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| Registros recuperados: 85 | |
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| Azema, Patrick; Maurouard, Elise; Lamy, Jean-baptiste; Degremont, Lionel. |
| Mortality associated with ostreid herpesvirus 1 (OsHV-1) has significantly impacted Crassostrea gigas farmers all around the world. Although selective breeding programs to improve OsHV-1 resistance can significantly reduce the mortality rate below 20%, husbandry practices have also been one way to limit or decrease mortality. The main objectives of this study were to describe the influence of two husbandry practices on OsHV-1-induced mortality in C. gigas spat and how different family lines respond to husbandry practices to gain a better understanding of the potential benefits of breeding management as a tool to adapt to improved practices. The first analysis investigated the importance of the size of C. gigas when challenged with OsHV-1 for the first... |
| Tipo: Text |
Palavras-chave: Mortality; Crassostrea gigas; Size; OsHV-1; Growing height. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00366/47717/47758.pdf |
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| De Lorgeril, Julien; Lucasson, Aude; Petton, Bruno; Toulza, Eve; Montagnani, Caroline; Clerissi, Camille; Vidal-dupiol, Jeremie; Chaparro, Cristian; Galinier, Richard; Escoubas, Jean Michel; Haffner, Philippe; Degremont, Lionel; Charriere, Guillaume; Lafont, Maxime; Delort, Abigail; Vergnes, Agnes; Chiarello, Marlene; Faury, Nicole; Rubio, Tristan; Leroy, Marc; Perignon, Adeline; Regler, Denis; Morga, Benjamin; Alunno-bruscia, Marianne; Boudry, Pierre; Le Roux, Frederique; Destoumieux-garzon, Delphine; Gueguen, Yannick; Mitta, Guillaume. |
| Infectious diseases are mostly explored using reductionist approaches despite repeated evidence showing them to be strongly in fluenced by numerous interacting host and environmental factors. Many diseases with a complex aetiology therefore remain misunderstood. By developing a holistic approach to tackle the complexity of interactions, we decipher the complex intra-host interactions underlying Pacific oyster mortality syndrome affecting juveniles of Crassostrea gigas, the main oyster species exploited worldwide. Using experimental infections reproducing the natural route of infection and combining thorough molecular analyses of oyster families with contrasted susceptibilities, we demonstrate that the disease is caused by multiple infection with an initial... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00461/57234/59228.pdf |
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| Degremont, Lionel; Lamy, Jean-baptiste; Pepin, Jean-francois; Travers, Marie-agnes; Renault, Tristan. |
| The Pacific oyster, Crassostrea gigas, is the most important commercial oyster species cultivated in the world. Meanwhile, the ostreid herpesvirus 1 (OsHV-1) is one of the major pathogens affecting the Pacific oyster, and numerous mortality outbreaks related to this pathogen are now reported worldwide. To assess the genetic basis of resistance to OsHV-1 infection in spat C. gigas and to facilitate breeding programs for such a trait, if any exist, we compared the mortality of half- and full-sib families using three field methods and a controlled challenge by OsHV-1 in the laboratory. In the field, three methods were tested: (A) one family per bag; (B) one family per small soft mesh bag and all families inside one bag; (C) same as the previous methods but... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00269/38066/36178.pdf |
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| Schmitt, Paulina; Santini, Adrien; Vergnes, Agnes; Degremont, Lionel; De Lorgeril, Julien. |
| Summer mortalities of Crassostrea gigas are a major concern in oyster aquaculture. They are the result of a complex interaction between the host, pathogens and environmental factors. Oyster genetics have been identified as an essential determinant of oyster susceptibility to summer mortalities. As the capability of oysters to circumvent diseases depends in part on their immune defenses, we aimed to analyze the gene expression and sequence polymorphism of 42 immune related genes in two oyster lines selected for their “High” (H) and “Low” (L) survival to summer mortalities. Results showed that the variability of gene expression and the sequence polymorphism acting on particular genes could enable the discrimination between H and L oyster lines. Besides, a... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00157/26861/24979.pdf |
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| Chavanne, Herve; Maurouard, Elise; Yonneau, Caroline; Heroin, Debora; Ledu, Christophe; Degremont, Lionel; Benabdelmouna, Abdellah. |
| Afin de permettre l’approvisionnement partiel des établissements ostréicoles en naissain « à survie améliorée », un protocole d’approvisionnement partiel de sauvegarde (PSI) a été mis en place en 2010 entre le CNC, les CRCs, les écloseurs et l’Ifremer afin de fournir aux ostréiculteurs du naissain présentant les meilleures chances de survie face aux mortalités estivales. Il avait ainsi été décidé que des écloseries privées produiraient du naissain triploïde « à survie améliorée » en 2010 à partir de géniteurs, femelles diploïdes et mâles tétraploïdes, sélectionnés et fournis par Ifremer. Sur la base notamment des recommandations des Assises de la Conchyliculture, l’opération a été reconduite en 2011 (PSII) et 2012 (PSIII). Suite aux productions réalisées... |
| Tipo: Text |
Palavras-chave: Mortalités; Crassostrea gigas; Huîtres creuses; Triploïde R; Sélection Génétique. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00143/25412/23563.pdf |
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| Degremont, Lionel. |
| L'analyse du polymorphisme des gènes de J'amylase chez Crassostrea gigas (Thunberg, 1793) a été établi sur deux générations dans le cadre du programme européen GENEPHYS (génétique et physiologie chez C.gigas). Après une amplification de l'ADN par PCR à partir de deux couples d'amorces qui sont spécifiques à chacun des deux gènes de l'amylase, une digestion par EcoRI de l'ADN amplifié suivie d'une électrophorése en gel d'agarose sont effectuées. Cette technique (RFLP) permet de déterminer le polymorphisme génétique des huîtres creuses. Une troisième génération a été réalisée afin d'obtenir quatre familles et d'en analyser le génotype. Ces familles ont été tout d'abord placées pendant cinq mois dans un milieu riche en nourriture, puis ensuite, chaque famille... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Amylase; Polymorphisme; Croissance; Efficacité d'assimilation. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00439/55109/56561.pdf |
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| Degremont, Lionel; Boudry, Pierre; Bedier, Edouard; Ropert, Michel; Soletchnik, Patrick; Huvet, Arnaud; Moal, Jeanne; Samain, Jean-francois. |
| In the scope of the Morest program, 3 series of bi-parental families of cupped oyster consisting of full and half-sib have been created in 2001, and then studied on a regular basis on several sites over the summer period. In October, major survival differences had been demonstrated between the 3 families. The average survival rate for the half-sib families monitored on the three sites varies from 17 to 97 %. Some of them showed high mortality for the three sites, indicating a strong genetic basis (h2 = 0.81 - 0.29) to the variations observed regarding survival. To a lesser extent, growth differences between the studied half-sib families indicate a weaker heritability for this character. .... |
| Tipo: Text |
Palavras-chave: Physiologie; Génétique; Naissain; Sélection; Croissance; Survie; Huîtres; Crassostrea gigas. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/acte-3490.pdf |
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| Degremont, Lionel. |
| In order to study genetic variability for survival during summer mortality events in the oyster Crassostrea gigas, a first generation (G1) was bred in 2001. 17 G1 half-sib families (HSF) were obtained ; each HSF was reared in three sites along the French coast during the summer period. Significant differences in survival were observed among HSF indicating a genetic basis for survival. In 2002, several HSF were selected on their survival performances to constitute a divergent selection (G2) (outbreed and inbred). Significant differences in survival were found among these offspring of the 'high' and 'low' selected groups in several laboratory experiments and in all sites. Growth performance was not influenced by selection on survival. This confirms the... |
| Tipo: Text |
Palavras-chave: Juvenile; Genetic; Growth; Summer mortality; Crassostrea gigas; Juvéniles; Héritabilité; Rendement; Croissance; Mortalités estivales; Crassostrea gigas. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/these-202.pdf |
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| Leprêtre, Maxime; Faury, Nicole; Segarra, Amelie; Claverol, Stéphane; Degremont, Lionel; Palos-ladeiro, Mélissa; Armengaud, Jean; Renault, Tristan; Morga, Benjamin. |
| Massive mortality outbreaks affecting Pacific oysters (Crassostrea gigas) spat/juveniles are often associated with the detection of a herpesvirus called ostreid herpesvirus type 1 (OsHV-1). In this work, experimental infection trials of C. gigas spat with OsHV-1 were conducted using two contrasted Pacific oyster families for their susceptibility to viral infection. Live oysters were sampled at 12, 26, and 144 h post infection (hpi) to analyze host-pathogen interactions using comparative proteomics. Shotgun proteomics allowed the detection of seven viral proteins in infected oysters, some of them with potential immunomodulatoy functions. Viral proteins were mainly detected in susceptible oysters sampled at 26 hpi, which correlates with the mortality and... |
| Tipo: Text |
Palavras-chave: Proteomics; Interactions; Antiviral response; OsHV-1; Pacific oysters. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00669/78075/80307.pdf |
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| Pernet, Fabrice; Barret, Jean; Le Gall, Patrik; Corporeau, Charlotte; Degremont, Lionel; Lagarde, Franck; Pepin, Jean-francois; Keck, Nicolas. |
| Experiments were conducted to investigate the effects of farming sites, seeding date, age of oysters, ploidy level and rearing structures on mortality, pathogens and energetic reserves of oysters Crassostrea gigas. Mortality of oysters coincided with infections involving, primarily, the ostreid herpesvirus OsHV-1 and, secondarily, bacteria of the group Vibrio splendidus, when seawater temperature was between 17 and 24°C. Mortality started in early May and lasted until late September, with an interruption in July and August when seawater temperatures rose above 24°C. Mortality varied with farming site: oysters maintained in the open Mediterranean Sea showed no mortality and OsHV-1 was occasionally detected at a low level only, while oysters maintained in... |
| Tipo: Text |
Palavras-chave: Pacific oyster; Mortality; Disease; Farming practices; Hydrodynamics; Energetic. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00086/19739/17379.pdf |
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| Degremont, Lionel; Bedier, Edouard; Soletchnik, Patrick; Ropert, Michel; Samain, Jean-francois; Boudry, Pierre. |
| The French project "Morest", coordinated by IFREMER, aims to a better understanding of the causes of summer mortalities in juvenile oysters by a multidisciplinary approach. Within this program, a first generation (G1) was bred in 2001 to assess to what extent genetic variability exists for this trait in French populations. 17 half-sib families (HSF) including 44 full-sib families (FSF) were obtained in the G1, and each FSF was reared in three sites along the French coast during the summer period. Significant differences in survival were observed among HSF, clearly indicating a genetic basis for survival. Estimation of heritability for survival was very high: 0.81  0.29. In 2002, 3 "good" HSF and 3 "bad" HSF were selected on their survival... |
| Tipo: Text |
Palavras-chave: Selection; Genetic; Mortalities; Crassostrea gigas; Oyster. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/acte-3439.pdf |
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| Delaporte, Maryse; Moal, Jeanne; Soudant, Philippe; Lambert, Christophe; Pouvreau, Stephane; Enriquez, Martha; Degremont, Lionel; Soletchnik, Patrick; Gagnaire, Beatrice; Ropert, Michel. |
| In the frame of MOREST project, a common biological material, resulting of a mixture of different families produced in experimental hatchery, was reared in two different environmental fields : Normandy and Charente. Concomitantly, a pool was conditioned at the Ifremer Argenton hatchery with three different algae levels : 4%, 8% and 12% of algal dry weight per oyster dry weight. During the experiments, five immune parameters were studied in parallel with survival rate and reproductive status (stages and intensity). Site location, seasonal variations and experimental diet level clearly influenced oyster immune parameters. Haemocyte counts were higher for oysters reared in Normandy than those reared in Charente and in hatchery. Granulocyte percentage was... |
| Tipo: Text |
Palavras-chave: Defense mechanisms; Nutrition; Seasonal variations; Physiology; Crassostrea gigas; Pacific oysters. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/acte-3500.pdf |
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| Moal, Jeanne; Bedier, Edouard; Fleury, Pierre-gildas; Langlade, Aime; Le Coguic, Yvette; Degremont, Lionel; Boudry, Pierre; Le Coz, Jean-rene; Pouvreau, Stephane; Enriquez-diaz, M.; Lambert, Christophe; Quere, Christele; Soudant, Philippe; Samain, Jean-francois. |
| Bi-parental families were produced in hatchery and tested in the field in 2001. Two sets of 5 families were constituted, selected on their high (R) and low (S) survival. These two sets were reared in Brittany from March to November 2002. Samplings were performed twice a month to obtain data on biometry, survival, reproductive cycle, biochemical composition, adenylate energy charge, hemolymph parameters (ions and defense system) and muscle strength. "R" and "S" oysters exhibited different reproductive effort and spawning strategy. "R" oysters allocated less energy in gonad than "S" ones and presented a complete spawning at the end of August contrary to the "S" which spawns partially. Mortality started in July when the seawater temperature reached 19 degree... |
| Tipo: Text |
Palavras-chave: Summer; Reproduction; Oyster culture; Mortality; Genetic diversity; Commercial species; Breeding. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/acte-3345.pdf |
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| Cochennec-laureau, Nathalie; Baud, Jean-pierre; Pepin, Jean-francois; Benabdelmouna, Abdellah; Soletchnik, Patrick; Lupo, Coralie; Garcia, Celine; Arzul, Isabelle; Boudry, Pierre; Huvet, Arnaud; Pernet, Fabrice; Bachere, Evelyne; Bedier, Edouard; Petton, Bruno; Gaussem, Florian; Stanisiere, Jean-yves; Degremont, Lionel. |
| Depuis 2008, la filière ostréicole française doit faire face à des surmortalités exceptionnelles des naissains d’huîtres creuses, Crassostrea gigas, (huîtres de moins d’un an) comprises entre 60 et 90% dans tous les sites d’élevage. Des cas de mortalité similaires ont été décrits en Irlande, dans les îles anglo-normandes, au Portugal en 2009 et au Royaume-Uni en 2010. Récemment deux épisodes de mortalité, associés à la présence d’un virus OsHV1 μvar (ou un variant très proche) ont été également décrits en Nouvelle Zélande (décembre 2010) et en Australie (janvier 2011) soulignant la vulnérabilité de la filière ostréicole dans le monde. L’objectif de ce document est de faire un point sur les recherches menées depuis l’apparition de ce phénomène et de... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00033/14423/11719.pdf |
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| Martenot, Claire; Faury, Nicole; Morga, Benjamin; Degremont, Lionel; Lamy, Jean-baptiste; Houssin, Maryline; Renault, Tristan. |
| Viral entry mechanisms of herpesviruses constitute a highly complex process which implicates several viral glycoproteins and different receptors on the host cell surfaces. This initial infection stage was currently undescribed for Ostreid herpes virus 1 (OsHV-1), a herpesvirus infecting bivalves including the Pacific oyster, Crassostrea gigas. To identify OsHV-1 glyproteins implicated in the attachment of the virus to oyster cells, three viral putative membrane proteins, encoded by ORF 25, 41, and 72, were selected and polyclonal antibodies against these targets were used to explore first interactions between the virus and host cells. In addition, effects of dextran sulfate, a negative charged sulfated polysaccharide, were investigated on OsHV-1 infection.... |
| Tipo: Text |
Palavras-chave: OsHV-1; Antiviral antibodies; Dextran sulfate; Interaction; Crassostrea gigas; Infection. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00501/61273/64847.pdf |
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| Azema, Patrick; Travers, Marie-agnes; De Lorgeril, Julien; Tourbiez, Delphine; Degremont, Lionel. |
| Since 2008, the emergent virus OsHV 1μvar has provoked massive mortality events in Crassostrea gigas spat and juveniles in France. Since 2012, mortality driven by the pathogenic bacteria Vibrio aestuarianus has stricken market sized adults. A hypothesis to explain the sudden increase in mortality observed in France since 2012 is that selective pressure due to recurrent viral infections could have led to a higher susceptibility of adults to Vibrio infection. In our study, two OsHV-1-resistant lines (AS and BS) and their respective controls (AC and BC) were experimentally challenged in the laboratory to determine their level of susceptibility to V. aestuarianus infection. At the juvenile stage, the selected lines exhibited lower mortality (14 and 33%) than... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00299/41054/40215.pdf |
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| Boudry, Pierre; Degremont, Lionel; Taris, Nicolas; Mccombie, Helen; Haffray, Pierrick; Ernande, Bruno. |
| To date, the most significant genetic improvement for the production of Pacific oyster (Crassostrea gigas) has been obtained through the breeding of triploids, especially since the development of tetraploids. Quantitative genetics studies suggest that significant gains, for disease resistance or for other traits of aquacultural interest, could be obtained in diploids using this approach. However, the limited extent of hatchery-propagation (versus natural recruitment) and/or various technical difficulties and biological characteristics of the species have retarded the development of selective breeding programs. Recently, in the U.S.A., Australia and New Zealand, countries where hatcheries are a major source of C. gigas juveniles, family-based selective... |
| Tipo: Text |
Palavras-chave: Microsatellite markers; Selective breeding; Genetic; Genetic variability; Crassostrea gigas; Pacific oysters. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/acte-3449.pdf |
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| Degremont, Lionel; Ledu, Christophe; Maurouard, Elise; Nourry, Max; Benabdelmouna, Abdellah. |
| The effect of ploidy on the mortality of Crassostrea gigas spat caused by the ostreid herpesvirus (OsHV-1) genotype μVar was investigated at five sites along the Atlantic coast in France in 2011. Sibling diploids and triploids were produced using either unselected or selected OsHV-1-resistant oysters. No significant interactions were found between the factors of environment, genotype and ploidy at the endpoint dates. The mean mortality rates at the sites were 62 and 59% for diploids and triploids, respectively, and the two rates were not significantly different. The mean mortality rates were 33 and 32% for sibling diploids and triploids, respectively, when OsHV-1-resistant parents were used, and 91 and 85%, respectively, when unselected parents were used.... |
| Tipo: Text |
Palavras-chave: Diploid; Triploid; Mortality; Crassostrea gigas; Ostreid herpesvirus OsHV-1. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00199/31028/29427.pdf |
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| Degremont, Lionel; Bedier, Edouard; Boudry, Pierre. |
| Response to divergent selection for "high" and "low" survival during the summer period, from July to October, was investigated in juvenile (six-month-old) Pacific oysters, Crassostrea gigas, by producing two sets of progenies in 2002 (Generation 2) and three sets of progenies in 2003 (Generation 3). A strict between-family approach was used and resistance of these selected progenies to summer mortality was assessed in three sites along French coasts, to determine their response to selection and estimate realized heritability of the trait. A significant difference in survival was observed between the "high" and "low" selected groups at all sites for all sets of progenies, indicating a significant genetic component. High realized heritabilities for survival... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Heritability; Juveniles; Summer mortality; Survival; Growth. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6950.pdf |
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| Registros recuperados: 85 | |
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