphism... |
| Tipo: Text |
Palavras-chave: SSCP; Mortality; Glutamine synthetase; Delta 9 desaturase; Crassostrea gigas. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3040.pdf |
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| Degremont, Lionel; Nourry, Max; Maurouard, Elise. |
| The ostreid herpesvirus 1 (OsHV-1) is one of the major pathogens affecting the Pacific oyster Crassostrea gigas, and numerous mortality outbreaks have been observed worldwide. We report the first results of our experimental breeding program using mass selection focused on survival and resistance to OsHV-1 after four generations of selection for two lines. These lines originated from two stocks of adult wild oysters sampled from the Marennes-Oléron Bay in 2008. Each line was spawned in February 2009 to produce the base populations. Both lines were then either protected from OsHV-1 or tested in the field in 2009 where they were exposed to OsHV-1. For each line during 2010 to 2013, one generation per year was produced using either the survivors of the... |
| Tipo: Text |
Palavras-chave: Survival; Crassostrea gigas; Realized heritability; Selection response; OsHV-1; Disease resistance. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00266/37751/36064.pdf |
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| Degremont, Lionel. |
| As with summer mortalities reported in France between 2001 and 2006, mortality caused by the Ostreid herpesvirus 1 (OsHV-1) in Crassostrea gigas affects mostly juveniles, although adults can also be impacted to a small extent. This could suggest that both mortalities have similar causes and that establishment of resistance, in particular to the Ostreid herpesvirus 1 (OsHV-1), depends on either the size or the age of oysters. The present study reports an investigation of both size and age using three cohorts produced during winter and three produced during summer. Each cohort contained oysters genetically selected to be resistant or susceptible to the summer mortality phenomenon, as well as unselected control oysters. Any abnormal mortality was recorded... |
| Tipo: Text |
Palavras-chave: Mortality; Crassostrea gigas; Disease resistance; Size; Age; Ostreid herpesvirus. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00157/26799/24909.pdf |
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| Samain, Jean-francois; Degremont, Lionel; Soletchnik, Patrick; Ropert, Michel; Bedier, Edouard; Mazurie, Joseph; Mazurie, Joseph; Martin, Jean-louis; Moal, Jeanne; Mathieu, Michel; Pouvreau, Stephane; Lambert, Christophe; Escoubas, Jean-michel; Nicolas, Jean-louis; Le Roux, Frédérique; Renault, Tristan; Burgeot, Thierry; Bacher, Cedric; Boudry, Pierre. |
| Complex interactions between oyster, environment and pathogens were observed during the MOREST (2001-2005) project on summer mortality events of Crassostrea gigas oysters in France. The talk will show how nutrition level increasing reproductive intensity generates a risk for pathogen infection under synergistic effect of temperature and stress. Moreover, a genetic component is associated to specific reproductive performances and spawning behaviour. To better understand origin of such resistance or susceptibility to summer mortality, other characteristics as stress susceptibility, energy management and hemocyte activities of oysters from the two phenotypes were compared. This first comparison suggests interactions between stress, reproduction and defence... |
| Tipo: Text |
Palavras-chave: Genetic; Pathologie; Mortality; Crassostrea gigas; Pacific oyster; Reproduction; Nutrition; Physilogy. |
| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/2006/acte-3467.pdf |
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| Tanguy, Arnaud; Boutet, Isabelle; Boudry, Pierre; Degremont, Lionel; Laroche, Jean; Moraga, Dario. |
| Phosphoglucomutase is a key enzyme in glycolysis and has been widely studied in vertebrates and some invertebrates but no molecular information is available in marine invertebrates despite the importance of this marker in ecological and genetical studies. In this work, we isolated a cDNA and the corresponding genomic sequence that encode PGM-2 locus in the Pacific oyster Crassostrea gigas. We used sequences drawn from the database to construct an evolutionary framework for examining the position of mollusc PGM sequences among prokaryotic and eukaryotic homologues and showed that oyster PGM gene organization was closer to vertebrates PGM genes than other invertebrates as previously found in other Lophotrochozoa species. We also investigated PGM mRNA... |
| Tipo: Text |
Palavras-chave: Gene expression; Xenobiotics; Mollusc; Phosphoglucomutase. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2220.pdf |
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| Benabdelmouna, Abdellah; Guyader, Tanguy; Ledu, Christophe; Laporte, Philippe; Degremont, Lionel. |
| Depuis son introduction en France, l’huître creuse du Pacifique Crassostrea gigas subit des épisodes répétés de mortalité estivale touchant principalement les juvéniles. A partir de 2008, un nouveau pallier a été franchi et ces épisodes de mortalité estivale se sont accrus en intensité, touchant jusqu’à 90% des lots. Actuellement, ces mortalités touchent l’ensemble des façades maritimes ainsi que plusieurs pays utilisant des naissains d’origine Française. L’ostréiculture Française est basée sur l’utilisation majoritaire de naissains sauvages issus d’un captage naturel (75 à 80%) réalisé au niveau des bassins d’Arcachon et de Marennes Oléron en complément avec l’utilisation de naissains, principalement triploïdes, produits par diverses écloseries privées... |
| Tipo: Text |
Palavras-chave: Huître creuse; Crassostrea gigas; Mortalité; Condition d'élevage; Historique des lots. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00063/17405/14910.pdf |
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| Degremont, Lionel; Maurouard, Elise; Connes, Coralie; Ledu, Christophe; Benabdelmouna, Abdellah. |
| Depuis 2008 l’ostréiculture française subit des mortalités massives d'huîtres creuses, Crassostrea gigas, qui menacent les approvisionnements en naissains et, par voie de conséquence, fragilise la filière ostréicole. C’est dans ce contexte qu'a été mis en place à partir de 2010 une opération désignée sous le terme plan de sauvegarde. Cette opération sous forme contractuelle fait intervenir l'Ifremer, des écloseries privées, le Ministère en charge de l'Agriculture et le CNC. Le premier plan de sauvegarde (PS1) a été initié en 2010, suivi par un deuxième en 2011 (PS2), et un troisième en 2012 (PS3). L’objectif premier de ce plan est d’apporter une réponse temporaire au déficit de production grandissant en fournissant aux écloseries des animaux présentant une... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00229/34041/32448.pdf |
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| Degremont, Lionel; Ernande, Bruno; Bedier, Edouard; Boudry, Pierre. |
| The multidisciplinary project "MOREST" aims to improve our understanding of causes of summer mortality in Crassostrea gigas juveniles in France and to reduce its impact on oyster production. As pail of the MOREST project, 43 full-sib families nested within 17 half-sib families were produced, planted out and tested in 3 sites during summer 2001 to assess to what extent genetic variability exists for this trait. A strong genetic basis was found for survival as narrow-sense heritability estimates ranged from 0.47 to 1.08, with higher values in sites where summer mortality was higher. Genetic correlations across sites were positive and very high for survival, indicating no genotype by environment interaction. In contrast, lower genetic variation was observed... |
| Tipo: Text |
Palavras-chave: Growth; Survival; Juveniles; Heritability; Crassostrea gigas. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2457.pdf |
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| Azema, Patrick; Lamy, Jean-baptiste; Boudry, Pierre; Renault, Tristan; Travers, Marie-agnes; Degremont, Lionel. |
| Background In France, two main diseases threaten Pacific oyster production. Since 2008, Crassostrea gigas spat have suffered massive losses due to the ostreid herpesvirus OsHV-1, and since 2012, significant mortalities in commercial-size adults have been related to infection by the bacterium Vibrio aestuarianus. The genetic basis for resistance to V. aestuarianus and OsHV-1 and the nature of the genetic correlation between these two traits were investigated by using 20 half-sib sire families, each containing two full-sib families. For each disease, controlled infectious challenges were conducted using naïve oysters that were 3 to 26 months old. In addition, siblings were tested under field, pond and raceway conditions to determine whether laboratory... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00372/48350/48518.pdf |
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| Burge, Colleen A.; Reecez, Kimberly S.; Dhar, Arun K.; Kirkland, Peter; Morga, Benjamin; Degremont, Lionel; Faury, Nicole; Wippel, Bryanda J. T.; Macintyre, Alanna; Friedman, Carolyn S.. |
| Economically devastating mortality events of farmed and wild shellfish due to infectious disease have been reported globally. Currently, one of the most significant disease threats to Pacific oyster Crassostrea gigas culture is the ostreid herpesvirus 1 (OsHV-1), in particular the emerging OsHV-1 microvariant genotypes. OsHV-1 microvariants (OsHV-1 mu vars) are spreading globally, and concern is high among growers in areas unaffected by OsHV-1. No study to date has compared the relative virulence among variants. We provide the first challenge study comparing survival of naive juvenile Pacific oysters exposed to OsHV-1 mu vars from Australia (AUS mu var) and France (FRA mu var). Oysters challenged with OsHV-1 mu vars had low survival (2.5%a exposed to AUS... |
| Tipo: Text |
Palavras-chave: Ostreid herpesvirus 1; Microvariant; OsHV-1 mu vars; POMS; Pacific oyster; Crassostrea gigas; Viral disease; QPCR; Alkalinity; Emerging infectious diseases. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00631/74277/73889.pdf |
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| Pepin, Jean-francois; Benabdelmouna, Abdellah; Bierne, Nicolas; Chasselin, Leo; Degremont, Lionel; Guesdon, Stephane; Lamy, Jean-baptiste; Le Moine, Olivier; Normand, Julien; Robert, Stephane; Soletchnik, Patrick. |
| Depuis 2014, des épisodes de mortalité anormale affectent les cheptels mytilicoles tant adultes que juvéniles. Dès l’année 2015, une étude spécifique cofinancée par la DPMA et réalisée par l’Ifremer a été initiée, l’action de recherche MORBLEU (Mortalité des moules Bleues). Les années 2015- 2017 ont permis de dégager des éléments de connaissance et des pistes relatifs aux facteurs biotiques et abiotiques qui semblent intervenir dans le phénomène de hausse de mortalité des moules depuis 2014. Pour l’année 2018, les actions d’observation et de suivis du milieu et des moules ont été fortement réduites et trois axes principaux ont été poursuivis : i) l’étude de la relation entre l’évolution des équilibres microbiens planctoniques et l’apparition de mortalités... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00588/70056/67999.pdf |
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| Degremont, Lionel; Garcia, Celine; Allen, Standish K., Jr.. |
| Oyster species suffer from numerous disease outbreaks, often causing high mortality. Because the environment cannot be controlled, genetic improvement for disease resistance to pathogens is an attractive option to reduce their impact on oyster production. We review the literature on selective breeding programs for disease resistance in oyster species, and the impact of triploidy on such resistance. Significant response to selection to improve disease resistance was observed in all studies after two to four generations of selection for Haplosporidium nelsoni and Roseovarius crassostrea in Crassostrea virginica, OsHV-1 in Crassostrea gigas, and Martelia sydneyi in Saccostrea glomerata. Clearly, resistance in these cases was heritable, but most of the studies... |
| Tipo: Text |
Palavras-chave: Disease resistance; Oyster; Selection; Pathogen; Genetic; Mortality. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00269/38049/36139.pdf |
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| Registros recuperados: 85 | |
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