|
|
|
| Registros recuperados: 85 | |
|
|
| 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 |
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
|
| |
|
|
| 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 |
| |
|
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
|
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
|
|
| Degremont, Lionel; Bedier, Edouard; Soletchnik, Patrick; Ropert, Michel; Samain, Jean-francois; Boudry, Pierre. |
| The French project "Morest", coordinated by IFREMER, aims to a better understanding of the causes of summer mortalities in juvenile oysters by a multidisciplinary approach. Within this program, a first generation (G1) was bred in 2001 to assess to what extent genetic variability exists for this trait in French populations. 17 half-sib families (HSF) including 44 full-sib families (FSF) were obtained in the G1, and each FSF was reared in three sites along the French coast during the summer period. Significant differences in survival were observed among HSF, clearly indicating a genetic basis for survival. Estimation of heritability for survival was very high: 0.81  0.29. In 2002, 3 "good" HSF and 3 "bad" HSF were selected on their survival... |
| Tipo: Text |
Palavras-chave: Selection; Genetic; Mortalities; Crassostrea gigas; Oyster. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/acte-3439.pdf |
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
| Registros recuperados: 85 | |
|
|
|
