Consulta: creatorFacets:"Degremont, Lionel"
Registros recuperados: 85
Data/hora: 01/06/2024 06:42:14

Effects of age and environment on the summer mortality in cupped oyster Crassostrea gigas during the first two years
Provedor de dados: 5
Autores: Degremont, Lionel; Boudry, Pierre; Soletchnik, Patrick; Bedier, Edouard; Ropert, Michel; Samain, Jean-francois.
Three successive generations were produced between 2001 and 2003 to assess to what extent genetic variability exists for survival in juvenile oysters Crassostrea gigas. For each generation, two groups were selected for their high ("R" for resistant) and low ("S" for susceptible) survival. Significant differences in mortality were observed during the first year in Riviere d'Auray (RA) (Brittany-France). However, low and similar mortality were observed for both groups, with no significant difference between groups in the first and second generation in this site, where the first summer is the critical, sensitive period with a clear age effect. In Baie des Veys (BDV) (Normandie-France), where mortalities usually mainly affect adults, mortality between groups,...
Tipo: Text
Palavras-chave: Crassostrea gigas; Spat; Spatial variations; Survival; Rearing; Mollusc culture; Marine molluscs; Environmental factors; Nursery grounds; Mortality causes; Biological age; Aquaculture techniques.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/acte-3385.pdf

Selective breeding to improve resistance against summer mortality in the Pacific oyster Crassostrea gigas : results after 3 generations
Provedor de dados: 5
Autores: Boudry, Pierre; Degremont, Lionel; Bedier, Edouard; Samain, Jean-francois.
Summer mortality of adults and juveniles has been reported in the Pacific oyster, Crassostrea gigas, for many years and in several countries. The French multidisciplinary program "Morest" aims to investigate the causes of the summer mortality in Crassostrea gigas. Within this program, we designed multi-site field experiments to assess to what extent genetic variability exists for summer mortality in French populations of C. gigas and to determine whether selective breeding could improve survival.
Tipo: Text
Palavras-chave: Growth; Resistance; Selective breeding; Genetic; Crassostrea gigas; Pacific oyster; Summer mortality.
Ano: 2004
URL: http://archimer.ifremer.fr/doc/2004/acte-3448.pdf

The identification of genes from the oyster Crassostrea gigas that are differentially expressed between progeny exhibiting opposed susceptibility to summer mortality
Provedor de dados: 5
Autores: Huvet, Arnaud; Degremont, Lionel; Labreuche, Yannick; Daniel, Jean-yves; Dubrunfaut, Thomas; Boudry, Pierre; Haure, Joel; Bedier, Edouard; Ropert, Michel; Herpin, Amaury; Cunningham, Charles; Moal, Jeanne; Samain, Jean-francois.
Summer mortality associated with juveniles of the oyster Crassostrea gigas is the result of a complex interaction between the host, pathogens and environment. Divergent selection based on summer survival have been applied to produce families with resistant and susceptible progeny. Here, we describe the use of suppression subtractive hybridization to generate 150 clones that were differentially regulated between resistant and susceptible F2 progeny. The nucleotide sequence of these 150 clones was determined. Among the 25 unique sequences that matched with the products of known genes, those putatively implicated in energy generation (12%) and immune function (16%), systems suspected to be implicated in summer mortality, were extended and analyzed by real...
Tipo: Text
Palavras-chave: Selection; Gene; Genetic; Summer mortality; Crassostrea gigas; Pacific oysters.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/acte-3447.pdf

Genetic basis of summer mortality in juvenile cupped oysters
Provedor de dados: 5
Autores: Degremont, Lionel; Boudry, Pierre; Bedier, Edouard; Ropert, Michel; Soletchnik, Patrick; Huvet, Arnaud; Moal, Jeanne; Samain, Jean-francois.
The French project "Morest", coordinated by IFREMER, aims to understand the causes of the summer mortalities in Crassostrea gigas. In 2001, three sets of families were bred following a nested half-sib mating design. 17 half-sib families (HSF) were obtained in this first generation (G1) and reared in 3 sites. Significant differences in survival were observed among HSF, and some HSF showed high levels of mortality in all sites, clearly indicating a genetic basis for survival. In 2002, a second generation (G2), including divergent selection and inbred lines, was constituted. Monitoring of survival and growth of G2s were the same as in 2001. Significant differences in survival were found between the offspring of the "high" and "low" selected groups and between...
Tipo: Text
Palavras-chave: Summer; Oyster culture; Juveniles mortality; Genetics; Commercial species; Breeding.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/2003/acte-3346.pdf

Dual transcriptomics of virus-host interactions: comparing two Pacific oyster families presenting contrasted susceptibility to ostreid herpesvirus 1
Provedor de dados: 5
Autores: Segarra, Amelie; Mauduit, Florian; Faury, Nicole; Trancart, Suzanne; Degremont, Lionel; Tourbiez, Delphine; Haffner, Philippe; Barbosa-solomieu, Valerie; Pepin, Jean-francois; Travers, Marie-agnes; Renault, Tristan.
Background:  Massive mortality outbreaks affecting Pacific oyster (Crassostrea gigas) spat in various countries have been associated with the detection of a herpesvirus called ostreid herpesvirus type 1 (OsHV-1). However, few studies have been performed to understand and follow viral gene expression, as it has been done in vertebrate herpesviruses. In this work, experimental infection trials of C. gigas spat with OsHV-1 were conducted in order to test the susceptibility of several bi-parental oyster families to this virus and to analyze host-pathogen interactions using in vivo transcriptomic approaches.  Results:  The divergent response of these oyster families in terms of mortality confirmed that susceptibility to OsHV-1 infection has a significant...
Tipo: Text
Palavras-chave: Interactions; Ostreid herpesvirus 1; Gene expression; Susceptibility; Crassostrea gigas.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00199/31029/29431.pdf

Gonad volume assessment in the oyster Crassostrea gigas: Comparison between a histological method and a Magnetic Resonance Imaging (MRI) method
Provedor de dados: 5
Autores: Flahauw, Emilie; Quellec, Stephane; Davenel, Armel; Degremont, Lionel; Lapegue, Sylvie; Hatt, Philippe-jacques.
Previous studies comparing Crassostrea gigas selected lines with different susceptibility to summer mortality concluded that the higher the reproductive effort the lower the survival. But theywere lacking individual followup of this reproductive effort which would be of great interest to help us to understand the physiology of the oysters facing summermortalities. Themost frequently usedmethod for assessing the volume of the gonad is to measure the area it occupies on histological sections. Gonad measurement by magnetic resonance imaging, in contrast, is non-destructive and therefore makes it possible to assess individual evolution as well as to compare individuals. The present study compared the values of gonad volume by thismethodwith the values of gonad...
Tipo: Text
Palavras-chave: Oyster; Crassostrea gigas; Reproduction; Histology; Magnetic resonance imaging; MRI.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00102/21309/19410.pdf

Effect of age and environment on the summer mortality in cupped oyster Crassostrea gigas during the first two years
Provedor de dados: 5
Autores: Degremont, Lionel; Boudry, Pierre; Soletchnik, Patrick; Bedier, Edouard; Ropert, Michel; Samain, Jean-francois.
Three successive generations were produced between 2001 and 2003 to assess to what extent genetic variability exists for this trait in juvenile oysters Crassostrea gigas.  For each generation, two groups were selected for their high ("R" for resistant) and low ("S" for susceptible) survival.  Significant differences of mortality were observed during the first year in Rivière d'Auray (RA) (Brittany-France).  However, low and similar mortality were observed for both groups, with no significant difference between groups in the first and second generation in this site, where the first summer is the critical sensitive period with a clear age effect.  In Baie des Veys (BDV) (Normandie-France), where mortalities usually mainly affect adults, mortality between...
Tipo: Text
Palavras-chave: Genetic variability; Genetic; Summer mortality; Crassostrea gigas; Pacific oysters.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/acte-3442.pdf

Mortalités d'huîtres creuses adultes (Crassostrea gigas) et infection à Vibrio aestuarianus - AESTU
Provedor de dados: 5
Autores: Travers, Marie-agnes; Degremont, Lionel; De Lorgeril, Julien; Azema, Patrick; Montagnani, Caroline; Benabdelmouna, Abdellah; Nicolas, Jean-louis; Le Roux, Frederique.
En 2012, le nombre de cas de mortalités d’huîtres creuses adultes rapportés dans le cadre du réseau Repamo, et dans lesquels la bactérie Vibrio aestuarianus a été isolée, a fortement augmenté. Afin d’apporter de premiers éléments de réponse concernant cette augmentation, les objectifs de cette étude étaient de déterminer si l’émergence/la ré-émergence de V. aestuarianus était associée (i) à l’apparition d’un génotype bactérien particulier et/ou (ii) à une sensibilité accrue de certains animaux. L’Ifremer dispose d’une collection de souches bactériennes appartenant majoritairement au genre Vibrio et qui comporte différents isolats de V. aestuarianus, collectés depuis 2001 pendant ou hors épisodes de mortalité. La comparaison de ces isolats en termes de...
Tipo: Text
Palavras-chave: Vibrio aestuarianus; Huître creuse; Crassostrea gigas; Bactérie; Ré-émergenece; Virulence; Génome; Statut immunitaire; Génétique.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00229/34037/32430.pdf

Characterization of summer mortalities of C. gigas oyster in France in relation to environmental parameters
Provedor de dados: 5
Autores: Soletchnik, Patrick; Ropert, Michel; Bedier, Edouard; Costil, K. S.; Dubois, Brice; Degremont, Lionel; Bouget, Jean-francois; Martin, Jean-louis; Enriquez-diaz, M.; Faury, Nicole; Le Moine, Olivier; Renault, Tristan; Gagnaire, Beatrice; Huvet, Arnaud; Moal, Jeanne; Samain, Jean-francois.
Field characterization of summer mortality was performed in France in the frame of the Morest project. Natural and hatchery spat were compared between three oyster production areas in France. Regardless of the natural or hatchery origin, oysters died during the reproduction period after temperature reaches 19 degree C. Thus, in southern areas, temperature accelerated gametogenesis of small spat (10mm) as well as adults, and mortality appeared for the two age classes. In contrast, sexual maturation proceeded more slowly in northern where spat mortality was lower compared to 18 months old oysters. However, critical gametogenesis and temperature were not sufficient to induce mortalities, as observed in examples with stable environment. Alternatively sediment...
Tipo: Text
Palavras-chave: Seasonal variation; Oyster culture; Mortality causes; Hatcheries; Gametogenesis; Environmental factors; Crassostrea gigas; Oysters.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/2003/acte-3348.pdf

Suivi national des mortalités au stade naissain d'un lot témoin et d'un lot à survie améliorée pour Crassostrea gigas
Provedor de dados: 5
Autores: 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

Etude transcriptomique, génétique et fonctionnelle de la gamétogenèse chez l'huître creuse Crassostrea gigas
Provedor de dados: 5
Autores: Bigot, L.; Dubos, M. P.; Dheilly, N.; Favrel, P.; Kellner, K.; Lelong, C.; Martinez, A. S.; Riviere, G.; Santerre, C.; Sourdaine, P.; Degremont, Lionel; Flahauw, Emilie; Hatt, Philippe-jacques; Heurtebise, Serge; Lapegue, Sylvie; Azzouzi, N.; Galibert, F.; Boudry, Pierre; Corporeau, Charlotte; Fabioux, Caroline; Guevelou, Eric; Huvet, Arnaud; Sussarellu, Rossana.
Le projet GAMETOGENES vise à améliorer les connaissances des bases physiologiques et génétiques de la reproduction et des métabolismes associés chez un mollusque d'importance économique l'huître creuse, Crassostrea gigas. Il a pour objectifs (1) la définition de marqueurs clés de la gamétogenèse, de l'investissement reproducteur et du déterminisme du sexe chez une espèce hermaphrodite à protandrie irrégulière (2) la recherche de QTL de survie aux mortalités estivales ou à l'effort de reproduction dont le succès repose sur l'augmentation de la densité de marqueurs sur les cartes génétiques existantes (SNP en particulier) et sur les liens qui pourront être établis entre ces cartes de liaison et une carte physique (3) le développement d'outils pour valider la...
Tipo: Text
Palavras-chave: Génétique; Huître creuse; Crassostrea gigas; Gamétogenèse; QTL; Marqueur; Physiologie.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00107/21781/19355.pdf

Hemocyte characteristics in families of oysters, Crassostrea gigas, selected for differential survival during summer and reared in three sites
Provedor de dados: 5
Autores: Lambert, Christophe; Soudant, Phillippe; Degremont, Lionel; Delaporte, Maryse; Moal, Jeanne; Boudry, Pierre; Jean, Frédéric; Huvet, Arnaud; Samain, Jean-francois.
High variability among individuals is often encountered when hemocyte characteristics are measured in bivalves. Such variability is suspected to result partly from genetic factors. In this study, hemocyte characteristics of six families of Crassostrea gigas were compared by flow cytometry at one sampling date in October 2001. These families were obtained from a nested, half-sibling cross design, and reared from July to October 2001 at three sites distributed along the French Atlantic coast from north to south: Baie des Veys (Normandy), Riviere d'Auray (Brittany) and Ronce (Marennes-oleron Basin, Poitou Charentes).   Among the 15 measured hemocyte characteristics, production of reactive oxygen species (ROS) of untreated hemocytes (maintained in filtered...
Tipo: Text
Palavras-chave: Genetic; Flow cytometry; Reactive oxygen species ROS; Adhesion; Hemocyte; Crassostrea gigas; Summer mortality.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3054.pdf

Single or dual experimental infections with Vibrio aestuarianus and OsHV-1 in diploid and triploid Crassostrea gigas at the spat, juvenile and adult stages
Provedor de dados: 5
Autores: Azema, Patrick; Travers, Marie-agnes; Benabdelmouna, Abdellah; Degremont, Lionel.
French production of the Pacific cupped oyster, Crassostrea gigas, is currently threatened by two pathogens, OsHV-1 and V. aestuarianus. While oysters selected for their higher resistance to OsHV-1 are now available for the industry, the impact of V. aestuarianus on such oysters is unknown, especially for triploids. In addition, experimental infection has used the virus or the bacteria alone, but there have been no investigations of dual exposure to these pathogens. This study is the first report of single or dual exposure in spat (Spat1 and Spat2), juvenile and adult naïve oysters. For each of the two stocks evaluated, unselected oysters and oysters selected for their higher resistance to OsHV-1 infection were tested, as well as their triploid siblings of...
Tipo: Text
Palavras-chave: Vibrio aestuarianus; OsHV-1; Dual exposure; Ploidy; Selection; Crassostrea gigas.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00347/45835/45918.pdf

The Pacific Oyster Mortality Syndrome, a Polymicrobial and Multifactorial Disease: State of Knowledge and Future Directions
Provedor de dados: 5
Autores: Petton, Bruno; Destoumieux Garzon, Delphine; Pernet, Fabrice; Toulza, Eve; De Lorgeril, Julien; Degremont, Lionel; Mitta, Guillaume.
The Pacific oyster (Crassostreae gigas) has been introduced from Asia to numerous countries around the world during the 20th century. C. gigas is the main oyster species farmed worldwide and represents more than 98% of oyster production. The severity of disease outbreaks that affect C. gigas, which primarily impact juvenile oysters, has increased dramatically since 2008. The most prevalent disease, Pacific oyster mortality syndrome (POMS), has become panzootic and represents a threat to the oyster industry. Recently, major steps towards understanding POMS have been achieved through integrative molecular approaches. These studies demonstrated that infection by Ostreid herpesvirus type 1 µVar (OsHV-1 µvar) is the first critical step in the infectious process...
Tipo: Text
Palavras-chave: Pacific oyster mortality syndrome; Polymicrobial disease; Multifactorial disease; Crassostrea gigas; OsHV-1; Opportunistic bacterial pathogens.
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00679/79158/81669.pdf

Etude du polymorphisme des gènes de l'amylase chez Crassostrea gigas : relation avec les paramètres physiologiques de l'assimilation et croissance
Provedor de dados: 5
Autores: Degremont, Lionel; Moal, Jeanne; Daniel, Jean-yves; Boudry, Pierre; Van Vormhoudt, A.; Sellos, D.; Samain, Jean-francois.
In the scope of the European program GENEPHYS, which aims to establish the relationship between the genetic base and the physiological characters in relation to the growth in Crassostrea gigas, it has been demonstrated that the most explanatory factors for the growth variability are assimilation performance and aneuploidy. A model linking the assimilation performances and the digestive equipment has been set up and more than 70% of the variability can be explained by two digestive enzymes: laminarinase and amylase. A number of laboratories have decided to focus on the latter.
Tipo: Text
Palavras-chave: Croissance; Génétique; Polymorphisme; Crassostrea gigas.
Ano: 2001
URL: http://archimer.ifremer.fr/doc/2001/acte-3269.pdf

Ecologically realistic model of infection for exploring the host damage caused by Vibrio aestuarianus
Provedor de dados: 5
Autores: Parizadeh, Leila; Tourbiez, Delphine; Garcia, Celine; Haffner, Philippe; Degremont, Lionel; Le Roux, Frederique; Travers, Marie-agnes.
Although vibrios are frequently associated with marine organisms mortality outbreaks, knowledge on their ecology and pathogenicity is sparse, thus limiting disease management and prophylactic strategies. Here, we investigated V. aestuarianus infection onset and progression in the wild, taking advantage of a “claire” pond: a semi‐closed system with limited seawater renewal, theoretically more adapted to disease transmission. We showed a positive association of the bacteria with oysters, which can constitute a reservoir for the bacteria in the winter. Moreover, passage through oysters was found to be necessary for experimental disease reproduction as vibrios shedding from diseased oysters has higher infectivity than from in vitro grown. We next developed an...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00446/55761/57423.pdf

Genetic variability and selective breeding for traits of aquacultural interest in the Pacific oyster (Crassostrea gigas)
Provedor de dados: 5
Autores: Boudry, Pierre; Degremont, Lionel; Taris, Nicolas; Mccombie, Helen; Haffray, Pierrick; Ernande, Bruno.
The most significant genetic improvement for production of Pacific oyster (Crassastrea 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 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 slowed the development of selective breeding programs. Recently, in the USA, Australia and New Zealand, family-based selective breeding programs have been initiated to improve growth and yield. In Europe, where both natural and...
Tipo: Text
Palavras-chave: Microsatellites; Quantitative genetic; Genetic variability; Crassostrea gigas; Oysters.
Ano: 2004
URL: http://archimer.ifremer.fr/doc/2004/publication-2861.pdf

Summer mortality of selected juvenile pacific oyster Crassostrea gigas under laboratory conditions and in comparison with field performance
Provedor de dados: 5
Autores: Degremont, Lionel; Soletchnik, Patrick; Boudry, Pierre.
This study reports mortality under laboratory conditions in unselected controls and two lines of juvenile Pacific oysters Crassostrea gigas, previously selected for their high or low survival in the field during the summer period. Oysters were also deployed in field conditions and mortality between both conditions was then compared. In the laboratory, mortality was observed in all experiments and it always lasted for a week indicating that mortality under laboratory conditions was a short-term event. It was also shown that mortality could be repeated for a batch in several experiments using oysters which never experienced any abnormal mortality. This approach could facilitate further studies to investigate the causes of mortality by allowing repeated...
Tipo: Text
Palavras-chave: Summer mortality; Crassostrea gigas; Laboratory; Field; Oyster; Juvenile.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00013/12432/9228.pdf

Evaluation de la survie du naissain de captage naturel chez l'huître creuse Crassostrea gigas en fonction de la période des pontes à partir de lots sélectionnés pour les caractères de survie et efforts de reproduction
Provedor de dados: 5
Autores: Degremont, Lionel; Bordeyne, Francois; Yonneau, Caroline; Maurouard, Elise; Nourry, Max.
Depuis 2008, les mortalités touchant le naissain Crassostrea gigas sont particulièrement élevées en France (&gt;70%), fragilisant de nombreuses entreprises ostréicoles. Cependant, une voie de sortie de crise proposée dès 2001 est la mise en place de programmes de sélection pour l’amélioration de la survie suite à la mise en évidence de la forte héritabilité de ce caractère au stade naissain chez C. gigas (Dégremont et al., 2007 ; Dégremont et al., 2010a). Ainsi, des familles d’huîtres C. gigas présentant des survies contrastées au stade naissain ont été reproduites et maintenues depuis 2002 par le Laboratoire de Génétique et Pathologie à la station Ifremer de La Tremblade. Ces lots d’huîtres ont été nommés « R » et « S » respectivement pour leur meilleure...
Tipo: Text
Palavras-chave: Génétique; Sélection génétique; Naissain; Huîtres creuses; Crassostrea gigas; Reproduction.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00065/17643/15179.pdf

Caractérisation précoce de la mortalité des lignées divergentes de Crassostrea gigas (G2)
Provedor de dados: 5
Autores: Degremont, Lionel; Soletchnik, Patrick; Doner, Anne.
2001 shows how important the "R" and "S" biological families are for experimentation as well as the need to "preserve" these families from mortality during the first year. The "experimental nursing" conditions do not allow the conservation of dozens of families with many members for 6 to 8 months. Precocious characterisation at around 4-5 months enables a first selection of the biological material, as well as a first answer to the "in lab" genetical selection of the families. After the first results in 2001 (Céline de Ambroggi, LCPC, L. Degremont), two "precocious characterisation of mortality" experiments are carried out in 2002 on the divergent lineage of some genetical families (LGP production). Two 15 day long experiments are conducted in la Tremblade...
Tipo: Text
Palavras-chave: Mortalités; Sélection; Physiologie; Genetique; Crassostrea gigas; Huîtres.
Ano: 2002
URL: http://archimer.ifremer.fr/doc/2002/acte-3406.pdf

The use of size and growing height to improve Crassostrea gigas farming and breeding techniques against OsHV-1
Provedor de dados: 5
Autores: 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

Immune-suppression by OsHV-1 viral infection causes fatal bacteraemia in Pacific oysters
Provedor de dados: 5
Autores: 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
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00461/57234/59228.pdf

New Insight for the Genetic Evaluation of Resistance to Ostreid Herpesvirus Infection, a Worldwide Disease, in Crassostrea gigas
Provedor de dados: 5
Autores: 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
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00269/38066/36178.pdf

Sequence polymorphism and expression variability of Crassostrea gigas immune related genes discriminate two oyster lines contrasted in term of resistance to summer mortalities
Provedor de dados: 5
Autores: 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
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00157/26861/24979.pdf

Plan de sauvegarde 2011 : synthèse de résultats 2011-2012
Provedor de dados: 5
Autores: 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

Etude du polymorphisme des gènes de l'amylase chez Crassostrea gigas (Thunberg, 1793). Relation avec les paramètres physiologiques de l'assimilation
Provedor de dados: 5
Autores: 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

Mortalités estivales et croissance du naissain de l'huître creuse Crassostrea gigas : étude de familles sélectionnées
Provedor de dados: 5
Autores: 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

Etude des bases génétiques de la mortalité estivale et des relations avec la croissance chez les juvéniles de l'huître creuse Crassostrea gigas
Provedor de dados: 5
Autores: 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

Comparative Proteomics of Ostreid Herpesvirus 1 and Pacific Oyster Interactions With Two Families Exhibiting Contrasted Susceptibility to Viral Infection
Provedor de dados: 5
Autores: 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

Mass mortalities of Pacific oysters Crassostrea gigas reflect infectious diseases and vary with farming practices in the Mediterranean Thau lagoon, France
Provedor de dados: 5
Autores: 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

Mortality associated with OsHV-1 in spat Crassostrea gigas: role of wild-caught spat in the horizontal transmission of the disease
Provedor de dados: 5
Autores: Degremont, Lionel; Benabdelmouna, Abdellah.
The French oyster production of Crassostrea gigas is based on two sources of spat: wild-caught (WC) and hatchery-produced (HP). Massive mortality related to the ostreid herpesvirus type 1 (OsHV-1) has affected both sources in France since 2008. We investigated the mortality in juvenile C. gigas due to the horizontal transmission of OsHV-1 within (separated condition) and between (mixed condition) the two spat sources in three environments from April to June 2010. In the separated condition, no mortality was observed in the HP batches, while the WC batches experienced moderate to high mortality (40–80 %). In contrast, the WC and HP batches experienced high mortality in all tested environments for the mixed condition. At the beginning of the trial, the HP...
Tipo: Text
Palavras-chave: Crassostrea gigas; Wild-caught; Hatchery-produced; Spat; Mortality; Horizontal transmission; Ostreid herpesvirus OsHV-1.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00188/29921/28387.pdf

Summer mortality in juvenile cupped oysters : response to selection in the field and in laboratory
Provedor de dados: 5
Autores: 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 &amp;#61617; 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

Effect of environmental and nutritive conditionings on defense mechanisms of oyster Crassostrea gigas during an annual cycle
Provedor de dados: 5
Autores: 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

Genetic and reproduction strategy in Crassostrea gigas mortality
Provedor de dados: 5
Autores: 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

Les surmortalités des naissains d’huîtres creuses, Crassostrea gigas : acquis des recherches en 2010
Provedor de dados: 5
Autores: 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
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00033/14423/11719.pdf

Exploring First Interactions Between Ostreid Herpesvirus 1 (OsHV-1) and Its Host, Crassostrea gigas: Effects of Specific Antiviral Antibodies and Dextran Sulfate
Provedor de dados: 5
Autores: 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

Can selection for resistance to OsHV-1 infection modify susceptibility to Vibrio aestuarianus infection in Crassostrea gigas? First insights from experimental challenges using primary and successive exposures
Provedor de dados: 5
Autores: 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
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00299/41054/40215.pdf

Genetic variability and selective breeding for traits of aquacultural interest in the Pacific oyster (Crassostrea gigas) (slides)
Provedor de dados: 5
Autores: 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

Effect of ploidy on the mortality of Crassostrea gigas spat caused by OsHV-1 in France using unselected and selected OsHV-1 resistant oysters
Provedor de dados: 5
Autores: 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

Summer mortality of hatchery-produced Pacific oyster spat (Crassostrea gigas). II. Response to selection for survival and its influence on growth and yield
Provedor de dados: 5
Autores: 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

Effects of age and environment on survival of summer mortality by two selected groups of the Pacific oyster Crassostrea gigas
Provedor de dados: 5
Autores: Degremont, Lionel; Boudry, Pierre; Ropert, Michel; Samain, Jean-francois; Bedier, Edouard; Soletchnik, Patrick.
This study investigated the effects of age (first or second summer of life) and environment (three study sites on French coasts) on summer mortality in Crassostrea gigas, using three generations of oysters produced during the Morest project. For each generation, two groups of oysters, selected either as 'resistant' (R) or 'susceptible' (S) to summer mortality at the age of 6 months in Rivière d'Auray (RA, South Brittany), were evaluated. In Ronce (Marennes-Oléron Bay) and RA, R oysters had low mortality during their first and second summers, while mortality was higher during the second summer in Baie des Veys (BDV, Normandy). In RA, S oysters exhibited higher mortality during their first summer than during their second, while the opposite result was found...
Tipo: Text
Palavras-chave: Summer mortality; Age; Environment; Genetic; Crassostrea gigas.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/2009/publication-6972.pdf

Genetically based resistance to summer mortality in the Pacific oyster (Crassostrea gigas) and its relationship with physiological, immunological characteristics and infection processes
Provedor de dados: 5
Autores: Samain, Jean-francois; Degremont, Lionel; Soletchnik, Patrick; Haure, Joel; Bedier, Edouard; Ropert, Michel; Moal, Jeanne; Huvet, Arnaud; Bacca, Helene; Van Wormhoudt, A; Delaporte, Maryse; Costil, K; Pouvreau, Stephane; Lambert, Christian; Boulo, Viviane; Soudant, Philippe; Nicolas, Jean-louis; Leroux, Frederique; Renault, Tristan; Gagnaire, Beatrice; Geret, Florence; Boutet, Isabelle; Burgeot, Thierry; Boudry, Pierre.
Summer mortality of Pacific oysters is known in several countries. However no specific pathogen has been systematically associated with this phenomenon. A complex combination of environmental and biological parameters has been suggested as the cause and is now starting to be identified. A high genetic basis was found for survival in oysters when a first generation (G1) was tested in three sites during summer. This paper presents a synthesis on physiological characteristics of two selected groups ('R' and 'S', from families selected for resistance and susceptibility to summer mortality respectively), of the second and third generations. R and S showed improvement or reduction of survival compared with the control in both field and laboratory trials...
Tipo: Text
Palavras-chave: ROS; Temperature; Stress; Hemocytes; Reproduction; Genetic selection; Resistant oyster; Crassostrea gigas; Pacific Oyster; Summer mortality.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2809.pdf

Development of four EST-SSR multiplex PCRs in the Pacific oyster (Crassostrea gigas) and their validation in parentage assignment
Provedor de dados: 5
Autores: Li, Ronghua; Li, Qi; Cornette, Florence; Degremont, Lionel; Lapegue, Sylvie.
We report four highly informative multiplex PCRs developed from twelve previously described ESTSSRs in Crassostrea gigas. We evaluated and validated these multiplex PCRs in twelve full-sib families. The average allelic richness and the polymorphism information content (PIC) were 11.1 and 0.811 respectively. The combined power of exclusion was greater than 99.99% using all four multiplex assays. A hundred and forty three tests of segregation ratios revealed 11 significant departures from expected Mendelian ratios. The frequency of null alleles was estimated as 4.9% of all the alleles segregating based on a within-family analysis of Mendelian segregation patterns. Parentage analysis of real offspring demonstrated that 97% of all offspring were unambiguously...
Tipo: Text
Palavras-chave: Pacific oyster; Crassostrea gigas; Microsatellite; EST; Multiplex PCR; Parentage assignment.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00013/12419/9999.pdf

Parental exposure to environmental concentrations of diuron leads to aneuploidy in embryos of the Pacific oyster, as evidenced by fluorescent in situ hybridization
Provedor de dados: 5
Autores: Barranger, Audrey; Benabdelmouna, Abdellah; Degremont, Lionel; Burgeot, Thierry; Akcha, Farida.
Changes in normal chromosome numbers (i.e. aneuploidy) due to abnormal chromosome segregation may arise either spontaneously or as a result of chemical/radiation exposure, particularly during cell division. Coastal ecosystems are continuously subjected to various contaminants originating from urban, industrial and agricultural activities. Genotoxicity is common to several families of major environmental pollutants, including pesticides, which therefore represent a potential important environmental hazard for marine organisms. A previous study demonstrated the vertical transmission of DNA damage by subjecting oyster genitors to short-term exposure to the herbicide diuron at environmental concentrations during gametogenesis. In this paper, Fluorescent in...
Tipo: Text
Palavras-chave: Aneuploidy; FISH; Diuron; Crassostrea gigas.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00238/34911/33216.pdf

Genetical basis of the plasticity of resource allocation in the Pacific oyster (Crassostrea gigas)
Provedor de dados: 5
Autores: Ernande, Bruno; Haure, Joel; Degremont, Lionel; Bedier, Edouard; Boudry, Pierre.
Phenotypic and genetic correlations between fitness-related life-history traits - such as survival, growth and reproductive allocation - have to be considered to better understand selective processes, both in the wild and in breeding programs. Quantitative genetic experiments, based on nested half-sib mating designs, were perfomed in the Pacific oyster C. gigas (1) to estimate genetic variance and the response to selection and (2) to document phenotypic and genetic trade-offs between life history traits. Physiological trade-offs, i.e. plastcity of resource allocation, were shown to vary among genotypes. Genetic polymorphism was primarily observed for the the plasticity of reproductive effort. In addition, the degree of plasticity in reproductive effort...
Tipo: Text
Palavras-chave: Genetic polymorphism; Genetic; Plasticity; Genetical basis; Crassostrea gigas; Pacific oysters.
Ano: 2002
URL: http://archimer.ifremer.fr/doc/2002/acte-3443.pdf

Differential Mortality and High Viral Load in Naive Pacific Oyster Families Exposed to OsHV-1 Suggests Tolerance Rather than Resistance to Infection
Provedor de dados: 5
Autores: Agnew, M. Victoria; Friedman, Carolyn S.; Langdon, Christopher; Divilov, Konstantin; Schoolfield, Blaine; Morga, Benjamin; Degremont, Lionel; Dhar, Arun K.; Kirkland, Peter; Dumbauld, Brett; Burge, Colleen A.
Pacific oysters, Crassostrea gigas, are one of the most productive aquaculture species in the world. However, they are threatened by the spread of Ostreid herpesvirus-1 (OsHV-1) and its microvariants (collectively “µvars”), which cause mass mortalities in all life stages of Pacific oysters globally. Breeding programs have been successful in reducing mortality due to OsHV-1 variants following viral outbreaks; however, an OsHV-1-resistant oyster line does not yet exist in the United States (US), and it is unknown how OsHV-1 µvars will affect US oyster populations compared to the current variant, which is similar to the OsHV-1 reference, found in Tomales Bay, CA. The goals of this study were to investigate the resistance of C. gigas juveniles produced by the...
Tipo: Text
Palavras-chave: OsHV-1; Mu vars; Oyster; Virus; Tolerance; Virulence; QPCR.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00665/77739/79862.pdf

Mortalités de moules bleues dans les secteurs mytilicoles : description et étude des facteurs liés, action –MORBLEU-2017
Provedor de dados: 5
Autores: Pepin, Jean-francois; Benabdelmouna, Abdellah; Bierne, Nicolas; Costes, Louis; Degremont, Lionel; Garcia, Celine; Guesdon, Stephane; Lamy, Jean-baptiste; Le Moine, Olivier; Morga, Benjamin; Normand, Julien; Robert, Stephane; Saunier, Alice; Soletchnik, Patrick; Travers, Marie-agnes.
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 et 2016 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 2017, les trois objectifs principaux étaient de : i) poursuivre la description du phénomène de mortalité ainsi que le contexte environnemental associé en effectuant une nouvelle campagne d’études et d’observations in situ, ii) tester des hypothèses...
Tipo: Text
Palavras-chave: Moules; Mytilus edulis; Mortalité; Statut cytogénétique; Anomalies génomiques; Populations; Facteurs environnementaux; Ecologie microbienne.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00503/61503/65337.pdf

Response to selection for increasing resistance to the spring mortality outbreaks in Mytilus edulis occurring in France since 2014
Provedor de dados: 5
Autores: Degremont, Lionel; Maurouard, Elise; Rabiller, Manuella; Glize, Philippe.
Massive spring mortality outbreaks have been reported in Mytilus spp. in France since 2014. The main areas affected are the Pertuis Charentais Sounds and the coast of the Pays de la Loire, which cultivate mainly M. edulis, and the putative causal agents remain unknown. We report the results of the first generation of mass selection focused on survival and resistance to the spring mortality in M. edulis. Two stocks of mussels were sampled in the Pertuis Charentais Sounds in 2014; one of these went through a spring mortality outbreak and the survivors were used to produce the selected stock, while the second stock was M. edulis considered to be naïve against the putative causal agents of the mortality outbreak and was used to produce the control stock. A...
Tipo: Text
Palavras-chave: Spring mortality; Survival; Mytilus edulis; Heritability; Selection.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00505/61619/65530.pdf

Is horizontal transmission of the Ostreid herpesvirus OsHV-1 in Crassostrea gigas affected by unselected or selected survival status in adults to juveniles?
Provedor de dados: 5
Autores: Degremont, Lionel; Guyader, Tanguy; Tourbiez, Delphine; Pepin, Jean-francois.
Massive mortality outbreaks, mostly affecting spat Crassostrea gigas, have been reported in France since 2008. Disease investigations revealed that most of the mortality events are related to the detection of the Ostreid herpesvirus 1 (OsHV-1 μVar). Meanwhile, selection to improve the survival in juvenile C. gigas has been successfully implemented in this context and selected oysters were found disease-resistant to OsHV-1 infection. This paper reports the first investigation of the horizontal transmission of the disease throughout cohabitation trials within batch and between batches using unselected and selected oysters for their higher survival. Two batches, unselected (AC) and selected (AR), were produced in February 2009 and deployed in the field in...
Tipo: Text
Palavras-chave: Crassostrea gigas; Disease resistance; Ostreid herpesvirus OsHV-1; Horizontal transmission; Pacific oyster.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00142/25310/23383.pdf

Ostreid herpesvirus 1 detection and relationship with Crassostrea gigas spat mortality in France between 1998 and 2006
Provedor de dados: 5
Autores: Garcia, Celine; Thebault, Anne; Degremont, Lionel; Arzul, Isabelle; Miossec, Laurence; Robert, Maeva; Chollet, Bruno; Francois, Cyrille; Joly, Jean-pierre; Ferrand, Sylvie; Kerdudou, Nolwenn; Renault, Tristan.
Since its molecular characterisation, Ostreid herpesvirus 1 (OsHV-1) has been regularly detected in Crassostrea gigas in France. Although its pathogenicity was demonstrated on larval stages, its involvement during mortality outbreaks at the juvenile stage was highly suspected but not evidenced. To investigate mortality outbreaks, the French National Network for Surveillance and Monitoring of Mollusc Health (REPAMO) carried out two surveys in juvenile C. gigas. The first survey lasted from 1998 to 2006 and was an epidemiological inquiry occurring when oyster farmers reported mortality outbreaks. The second survey, a longitudinal one, was set up in 1998 to complete the network observations on OsHV-1. Data analysis showed a specific pattern of mortality...
Tipo: Text
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00040/15110/12572.pdf

Apport d'un programme de génétique à une filière de production aquacole : l'exemple de l'ostréiculture
Provedor de dados: 5
Autores: Lapegue, Sylvie; Bedier, Edouard; Goyard, Emmanuel; Degremont, Lionel; Baud, Jean-pierre; Gerard, Andre; Goulletquer, Philippe; Boudry, Pierre.
Two oyster species are currently present along the French coasts : the indigenous European flat oyster (Ostrea edulis), and the Pacific cupped oyster (Crassostrea gigas), that has been introduced from Japan since the beginning of the 70ies. The flat oyster successively suffered from two protozoan diseases during the 60ies and its production decreased from 20 000 tons/year by that time to 1 500 tons/year nowadays. Consequently, the oyster production is principally (99%) based upon the Pacific oyster species with approximately 150 000 tons/year among which 90% are grown from the natural spat. However, the hatchery production of this species is developing and was estimated to 400 to 800 millions spat in 2002. Moreover, strengthened relationships between...
Tipo: Text
Palavras-chave: Growth; Selection; Genetic breeding; Genetic; Ostrea edulis; Crassostrea gigas; Oysters; Croissance; Sélection; Amélioration génétique; Génétique; Ostrea edulis; Crassostrea gigas; Huîtres.
Ano: 2004
URL: http://archimer.ifremer.fr/doc/2003/acte-3491.pdf

Double résistance aux infections dues aux organismes pathogènes Vibrio aestuarianus et OsHV-1 chez l’huître creuse Crassostrea gigas – DORE. Rapport scientifique final de l’étude DORE, convention DPMA-Ifremer 2016
Provedor de dados: 5
Autores: Degremont, Lionel; Maurouard, Elise; Godfrin, Yoann; Travers, Marie-agnes; Morga, Benjamin; Lamy, Jean-baptiste; Benabdelmouna, Abdellah.
Depuis 2012, le nombre de cas de mortalités d’huîtres creuses adultes (Crassostrea gigas) rapportés dans le cadre des réseaux de surveillance de l’Ifremer, et dans lesquels la bactérie Vibrio aestuarianus a été isolée, a fortement augmenté. Les objectifs de cette étude étaient (1) d’étudier la sensibilité des huîtres C. gigas à une infection à V. aestuarianus pour des lots diploïdes et triploïdes et (2) déterminer la réponse à la sélection pour une meilleure résistance à V. aestuarianus pour des huîtres C. gigas. Neuf stocks ont été utilisés, répartis en trois niveaux de sélection, chacun étant donc répliqué par trois pontes. Pour chaque stock, un lot diploïde (2n), un lot triploïde (3n_chim) produit par la rétention d’un globule polaire, et trois lots...
Tipo: Text
Palavras-chave: Vibrio aestuarianus; OsHV-1; Sélection; Résistance; Triploïdes; Huître creuse; Crassostrea gigas; Vibrio aestuarianus; OsHV-1; Selective breeding; Disease resistance Pacific oyster; Crassostrea gigas; Triploids.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00404/51530/52140.pdf

Characterisation of physiological and immunological differences between Pacific oysters (Crassostrea gigas) genetically selected for high or low survival to summer mortalities and fed different rations under controlled conditions
Provedor de dados: 5
Autores: Delaporte, Maryse; Soudant, P; Lambert, C; Jegaden, M; Moal, Jeanne; Pouvreau, Stephane; Degremont, Lionel; Boudry, Pierre; Samain, Jean-francois.
Within the framework of a national scientific program named "MORtalites ESTivales de l'huitre creuse Crassostrea gigas" (MOREST), a family-based experiment was developed to study the genetic basis of resistance to summer mortality in the Pacific oyster, Crassostrea gigas. As part of the MOREST project, the second generation of three resistant families and two susceptible families were chosen and pooled into two respective groups: "R" and "S". These two groups of oysters were conditioned for 6 months on two food levels (4% and 12% of oyster soft-tissue dry weight in algal dry weight per day) with a temperature gradient that mimicked the Marennes-Oleron natural cycle during the oyster reproductive period. Oyster mortality remained low for the first two...
Tipo: Text
Palavras-chave: Summer mortality; Reproduction; Reactive oxygen species ROS; Hemocyte parameters; Genetic selection; Crassostrea gigas.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3578.pdf

Several strains, one disease: experimental investigation of Vibrio aestuarianus infection parameters in the Pacific oyster, Crassostrea gigas
Provedor de dados: 5
Autores: Travers, Marie-agnes; Tourbiez, Delphine; Parizadeh, Leila; Haffner, Philippe; Kozic-djellouli, Angelique; Aboubaker, Mohamed; Koken, Marcel; Degremont, Lionel; Lupo, Coralie.
This study investigated oyster infection dynamics by different strains of Vibrio aestuarianus isolated before and after the apparent re-emergence of this pathogen observed in France in 2011. We conducted experiments to compare minimal infective dose, lethal dose 50 and bacterial shedding for six V. aestuarianus strains. Whatever the strain used, mortality was induced in juvenile oysters by intramuscular injection and reached 90–100% of mortality within 5 days. Moreover, bacterial shedding was comparable among strains and reached its maximum after 20 h (≈10 EXP5 bacteria/mL/animal). Similarly, our first estimations of lethal dose 50 were comparable among strains (minimal infective dose around 0.4 × 10EXP5 bacteria/mL and LD50 around 10EXP5 bacteria/mL) by...
Tipo: Text
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00386/49768/50308.pdf

Genetic variation and trade-offs for reproduction ans survival in the Pacific oyster Crassostrea gigas
Provedor de dados: 5
Autores: 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

Mortalités massives de l'huître creuse - Rapport final du programme de recherche sur l'étude de la cinétique de détection d'agents infectieux associés à des épisodes de mortalités de naissains d'huîtres creuses Crassostrea gigas sur un site ostréicole de Marennes-Oléron (CIDAGINF 2009-2010)
Provedor de dados: 5
Autores: Saulnier, Denis; Pepin, Jean-francois; Guesdon, Stephane; Degremont, Lionel; Faury, Nicole; Haffner, Philippe; Renault, Tristan; Travers, Marie-agnes; Tourbiez, Delphine; Geairon, Philippe; Le Moine, Olivier; Seugnet, Jean-luc; Soletchnik, Patrick.
This study aims to improve understanding of causes of mortalities in oyster Crassostrea gigas in pertuis charentais related to environmental parameters and the kinetics of targeted infectious agents, such as bacteria Vibrio splendidus (group ) and V. aestuarianus and Ostreid herpesvirus OsHV-1. Two sampling campaigns were carried out on the site of Agnas in 2009 and 2010, before, during or following mortality events of spat from March to September. The approach is to detect and quantify in short time step infectious agents from tissues of farmed oysters placed on rack and in various samples taken nearby: native oysters and other species (wild mussels and barnacles), seawater and sediment. With physical and chemical automatic probes placed on the site,...
Tipo: Text
Palavras-chave: Huître creuse; Crassostrea gigas; Mortalité; Virus herpès; Vibrions; Environnement; Pertuis Charentais; Pacific oyster; Crassostrea gigas; Mortality; Herpes virus; Vibrios; Environment; Pertuis Charentais.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00058/16920/14400.pdf

Factors other than metalloprotease are required for full virulence of French Vibrio tubiashii isolates in oyster larvae
Provedor de dados: 5
Autores: Mersni-achour, Rachida; Ben Cheikh, Yosra; Pichereau, Vianney; Doghri, Ibtissem; Etien, Cedric; Degremont, Lionel; Saulnier, Denis; Fruitier-arnaudin, Ingrid; Travers, Marie-agnes.
Vibrio tubiashii is a marine pathogen isolated from larval and juvenile bivalve molluscs causing bacillary necrosis. Recent studies demonstrated the isolation of this species in a French experimental hatchery/nursery affecting Crassostrea gigas spat in 2007. Here, using larvae of C. gigas as an interaction model, we showed that the French V. tubiashii is virulent to larvae and can cause bacillary necrosis symptoms with a LD50 about 2.3 × 103 cfu ml-1 after 24 h. Moreover, complete or GP- HPLC fractionated extracellular products (ECPs) of this strain appeared toxic to larvae. MS-MS analysis of the different ECPs fractions revealed the existence of an extracellular metalloprotease and other suspected virulence factors. This observation is also supported by...
Tipo: Text
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00252/36367/34907.pdf

The identification of genes from the oyster Crassostrea gigas that are differentially expressed in progeny exhibiting opposed susceptibility to summer mortality
Provedor de dados: 5
Autores: Huvet, Arnaud; Herpin, Amaury; Degremont, Lionel; Labreuche, Yannick; Samain, Jean-francois; Cunningham, Charles.
Summer mortality associated with juveniles of the oyster Crassostrea gigas is probably the result of a complex interaction between the host, pathogens and environmental factors. Genetic variability in the host appears to be a major determinant in its sensitivity to summer mortality. Previously, divergent selection criteria based on summer survival have been applied to produce oyster families with resistant and susceptible progeny. In this paper, we describe the use of suppression subtractive hybridization to generate 150 C gigas clones that were differentially regulated between resistant and susceptible F2 progeny. The nucleotide sequence of these clones was determined. In 28%, the inferred amino sequence was found to match the products of known genes, 14%...
Tipo: Text
Palavras-chave: Suppression subtractive hybridization; Oysters; Differentially regulated genes; Bivalves; Bacterial challenge.
Ano: 2004
URL: http://archimer.ifremer.fr/doc/2004/publication-651.pdf

Evidence of herpesvirus (OsHV-1) resistance in juvenile Crassostrea gigas selected for high resistance to the summer mortality phenomenon
Provedor de dados: 5
Autores: Degremont, Lionel.
During the MOREST project (2001–2006), oyster summer mortality was extensively investigated in Crassostrea gigas in France. However, significant increases in magnitude and geographic distribution of summer mortality episodes have been reported since 2008. This paper investigates the response to selection for survival, which was successfully performed between 2001 and 2003, in this new context. It also examines the relationship between the mortality and the three pathogens Vibrio aestuarianus, V. splendidus and the Ostreid herpesvirus 1 (OsHV-1). Three batches of juvenile (6-month-old) Crassostrea gigas were produced in February 2009 and tested in the field in the Marennes-Oléron Bay during summer (August and September) 2009: one control batch, one batch...
Tipo: Text
Palavras-chave: Summer mortality; Crassostrea gigas; Disease resistance; Ostreid herpesvirus; Vibrio sp; Oyster.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00033/14472/11770.pdf

Differential basal expression of immune genes confers Crassostrea gigas resistance to Pacific Oyster Mortality Syndrome
Provedor de dados: 5
Autores: De Lorgeril, Julien; Petton, Bruno; Lucasson, Aude; Perez, Valérie; Stenger, Pierre-louis; Degremont, Lionel; Montagnani, Caroline; Escoubas, Jean Michel; Haffner, Philippe; Allienne, Jean-françois; Leroy, Marc; Lagarde, Franck; Vidal Dupiol, Jeremie; Gueguen, Yannick; Mitta, Guillaume.
Background: As a major threat to the oyster industry, Pacific Oyster Mortality Syndrome (POMS) is a polymicrobial disease affecting the main oyster species farmed across the world. POMS affects oyster juveniles and became panzootic this last decade, but POMS resistance in some oyster genotypes has emerged. While we know some genetic loci associated with resistance, the underlying mechanisms remained uncharacterized. So, we developed a comparative transcriptomic approach using basal gene expression profiles between different oyster biparental families with contrasted phenotypes when confronted to POMS (resistant or susceptible). Results: We showed that POMS resistant oysters show differential expression of genes involved in stress responses, protein...
Tipo: Text
Palavras-chave: Pacific oyster; Oyster disease; Resistance; OsHV-1; Antiviral molecular pathways; Invertebrate immunity.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00602/71369/69811.pdf

Relative importance of family, site, and field placement timing on survival, growth, and yield of hatchery-produced Pacific oyster spat (Crassostrea gigas)
Provedor de dados: 5
Autores: 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

Analysis of genome-wide differentiation between native and introduced populations of the cupped oysters Crassostrea gigas and Crassostrea angulata
Provedor de dados: 5
Autores: 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

Etude de faisabilité d’opérations de ‘repeuplement orienté’ dans deux sites français de captage de l’huître creuse (Crassostrea gigas)
Provedor de dados: 5
Autores: 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
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00083/19410/17013.pdf

Evaluation of the gonad volume throughout magnetic resonance imaging in Crassostrea gigas and comparison with the histological method
Provedor de dados: 5
Autores: 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

Mortalités massives de l’Huître creuse: causes et perspectives
Provedor de dados: 5
Autores: 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
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00043/15404/12764.pdf

Genetic polymorphism of glutamine synthetase and delta-9 desaturase in families of Pacific oyster Crassostrea gigas and susceptibility to summer mortality
Provedor de dados: 5
Autores: 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

Mortality investigation of Mytilus edulis and Mytilus galloprovincialis in France: An experimental survey under laboratory conditions
Provedor de dados: 5
Autores: Benabdelmouna, Abdellah; Garcia, Celine; Ledu, Christophe; Lamy, Pierre; Maurouard, Elise; Degremont, Lionel.
In the context of mass mortality outbreaks affecting adult and juvenile mussels since 2014 in France, two investigations were conducted to study mussel mortality under laboratory conditions in 2015. The first investigated the horizontal transmission of a putative causal agent of the mortality among two stocks of wild Mytilus edulis and the potential genetic resistance of adults and their progenies. The second evaluated the resistance of pure and hybrid crosses of M. edulis and M. galloprovincialis at the spat stage to a mortality outbreak. For the first time in France, we described several mortality outbreaks affecting spat and adult mussels under laboratory conditions. Mortality was observed for seawater temperatures ranging from 10 to 23 °C, although the...
Tipo: Text
Palavras-chave: Mytilus edulis; Mytilus galloprovincialis; Interspecific hybrids; Mortality outbreaks.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00445/55696/57364.pdf

Breeding and Domestication of Eastern Oyster (  Crassostrea virginica  ) Lines for Culture in the Mid-Atlantic, Usa: Line Development and Mass Selection for Disease Resistance
Provedor de dados: 5
Autores: Frank-lawale, Anu; Allen, Standish K.; Degremont, Lionel.
A selective breeding program for Crassostrea virginica was established in 1997 as part of an initiative in Virginia to address declining oyster harvests caused by the two oyster pathogens Haplosporidium nelsoni (MSX) and Perkinsus marinus (Dermo). Housed in the Aquaculture Genetics and Breeding Technology Center (ABC), the objective of the program was to develop and disseminate disease-resistant lines that would enable an oyster culture industry. Today, culture of disease-resistant cultivars accounts formore than 90%of oyster production in the state, where 28.1 million half-shell oysters and 2 billion eyed larvae were sold in 2012. Results of our line development program as of 2006 are reported. Eight ABC lines from 3 genetic groups—East Coast (EC),...
Tipo: Text
Palavras-chave: Crassostrea gigas; Oysters; Selective breeding; Disease resistance; Chesapeake Bay; Growth; Genetic improvement; MSX; Dermo.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00188/29950/28395.pdf

Mass selection for survival and resistance to OsHV-1 infection in Crassostrea gigas spat in field conditions: response to selection after four generations
Provedor de dados: 5
Autores: 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

Size and genotype affect resistance to mortality caused by OsHV-1 in Crassostrea gigas
Provedor de dados: 5
Autores: 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

Nutrition and reproduction are key parameters in the interaction process leading to Crassostrea gigas oyster summer mortality in France
Provedor de dados: 5
Autores: 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

Molecular identification and expression of the phosphoglucomutase (PGM) gene from the Pacific oyster Crassostrea gigas
Provedor de dados: 5
Autores: 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

Etude de la CINétique et DIffusion de la MORtalité (CINDIMOR) chez les juvéniles de l'huître creuse Crassostrea gigas
Provedor de dados: 5
Autores: 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

Plan de sauvegarde 2012, 3ème édition : synthèse des résultats 2012-2013
Provedor de dados: 5
Autores: 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
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00229/34041/32448.pdf

Summer mortality of hatchery-produced Pacific oyster spat (Crassostrea gigas). I. Estimation of genetic parameters for survival and growth
Provedor de dados: 5
Autores: 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

Genetic parameters of resistance to Vibrio aestuarianus, and OsHV-1 infections in the Pacific oyster, Crassostrea gigas, at three different life stages
Provedor de dados: 5
Autores: 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
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00372/48350/48518.pdf

First comparison of French and Australian OsHV-1 mu vars by bath exposure
Provedor de dados: 5
Autores: 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

Signature d'expression de gènes, Marqueur prédictif de capacités de survie chez l'huître Crassostrea gigas
Provedor de dados: 5
Autores: Bachere, Evelyne; Degremont, Lionel; Piquemal, David; Roman, Bruno; Noguier, Florian.
Dans le contexte des mortalités massives d'huîtres Crassostrea gigas, les mécanismes moléculaires et les bases génétiques impliquées dans la capacité de survie des huîtres ont été explorées par des approches de génomique à très haut débit. Ces travaux se sont centrés dans un premier temps sur la survie à des infections par des Vibrio virulents pour lesquels des infections expérimentales étaient reproductibles et standardisées en laboratoire. Ces analyses ont conduit à la mise en évidence d'une série de gènes dont l’expression peut prédire la capacité des huîtres à survivre aux infections à vibrios (Rosa et al. 2012). Depuis 2013, les travaux ont permis la validation de la signature de survie qui a pu être corrélée avec les capacités de survie des huîtres...
Tipo: Text
Palavras-chave: Huître creuse; Signature d'expression de gènes; QPCR; Biostatistique; Capacité de survie; Phénotypage; Héritabilité; Pacific oyster; Gene expression signature; QPCR; Biostatistics; Survival capacity; Phenotyping; Heritability.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00434/54551/55925.pdf

Mortalités de moules bleues dans les secteurs mytilicoles : description et étude des facteurs liés, action – MORBLEU-2018
Provedor de dados: 5
Autores: 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
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00588/70056/67999.pdf

Genetic improvement for disease resistance in oysters: a review
Provedor de dados: 5
Autores: 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

Mortalités de moules bleues dans les secteurs mytilicoles charentais et vendéens : description et facteurs liés – MORBLEU
Provedor de dados: 5
Autores: Pepin, Jean-francois; Benabdelmouna, Abdellah; Degremont, Lionel; Guesdon, Stephane; Le Moine, Olivier; Morga, Benjamin; Bierne, Nicolas; Travers, Marie-agnes; Robert, Stephane; Soletchnik, Patrick.
Depuis 2014, des épisodes de mortalité anormale affectent les cheptels mytilicoles tant adultes que juvéniles. Dès l’année 2015, une première année d’étude a été réalisée au travers de l’action MORBLEU (Mortalité des moules Bleues). Elle a été menée dans les Pertuis charentais et la baie de Bourgneuf. Dans ce même contexte, elle a été reconduite en 2016 afin de poursuivre l’analyse des données collectées en 2015, renouveler une campagne d’étude et d’observation in situ, formuler des hypothèses autour de facteurs favorisants ces épisodes de mortalité de moules, développer des essais permettant de tester ces hypothèses dans le futur et produire des lots de moules pour ces essais et pour caractériser le potentiel adaptatif des animaux face aux épisodes de...
Tipo: Text
Palavras-chave: Moules; Mytilus edulis; Facteurs environnementaux; Mortalité; Equilibre microbien; Populations; Qualité cytogénétique; Anomalies hémocytaires; Expression de gènes; Physiologie.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00391/50288/50978.pdf

Procédures d'échantillonnage pour la conservation des espèces aquacoles dans la Cryobanque Nationale
Provedor de dados: 5
Autores: Vandeputte, Marc; Labbe, Catherine; Suquet, Marc; Fauvel, Christian; Goardon, Lionel; Duclos, Delphine; Danchin-burge, Coralie; Vergnet, Alain; Rault, Paul; Degremont, Lionel; Benabdelmouna, Abdellah; Brizard, Raphael; Haffray, Pierrick.
Tipo: Text
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00098/20975/18597.pdf

Response to divergent selection for resistance to summer mortality in Pacific oyster spat : genetic parameters and correlated responses with subsequent survival and growth
Provedor de dados: 5
Autores: Boudry, Pierre; Bedier, Edouard; Ernande, Bruno; Degremont, Lionel.
The multidisciplinary program "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 part of this program, four successive generations of families were bred between 2001 and 2005 in our research hatchery in La Tremblade. Survival and growth were recorded in the field in three sites along the French coast (Ronce, Rivière d'Auray and Baie des Veys). The first generation (44 full-sib families nested within 17 half-sib families) was tested during summer 2001 to assess to what extent genetic variability exists for spat survival.  An important genetic basis was found (estimated narrow-sense heritability among sites = 0.83 ± 0.40). In contrast, lower...
Tipo: Text
Palavras-chave: Survival; Growth; Genetic parameters; Summer mortality; Selection; Genetic; Crassostrea gigas; Pacific oysters.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/acte-3458.pdf

Les pratiques culturales peuvent-elles permettre de réduire la surmortalité du naissain d'huîtres creuses? Récapitulatif des essais d'élevage et expérimentations zootechniques menés sur le territoire français entre 2008 et 2010
Provedor de dados: 5
Autores: Soletchnik, Patrick; Mazurie, Joseph; Allain, Gwenhael; Bedier, Edouard; Benabdelmouna, Abdellah; Blin, Jean-louis; Bouquet, Anne-lise; Cochet, Hélène; Degremont, Lionel; Gaussem, Florian; Gervasoni, Erika; Glize, Philippe; Petton, Bruno; Roussel, Pierre-yves; Pernet, Fabrice.
This paper summarizes knowledge about relations between husbandry practices and oyster spat mortalities since 2008 in France. These relations are strictly analyzed from a panel of experiments set on the shore (in outdoor experiments) by Ifremer teams and technical institutes all over French coasts. Results show some practices are able to reduce spat mortality with some influencing factors relevant of spat quality (sanitary status, natural or genetic selection) or husbandry practices. Spat “free” of virus is able to survive up to 90% when it is isolated and confined in ponds or nursery, during an epidemic crisis. When outbreaks occurred in oyster beds, natural or nursery spat died in almost same proportions. In 2010, some studies conducted in Mediterranean...
Tipo: Text
Palavras-chave: Surmortalité; Naissain; Huître creuse; OsHV-1; Pratiques culturales; Mortality; Spat; Cupped oyster; Crassostrea gigas; OsHV-1; Cultural practices.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00032/14280/25847.pdf

Caractérisation sur estran et en laboratoire des 3 séries produites en troisième génération : G3SD - G3C1 - G3C2
Provedor de dados: 5
Autores: Degremont, Lionel; Fortin, Adeline; Boudry, Pierre.
Dans le cadre du programme MOREST, une première génération d'huître creuse Crassostrea gigas (G1) a été réalisée en 2001 à partir d'un plan de croisement hiérarchisé par les mâles. La caractérisation sur estran de 44 familles de plein-frères réparties en 17 familles de demi-frères a permis d'estimer l'héritabilité de la survie des naissains en période estivale. La valeur obtenue (h2 = 0,81 ± 0,29) indique que la majorité de la variance phénotypique est d'origine génétique. A partir de familles G1 sélectionnées pour les performances de survies, une sélection divergente visant à améliorer ou diminuer la survie du naissain en période estivale a été réalisée en 2002 et constitue la seconde génération (G2). La sélection divergente comprend deux séries de...
Tipo: Text
Palavras-chave: Huître creuse; Crassostrea gigas; Génétique; Sélection; Estran.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/00035/14668/11970.pdf