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Sylvain Huchette - One of the best experts on this subject based on the ideXlab platform.
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ocean acidification impacts growth and shell mineralization in juvenile abalone Haliotis tuberculata
Marine Biology, 2020Co-Authors: Sabine Roussel, Aicha Badou, Stephanie Auzouxbordenave, Nathalie Wessel, Sophie G Martin, Saloua Mzoudi, Solene Avignon, Sylvain HuchetteAbstract:Ocean acidification (OA) is a major global driver that leads to substantial changes in seawater carbonate chemistry, with potentially serious consequences for calcifying organisms. Marine shelled molluscs are ecologically and economically important species, providing essential ecosystem services and food sources for other species. Due to their physiological characteristics and their use of calcium carbonate (CaCO3) to build their shells, molluscs are among the most vulnerable invertebrates with regard to OA, with early developmental stages being particularly sensitive to pH changes. This study investigated the effects of CO2-induced OA on juveniles of the European abalone Haliotis tuberculata, a commercially important gastropod species. Six-month-old juvenile abalones were cultured for 3 months at four pH levels (8.1, 7.8, 7.7, 7.6) representing current and predicted near-future conditions. Survival, growth, shell microstructure, thickness, and strength were compared across the four pH treatments. After 3 months of exposure, significant reductions in juvenile shell length, weight, and strength were revealed in the pH 7.6 treatment. Scanning electron microscopy observations also revealed modified texture and porosity of the shell mineral layers as well as alterations of the periostracum at pH 7.6 which was the only treatment with an aragonite saturation state below 1. It is concluded that low pH induces both general effects on growth mechanisms and corrosion of deposited shell in H. tuberculata. This will impact both the ecological role of this species and the costs of its aquaculture.
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impact of nine macroalgal diets on growth and initial reproductive investment in juvenile abalone Haliotis tuberculata
Aquaculture, 2019Co-Authors: Sabine Roussel, Nelly Le Goic, Claire Caralp, Catherine Leblanc, Fabienne Le Grand, Valerie Stigerpouvreau, Celine Coulombet, Sylvain HuchetteAbstract:The commercial culture of Haliotis tuberculata has recently started in Europe. As abalone is herbivorous, the use of local collected algae as feed may appear advantageous. The nutritional value of eight monospecific seaweed diets was studied using Palmaria palmata (Rhodophyta), filamentous algae, mainly Gracilaria sp. (Rhodophyta), Enteromorpha sp. and Ulva lactuca (Chlorophyta), together with Saccharina latissima, Saccorhiza polyschides, Laminaria digitata and Laminaria hyperborea (Ochrophyta, Phaeophyceae) and a mixed macroalgal diet. An integrative approach consisted in monitoring the seasonal composition changes of these algae in terms of protein, lipid, soluble carbohydrate, fatty acid and amino-acid contents, and to relate it to seasonal growth and reproduction investment during a large-scale experiment. Abalone and algae were studied for one year in commercial sea-cage structures. Abalone fed with monospecific diet using either P. palmata or S. latissima, and with mixed diet presented the best growth rate, muscle ratio and gonad development. Seasonal daily weight gain was mainly associated with n-3/n-6 ratio, soluble carbohydrate content and total protein content. In term of amino-acid contents, the daily weight gain was associated with free phenylalanine as well as isoleucine levels. Moreover, 90% of 2-years old abalone started gonad development but less than a quarter featured a fully matured gonad. The gonad development of H. tuberculata was mostly associated to total valine, methionine, leucine, arginine and isoleucine levels. The age of initial sexual maturity in H. tuberculata turned to be a highly plastic trait in response to different growth rates and algal diets. Even if P. palmata is the best option for growth performance, mixed diets should probably be preferred to a monospecific diet in order to avoid too high pressure on a single algal resource.
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Effect of CO2–induced ocean acidification on the early development and shell mineralization of the European abalone (Haliotis tuberculata)
Journal of Experimental Marine Biology and Ecology, 2018Co-Authors: Nathalie Wessel, Sylvain Huchette, Christine Paillard, Aicha Badou, Ewan Harney, Flavia L D Nunes, Sophie G Martin, Philippe Dubois, Vivien Julia, Stéphanie Auzoux-bordenaveAbstract:Abstract Ocean acidification is a major global stressor that leads to substantial changes in seawater carbonate chemistry, with potentially significant consequences for calcifying organisms. Marine shelled mollusks are ecologically and economically important species providing essential ecosystem services and food sources for other species. Because they use calcium carbonate (CaCO3) to produce their shells, mollusks are among the most vulnerable invertebrates to ocean acidification, with early developmental stages being particularly sensitive to pH changes. This study investigated the effects of CO2-induced ocean acidification on larval development of the European abalone Haliotis tuberculata, a commercially important gastropod species. Abalone larvae were exposed to a range of reduced pHs (8.0, 7.7 and 7.6) over the course of their development cycle, from early-hatched trochophore to pre-metamorphic veliger. Biological responses were evaluated by measuring the survival rate, morphology and development, growth rate and shell calcification. Larval survival was significantly lower in acidified conditions than in control conditions. Similarly, larval size was consistently smaller under low pH conditions. Larval development was also affected, with evidence of a developmental delay and an increase in the proportion of malformed or unshelled larvae. In shelled larvae, the intensity of birefringence decreased under low pH conditions, suggesting a reduction in shell mineralization. Since these biological effects were observed for pH values expected by 2100, ocean acidification may have potentially negative consequences for larval recruitment and persistence of abalone populations in the near future.
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effect of co2 induced ocean acidification on the early development and shell mineralization of the european abalone Haliotis tuberculata
Journal of Experimental Marine Biology and Ecology, 2018Co-Authors: Sylvain Huchette, Aicha Badou, Nathalie Wessel, Sophie G Martin, Philippe Dubois, Vivien Julia, Flavia L D NunesAbstract:Abstract Ocean acidification is a major global stressor that leads to substantial changes in seawater carbonate chemistry, with potentially significant consequences for calcifying organisms. Marine shelled mollusks are ecologically and economically important species providing essential ecosystem services and food sources for other species. Because they use calcium carbonate (CaCO3) to produce their shells, mollusks are among the most vulnerable invertebrates to ocean acidification, with early developmental stages being particularly sensitive to pH changes. This study investigated the effects of CO2-induced ocean acidification on larval development of the European abalone Haliotis tuberculata, a commercially important gastropod species. Abalone larvae were exposed to a range of reduced pHs (8.0, 7.7 and 7.6) over the course of their development cycle, from early-hatched trochophore to pre-metamorphic veliger. Biological responses were evaluated by measuring the survival rate, morphology and development, growth rate and shell calcification. Larval survival was significantly lower in acidified conditions than in control conditions. Similarly, larval size was consistently smaller under low pH conditions. Larval development was also affected, with evidence of a developmental delay and an increase in the proportion of malformed or unshelled larvae. In shelled larvae, the intensity of birefringence decreased under low pH conditions, suggesting a reduction in shell mineralization. Since these biological effects were observed for pH values expected by 2100, ocean acidification may have potentially negative consequences for larval recruitment and persistence of abalone populations in the near future.
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relationships between growth survival physiology and behaviour a multi criteria approach to Haliotis tuberculata phenotypic traits
Aquaculture, 2017Co-Authors: Sebastien Lachambre, Sylvain Huchette, Pierre Boudry, Antoine Riocabello, Timothee Fustec, Sabine RousselAbstract:Abalone growth rate is often identified among important traits to improve through selective breeding. However, the rapid success of some selective breeding plans has sometimes led to negative effects in some aquaculture species due to trade-offs. One of them is the loss of homeostasis of selected animals which results in the inability to resist the stress experienced during the rearing process. In this context, this study aimed to analyze the phenotypic relationships between growth, and physiological and behavioural traits in Haliotis tuberculata under stressful conditions. Eleven traits related to growth, immunity, reproduction and behaviour were recorded under laboratory conditions. A total of 120 adults from wild or farm origin were first monitored during a 3-week stress period (high density and acute stress handling) during winter, followed by 6 months on-growing in sea-cages. Relationships between parameters were analyzed using a multi-factorial approach. Wild and farm stocks could only be discriminated on behaviour traits, confirming that the French abalone industry is in the beginning of the domestication process. After 3 weeks of chronic stress, the righting latency of an abalone was linked to better survival and faster growth. Abalones having the best growth after 6 months were characterized by higher activity during the previous winter period, whereas an early gonad maturation reduced the growth in summer. Our results provide a basis for the establishment of a multi-trait breeding program to improve the growth rate while controlling the evolution of physiological and behavioural traits.ăStatement of relevanceăThe relationships of behavioural and physiological variables with survival and weight gain after application of important stressors were studied in order to provide a better understanding of Haliotis tuberculata biology during early domestication stage. This paper will give information on new targets and tools for selective breeding.
Christine Paillard - One of the best experts on this subject based on the ideXlab platform.
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Characterization of a laccase-like activity in the hemolymph of the abalone Haliotis tuberculata
Aquaculture, 2020Co-Authors: Cedric Le Bris, Christine Paillard, Maxime Lepretre, Fabienne GuerardAbstract:International audienceAlong French coasts, the abalone Haliotis tuberculata is affected by mass mortality events caused by both immune depression and the pathogen Vibrio harveyi. During this immune depression various immune parameters have been monitored including phenoloxidase (PO) activity, which significantly decreases. Nevertheless the basal PO activity level, to date, has not been characterized biochemically and the PO subclass involved has not been identified. The aim of this study was to use various substrates and inhibitors, specific to one or more PO subclasses, to biochemically characterize enzymatic activity. Among specific and non-specific substrates, PO had the highest affinity for dopamine (K-m = 1.92, V-max = 0.086). Tyrosinase-specific substrates were not oxidized whereas both laccase-specific substrates tested were oxidized. Results obtained with the different inhibitors tested are in agreement with the results obtained with substrates. In fact, the laccase-specific CTAB totally inhibited PO activity and the IC50 for this inhibitor was the lowest of any tested. The molecular weight has been estimated between 83 and 106 kDa
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Effect of CO2–induced ocean acidification on the early development and shell mineralization of the European abalone (Haliotis tuberculata)
Journal of Experimental Marine Biology and Ecology, 2018Co-Authors: Nathalie Wessel, Sylvain Huchette, Christine Paillard, Aicha Badou, Ewan Harney, Flavia L D Nunes, Sophie G Martin, Philippe Dubois, Vivien Julia, Stéphanie Auzoux-bordenaveAbstract:Abstract Ocean acidification is a major global stressor that leads to substantial changes in seawater carbonate chemistry, with potentially significant consequences for calcifying organisms. Marine shelled mollusks are ecologically and economically important species providing essential ecosystem services and food sources for other species. Because they use calcium carbonate (CaCO3) to produce their shells, mollusks are among the most vulnerable invertebrates to ocean acidification, with early developmental stages being particularly sensitive to pH changes. This study investigated the effects of CO2-induced ocean acidification on larval development of the European abalone Haliotis tuberculata, a commercially important gastropod species. Abalone larvae were exposed to a range of reduced pHs (8.0, 7.7 and 7.6) over the course of their development cycle, from early-hatched trochophore to pre-metamorphic veliger. Biological responses were evaluated by measuring the survival rate, morphology and development, growth rate and shell calcification. Larval survival was significantly lower in acidified conditions than in control conditions. Similarly, larval size was consistently smaller under low pH conditions. Larval development was also affected, with evidence of a developmental delay and an increase in the proportion of malformed or unshelled larvae. In shelled larvae, the intensity of birefringence decreased under low pH conditions, suggesting a reduction in shell mineralization. Since these biological effects were observed for pH values expected by 2100, ocean acidification may have potentially negative consequences for larval recruitment and persistence of abalone populations in the near future.
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de novo assembly and annotation of the european abalone Haliotis tuberculata transcriptome
Marine Genomics, 2016Co-Authors: Ewan Harney, Sylvain Huchette, Christine Paillard, Olivier Basuyaux, Pierre Boudry, Bruno Dubief, Markus Schilhabel, Flavia L D NunesAbstract:The European abalone Haliotis tuberculata is a delicacy and consequently a commercially valuable gastropod species. Aquaculture production and wild populations are subjected to multiple climate-associated stressors and anthropogenic pressures, including rising sea-surface temperatures, ocean acidification and an emerging pathogenic Vibrio infection. Transcript expression data provides a valuable resource for understanding abalone responses to variation in the biotic and abiotic environment. To generate an extensive transcriptome, we performed next-generation sequencing of RNA on larvae exposed to temperature and pH variation and on haemolymph of adults from two wild populations after experimental infection with Vibrio harveyi. We obtained more than 1.5 billion raw paired-end reads, which were assembled into 328,519 contigs. Filtration and clustering produced a transcriptome of 41,099 transcripts, of which 10,626 (25.85%) were annotated with Blast hits, and 7380 of these were annotated with Gene Ontology (GO) terms in Blast2Go. A differential expression analysis comparing all samples from the two life stages identified 5690 and 10,759 transcripts with significantly higher expression in larvae and adult haemolymph respectively. This is the greatest sequencing effort yet in the Haliotis genus, and provides the first high-throughput transcriptomic resource for H. tuberculata.
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genomics technical resourcesde novo assembly and annotation of the european abalone Haliotis tuberculata transcriptome
Marine Genomics, 2016Co-Authors: Ewan Harney, Sylvain Huchette, Christine Paillard, Olivier Basuyaux, Pierre Boudry, Bruno Dubief, Markus Schilhabel, Flavia L D NunesAbstract:The European abalone Haliotis tuberculata is a delicacy and consequently a commercially valuable gastropod species. Aquaculture production and wild populations are subjected to multiple climate-associated stressors and anthropogenic pressures, including rising sea-surface temperatures, ocean acidification and an emerging pathogenic Vibrio infection. Transcript expression data provides a valuable resource for understanding abalone responses to variation in the biotic and abiotic environment. To generate an extensive transcriptome, we performed next-generation sequencing of RNA on larvae exposed to temperature and pH variation and on haemolymph of adults from two wild populations after experimental infection with Vibrio harveyi. We obtained more than 1.5 billion raw paired-end reads, which were assembled into 328,519 contigs. Filtration and clustering produced a transcriptome of 41,099 transcripts, of which 10,626 (25.85%) were annotated with Blast hits, and 7380 of these were annotated with Gene Ontology (GO) terms in Blast2Go. A differential expression analysis comparing all samples from the two life stages identified 5690 and 10,759 transcripts with significantly higher expression in larvae and adult haemolymph respectively. This is the greatest sequencing effort yet in the Haliotis genus, and provides the first high-throughput transcriptomic resource for H. tuberculata.
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differential resistance to bacterial infection of two populations of the european abalone Haliotis tuberculata against the bacterium vibrio harveyi
Fish & Shellfish Immunology, 2016Co-Authors: Bruno Dubief, Olivier Basuyaux, Olivier Richard, Flavia L D Nunes, Christine PaillardAbstract:Since 1997, populations of the European abalone Haliotis tuberculata suffer mass mortalities attributed to the bacterium Vibrio harveyi. These mortalities typically coincide with the spawning season and when temperatures exceed 17 ° C, a temperature below which the bacterial proliferation is insufficient to cause damage to the abalone. To study abalone resistance mechanisms, experimental infections were carried out on geographically distinct populations thought to have differential response to disease in the field. A first set of successive infections identified one resistant (11% mortality) and one susceptible (58% mortality) population. Two sets of successive infections were used to highlight the resistance mechanisms of this population: (1) to evaluate the immune state of the resistant population compared to a susceptible, and (2) to compare differences in global gene expression (RNA-Seq) of hemocytes in the resistant and susceptible populations. While in vivo quantification of phagocytosis by flow cytometry showed strong inhibition following the first infection, inhibition of phagocytosis was less pronounced following the second infection, suggesting an immune priming effect. Fluorescent 3D microscopy (Vivatome) validated the capability of abalone hemocytes to phagocytose V. harveyi. In vitro analyses showed a significant negative impact of extracellular products of V. harveyi on phagocytosis. Furthermore, the RNA-Seq analysis showed 2956 transcripts (24, 9% annotated) with altered expression between the resistant and susceptible abalone populations following experimental infection. In the total annotated transcriptome, 288 transcripts were related to immune functions, including several F-type lectins, toll-like receptor, tumor necrosis factor and other immune genes of interest.
Sabine Roussel - One of the best experts on this subject based on the ideXlab platform.
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ocean acidification impacts growth and shell mineralization in juvenile abalone Haliotis tuberculata
Marine Biology, 2020Co-Authors: Sabine Roussel, Aicha Badou, Stephanie Auzouxbordenave, Nathalie Wessel, Sophie G Martin, Saloua Mzoudi, Solene Avignon, Sylvain HuchetteAbstract:Ocean acidification (OA) is a major global driver that leads to substantial changes in seawater carbonate chemistry, with potentially serious consequences for calcifying organisms. Marine shelled molluscs are ecologically and economically important species, providing essential ecosystem services and food sources for other species. Due to their physiological characteristics and their use of calcium carbonate (CaCO3) to build their shells, molluscs are among the most vulnerable invertebrates with regard to OA, with early developmental stages being particularly sensitive to pH changes. This study investigated the effects of CO2-induced OA on juveniles of the European abalone Haliotis tuberculata, a commercially important gastropod species. Six-month-old juvenile abalones were cultured for 3 months at four pH levels (8.1, 7.8, 7.7, 7.6) representing current and predicted near-future conditions. Survival, growth, shell microstructure, thickness, and strength were compared across the four pH treatments. After 3 months of exposure, significant reductions in juvenile shell length, weight, and strength were revealed in the pH 7.6 treatment. Scanning electron microscopy observations also revealed modified texture and porosity of the shell mineral layers as well as alterations of the periostracum at pH 7.6 which was the only treatment with an aragonite saturation state below 1. It is concluded that low pH induces both general effects on growth mechanisms and corrosion of deposited shell in H. tuberculata. This will impact both the ecological role of this species and the costs of its aquaculture.
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impact of nine macroalgal diets on growth and initial reproductive investment in juvenile abalone Haliotis tuberculata
Aquaculture, 2019Co-Authors: Sabine Roussel, Nelly Le Goic, Claire Caralp, Catherine Leblanc, Fabienne Le Grand, Valerie Stigerpouvreau, Celine Coulombet, Sylvain HuchetteAbstract:The commercial culture of Haliotis tuberculata has recently started in Europe. As abalone is herbivorous, the use of local collected algae as feed may appear advantageous. The nutritional value of eight monospecific seaweed diets was studied using Palmaria palmata (Rhodophyta), filamentous algae, mainly Gracilaria sp. (Rhodophyta), Enteromorpha sp. and Ulva lactuca (Chlorophyta), together with Saccharina latissima, Saccorhiza polyschides, Laminaria digitata and Laminaria hyperborea (Ochrophyta, Phaeophyceae) and a mixed macroalgal diet. An integrative approach consisted in monitoring the seasonal composition changes of these algae in terms of protein, lipid, soluble carbohydrate, fatty acid and amino-acid contents, and to relate it to seasonal growth and reproduction investment during a large-scale experiment. Abalone and algae were studied for one year in commercial sea-cage structures. Abalone fed with monospecific diet using either P. palmata or S. latissima, and with mixed diet presented the best growth rate, muscle ratio and gonad development. Seasonal daily weight gain was mainly associated with n-3/n-6 ratio, soluble carbohydrate content and total protein content. In term of amino-acid contents, the daily weight gain was associated with free phenylalanine as well as isoleucine levels. Moreover, 90% of 2-years old abalone started gonad development but less than a quarter featured a fully matured gonad. The gonad development of H. tuberculata was mostly associated to total valine, methionine, leucine, arginine and isoleucine levels. The age of initial sexual maturity in H. tuberculata turned to be a highly plastic trait in response to different growth rates and algal diets. Even if P. palmata is the best option for growth performance, mixed diets should probably be preferred to a monospecific diet in order to avoid too high pressure on a single algal resource.
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seasonal and diurnal variability in carbon respiration calcification and excretion rates of the abalone Haliotis tuberculata l
Journal of the Marine Biological Association of the United Kingdom, 2019Co-Authors: Jacques Clavier, Coraline Chapperon, Clement Dugue, Erwan Amice, Manon Le Goff, Sabine RousselAbstract:Abalone ( Haliotis spp.) are commercially important marine shellfish species worldwide. Knowledge about the physiology of abalone that impacts life-history traits is important for a better understanding of the biology of the species and the impact of stressful husbandry procedures at different seasons. The present study quantified the seasonal and diurnal variations in four physiological parameters of the European species Haliotis tuberculata , i.e. carbon aerial and aquatic respiration, calcification and excretion rates, and the effect of prolonged aerial exposure upon abalone aerial respiration. We also investigated the effect of individual size upon these physiological parameters. Aquatic respiration and calcification rates showed an allometric relationship with biomass. All parameters showed lower rates in cool season and higher rates in warmer season. Temperature was assumed to be the primary driver of the reported seasonal variability in physiological parameters, although reproductive needs and nutrition may also contribute to the observed patterns. Importantly, abalone did not stop calcifying in winter, and calcified more at night than during the day. Abalone did not respire more underwater at night-time than at daytime, however they excreted more overnight. The low air:aquatic ratio (0.2) is likely to be an energy-saving strategy for emerged H. tuberculata individuals. This study highlights the temporal heterogeneity in physiological rates of H. tuberculata , which constitutes a species recently domesticated in Europe.
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relationships between growth survival physiology and behaviour a multi criteria approach to Haliotis tuberculata phenotypic traits
Aquaculture, 2017Co-Authors: Sebastien Lachambre, Sylvain Huchette, Pierre Boudry, Antoine Riocabello, Timothee Fustec, Sabine RousselAbstract:Abalone growth rate is often identified among important traits to improve through selective breeding. However, the rapid success of some selective breeding plans has sometimes led to negative effects in some aquaculture species due to trade-offs. One of them is the loss of homeostasis of selected animals which results in the inability to resist the stress experienced during the rearing process. In this context, this study aimed to analyze the phenotypic relationships between growth, and physiological and behavioural traits in Haliotis tuberculata under stressful conditions. Eleven traits related to growth, immunity, reproduction and behaviour were recorded under laboratory conditions. A total of 120 adults from wild or farm origin were first monitored during a 3-week stress period (high density and acute stress handling) during winter, followed by 6 months on-growing in sea-cages. Relationships between parameters were analyzed using a multi-factorial approach. Wild and farm stocks could only be discriminated on behaviour traits, confirming that the French abalone industry is in the beginning of the domestication process. After 3 weeks of chronic stress, the righting latency of an abalone was linked to better survival and faster growth. Abalones having the best growth after 6 months were characterized by higher activity during the previous winter period, whereas an early gonad maturation reduced the growth in summer. Our results provide a basis for the establishment of a multi-trait breeding program to improve the growth rate while controlling the evolution of physiological and behavioural traits.ăStatement of relevanceăThe relationships of behavioural and physiological variables with survival and weight gain after application of important stressors were studied in order to provide a better understanding of Haliotis tuberculata biology during early domestication stage. This paper will give information on new targets and tools for selective breeding.
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Relationships between growth, survival, physiology and behaviour — A multi-criteria approach to Haliotis tuberculata phenotypic traits
Aquaculture, 2017Co-Authors: Sebastien Lachambre, Sylvain Huchette, Pierre Boudry, Timothee Fustec, Antoine Rio-cabello, Sabine RousselAbstract:Abalone growth rate is often identified among important traits to improve through selective breeding. However, the rapid success of some selective breeding plans has sometimes led to negative effects in some aquaculture species due to trade-offs. One of them is the loss of homeostasis of selected animals which results in the inability to resist the stress experienced during the rearing process. In this context, this study aimed to analyze the phenotypic relationships between growth, and physiological and behavioural traits in Haliotis tuberculata under stressful conditions. Eleven traits related to growth, immunity, reproduction and behaviour were recorded under laboratory conditions. A total of 120 adults from wild or farm origin were first monitored during a 3-week stress period (high density and acute stress handling) during winter, followed by 6 months on-growing in sea-cages. Relationships between parameters were analyzed using a multi-factorial approach. Wild and farm stocks could only be discriminated on behaviour traits, confirming that the French abalone industry is in the beginning of the domestication process. After 3 weeks of chronic stress, the righting latency of an abalone was linked to better survival and faster growth. Abalones having the best growth after 6 months were characterized by higher activity during the previous winter period, whereas an early gonad maturation reduced the growth in summer. Our results provide a basis for the establishment of a multi-trait breeding program to improve the growth rate while controlling the evolution of physiological and behavioural traits.ăStatement of relevanceăThe relationships of behavioural and physiological variables with survival and weight gain after application of important stressors were studied in order to provide a better understanding of Haliotis tuberculata biology during early domestication stage. This paper will give information on new targets and tools for selective breeding.
Bernard Kloareg - One of the best experts on this subject based on the ideXlab platform.
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purification and determination of the action pattern of Haliotis tuberculata laminarinase
Carbohydrate Research, 1998Co-Authors: Valerie Lepagnoldescamps, Philippe Potin, Christophe Richard, Marc Lahaye, Jeanclaude Yvin, Bernard KloaregAbstract:Abstract The major laminarinase activity (EC 3.2.1.39) from the gastropodean marine mollusc Haliotis tuberculata was purified to homogeneity by cation exchange chromatography and its action pattern was investigated by HPAEC-PAD analysis of the degradation of various laminarin samples. It consists of a 60 kDa protein capable of depolymerizing the unbranched portions of the β -(1→3), β -(1→6)-glucan, down to laminaritriose. The enzyme operates via a molecular mechanism retaining the anomeric configuration. As the purified protein does not cleave the β -(1→6) linkages, it can be used for the structural analysis of laminarins.
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hplc analysis of saturated or unsaturated oligoguluronates and oligomannuronates application to the determination of the action pattern of Haliotis tuberculata alginate lyase
Carbohydrate Research, 1996Co-Authors: Alain Heyraud, Christophe Richard, Philippe Colinmorel, Sylvie Girond, Bernard KloaregAbstract:Abstract The chromatographic behaviour of various saturated and unsaturated oligouronates obtained by acid or enzymatic degradation of homopolymeric blocks of alginates was investigated by isocratic anion exchange liquid chromatography. This approach was then applied to the determination of the catalytic properties of Haliotis tuberculata alginate lyase. This enzyme presents a high affinity for poly-β- d -mannuronate blocks, leading to the release of O -(4-deoxy-α- l - erythro -hex-4-enopyranosyluronic acid)-(1 → 4)- O -(β- d -mannopyranosyluronic acid)-(1 → 4)- O -β- d -mannopyranuronic acid as the main end reaction product. Kinetic analysis with oligomannuronates of various sizes indicate that the catalytic site of Haliotis tuberculata lyase (abalone) best accommodates an oligomannuronate pentamer. The abalone lyase, however, is also capable of cleaving the G—M linkages of alginate heteropolymeric sequences. In contrast, it does not degrade the G—G nor the M—G diads. This lyase should therefore be referred to as a mannuronate β-eliminase, indicating that the enzyme performs β-elimination on mannuronate residues only, from both the M—M and G—M diads of alginates.
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nmr spectroscopy analysis of oligoguluronates and oligomannuronates prepared by acid or enzymatic hydrolysis of homopolymeric blocks of alginic acid application to the determination of the substrate specificity of Haliotis tuberculata alginate lyase
Carbohydrate Research, 1996Co-Authors: Alain Heyraud, Sylvie Girond, Christine Leonard, Cyril Rochas, Bernard KloaregAbstract:Abstract The 1H and 13C NMR chemical shifts of the various saturated and unsaturated trimers obtained by acid or enzymatic depolymerisation of homopolymeric blocks of alginates are reported. In addition, 13C NMR chemical shifts are assigned for several saturated oligomers of higher polymerisation degrees. Breakdown of alginate and of homopolymeric alginate blocks by Haliotis tuberculata alginate lyase was monitored with 1H NMR spectroscopy and the signals relevant to the identification of the lyase products are pointed out. The enzyme performs β-elimination on the mannuronic acid residues, independently of their immediately surrounding neighbours. Application of this approach to the analysis of the substrate specificity of alginate lyases is discussed.
Stephanie Auzouxbordenave - One of the best experts on this subject based on the ideXlab platform.
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ocean acidification impacts growth and shell mineralization in juvenile abalone Haliotis tuberculata
Marine Biology, 2020Co-Authors: Sabine Roussel, Aicha Badou, Stephanie Auzouxbordenave, Nathalie Wessel, Sophie G Martin, Saloua Mzoudi, Solene Avignon, Sylvain HuchetteAbstract:Ocean acidification (OA) is a major global driver that leads to substantial changes in seawater carbonate chemistry, with potentially serious consequences for calcifying organisms. Marine shelled molluscs are ecologically and economically important species, providing essential ecosystem services and food sources for other species. Due to their physiological characteristics and their use of calcium carbonate (CaCO3) to build their shells, molluscs are among the most vulnerable invertebrates with regard to OA, with early developmental stages being particularly sensitive to pH changes. This study investigated the effects of CO2-induced OA on juveniles of the European abalone Haliotis tuberculata, a commercially important gastropod species. Six-month-old juvenile abalones were cultured for 3 months at four pH levels (8.1, 7.8, 7.7, 7.6) representing current and predicted near-future conditions. Survival, growth, shell microstructure, thickness, and strength were compared across the four pH treatments. After 3 months of exposure, significant reductions in juvenile shell length, weight, and strength were revealed in the pH 7.6 treatment. Scanning electron microscopy observations also revealed modified texture and porosity of the shell mineral layers as well as alterations of the periostracum at pH 7.6 which was the only treatment with an aragonite saturation state below 1. It is concluded that low pH induces both general effects on growth mechanisms and corrosion of deposited shell in H. tuberculata. This will impact both the ecological role of this species and the costs of its aquaculture.
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an integrated investigation of the effects of ocean acidification on adult abalone Haliotis tuberculata
Ices Journal of Marine Science, 2020Co-Authors: Solene Avignon, Aicha Badou, Stephanie Auzouxbordenave, Sophie G Martin, Philippe Dubois, Manon Coheleach, Nicolas Richard, Sarah Di GiglioAbstract:Ocean acidification (OA) and its subsequent changes in seawater carbonate chemistry are threatening the survival of calcifying organisms. Due to their use of calcium carbonate to build their shells, marine molluscs being particularly vulnerable. This study investigated the effect of CO2-induced OA on adult European abalone (Haliotis tuberculata) using a multi- parameter approach. Biological (survival, growth), physiological (pHT of haemolymph, phagocytosis, metabolism, gene expression) and structural responses (shell strength, nanoindentation measurements, SEM imaging of microstructure) were evaluated throughout a 5-month exposure to ambient (8.0) and low (7.7) pH conditions. During the first two months, the haemolymph pH was reduced, indicating that abalone do not compensate for the pH decrease of their internal fluid. Overall metabolism and immune status were not affected, suggesting that abalone maintain their vital functions when facing OA. However, after four months of exposure, adverse effects on shell growth, calcification, microstructure and resistance were highlighted, whereas the haemolymph pH was compensated. Significant reduction in shell mechanical properties were revealed at pH 7.7, suggesting that OA altered the biomineral architecture leading to a more fragile shell. It is concluded that under lower pH, abalone metabolism is maintained at a cost to growth and shell integrity. This may impact both abalone ecology and aquaculture.
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shell growth microstructure and composition over the development cycle of the european abalone Haliotis tuberculata
Marine Biology, 2015Co-Authors: Stephanie Auzouxbordenave, Aicha Badou, C Brahmi, M De Rafelis, Sylvain HuchetteAbstract:The shell of the European abalone Haliotis tuberculata is a model for studying mechanisms of mollusc shell formation, but the early steps of shell formation and calcification remain poorly documented. The microstructure and the mineralogical and geochemical composition of larval and juvenile shells were investigated by scanning electron microscopy, infrared spectroscopy and ion microprobe analyses (NanoSIMS). Analyses were performed on shells obtained from controlled fertilisations at the hatchery France-Haliotis (Plouguerneau, France) in July 2009 and 2010 using abalone from Roscoff. Shell cross sections revealed the microstructural arrangement of the developing shell, showing progressive biomineral organisation into two differentiated layers, i.e. the outer granular and the internal nacreous layer. Infrared analysis confirmed that the European abalone shell, at every stage of development, was mostly composed of CaCO3 in the form of aragonite. Variations in trace element composition, i.e. Sr/Ca, were measured in the different stages and correlated with micro-structural changes in the shells. Experimental manganese labelling of live abalones produced cathodoluminescence marks in the growing shell sections. The increase in shell thickness can be used to determine the growth rate of an early adult abalone shell.
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in vitro effects of triclosan and methyl triclosan on the marine gastropod Haliotis tuberculata
Comparative Biochemistry and Physiology C-toxicology & Pharmacology, 2012Co-Authors: Beatrice Gaume, Stephanie Auzouxbordenave, Nathalie Bourgougnon, Benoit Roig, Gilles BedouxAbstract:Abstract Triclosan (2,4,4′-trichloro-2′-hydroxy-diphenyl ether; TCS) is an antibacterial agent incorporated in a wide variety of household and personal care products. Because of its partial elimination in sewage treatment plants, TCS is commonly detected in natural waters and sediments. Moreover, due to its high hydrophobicity, TCS accumulates in fatty tissues in various aquatic organisms. TCS can be converted into methyl-triclosan (2,4,4′-trichloro-2′-methoxydiphenyl ether; MTCS) after biological methylation. In this study, the acute cytotoxicity of TCS and MTCS in short-term in vitro experiments was assessed on cell cultures from the European abalone Haliotis tuberculata. The results showed that morphology and density of hemocyte are affected from a concentration of 8 μM TCS. Using the XTT reduction assay, TCS has been demonstrated to decrease hemocyte metabolism activity in a dose- and time-dependent exposure. The IC50 was evaluated at 6 μM for both hemocyte and gill cells after a 24 h-incubation with TCS. A significant cytotoxicity of MTCS was also observed from 4 μM in 24 h-old hemocyte culture. Our results reveal a toxic effect of TCS and MTCS on immune (hemocytes) and/or respiratory cells (gill cells) of the abalone, species living in coastal waters areas and exposed to anthropogenic pollution.
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identification of two carbonic anhydrases in the mantle of the european abalone Haliotis tuberculata gastropoda haliotidae phylogenetic implications
Journal of Experimental Zoology, 2012Co-Authors: Beatrice Gaume, Stephanie Auzouxbordenave, Benjamin Marie, Nathalie Guichard, Sidney Delgado, Isabelle Zanellacleon, Michel Becchi, Jeanyves SireAbstract:Carbonic anhydrases (CAs) represent a diversified family of metalloenzymes that reversibly catalyze the hydration of carbon dioxide. They are involved in a wide range of functions, among which is the formation of CaCO(3) skeletons in metazoans. In the shell-forming mantle tissues of mollusks, the location of the CA catalytic activity is elusive and gives birth to contradicting views. In the present paper, using the European abalone Haliotis tuberculata, a key model gastropod in biomineralization studies, we identified and characterized two CAs (htCA1 and htCA2) that are specific of the shell-forming mantle tissue. We analyzed them in a phylogenetic context. Combining various approaches, including proteomics, activity tests, and in silico analyses, we showed that htCA1 is secreted but is not incorporated in the organic matrix of the abalone shell and that htCA2 is transmembrane. Together with previous studies dealing with molluskan CAs, our findings suggest two possible modes of action for shell mineralization: the first mode applies to, for example, the bivalves Unio pictorum and Pinctada fucata, and involves a true CA activity in their shell matrix; the second mode corresponds to, for example, the European abalone, and does not include CA activity in the shell matrix. Our work provides new insight on the diversity of the extracellular macromolecular tools used for shell biomineralization study in mollusks.
