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| Registros recuperados: 41 | |
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| Normand, Julien; Huvet, Arnaud; Fabioux, Caroline; Raguenes, Morgane; Boudry, Pierre. |
| Genetic improvement of the Pacific oyster, Crassostrea gigas, can be achieved through triploidisation, which leads to partially sterility, allowing higher growth and survival together with improved meat quality during the reproductive period. Most triploids are not fully sterile and the genetic and environmental factors involved in their partial fertility remained to be investigated. We examined gametogenesis by image analysis of histological cross sections in diploid (2n) and triploid oysters obtained either by crossing tetraploids and diploid broodstock (« natural » triploids: 3nn) or from second polar body retention (« chemical » triploids: 3nc). 5-month old triploid spat reared in a standard intensive nursery system only showed a reduction of 50% of... |
| Tipo: Text |
Palavras-chave: Gametogenesis; Triploid; Crassostrea gigas; Genetic; Oysters. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/acte-3327.pdf |
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| Normand, Julien; Ernande, Bruno; Haure, Joel; Mccombie, Helen; Boudry, Pierre. |
| Early reproductive effort and growth were measured in 3 groups of the Pacific oyster Crassostrea gigas: 1 diploid group and 2 triploid groups resulting from either chemical induction (3nCB) or crosses between tetraploid and diploid parents (3nDT). Oysters were reared under intensive nursery conditions and sampled when 5 mo old. Reproductive effort was estimated by cross-sectional area measurements of the visceral mass (i.e. gonadic occupation) and maturation stage was assessed by qualitative histology. As expected, comparison of the reproductive patterns of these 3 groups revealed a lower reproductive effort in triploid individuals relative to diploid. However, gonadic occupation in triploid oysters was higher than expected in both 3nCB and 3nDT groups, as... |
| Tipo: Text |
Palavras-chave: Triploidy; Oyster; Gametogenesis; Crassostrea gigas. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6978.pdf |
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| Enriquez-diaz, M.; Pouvreau, Stephane; Chavez-villalba, J.; Le Pennec, M.. |
| The progress of gametogenesis was studied in oysters Crassostrea gigas having the same origin (Tremblade), but cultured during 1 year in two distinctive French marine areas, the Baie des Veys and Marennes-Ol,ron. We assessed seasonal changes in the reproduction cycle on the basis of stereological techniques to estimate reproductive investment and measurement of gonad evolution area by quantitative histology. From a qualitative point of view, both oyster groups presented typical reproductive stages, but showed differential timing, in particular during the sequence of spawning and duration of the re-absorption stage. Oysters in Baie des Veys had a single partial spawning in August and a re-absorption stage that extended until winter. Oysters in... |
| Tipo: Text |
Palavras-chave: Stereology; Reproductive investment; Pacific oysters; Image analysis; Gametogenesis; Crassostrea gigas. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-7300.pdf |
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| Fauvel, Christian; Suquet, Marc; Severe, Armelle; Mylonas, Constantinos C.; Papandroulakis, Nikos. |
| The potential of wreckfish (Polyprion americanus) to breed in captivity was examined. Ovarian activity varied seasonally, with vitellogenesis beginning in November and ending in May. Slow-release implant with gonadotropin-releasing hormone agonist (GnRHa) prevented atresia, and both GnRHa injections or implants at the end of vitellogenesis triggered ovulation after 7 days. Spontaneous spawning was obtained only in one female, and the few eggs produced were of poor viability. Manual stripping and artificial fertilization produced viable gametes and embryos. Therefore, present captivity conditions inhibited final oocyte maturation (FOM) and spawning, but not vitellogenesis and spermatogenesis. GnRHa treatments stimulate FOM and ovulation of viable eggs. |
| Tipo: Text |
Palavras-chave: Aquaculture; Polyprion americanus; Wreckfish; GnRHa; Gametogenesis. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-6554.pdf |
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| Normand, Julien; Le Pennec, Marcel; Boudry, Pierre. |
| We compared the temporal dynamics of gametogenesis in diploid and triploid Pacific oysters (Crassostrea gigas) using histology. Oysters were reared in an estuarine farming site in Brittany over 3 years and their gametogenesis was monitored over the exceptionally hot summer of 2003. Both diploids and triploids showed active gametogenesis, but a high proportion of triploids remained at early stages of gonad development. Gametogenesis of triploids was characterized by the simultaneous occurrence of gonias and immature cytes together with mature gametes rather than overall retardation, though some triploids showed complete gonad maturation. Evidence of spawning was seen in both groups, and the quantity of germinal products emitted appeared to be similar in... |
| Tipo: Text |
Palavras-chave: Triploidy; Crassostrea gigas; Oyster; Gametogenesis. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4152.pdf |
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| Fabioux, Caroline; Pouvreau, Stephane; Leroux, Frederique; Huvet, Arnaud. |
| The vasa gene is,a key determinant for germline formation in eukaryotes. This gene, highly conserved through evolution, encodes a RNA helicase protein member of the DEAD-box family. To understand the germline formation in oyster, we report here the isolation and the characterization of a vasa orthologue in Crassostrea gigas (Oyvlg). OyVLG contained the eight consensus domains of the DEAD-box including those providing RNA unwinding activity. The expression pattern of Oyvlg was examined in adult oyster tissues at different reproductive stages. Its expression was restricted to germline cells both in males and females, including germinal stem cells and auxiliary cells. The expression of Oyvlg, strongest in early germ cells, decreased as the maturation... |
| Tipo: Text |
Palavras-chave: RNA helicase; DEAD box; Vasa; Germline; Gametogenesis; Oyster. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-646.pdf |
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| Roberts Jr, D. |
| Circannual, diel, and lunal periodic mechanisms in naturally reproducing stocks of tropical and subtropical fishes are reviewed. Manipulations of biological clocks, used to control reproduction in captive broodstocks, are detailed. Experiments to induce controlled maturation and spawning in fishes either test efficacy of changing environmental conditions (regimes), or constant environmental conditions (controlled). Data have been generated in experimental/scientific studies, as well as applied research. Effects of controlled environmental regimes on serum steroids, gametogenesis, spawning, fry performance and egg quality are summarized for selected members of Centropomidae, Serranidae, and Sciaenidae. |
| Tipo: Text |
Palavras-chave: Sciaenidae; Serranidae; Centropomidae; Fish culture; Controlled conditions; Sexual maturity; Photoperiods; Fish eggs; Gametogenesis; Steroids; Animal reproductive organs; Brood stocks; Marine fish; Spawning; Sexual reproduction. |
| Ano: 1989 |
URL: http://archimer.ifremer.fr/doc/1989/acte-1437.pdf |
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| Pouvreau, Stephane; Gangnery, Aline; Tiapari, Jerome; Lagarde, Franck; Garnier, Matthieu; Bodoy, Alain. |
| The gametogenic cycle and the reproductive effort of the blacklip pearl oyster, Pinctada margaritifera, cultivated in Takapoto lagoon were studied for a 1-year period (March 1997-April 1998) by bimonthly observations of gonadal sections, dry tissue weights and gonadal index in a population of pearl oyster composed of three age-groups. pearl oysters attained sexual maturity in the end of their first year (height approximate to 40 mm), implying that P. margaritifera is a late-maturing species in comparison with other Pteriidae. This species was also confirmed to be a marked protandrous successive hermaphrodite in culture, with 100 % of males at first maturity and 75 % in older pearl oyster (height > 120 mm). The general pattern of gametogenic activity,... |
| Tipo: Text |
Palavras-chave: French Polynesia; Reproductive effort; Reproductive cycle; Tropical aquaculture; Gametogenesis; Blacklip pearl oyster; Polynésie française; Effort de reproduction; Cycle de reproduction; Aquaculture tropicale; Gamétogenèse; Huître perlière. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-1391.pdf |
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| Gonzales, Ricardo; Quillien, Virgile; Robert, Rene. |
| To determine the effects of food quality on Ostrea edulis reproduction, European flat oysters were conditioned during two sets of experiments, carried out in spring and autumn, during 40 days at 19 degrees C, in 50 l transparent flow-through tanks, in triplicate, and fed constantly at 900 mu m(3) mu l(-1), with eight different types of microalgae. Four species were fed per group of trials: Isochrysis affinis galbana, Chaetoceros gracilis, Skeletonema marinoi, and Tetraselmis suecica were fed to flat oysters in the first set; whereas Rhodomonas salina, Thalassiosira weissflogii, Thalassiosira pseudonana, and Pavlova lutheri were provided during the second set of experiments. At the beginning and end of both conditioning periods, oysters were sampled and... |
| Tipo: Text |
Palavras-chave: Ostrea edulis; Broodstock conditioning; Gametogenesis; Microalgal diets. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00144/25497/24163.pdf |
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| Bourles, Yves. |
| The Pacific oyster (Crassostrea gigas) is a major cultivated shellfish resource in France, which represented a tumover of 220 millions € in 2000. Mass mortalities among this commercially important bivalve species are known in France since about 40 years, but have become a recun'ing obstacle for growers of oysters and a threaten for commercial production along the French Atlantic coast in the last 20 years. Since 2000, IFREMER is canying out a multidisciplinary program, MOREST, ta understand the problem of summer mortality, and possibly ta solve il. As part of the MOREST program, the present study focuses on the relationship between gametogenesis, metabo lism and mortality of 7-month, i.e. juvenil e, C. gigas. In April 2004, a total of 2250 oysters were... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Naissain; Mortalité estivale; Gamétogenèse; Bilan énergétique; Crassostrea gigas; Spot; Summer mortalities; Gametogenesis; Energy budget. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/00448/55961/57444.pdf |
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| Le Moullac, Gilles; Hui, Belinda; Vonau, Vincent; Levy, Peva; Cochard, Jean-claude. |
| Preliminary experiments allowed defining basic requirements of Pinctada margaritifera for somatic and gonadic growth in controlled conditions. This study was continued by observation of the gametogenesis at a cellular level. In April/May 2008, 125 oysters were conditioned for 30 days in 25 tubular tanks (30 L). Water was renewed 4 times/hour. A mixed (v:v) diet of Isochrysis galbana (T-Iso) and Chaetoceros gracilis was supplied continuously. A control batch of 125 oysters was maintained in trays in the lagoon. An initial sample of 30 individuals was made. Gonadic changes were first characterized using a gonadal development index (GDI) based on the ratio of the gonad area to the total visceral mass area on a sagittal section of the body. Histological... |
| Tipo: Text |
Palavras-chave: Pearl oyster; Reproduction; Gametogenesis; Broodstock. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00029/14010/11196.pdf |
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| Guevelou, Eric; Huvet, Arnaud; Galindo-sanchez, Clara E.; Milan, Massimo; Quillien, Virgile; Daniel, Jean-yves; Quere, Claudie; Boudry, Pierre; Corporeau, Charlotte. |
| The hermaphrodite Pacific oyster Crassostrea gigas displays a high energy allocation to reproduction. We studied the expression of AMP-activated protein kinase (AMPK) during gametogenesis in the gonad and characterized the mRNA sequences of the AMPK subunits: the AMPK alpha mRNA sequence was previously characterized; we identified AMPK beta, AMPK gamma, and mRNAs of putative AMPK-related targets following bioinformatics mining on existing genomic resources. We analyzed the mRNA expression of the AMPK alpha, beta, and gamma subunits in the gonads of male and female oysters through a reproductive cycle, and we quantified the mRNA expression of genes belonging to fatty acid and glucose metabolism. AMPK alpha mRNA levels were more abundant in males at the... |
| Tipo: Text |
Palavras-chave: AMP-activated protein kinase; Crassostrea gigas; Gametogenesis; Marine bivalve; Reproduction. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00168/27911/26470.pdf |
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| Jorge Eduardo, Chávez Villalba. |
| In France, 90% of the annual cup oyster (Crassostrea gigas) production comes from larvae caught in the Arcachon and Marennes-Oléron basins. However, the spat catch shows many interannual irregularities and oyster farmers increasingly say they need spat outside of the reproductive period. Thus, the role of hatcheries in Japanese oyster spat production in France is becoming increasingly evident. However, the current state of knowledge about cup oyster reproduction in controlled conditions is limited, and hatchery professionals must confront various problems to optimise treatment of genitors so as to obtain larval breeds in good health and a lengthening of the reproductive season. To respond to this, we have carried out a study on three aspects that seem... |
| Tipo: Text |
Palavras-chave: Water temperature; Biochemical studies; Gametogenesis; Breeder conditioning; Larval rearing. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/these-1456.pdf |
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| Le Moullac, Gilles; Soyez, Claude; Sham-koua, Manaarii; Levy, Peva; Moriceau, Jacques; Vonau, Vincent; Maihota, Mayalen; Cochard, Jean-claude. |
| This study aimed to model the food intake of P. margaritifera in order to examine the relationship between food level and reproductive activity. The effect of microalgae concentration on ingestion rate and assimilation efficiency was studied over a broad concentration range, using a mixture of Isochrysis galbana and Chaetoceros gracilis. Reproductive effort was assessed using three microalgae concentrations of 0.5, 7 and 18 cell μL-1. Reproductive status was assessed by gonad development index (GDI) – the ratio of the gonad surface to the visceral mass surface – and histological analysis of the gonad based on the presence (continuous or discontinuous) or the absence of gonial cells (GC). Ingestion is a saturating function of seston concentration for... |
| Tipo: Text |
Palavras-chave: Pinctada margaritifera; Food level; Ingestion rate; Reproduction; Gametogenesis. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00050/16085/13562.pdf |
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| Mcfarland, Katherine; Soudant, Philippe; Jean, Frederic; Volety, Aswani K.. |
| Understanding the population dynamics of invasive species, such as the green mussel Perna viridis (Linnaeus, 1758), can aid in explaining the success of newly introduced populations and help predict the potential for spread. During a two-year field study of established populations in the invaded region of southwest Florida, year round gametogenesis and continuous spawning capabilities were observed through histological analysis of mussels collected monthly. This was supported by overall stable energetic reserves as measured through proximal biochemical composition (protein, glycogen and lipid content). However, egg outputs in the summer (6.4 x 10(6) +/- 2.6 x 10(6) eggs / female) were significantly higher than egg outputs of winter-spawned mussels (7.7 x... |
| Tipo: Text |
Palavras-chave: Gametogenesis; Protein; Glycogen; Lipid; Induced spawning. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00616/72842/72974.pdf |
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| Huvet, Arnaud; Beguel, Jean-philippe; Pereira Cavaleiro, Nathalia; Thomas, Yoann; Quillien, Virgile; Boudry, Pierre; Alunno-bruscia, Marianne; Fabioux, Caroline. |
| Feeding strategies and digestive capacities can have important implications for variation in energetic pathways associated with ecological and economically important traits, such as growth or reproduction in bivalve species. Here, we investigated the role of amylase in the digestive processes of Crassostrea gigas, using in vivo RNA interference. This approach also allowed us to investigate the relationship between energy intake by feeding and gametogenesis in oysters. Double-stranded (ds)RNA designed to target the two α-amylase genes A and B was injected in vivo into the visceral mass of oysters at two doses. These treatments caused significant reductions in mean mRNA levels of the amylase genes: −50.7% and −59% mRNA A, and −71.9% and −70.6% mRNA B in 15... |
| Tipo: Text |
Palavras-chave: Alpha-Amylase; DsRNA; Gametogenesis; Marine bivalve; Dynamic energy budget. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00271/38239/36422.pdf |
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| Normand, Julien; Ernande, Bruno; Boudry, Pierre. |
| Today, triploidy is the most common method used to genetically improve marine bivalve aquaculture production. In the Pacific oyster Crassostrea gigas, triploidy affects many traits. The most proeminent one is reproductive effort, which is greatly reduced compared to diploids. The combined effects of physiological trade-offs between survival, growth and reproduction together with the reduction of reproductive effort in triploids explains the global enhancement of yield observed. However, the sterility of triploid oysters is only partial and some triploid individuals can show normal gametogenesis (i.e. similar to diploids), especially under warm conditions. In diploid oysters, the heritability of reproductive effort has been shown to be relatively low, but a... |
| Tipo: Text |
Palavras-chave: Parentage analysis; Triploidy; Oyster; Quantitative genetics; Gametogenesis. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/acte-4525.pdf |
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| Registros recuperados: 41 | |
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