The Experts below are selected from a list of 1524 Experts worldwide ranked by ideXlab platform
Yves Guéguen - One of the best experts on this subject based on the ideXlab platform.
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Response of the pearl oyster Pinctada margaritifera to cadmium and chromium: Identification of molecular biomarkers
Marine Pollution Bulletin, 2017Co-Authors: Yves Guéguen, Denis Saulnier, Pierre Garen, Adrien Santini, Kevin Magré, Solène Bernagout, Marine Nohl, Patrick Bouisset, Herehia Helme, Serge PlanesAbstract:This study was designed to identify in the pearl oyster Pinctada margaritifera, used as a bio-accumulator, molecular biomarkers for the presence of heavy metals in the lagoon environment. Pearl oysters were exposed to 2 concentrations (1 and 10 μg L− 1) of cadmium (Cd) and chromium (Cr) compared to a control. Twelve target genes encoding proteins potentially involved in the response to heavy metal contamination with antioxidant, detoxification or apoptosis activities were selected. P. margaritifera accumulated Cd but not Cr, and mortality was related to the amount of Cd accumulated in tissues. In response to Cd-Cr contamination, metallothionein (MT) was significantly up-regulated by Cd-Cr at both concentrations, while 7 others (SOD, CAT, GPX, GSTO, GSTM, CASP, MDR) were down-regulated. Based on the development of these molecular tools, we propose that the pearl oyster, P. margaritifera, could be used as a sentinel species for heavy metal contamination in the lagoons of tropical ecosystems.
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Pinctada margaritifera responses to temperature and pH: Acclimation capabilities and physiological limits
Estuarine Coastal and Shelf Science, 2016Co-Authors: Gilles Le Moullac, Nabila Gaertner-mazouni, Oihana Latchere, Juliette Fremery, Alain Lo Yat, Corinne Belliard, Jérémie Vidal-dupiol, Claude Soyez, Denis Saulnier, Yves GuéguenAbstract:The pearl culture is one of the most lucrative aquacultures worldwide. In many South Pacific areas, it depends on the exploitation of the pearl oyster Pinctada margaritifera and relies entirely on the environmental conditions encountered in the lagoon. In this context, assessing the impact of climatic stressors, such as global warming and ocean acidification, on the functionality of the resource in terms of renewal and exploitation is fundamental. In this study, we experimentally addressed the impact of temperature (22, 26, 30 and 34 °C) and partial pressure of carbon dioxide pCO2 (294, 763 and 2485 μatm) on the biomineralization and metabolic capabilities of pearl oysters. While the energy metabolism was strongly dependent on temperature, results showed its independence from pCO2 levels; no interaction between temperature and pCO2 was revealed. The energy metabolism, ingestion, oxygen consumption and, hence, the scope for growth (SFG) were maximised at 30 °C and dramatically fell at 34 °C. Biomineralization was examined through the expression measurement of nine mantle's genes coding for shell matrix proteins involved in the formation of calcitic prisms and/or nacreous shell structures; significant changes were recorded for four of the nine (Pmarg-Nacrein A1, Pmarg-MRNP34, Pmarg-Prismalin 14 and Pmarg-Aspein). These changes showed that the maximum and minimum expression of these genes was at 26 and 34 °C, respectively. Surprisingly, the modelled thermal optimum for biomineralization (ranging between 21.5 and 26.5 °C) and somatic growth and reproduction (28.7 °C) appeared to be significantly different. Finally, the responses to high temperatures were contextualised with the Intergovernmental Panel on Climate Change (IPCC) projections, which highlighted that pearl oyster stocks and cultures would be severely threatened in the next decade
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Temperature and food influence shell growth and mantle gene expression of shell matrix proteins in the pearl oyster Pinctada margaritifera
PLoS ONE, 2014Co-Authors: Caroline Joubert, Clémentine Linard, Gilles Le Moullac, Claude Soyez, Denis Saulnier, Chin-long Ky, Vaihiti Teaniniuraitemoana, Yves GuéguenAbstract:In this study, we analyzed the combined effect of microalgal concentration and temperature on the shell growth of the bivalve Pinctada margaritifera and the molecular mechanisms underlying this biomineralization process. Shell growth was measured after two months of rearing in experimental conditions, using calcein staining of the calcified structures. Molecular mechanisms were studied though the expression of 11 genes encoding proteins implicated in the biomineralization process, which was assessed in the mantle. We showed that shell growth is influenced by both microalgal concentration and temperature, and that these environmental factors also regulate the expression of most of the genes studied. Gene expression measurement of shell matrix protein thereby appears to be an appropriate indicator for the evaluation of the biomineralization activity in the pearl oyster P. margaritifera under varying environmental conditions. This study provides valuable information on the molecular mechanisms of mollusk shell growth and its environmental control.
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Evidence of donor effect on cultured pearl quality from a duplicated grafting experiment on Pinctada margaritifera using wild donors
Aquatic Living Resources, 2012Co-Authors: Alexandre Tayale, Yves Guéguen, Nathalie Cochennec-laureau, Cathy Treguier, Jacqueline Le Grand, Caroline MontagnaniAbstract:Producing high quality cultured black pearls from Pinctada margaritifera is one of the major challenges for the “pearl oyster” industry in French Polynesia. In order to assess donor effect on cultured pearl quality, wild Pinctada margaritifera originating from the Tuamotu Archipelago were used in a duplicated grafting experiment. After 12 months of culture, nucleus retention was assessed and seven pearl quality traits recorded on the 454 cultured pearls harvested from the experiment. The traits scored were nacre thickness and pearl weight, surface defects, lustre, grade, and the colour components: 1) darkness of cultured pearl colour, and 2) visual perception of colour class (bodycolor and/or overtone). Our results demonstrate for the first time that individual wild donors of implanted mantle grafts significantly affect these seven quality traits in P. margaritifera cultured pearls. This finding was repeated in two series of grafts made by different professional grafters. The wild donors could be ranked from “best” (e.g., the donor whose grafts produced the cultured pearl with the maximum lustre) to the “worst”. Moreover, we showed strong correlations between: 1) cultured pearl nacre thickness and grade, with grade A showing the greatest nacre thickness on average compared with grade D and rejects; and 2) nacre thickness/cultured pearl weight and colour components (darkness and visual “colour categories”), with the palest cultured pearls (i.e. white cultured pearls) being the smallest (lowest nacre thickness and weight). Thus, one way of enhancing P. margaritifera foundation stocks for a selective breeding program could be to select the “best” donors, using appropriate molecular tools. Generation of selected donor lines from these stocks through hatchery production would be one way to increase the quality of cultured pearl farming of P. margaritifera in French Polynesia.
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Pmarg‐Pearlin is a Matrix Protein Involved in Nacre Framework Formation in the Pearl Oyster Pinctada margaritifera
ChemBioChem, 2011Co-Authors: Caroline Montagnani, Yves Guéguen, Corinne Belliard, Elodie Fleury, Alexandre Tayale, Benjamin Marie, Frédéric Marin, F. Riquet, Isabelle Zanella-cléon, David PiquemalAbstract:The shell of pearl oysters is organized in multiple layers of CaCO(3) crystallites packed together in an organic matrix. Relationships between the components of the organic matrix and mechanisms of nacre formation currently constitute the main focus of research into biomineralization. In this study, we characterized the pearlin protein from the oyster Pinctada margaritifera (Pmarg); this shares structural features with other members of a matrix protein family, N14/N16/pearlin. Pmarg pearlin exhibits calcium- and chitin-binding properties. Pmarg pearlin transcripts are distinctively localized in the mineralizing tissue responsible for nacre formation. More specifically, we demonstrate that Pmarg pearlin is localized within the interlamellar matrix of nacre aragonite tablets. Our results support recent models for multidomain matrix protein involvement in nacreous layer formation. We provide evidence here for the existence of a conserved family of nacre-associated proteins in Pteriidae, and reassess the evolutionarily conserved set of biomineralization genes related to nacre formation in this taxa.
Emmanuel Goyard - One of the best experts on this subject based on the ideXlab platform.
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spatio temporal variation in the genetic composition of wild populations of pearl oyster Pinctada margaritifera cumingii in french polynesia following 10 years of juvenile translocation
Molecular Ecology, 2004Co-Authors: Sophie Arnaudhaond, F. Blanc, Pierre Boudry, T. Seaman, Vincent Vonau, Francois Bonhomme, Jean Prou, Emmanuel GoyardAbstract:The genetic impact of the cultural practice of spat collection and translocation between genetically distinct stocks of black-lipped pearl oyster, Pinctada margaritifera cumingii , was studied by comparing samples collected in the 1980s and 2000s from seven atolls in French Polynesia. An AMOVA revealed homogenization of the previously genetically distinct wild stocks of Tuamotu-Gambier and Society archipelagos (the indices of genetic differentiation among archipelagos and among populations within archipelagos, respectively, Φ CT and Φ ST , decreased from 0.032* and 0.025*, respectively, to 0.006 NS and 0.007 NS ). These results suggest high success of spontaneous reproduction in farms, probably due to the very high density of cultivated pearl oysters, and underline the importance of genetic monitoring of future hatchery produced stocks.
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Spatio‐temporal variation in the genetic composition of wild populations of pearl oyster (Pinctada margaritifera cumingii) in French Polynesia following 10 years of juvenile translocation
Molecular Ecology, 2004Co-Authors: Sophie Arnaud-haond, F. Blanc, Pierre Boudry, T. Seaman, Vincent Vonau, Francois Bonhomme, Jean Prou, Emmanuel GoyardAbstract:The genetic impact of the cultural practice of spat collection and translocation between genetically distinct stocks of black-lipped pearl oyster, Pinctada margaritifera cumingii , was studied by comparing samples collected in the 1980s and 2000s from seven atolls in French Polynesia. An AMOVA revealed homogenization of the previously genetically distinct wild stocks of Tuamotu-Gambier and Society archipelagos (the indices of genetic differentiation among archipelagos and among populations within archipelagos, respectively, Φ CT and Φ ST , decreased from 0.032* and 0.025*, respectively, to 0.006 NS and 0.007 NS ). These results suggest high success of spontaneous reproduction in farms, probably due to the very high density of cultivated pearl oysters, and underline the importance of genetic monitoring of future hatchery produced stocks.
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New anonymous nuclear DNA markers for the pearl oyster Pinctada margaritifera and other Pinctada species
Molecular Ecology Notes, 2002Co-Authors: Sophie Arnaud-haond, Denis Saulnier, Pierre Boudry, T. Seaman, Vincent Vonau, Francois Bonhomme, Emmanuel GoyardAbstract:The black-lipped oyster Pinctada margaritifera is highly exploited in French Polynesia where the pearl industry relies mostly on spat collection, and therefore on resources available in the wild. Little is known of these resources, and population genetic studies would be useful to improve management. We used two methods, direct amplification of length polymorphism (DALP) and exon primed intron crossing (EPIC) to develop five new nuclear markers presenting length polymorphism. Although these markers remained anonymous after using blast on GenBank, they are codominant and follow Hardy–Weinberg equilibrium. Tests on related species or subspecies of Pinctada gave encouraging results.
Denis Saulnier - One of the best experts on this subject based on the ideXlab platform.
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Phenotype plasticity, local adaptation, and biofouling influence on growth of the pearl oyster Pinctada margaritifera: A common garden approach
Aquaculture, 2019Co-Authors: V. Hulot, Denis Saulnier, Oihana Latchere, N. Maihota, Nabila Gaertner-mazouniAbstract:Abstract The purpose of our study is to investigate (1) the influence of phenotype plasticity and local adaptation on pearl-oyster physiology by testing the persistence of growth differentiation of two pearl oyster populations (Arutua and Mangareva) in common garden experiment; (2) to quantify the influence of biofouling development on the growth of each pearl oyster population. According to our observations, the growth rate in terms of total oyster weight suggested better growth performance of the pearl oyster Pinctada margaritifera in Mangareva (0.21–0.24 ± 0.01 g.day−1) than Arutua (0.14–0.15 ± 0.01 g.day−1). However, similar growth performances are observed at the Vairao common garden site for oyster stocks from Mangareva (0.07 ± 0.01 mm.day−1 or 0.15 ± 0.01 g.day−1) and Arutua (0.07 ± 0.01 mm.day−1 or 0.13 ± 0.01 g.day−1). Our results suggest that growth performance variability observed at the pearl farming sites of Arutua and Mangareva is due more to phenotypic plasticity than to local adaptation. This result thus accords a major importance to site selection for the pearl farming optimization process. Biofouling dynamics on Pinctada margaritifera shells differed radically between Arutua and Mangareva sites. In Arutua, biofouling colonization was relatively slow (0.016 g.oyster−1.month−1) and was mainly composed of sponges and bivalves. On Mangareva, the colonization process appeared faster and more continuous over the study period (0.15–0.18 g.oyster−1.month−1) and the biofouling community was dominated by tunicates. On the basis of our results obtained on growth performance between cleaned and uncleaned stock in Arutua and Mangareva, biofouling development after 14–15 months of colonization does not appear to have any negative effect on P. margaritifera growth. Due to the high cost of biofouling management in pearl farming facilities, our results suggest once more that reconsideration of the pearl farming management process is needed.
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Response of the pearl oyster Pinctada margaritifera to cadmium and chromium: Identification of molecular biomarkers
Marine Pollution Bulletin, 2017Co-Authors: Yves Guéguen, Denis Saulnier, Pierre Garen, Adrien Santini, Kevin Magré, Solène Bernagout, Marine Nohl, Patrick Bouisset, Herehia Helme, Serge PlanesAbstract:This study was designed to identify in the pearl oyster Pinctada margaritifera, used as a bio-accumulator, molecular biomarkers for the presence of heavy metals in the lagoon environment. Pearl oysters were exposed to 2 concentrations (1 and 10 μg L− 1) of cadmium (Cd) and chromium (Cr) compared to a control. Twelve target genes encoding proteins potentially involved in the response to heavy metal contamination with antioxidant, detoxification or apoptosis activities were selected. P. margaritifera accumulated Cd but not Cr, and mortality was related to the amount of Cd accumulated in tissues. In response to Cd-Cr contamination, metallothionein (MT) was significantly up-regulated by Cd-Cr at both concentrations, while 7 others (SOD, CAT, GPX, GSTO, GSTM, CASP, MDR) were down-regulated. Based on the development of these molecular tools, we propose that the pearl oyster, P. margaritifera, could be used as a sentinel species for heavy metal contamination in the lagoons of tropical ecosystems.
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Influence of preoperative food and temperature conditions on pearl biogenesis in Pinctada margaritifera
Aquaculture, 2017Co-Authors: Oihana Latchere, Nabila Gaertner-mazouni, Kevin Magré, Gilles Le Moullac, Julie Fievet, Denis SaulnierAbstract:Trophic conditions and water temperature strongly influence bivalve physiological processes and metabolism. In black-lip pearl oyster Pinctada margaritifera, these parameters have been shown to affect shell biomineralization. The present study investigated the effect of preoperative food level (i.e., microalgal concentration) and temperature on pearl biomineralization. Donor and recipient oysters were conditioned at different levels of food and temperature during the preoperative phase to evaluate the influence of these factors on 1) pearl retention rate (grafting success), 2) expression of genes involved in biomineralization in the mantle and pearl sac and 3) pearl quality traits. Our study confirmed the influence of both microalgal concentration and temperature on shell growth. Food level of donor oysters was decisive for pearl biomineralization, with donors that had been fed at a high microalgal concentration producing pearl sacs with significantly higher biomineralization capabilities and faster nacre establishment during early stages of pearl formation. However, food level showed no effects on quality traits of the pearls harvested 12 months postgrafting, while preoperative temperature only influenced the relative expression of two genes in pearl sacs at 12 months postgrafting. No significant effects of the preoperative conditioning of recipient oysters were detected in either experiment considering gene expression measurements and pearl quality traits. However, mortality was significantly lower in grafted recipient oysters fed at an intermediate trophic level. Finally, pearl weight was shown to be positively correlated with recipient oyster growth.
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Culture site dependence on pearl size realization in Pinctada margaritifera in relation to recipient oyster growth and mantle graft biomineralization gene expression using the same donor phenotype
Estuarine Coastal and Shelf Science, 2016Co-Authors: Lore Le Pabic, Denis Saulnier, Sophie Parrad, Manaarii Sham Koua, Seiji Nakasai, Dominique DevauxAbstract:Size is the most important and valuable quality of the cultured black-lip pearl, Pinctada margaritifera. As this pearl aquaculture is carried out at numerous grow-out sites, this study analyzes the environmental influence on pearl size parameters (nacre weight and thickness) in relation to the recipient oyster biometric parameters (shell thickness, height, width, and oyster weight) at harvest time. Toward this end, an experimental graft was designed by using a homogeneous donor oyster phenotype. The recipient oysters were randomly and equally transferred and reared in five commercial and contrasting grow-out locations. Overall inter-site comparisons revealed that the cultured pearl size (N = 2168) and the biometric parameters of the recipient oysters were highest for sites with warmer temperatures with low seasonal variation in comparison to the southern latitude sites. These results were supported by positive correlations between pearl nacre thickness and recipient oyster shell thickness, height, and width. In parallel, the biomineralization potential of the mantle graft was screened through four genes encoding aragonite (Pif 177, MSI60) and calcite (shematrin 9, aspein). As the gene expression levels were the same among all the donor oysters, this finding demonstrates that: 1) the pearl sac that originated from the mantle graft was not isolated from environmental variations during the culture period and 2) the phenotypic expressions of the two biomineralizing tissues in the recipient oyster were consistent (shell and pearl). In the near future, this knowledge will be helpful at the production sites of genetically selected donor oyster lines for growth produced in hatchery systems. Culture site dependence on pearl size realization in Pinctada margaritifera in relation to recipient oyster growth and mantle graft biomineralization gene expression using the same donor phenotype. Available from: https://www.researchgate.net/publication/299384948_Culture_site_dependence_on_pearl_size_realization_in_Pinctada_margaritifera_in_relation_to_recipient_oyster_growth_and_mantle_graft_biomineralization_gene_expression_using_the_same_donor_phenotype [accessed Oct 18 2017].
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Pinctada margaritifera responses to temperature and pH: Acclimation capabilities and physiological limits
Estuarine Coastal and Shelf Science, 2016Co-Authors: Gilles Le Moullac, Nabila Gaertner-mazouni, Oihana Latchere, Juliette Fremery, Alain Lo Yat, Corinne Belliard, Jérémie Vidal-dupiol, Claude Soyez, Denis Saulnier, Yves GuéguenAbstract:The pearl culture is one of the most lucrative aquacultures worldwide. In many South Pacific areas, it depends on the exploitation of the pearl oyster Pinctada margaritifera and relies entirely on the environmental conditions encountered in the lagoon. In this context, assessing the impact of climatic stressors, such as global warming and ocean acidification, on the functionality of the resource in terms of renewal and exploitation is fundamental. In this study, we experimentally addressed the impact of temperature (22, 26, 30 and 34 °C) and partial pressure of carbon dioxide pCO2 (294, 763 and 2485 μatm) on the biomineralization and metabolic capabilities of pearl oysters. While the energy metabolism was strongly dependent on temperature, results showed its independence from pCO2 levels; no interaction between temperature and pCO2 was revealed. The energy metabolism, ingestion, oxygen consumption and, hence, the scope for growth (SFG) were maximised at 30 °C and dramatically fell at 34 °C. Biomineralization was examined through the expression measurement of nine mantle's genes coding for shell matrix proteins involved in the formation of calcitic prisms and/or nacreous shell structures; significant changes were recorded for four of the nine (Pmarg-Nacrein A1, Pmarg-MRNP34, Pmarg-Prismalin 14 and Pmarg-Aspein). These changes showed that the maximum and minimum expression of these genes was at 26 and 34 °C, respectively. Surprisingly, the modelled thermal optimum for biomineralization (ranging between 21.5 and 26.5 °C) and somatic growth and reproduction (28.7 °C) appeared to be significantly different. Finally, the responses to high temperatures were contextualised with the Intergovernmental Panel on Climate Change (IPCC) projections, which highlighted that pearl oyster stocks and cultures would be severely threatened in the next decade
Paul C Southgate - One of the best experts on this subject based on the ideXlab platform.
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Haemocyte persistence after grafting for pearl production in Pinctada margaritifera (Linnaeus, 1758).
Fish & Shellfish Immunology, 2015Co-Authors: Pranesh Kishore, Paul C SouthgateAbstract:The grafting process used for pearl production in pearl oysters triggers a significant haemocyte response which has an influence on the quality of pearls formed. One hundred and ten selected healthy adult Pinctada margaritifera were grafted for pearl production. Beginning two days after grafting, oysters were sacrificed regularly until the 48th day and the pearl-sacs of sampled oysters were sectioned for histological analysis. The level of haemocytes present in the pearl-sacs decreased overtime with the samples from day 2 showing the highest levels. Haemocyte levels also varied between samples from a particular day. The exact cause(s) of varying levels of haemocyte accumulation during pearl-sac development in P. margaritifera is not known. However, it is reasonable to assume that haemocyte production is positively related to the degree of damage caused to host oyster tissues during the grafting procedure. While haemocytes have an important wound healing role in pearl oysters, excessive haemocyte presence may be detrimental to maximizing pearl quality.
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Histological changes in the gonad of the blacklip pearl oyster (Pinctada margaritifera Linnaeus, 1758) during the reproductive season in North Queensland, Australia
Molluscan Research, 2005Co-Authors: Héctor Acosta-salmón, Paul C SouthgateAbstract:Histological changes in the gonad of cultured blacklip pearl oysters (Pinctada margaritifera) were studied during the main reproductive season. Collection of oysters from culture stock held at Magnetic Island and Orpheus Island, north Queensland, was conducted between August 2003 and February 2004 and oysters from each site were collected every month. Samples of gonad tissue from the oysters were processed for histological analysis. The sex ratio of oysters at both sites was skewed towards males. Active gonad development was recorded in all months during the study. Results of this study indicate that reproduction of P. margaritifera at Orpheus Island and Magnetic Island is a continuous process between August and February, as shown by the presence of ripe and partially spawned oysters during the majority of this period.
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mantle regeneration in the pearl oysters Pinctada fucata and Pinctada margaritifera
Aquaculture, 2005Co-Authors: Hector Acostasalmon, Paul C SouthgateAbstract:Abstract Mantle tissue in pearl oysters (Pteriidae) is responsible for secreting the mother-of-pearl or nacre lining the shell. When grafted into another oyster, excised mantle tissue, commonly called ‘saibo’, is responsible for cultured pearl production. This study was undertaken to assess the process of mantle regeneration in the Akoya pearl oyster Pinctada fucata and the blacklip pearl oyster Pinctada margaritifera following mantle excision. Prior to saibo excision, oysters were anaesthetized with 2 mL L −1 propylene phenoxetol. Saibo tissue was excised from 50 P . fucata and 10 P. margaritifera . After excision, all oysters were returned to culture conditions. All oysters were maintained in panel (pocket) nets on a long-line at Magnetic Island, north Queensland, Australia. Oysters were anaesthetized and sacrificed 3, 6, 9, 12, 15, 20, 30, 45, 60 and 90 days after saibo excision to assess mantle regeneration using histological and histochemical techniques. Survival over the 90-day study was 100% and 70% for P. fucata and P. margaritifera , respectively. After excision, the mantle tissue healed within the first three days and began growing as connective tissue. Muscular development was seen between days 60 and 90 after excision. Shell formation abilities were recovered by day 15 when secretory cells and conchiolin secretions were first observed. Both P. fucata and P. margaritifera regenerated mantle to its original extent within the 90-day study. This is the first description of in vivo mantle regeneration in pearl oysters and the results have major implications for the lucrative cultured pearl industry. Our results indicate that mantle tissue donors need not be killed for pearl production. Those producing saibo that results in good quality pearls could be used as future parent-stock in breeding programs or for subsequent saibo donation and pearl production.
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CRYOPRESERVATION OF BLACK-LIP PEARL OYSTER (Pinctada margaritifera, L.) SPERMATOZOA: EFFECTS OF CRYOPROTECTANTS ON SPERMATOZOA MOTILITY
Journal of Shellfish Research, 2005Co-Authors: Lauren Lyons, Dean R. Jerry, Paul C SouthgateAbstract:Abstract Cryopreservation of sperm is seen as an important step in developing effective hatchery culture techniques for the black-lip pearl oyster, Pinctada margaritifera. As a preliminary investigation into cryopreservation of the gametes of this species we tested 5 cryoprotectant agent combinations for their ability to retain sperm motility: (1) 1 M trehalose and 5, 10 and 15% dimethyl sulphoxide (DMSO); (2) Hanks calcium-free balanced salt solution (C-F HBSS) and 5%, 10% and 15% DMSO; (3) C-F HBSS and 5, 10 and 15% propylene glycol (PG); (4) 1 M trehalose and an equal combination of DMSO and PG making up 5, 10, 15% total volume; and (5) C-F HBSS and an equal combination of DMSO and PG making up 5%, 10% and 15% total volume. Total, rapid and progressive sperm motilities were estimated through computer assisted sperm analysis (CASA). Sperm cryopreserved in 1 M trehalose and 5% DMSO retained the highest total (86.0 ± 1.2% SE), progressive (46.0 ± 1.2% SE) and rapid (25.1 ± 0.6% SE) motilities of all cryop...
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Should slow growing pearl oyster (Pinctada margaritifera) spat (Runts) be discarded
Journal of Shellfish Research, 2003Co-Authors: Josiah H. Pit, Paul C SouthgateAbstract:In this laboratory, hatchery-produced Pinctada margaritifera juveniles are routinely graded at 3.5 mo of age, when spat of 10 mm) of hatchery-produced blacklip pearl oyster (P. mararitifera) spat from the same cohort. The three size classes were classified as runts, normal growers, and fast growers, and had mean (±SE; n = 30) dorso-ventral shell heights (DVHs) of 4.5 ± 0.1, 8.6 ± 0.3, and 12.8 ± 0.2 mm, respectively, at the start of the 4-mo experiment. The mean DVH at completion of the study for each initial size class ( 10 mm) was 24.6 ± 0.4, 32.3 ± 0.4, and 35.6 ± 0.4 mm, respectively. All differed significantly from each other (P 10mm) over the 4-mo period was greatest in oysters from the 5-lO-mm size class (mean DVH 23.3 ± 0.4 mm) and lowest in oysters from the 10-mm size class (178 ± 7%). A number of oysters in the
Vincent Vonau - One of the best experts on this subject based on the ideXlab platform.
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Hatchery-scale trials using cryopreserved spermatozoa of black-lip pearl oyster, Pinctada margaritifera
Aquatic Living Resources, 2011Co-Authors: Belinda Hui, Vincent Vonau, Jacques Moriceau, Roger Tetumu, Vincent Vanaa, Marina Demoy-schneider, Marc Suquet, Gilles Le MoullacAbstract:Cryopreservation is a valuable tool for genetic improvement programs. Several bivalve mollusc species have already been the subject of such programs and the Tahitian black pearl oyster industry is now planning the de- velopment of selective breeding for desirable traits in Pinctada margaritifera. The ability to cryopreserve spermatozoa would, therefore, offer significant benefits to the cultured black pearl industry. Spermatozoa were cryopreserved with cryoprotectant agent (CPA) 0.7 M trehalose in 0.8 M Me2SO and a two-step freezing process was used: straws were first maintained in nitrogen vapour for 10 minutes, then directly plunged into liquid nitrogen and stored for one week before use. The viability of thawed sperm was 23% lower than that of fresh sperm. When using thawed sperm, there- fore, a higher sperm/egg ratio of 100 000:1 was required to reach 80% oocyte fertilization, compared with 100:1 for fresh sperm. Nevertheless, this first demonstration of cryopreserved sperm fertility in black pearl oyster confirms the hatchery applicability of the cryopreservation technique defined here. Monitoring for larval viability during the first 23 days of life revealed no significant differences between the progeny produced with cryopreserved sperm and that produced using fresh sperm.
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Effect of food conditioning on gonadic activity in the oyster Pinctada margaritifera
2009Co-Authors: Gilles Le Moullac, Vincent Vonau, Belinda Hui, Peva Levy, Jean-claude CochardAbstract: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 sections were made to analyse gametogenesis cellular lines. Initial and final GDI distribution of control oysters did not vary and followed the normal law. In conditioned oysters GDI distribution appeared flattened. Analysis of GDI data showed that reproductive effort was significantly lower (P
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spatio temporal variation in the genetic composition of wild populations of pearl oyster Pinctada margaritifera cumingii in french polynesia following 10 years of juvenile translocation
Molecular Ecology, 2004Co-Authors: Sophie Arnaudhaond, F. Blanc, Pierre Boudry, T. Seaman, Vincent Vonau, Francois Bonhomme, Jean Prou, Emmanuel GoyardAbstract:The genetic impact of the cultural practice of spat collection and translocation between genetically distinct stocks of black-lipped pearl oyster, Pinctada margaritifera cumingii , was studied by comparing samples collected in the 1980s and 2000s from seven atolls in French Polynesia. An AMOVA revealed homogenization of the previously genetically distinct wild stocks of Tuamotu-Gambier and Society archipelagos (the indices of genetic differentiation among archipelagos and among populations within archipelagos, respectively, Φ CT and Φ ST , decreased from 0.032* and 0.025*, respectively, to 0.006 NS and 0.007 NS ). These results suggest high success of spontaneous reproduction in farms, probably due to the very high density of cultivated pearl oysters, and underline the importance of genetic monitoring of future hatchery produced stocks.
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Spatio‐temporal variation in the genetic composition of wild populations of pearl oyster (Pinctada margaritifera cumingii) in French Polynesia following 10 years of juvenile translocation
Molecular Ecology, 2004Co-Authors: Sophie Arnaud-haond, F. Blanc, Pierre Boudry, T. Seaman, Vincent Vonau, Francois Bonhomme, Jean Prou, Emmanuel GoyardAbstract:The genetic impact of the cultural practice of spat collection and translocation between genetically distinct stocks of black-lipped pearl oyster, Pinctada margaritifera cumingii , was studied by comparing samples collected in the 1980s and 2000s from seven atolls in French Polynesia. An AMOVA revealed homogenization of the previously genetically distinct wild stocks of Tuamotu-Gambier and Society archipelagos (the indices of genetic differentiation among archipelagos and among populations within archipelagos, respectively, Φ CT and Φ ST , decreased from 0.032* and 0.025*, respectively, to 0.006 NS and 0.007 NS ). These results suggest high success of spontaneous reproduction in farms, probably due to the very high density of cultivated pearl oysters, and underline the importance of genetic monitoring of future hatchery produced stocks.
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New anonymous nuclear DNA markers for the pearl oyster Pinctada margaritifera and other Pinctada species
Molecular Ecology Notes, 2002Co-Authors: Sophie Arnaud-haond, Denis Saulnier, Pierre Boudry, T. Seaman, Vincent Vonau, Francois Bonhomme, Emmanuel GoyardAbstract:The black-lipped oyster Pinctada margaritifera is highly exploited in French Polynesia where the pearl industry relies mostly on spat collection, and therefore on resources available in the wild. Little is known of these resources, and population genetic studies would be useful to improve management. We used two methods, direct amplification of length polymorphism (DALP) and exon primed intron crossing (EPIC) to develop five new nuclear markers presenting length polymorphism. Although these markers remained anonymous after using blast on GenBank, they are codominant and follow Hardy–Weinberg equilibrium. Tests on related species or subspecies of Pinctada gave encouraging results.