Éditeur(s) : Elsevier
Résumé : Red drum larvae were fed from day 11 to day 24 post-hatch, with Artemia (LP group) or two isoproteinic-formulated diets with varying lipid levels, 15% (L15 group) and 30% (L30 group). The lipid fraction was composed of a mixture of cod liver oil and soy lecithin. Larvae fed Artemia exhibited the greatest length, L30 diet induced a larvae length significantly greater than that obtained with L15 diet (P < 0,05). No difference was observed in larvae survival among the three dietary groups. The increase in dietary lipid concentration led to an increase in amylase and trypsin secretion levels in 24-day-old larvae. The pancreatic secretion level measured in L30 group was close to that of LP group, suggesting that the maturation of the pancreatic functions was normally developed. Red drum larvae fed the diet containing the higher lipid content (L30) exhibited a more developed brush border membrane digestion in the intestine than larvae fed L15 diet (P < 0.05). Phospholipase A2 was stimulated by the increase of phospholipids in the diet, but no difference was observed for lipase between the two compound diet-fed groups; the LP group exhibited the lowest lipase activity. A plateau in lipase activity may have occurred in red drum larvae from 15% fat level in the diet, suggesting that the maximal lipase activity was reached with 12% neutral lipid in the diet. The positive effects observed with high dietary fat may be due to the phospholipid fraction of the lipid mixture used.
Aquaculture (0044-8486) (Elsevier), 2000-04 , Vol. 184 , N. 3-4 , P. 339-347

Droits : 2000 Elsevier
http://archimer.ifremer.fr/doc/2000/publication-503.pdf
DOI:10.1016/S0044-8486(99)00325-7
http://archimer.ifremer.fr/doc/00000/503/

Éditeur(s) : Elsevier
Résumé : Marine fish larvae undergo major morphological and cellular changes during the first month of life. The ontogeny of the gastrointestinal tract combines these two aspects of the larval development and is very interesting in that the timing of functional changes appears genetically hard-wired. The goal of this paper is to give an overview of the gastrointestinal development process in marine fish larvae, with particular attention to three species: sea bass; red drum; and sole, since the description of gut maturation in fish larvae was initiated during the last decade with these species. During the early stages, marine fish larvae exhibit particular digestive features. Concerning the exocrine pancreas, amylase expression decreases with age from the third week post-hatching in sea bass and red drum (approximately 400 degree days), whereas expression of other enzymes (trypsin, lipase, phospholipase A2...) increases until the end of the larva period. Moreover, secretory function of the exocrine pancreas progressively develops and becomes efficient after the third week of life. Concerning the intestine, enzymes of the enterocyte cytosol (in particular peptidase) have higher activity in young larvae than in older. Approximately in the fourth week of post-hatching development in sea bass, red drum and sole larvae, the cytosolic activities dramatically decline concurrently with a sharp increase in membranous enzyme activities of the brush border, such as alkaline phosphatase, aminopeptidase N, maltase... This process characterises the normal maturation of enterocytes in developing fish larvae and also in other vertebrates' species. The establishment of an efficient brush border membrane digestion represents the adult mode of digestion of enterocytes. This paper also describes the role of diet on the development of the gastrointestinal tract. Indeed, the maturational process of digestive enzyme can be enhanced, stopped, or delayed depending on the composition of the diet.
Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology (1532-0456) (Elsevier), 2001-12 , Vol. 130 , N. 4 , P. 477-487

Droits : 2001 Elsevier Science Inc. All rights reserved
http://archimer.ifremer.fr/doc/2001/publication-650.pdf
DOI:10.1016/S1532-0456(01)00274-5
http://archimer.ifremer.fr/doc/00000/650/

Éditeur(s) : Université de Nantes
Résumé : The reproductive cycle of Megathura crenulata was documented and quantification of oocyte lipid reserves with lipo-specific stains was explored in both this species and in Crassostrea gigas. The necessity of providing food to female broodstock C. gigas in spring was re-evaluated, because subsequent larval and post-larval rearing performance was not affected by broodstock starvation during conditioning. Developmental study of the organs responsible of particle processing in C. gigas allowed the identification of critical stages related to the ontogenesis of each organ, as well as a better understanding of the evolution of these organs, highly-modified in the Ostreidae. Ciliary type identification and mucocyte mapping from post-larval to adult stage showed that the heterorhabdic specialization precedes the anatomic formation of gill plicae specific to this condition.
Le cycle reproducteur de Megathura crenulata a été documenté et la quantification des réserves ovocytaires par des colorants lipospécifiques a été tentée, sans résultats concluants pour cette espèce, ni pour Crassostrea gigas. L'intérêt d'une alimentation des géniteurs femelles C. gigas au printemps est re-évalué, car la performance ultérieure des élevages larvaires et post-larvaires n'a pas été affectée par le jeûne imposé lors du conditionnement. L'étude du développement des organes impliqués dans le traitement des particules chez C. gigas a permis d'identifier des stades critiques associés à l'ontogenèse de chaque organe, ainsi qu'une meilleure compréhension de l'évolution de ces organes si particuliers chez les Ostreidae. L'examen des types ciliaires et la cartographie des mucocytes de la post-larve à l'adulte ont montré que la spécialisation hétérorhabdique précède même la formation anatomique des plis branchiaux caractéristiques de cette condition.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2005/these-1371.pdf
http://archimer.ifremer.fr/doc/00000/1371/

Résumé : This report is presented by Chantal Cahu for obtaining accreditation to supervise research. Since 1981, her research activity has addressed the study of reproducers' nutrition and the young stages of development of marine organisms belonging to two different branch lines, crustaceans and fish. This work, performed in a base-lined research body, IFREMER, is placed within a more general programme of aquaculture development. Indeed, whatever species are at issue, the development of aquaculture in France, as at the global level, is based on the production of juveniles in hatcheries. My work has therefore more precisely the goal of acquiring knowledge about the nutritional needs, mechanisms of digestion and the development of these animals in order to improve the production of prawn post-larvae and fish alevin in the hatchery. This work took place in three main periods that appear in this report: - The study of reproducers' nutrition and its influence on the quality of the Penaeid prawn's eggs and larvae. My work has focused mainly on the effect of lipids and vitamins on the development of eggs and larvae. - The study of the ontogenesis of the digestive functions and the nutritional needs of sea fish larvae, with bass as the model. The goal was to determine the specific nutritional needs of the young stages by studying the implementation and regulation of pancreatic and intestinal digestive enzymes. - The study of the regulation of certain developmental genes by means of nutrients, so as to understand how these nutrients behave during ontogenesis, particularly during development of the skeleton.
Ce mémoire est présentée par Chantal Cahu pour pour l'obtention d'une habilitation a diriger des recherches. Depuis 1981, son activité de recherche concerne l'étude de la nutrition des reproducteurs et des jeunes stades de développement d'organismes marins appartenant à deux embranchements différents, les crustacés et les poissons. Ce travail réalisé dans un organisme de recherche finalisée, l'Ifremer, se situe dans un programme plus général de développement de l'aquaculture. En effet, quelles que soient les espèces en jeu, le développement de l'aquaculture en France comme au niveau mondial repose sur la production de juvéniles en écloserie. Mon travail a donc plus précisément pour objectif l'acquisition de connaissances sur les besoins nutritionnels, les mécanismes de digestion et le développement des ces animaux afin d'améliorer la production de post-larves de crevettes et d'alevins de poissons en écloserie. Ce travail s'est déroulé en trois grandes périodes qui apparaissent dans ce mémoire : - L'étude de la nutrition des reproducteurs et son influence sur la qualité des oeufs et des larves de crevettes Pénéides. Mon travail a essentiellement porté sur l'effet des lipides et des vitamines sur le développement des oeufs et des larves. - L'étude de l'ontogenèse des fonctions digestives et les besoins nutritionnels des larves de poissons marins, avec le bar comme modèle. Le but était de déterminer les besoins nutritionnels spécifiques des jeunes stades, en étudiant la mise en place et la régulation des enzymes digestives pancréatiques et intestinales. - L'étude de la régulation de certains gènes du développement par les nutriments, de façon à comprendre comment ces nutriments agissent lors de l'ontogenèse, notamment lors du développement du squelette.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2006/rapport-2086.pdf
http://archimer.ifremer.fr/doc/00000/2086/

Résumé : The caledonian blue shrimp Litopenaeus stylirostris is the second largest export commodity in New Caledonia. This industry is based on 19 production farms but also four hatcheries, two feed production units and two packing plants. The maximum production was reached in 2005 with 2400 tons. Supply of juveniles by hatchery is the bottle neck of the production chain because this species is not present in the natural environment. Recent problems of larval survival led some scientists to work on eco-physiology to propose adaptations of larval rearing protocol. Salinity of the rearing environment is taken as an example to study the influence of abiotic parameters on the animal physiology according to its development stage. The influence of salinity on survival and growth was evaluated at different development stages in Litopenaeus stylirostris. The study showed that ocean salinity (33-35 ppt) should be maintained during the larval stage, but after the post-larval metamorphosis, better growth could be achieved by lowering the salinity gradually to 27 ppt. This measure is now applied routinely in the Saint Vincent's hatchery and is the result of research in eco-physiology showing that the blue shrimp iso-osmotic point is around 27 ppt.
La crevette bleue calédonienne Litopenaeus stylirostris est au deuxième rang des produits exportés en Nouvelle-Calédonie. L’industrie crevetticole calédonienne est basée sur 19 fermes de production mais également 4 écloseries, 2 provendiers et 2 usines de conditionnement. La production maximale a été atteinte en 2005 avec 2400 tonnes. La fourniture de juvéniles par les écloseries est le point crucial de la chaîne de production car cette espèce n’est pas présente dans le milieu naturel. Les récents problèmes de survie larvaire ont orienté une partie de la recherche vers l’éco-physiologie en vue de proposer des adaptations du protocole d’élevage. La salinité du milieu d’élevage est prise comme exemple pour étudier l’influence d’un paramètre abiotique sur la physiologie de l’animal en fonction de son stade de développement. L’influence de la salinité sur la survie et la croissance a été évaluée aux différents stades de développement chez Litopenaeus stylirostris. L'étude a permis de montrer que la salinité océanique (33-35 ppt) devait être maintenue durant la phase larvaire mais qu'après la métamorphose en post-larve, une meilleure croissance pouvait être obtenue en abaissant la salinité progressivement à 27 ppt. Cette mesure est maintenant appliquée en routine en élevage larvaire à l'écloserie de Saint-Vincent et découle des recherches menées en éco-physiologie qui situe le point iso-osmotique de la crevette bleue autour de 27 ppt.

Droits : 2011 Ifremer
http://archimer.ifremer.fr/doc/00115/22658/20603.pdf
http://archimer.ifremer.fr/doc/00115/22658/

Éditeur(s) : Université de la Polynésie Française
Résumé : The ontogeny of osmoregulation was studied in the blue shrimp Litopenaeus stylirostris in New Caledonia. The implication of branchial organs in ionic regulation was first demonstrated in juveniles by immunolocalization of three ion transporting proteins ( namely NKA, co-transporter NKCC1 and CFTR ) and ionocyte detection was done by means of electron microscopy. The role of the main ion transporting enzyme, NKA, was subsequently investigated during post-embryonic development using an integrative approach associating physiological, histological, immunological and biomolecular studies. Results obtained allowed us to propose a model of the osmoregulatory pattern in L. stylirostris based on weak regulation in the early stages, then progressively this species acquires the adult pattern of hyper-hypo-regulation after metamorphosis with the concurrent development of epipodites and gills. Strong NKA immunofluorescence and abundance of NKA transcripts in these two tissues compared to others organs suggest their functional implication in osmoregulatory processes. The results of this study allow us to increase our knowledge of the penaeid shrimp osmoregulation and to propose zootechnical measures to improve the animal physiological comfort. These propositions have been already tested during larval rearing trials, leading a two-fold-growth in 19 days-old postlarvae.
L’étude de l’ontogenèse de l’osmorégulation a été entreprise chez la crevette bleue Litopenaeus stylirostris en Nouvelle-Calédonie. L’implication des tissus de la cavité branchiale dans la régulation ionique a été déterminée au préalable chez des juvéniles par immunolocalisation de trois transporteurs protéiques d’ions, ( la NKA, le co-transporteur NKCC1 et le CFTR ) et par la détection de ionocytes en microscopie électronique. Le rôle de la NKA a été particulièrement étudié et son implication a été examinée au cours du développement post-embryonnaire par une approche intégrative associant des études physiologiques, histologiques, immunologiques et moléculaires. Cette démarche nous a permis de proposer un modèle d’osmorégulation chez L. stylirostris: de faible régulatrice dans les premiers jours de sa vie, cette espèce évolue vers l’hyper-hypo-régulation après la métamorphose avec le développement progressif des épipodites et des branchies. L’immunofluorescence prononcée de la NKA ainsi que l’abondance des transcrits du gène codant la NKA dans les tissus de ces deux organes suggèrent leur implication fonctionnelle dans l’ionorégulation. Les résultats de ce travail nous ont permis d’accroître nos connaissances sur l’osmorégulation chez les pénéidés et de proposer des améliorations zootechniques visant à augmenter leur confort physiologique. Ces préconisations ont fait l’objet de premiers essais en conditions d’élevage et se sont traduites par un doublement de la croissance des post-larves de 19 jours.

Droits : 2011 The author, Univ. Polynésie Française
http://archimer.ifremer.fr/doc/00052/16314/13816.pdf
http://archimer.ifremer.fr/doc/00052/16314/

Résumé : L’ouvrage « Elevage de la Crevette Bleue en Nouvelle-Calédonie – Bases biologiques et zootechnie » est sans aucun doute le document de référence dont la crevetticulture de Nouvelle-Calédonie avait besoin. L’élaboration de cette synthèse des connaissances a été initiée lors du déroulement du projet de recherche Ifremer DESANS (DEfi SANté Stylirostris) construit sur la période 2003-2006 et a été finalisée sous le projet DEDUCTION (DEveloppement DUrable de la Crevetticulture, Traitement de l’Information et Observatoire de la filière en Nouvelle-calédonie) en cours sur la période 2007-2010.Il décrit les nombreux éléments à prendre en compte pour la création d’une ferme, qu’il s’agisse de la façon de constituer le dossier, des réalités socio-économiques, des caractéristiques du milieu et des coûts.D’emblée,le futur éleveur saura que seule une approche systémique permettra de positionner le projet dans son contexte environnemental. Les auteurs étudient ensuite l’impact des principaux paramètres physico-chimiques et biologiques du milieu sur la santé et la croissance des crevettes en introduisant la notion dynamique de «fonctionnement écologique» d’un bassin, la troisième partie traitant des causes de l’instabilité de l’écosystème que chacun d’eux constitue. Enfin, sont décrites les méthodes à mettre en œuvre dans la conduite des élevages, depuis l’introduction des post-larves jusqu’à la récolte et enfin le conditionnement.

Droits : 2009 Ifremer
http://archimer.ifremer.fr/doc/00251/36229/34789.pdf
http://archimer.ifremer.fr/doc/00251/36229/

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Marine organisms are under threat globally from a suite of anthropogenic sources, but the current emphasis on global climate change has deflected the focus from local impacts. While the effect of increased sedimentation on the settlement of coral species is well studied, little is known about the impact on larval fish. Here, the effect of a laterite “red soil” sediment pollutant on settlement behaviour and post-settlement performance of reef fish was tested. In aquarium tests that isolated sensory cues, we found significant olfaction-based avoidance behaviour and disruption of visual cue use in settlement-stage larval fish at 50 mg L−1, a concentration regularly exceeded in situ during rain events. In situ light trap catches showed lower abundance and species richness in the presence of red soil, but were not significantly different due to high variance in the data. Prolonged exposure to red soil produced altered olfactory cue responses, whereby fish in red soil made a likely maladaptive choice for dead coral compared to controls where fish chose live coral. Other significant effects of prolonged exposure included decreased feeding rates and body condition. These effects on fish larvae reared over 5 days occurred in the presence of a minor drop in pH and may be due to the chemical influence of the sediment. Our results show that sediment pollution of coral reefs may have more complex effects on the ability of larval fish to successfully locate suitable habitat than previously thought, as well as impacting on their post-settlement performance and, ultimately, recruitment success.
ISSN: 0029-8549

hal-01270670
https://hal-univ-perp.archives-ouvertes.fr/hal-01270670
DOI : 10.1007/s00442-015-3367-6

Éditeur(s) : HAL CCSD Frontiers
Résumé : International audience
Important set of studies have demonstrated the endocrine disrupting activity of Bisphenol A (BPA). The present work aimed at defining estrogenic-like activity of several BPA structural analogs, including BPS, BPF, BPAF, and BPAP, on 4- or 7-day post-fertilization (dpf) zebrafish larva as an in vivo model. We measured the induction level of the estrogen-sensitive marker cyp19a1b gene (Aromatase B), expressed in the brain, using three different in situ/in vivo strategies: (1) Quantification of cyp19a1b transcripts using RT-qPCR in wild type 7-dpf larva brains exposed to bisphenols; (2) Detection and distribution of cyp19a1b transcripts using in situ hybridization on 7-dpf brain sections (hypothalamus); and (3) Quantification of the cyp19a1b promoter activity in live cyp19a1b-GFP transgenic zebrafish (EASZY assay) at 4-dpf larval stage. These three different experimental approaches demonstrated that BPS, BPF, or BPAF exposure, similarly to BPA, significantly activates the expression of the estrogenic marker in the brain of developing zebrafish. In vitro experiments using both reporter gene assay in a glial cell context and competitive ligand binding assays strongly suggested that up-regulation of cyp19a1b is largely mediated by the zebrafish estrogen nuclear receptor alpha (zfERα). Importantly, and in contrast to other tested bisphenol A analogs, the bisphenol AP (BPAP) did not show estrogenic activity in our model
ISSN: 1662-4548

hal-01299976
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01299976
PUBMED : 27047331
DOI : 10.3389/fnins.2016.00112
PUBMEDCENTRAL : PMC4805609

Éditeur(s) : Université de La Rochelle
Résumé : Shrimp aquaculture in New Caledonia is a developing industry, exclusively based on the species Litopenaeus stylirostris. However, it is subject to mortalities during grow out as observed all over the world. Since 1993, shrimp reared during the cold period are affected by a disease named "syndrome 93". As a consequence, the whole industry has become seasonal and produces essentially during the warm season. The climatic conditions during the periods of transition between the two main seasons could be responsible for an environmental stress and the origin reason for mortality outbreaks. Stocking density is the main risk factor. It increases the probability of the appearance and development of the epizooty in the pond. The "Summer Syndrome", a septicemic vibriosis caused by Vibrio nigripulchritudo, was identified for the first time in December 1997 in an intensive shrimp farm (DF). It has become enzootic ever since and is expressed after 50d of rearing. Since 2003, two others farms located near DF have developed the disease. As a consequence, the summer syndrome is considered to be a potential threat for all the industry. Between 1991 and 2005, the increase of feed input and nitrogen levels in feed has led to a significant increase in the growth rate over the years in the farms affected by the disease. In consequence, an early eutrophication of the water is observed, which is concomitant with the beginning of the mortality outbreaks. An early eutrophication and the virulence level of the pathogen are considered as the main risk factors of the disease. Factors may act synergistically to explain the summer syndrome. As part of a multidisciplinary approach (pathology – physiology – environment), two high-frequency surveys were carried out to analyse the pond ecosystem. Since the feed quantity increases with the biomass of shrimp, the eutrophication level of the pond ecosystem will also tend to increase with the duration of rearing. During the first part of the rearing, the abundance of each picoplankton type is exceptionally high and picophytoplankton dominated the autotrophic compartment. The nanophytoplankton dominated the second part of the rearing and was more unstable. The shift from pico to nanophytoplankton could be considered as an environmental stress and was observed in relation to the beginning of the mortalities, whatever the disease. Shift intensity could play a role by inducing directly or indirectly a stress for shrimp and/or a growth and/or virulence factors of the pathogen. Results from sediment studies show that mortality was best characterized by TAN concentration in pore water and even more when the TAN concentration was high. TAN and pH are potential stress factors for shrimp reared in ponds affected by these diseases.
L'aquaculture mondiale de crevettes est un secteur à très forte croissance. Toutefois, les problèmes liés aux maladies dans les élevages ne cessent d'augmenter depuis 1980. Au cours du développement de la filière de Nouvelle-Calédonie, deux épisodes saisonniers de mortalités associées à la présence de Vibrio pathogènes sont apparus et ont fortement perturbé les techniques et les schémas de production. Les premières mortalités hivernales, décrites sous le nom de « syndrome 93 » ont été observées en mai 1993. Elles ont affecté depuis tous les élevages de saison froide de toutes les fermes de production. Les conditions climatiques pendant les périodes de transitions entre les deux principales saisons caractérisant le climat de la Nouvelle-Calédonie, seraient responsables d'un stress environnemental à l'origine du déclenchement du syndrome 93. La densité initiale d'ensemencement, apparaît comme le principal facteur de risque, augmentant la probabilité d'apparition de la maladie et l'ampleur de ses effets. Le « syndrome d'été » a été identifié pour la première fois en 1997 dans une ferme pratiquant une production intensive. Il s'est déclaré depuis 2003 dans deux autres fermes géographiquement proches. Les mortalités apparaissent 58 jours en moyenne après l'ensemencement des post-larves dans les bassins. La recherche d'une croissance maximale des animaux a induit, avec les années, une intensification progressive du système caractérisée par une augmentation de la quantité d'aliment distribuée. L'examen des données historiques fait apparaître une eutrophisation du milieu de plus en plus précoce concomitante au déclenchement des mortalités. En l'état actuel de nos connaissances, cette évolution précoce de l'écosystème en présence de façon récurrente de la souche hautement pathogène du Vibrio incriminé et à une période où la fréquence des mues des crevettes est élevée, constitue le principal facteur de risque de la maladie. Avec l'apport croissant en aliment, la colonne d'eau évolue vers une autotrophie croissante alors que le sédiment devient de plus en plus hétérotrophe au fur et à mesure que l'élevage progresse. Au cours du processus d'eutrophisation, le compartiment autotrophe montre une succession de deux assemblages. Le picophytoplancton domine sur la première partie de l'élevage et laisse place à du nanophytoplancton en seconde partie. Cette phase de transition, concomitante à l'apparition des mortalités quel que soit le syndrome, caractérise un stress environnemental dont l'intensité pourrait favoriser ou non le déclenchement des mortalités. Les suivis de différents indicateurs dans les sédiments - pH, potentiel d'oxydoréduction et concentration en ammoniaque dans l'eau interstitielle – indiquent dans les bassins déclarant les épizooties des conditions qui ont été définies expérimentalement comme potentiellement plus stressantes pour les animaux.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2007/these-2643.pdf
http://archimer.ifremer.fr/doc/00000/2643/

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Marine organisms are under threat globally from a suite of anthropogenic sources, but the current emphasis on global climate change has deflected the focus from local impacts. While the effect of increased sedimentation on the settlement of coral species is well studied, little is known about the impact on larval fish. Here, the effect of a laterite “red soil” sediment pollutant on settlement behaviour and post-settlement performance of reef fish was tested. In aquarium tests that isolated sensory cues, we found significant olfaction-based avoidance behaviour and disruption of visual cue use in settlement-stage larval fishat 50 mg L−1, a concentration regularly exceeded in situ during rain events. In situ light trap catches showed lower abundance and species richness in the presence of red soil, but were not significantly different due to high variance in the data. Prolonged exposure to red soil produced altered olfactory cue responses, whereby fish in red soil made a likely maladaptive choice for dead coral compared to controls where fish chose live coral. Other significant effects of prolonged exposure included decreased feeding rates and body condition. These effects on fish larvae reared over 5 days occurred in the presence of a minor drop in pH and may be due to the chemical influence of the sediment. Our results show that sediment pollution of coral reefs may have more complex effects on the ability of larval fish to successfully locate suitable habitat than previously thought, as well as impacting on their post-settlement performance and, ultimately, recruitment success.
ISSN: 0029-8549

hal-01346933
https://hal-uvsq.archives-ouvertes.fr/hal-01346933
https://hal-uvsq.archives-ouvertes.fr/hal-01346933/document
https://hal-uvsq.archives-ouvertes.fr/hal-01346933/file/ms%20O%27Connor%20et%20al%20%202014%20%28Oecologia%29.pdf
PUBMED : 26080759

Éditeur(s) : Elsevier
Résumé : The New Caledonia blue shrimp Litopenaeus stylirostris is commercially produced under semi-intensive rearing conditions. The size of the farming earthen ponds (5–10 ha) and the subsequent production constraints make it difficult to use them as experimental units for random experiments. Moreover, since every pond has its own characteristics, ponds' effects cannot be ruled out, thus making it hard to define true replicates. In order to design future experiments under conditions resembling those used in production, we evaluated the possible use of floating cages as experimental units with the aim of assessing treatment effects with a reasonable statistical power. To this end, two sets of floating cages were placed respectively in two different ponds in a commercial farm. In both cases the zootechnical conditions in the cages were similar in post-larvae origin, management, and diet and feeding regime. The aim of the study was to evaluate on a technical basis the possibility of rearing shrimps in floating cages set up in earthen ponds and to assess this method from a statistical standpoint. Shrimps reared in and outside the cages showed comparable growth and survival rates. The variability in the zootechnical parameters between cages, expressed as the estimated coefficient of variation (CV) for survival rate, total final biomass (g), final body weight (g), daily increment in body weight (g day− 1) and FCR were 11.0, 13.7, 4.4, 5.4, and 7.0%, respectively. On the basis of these figures, we calculated for a given statistical power (80%) the number of replicates (cages) that would be required to reveal significant differences between two treatments, at a 5% level of significance. We found that for expected differences of 20% from the control mean, 3 and 6 floating cages per treatment would be reasonable to determine statistical differences for growth parameters and survival rate, respectively. Moreover, we showed a significant pond effect in regard to survival and growth between the two sets of cages. These results illustrated the within-farm variability among the ponds, and confirmed that the specific characteristics of each pond from the same farm make it difficult to use the ponds themselves as experimental units. The study demonstrates that rearing in floating cages is an economical, powerful and sensitive experimental tool for shrimp culture studies specifically carried out under conditions close to semi-intensive production.
Aquaculture (0044-8486) (Elsevier), 2008-07 , Vol. 279 , N. 1-4 , P. 63-69

Droits : 2008 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2008/publication-4363.pdf
DOI:10.1016/j.aquaculture.2008.03.053
http://archimer.ifremer.fr/doc/00000/4363/

Éditeur(s) : HAL CCSD
Résumé : International audience
The subterranean environment is often described as “extreme” and food poor. Laboratory experiments have shown that blind Mexican tetra Astyanax mexicanus (De Filippi, 1853) cavefish are better at finding food in the dark than surface fish. Several morphological and behavioural attributes that could foster this obvious adaptive response to cave environments have been described. Nonetheless, it is currently unknown what young cavefish actually eat in their natural cave environment. Our results from the Pachón cave in México during the dry and rainy season show that fry are efficient predators in their natural cave environment. Their primary food item is aquatic crustaceans. The guts of post-larval, pre-juvenile stage individuals (n=9) contained an average of 17.9 water fleas (Cladocera), copepods, ostracods, and isopods. Thus, the fry in this cave are well-fed. The Pachón cave environment does not appear to be “food poor” for juvenile cavefish. Food regimes change between post-larval and adult stages to become more dependent on partially decomposed material, guano, or detritus from the mud. We discuss the data with regards to our current developmental and genetic understanding of cavefish morphological and behavioural evolution, particularly regarding its enhanced Vibration Attraction Behaviour (VAB).
Subterranean Biology

hal-01432027
https://hal.archives-ouvertes.fr/hal-01432027
DOI : 10.3897/subtbiol.21.11046

Éditeur(s) : Elsevier Science Bv
Résumé : In this study, three microdiets were tested on weaning of Florida pompano larvae: Otohime, Gemma and a reference diet LR803. The experimental system was stocked with 11-day-old larvae, which were co-fed micro-diets and live food from 11 dph to 17 dph then micro-diets only until 28 dph. Survival from 11 dph to 28 dph was similar for all treatments, with an average of 33%. At the end of the trial, the Gemma larvae were significantly longer and heavier than larvae fed the other diets. Significant differences were observed in fatty acid composition of the diets and larvae between treatments. The Gemma larvae incorporated the lowest amount of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (ARA). However, they had the highest DHA/EPA and ARA/EPA ratios, which is in agreement with the concept that the proportions of polyunsaturated fatty acids could be of greater importance than their absolute amount. Results from the enzyme analysis suggest that fishmeal is suitable as the main protein source for Florida pompano larvae compared to krill meal. This study gives new insights on Florida pompano early nutritional requirements and demonstrated the full functionality of the pancreas at 16 days post hatch, opening possibilities of an earlier weaning time.
Aquaculture (0044-8486) (Elsevier Science Bv), 2014-02 , Vol. 422 , P. 268-276

Droits : 2013 Elsevier B.V. All rights reserved
http://archimer.ifremer.fr/doc/00169/28067/26282.pdf
DOI:10.1016/j.aquaculture.2013.12.006
http://archimer.ifremer.fr/doc/00169/28067/

Éditeur(s) : PSIC 11 - 11th Pacific Science Inter-Congress : Pacific Countries and their Ocean: Facing Local and Global Changes / 2nd Symposium on French Research in the Pacific. March 2 - 6, 2009 Tahiti, French Polynesia.
Résumé : In aquaculture, Artemia nauplii are commonly used as live prey; and represent 40 % of the total aquaculture feed demands in the early stages. However, the production of Brine shrimp is very unstable from one year to another and in the late 90’s, only 20 % of the world aquaculture need was covered. An insufficient offer leads to higher prices of the Artemia cysts and consequently, the price of shrimp juveniles from hatchery. In New Caledonia, marine aquaculture is mainly based on the blue shrimp Litopenaeus stylirostris. From Zoea 3 to 10 days old post-larvae (P10), the shrimp are mainly fed with live preys. Eleven kilos of Artemia cyst are necessary for producing one million of P10. From a sanitary point of view, Artemia can be a virus carrier and Vibrio population increase is often detected in the larval rearing tank the day after the feeding with live prey. Up to now, Brine shrimp are delivered in excess but with the cost and sanitary problems, Saint-Vincent laboratory has started some experiments in order to optimise the use of Artemia in shrimp larval rearing. The first tests were conducted to determine the effect of the Artemia quantity on the growth and the survival rate at different post-larval stages (P8-P11, P5-P8 and M3-P3). It was shown that four to twelve times fold Artemia was necessary for P8-P11 compared to M3-P3. And it was also noticed that the “optimized”quantity of live food at M3-P3 was twice lower than the recommended amount of the hatchery feeding protocol in New Caledonia. A better knowledge of the real feed requirement in the early life of the blue shrimp will be helpful to decrease the cysts quantities used in shrimp hatcheries but also the associated sanitary impact. And further, these results will give data for developing formulated diets which will replace the live prey and will increase the biosecurity and the sustainability of the production of the blue juvenile shrimp in New Caledonia.
En aquaculture, les nauplii d’Artemia sont largement utilisés comme proies vivantes et représentent près de 40 % des besoins en aliments pour la production des stades précoces. Cependant, l’approvisionnement en Artemia peut fluctuer de façon importante d’une année sur l’autre. Ainsi vers la fin des années 90, la demande mondiale a pu être satisfaite seulement à hauteur de 20%. Les années avec une offre insuffisante correspondent à des augmentations importantes du cours mondial des cystes d’artemia avec des répercussions sur le prix des animaux juvéniles produits en écloserie. En Nouvelle-Calédonie, l’aquaculture marine est principalement basée sur la crevette bleue Litopenaeus stylirostris. Les larves de cette espèce, à partir du stade Zoé 3, se nourrissent essentiellement de proies vivantes. Ainsi pour produire un million de Post-larves de 10 jours il faut compter 11 kilos de cystes d’Artemia. Outre le problème posé par le coût, les artemii peuvent également représenter un risque sanitaire pour l’écloserie. En effet certaines souches sont infectées par des virus qui peuvent contaminer les crevettes et de façon plus générale l’introduction des artemii dans le volume d’élevage larvaire s’accompagne le plus souvent d’une flambée de la flore vibrionacée. Jusqu’à présent, les Artemii étaient distribuées en excès cependant du fait de leur coût et des risques sanitaires, le laboratoire de St Vincent a débuté un travail pour optimiser leur utilisation en production larvaire de crevette. Ainsi, nos premières expérimentation sur l’effet de la dose en artemii sur le développement et la survie des larves de crevettes ont permis de déterminer les rations optimales pour les stades larvaires P8-P11, P5-P8 et M3-P3. Nous avons ainsi montré que la ration de proies vivantes était 4 à 12 fois plus importante à P8-P11 qu’à M3-P3. Par ailleurs la dose optimale déterminée au cours de nos expérimentations était pour les stades M3-P3 deux fois moins élevée que celle préconisée par le protocole actuel des écloseries commerciales de Nouvelle-Calédonie. Nous voyons ainsi, qu’une meilleure compréhension des besoins alimentaires de la crevette au cours de son développement permettra de diminuer de façon substantielle les proies vivantes utilisées ainsi que le risque sanitaire associé. A terme, ces travaux donneront des bases au développement d’aliments inertes en remplacement des proies vivantes et à la production durable, en conditions de biosécurité, des crevettes bleues juvéniles pour la filière Calédonienne

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00198/30877/29245.pdf
http://archimer.ifremer.fr/doc/00198/30877/

Éditeur(s) : The 11th Pacific Science Inter-Congress : Pacific Countries and their Ocean: Facing Local and Global Changes. March 2 - 6, 2009 Tahiti, French Polynesia
Résumé : New Caledonian shrimp farming feasibility studies started in the mid-seventies. Today ca. 2000 tons of Litopenaeus stylirostris, introduced in 1978, are semi-intensively produced each year. Since fifteen years, production has been impacted by two seasonal vibriosis, the “Summer” syndrome caused by Vibrio nigripulchritudo in relation to pond bottom and water column quality, and the “Winter Syndrome” caused by Vibrio penaeicida in relation to drastic temperature drops . With the ambition of elucidating processes possibly leading to mortality outbreaks in ponds, Ifremer has been conducting a research program since 2003 under the DESANS project (2003-2006) and the present DEDUCTION project, equally funded by the South and North Provinces and by the Government of New Caledonia. This program has been designed in a multidisciplinary approach integrating the suspected multifactorial origin of shrimp mortalities. Environment quality in ponds (either sediment or water column) plays a major role in the shrimp ecophysiological status, influencing sensitivity to pathogens . DEDUCTION focuses on a better knowledge of phytoplankton composition and biogeochemical fluxes at the sediment-water interface in ponds. Impact of farm discharges is also investigated. In addition, a more fundamental work is conducted to understand the pathogenicity mechanisms of these two Vibrio species but also to prevent the occurrence of viral infections through a RNA interference approach. Markers of the ecophysiological status of broodstock, larvae, post-larvae and reared animals, such as enzymes testifying from an oxidative stress, are developed. Gain of performance (resistance to pathogens and growth) were obtained on hybrids of the New Caledonian and introduced Hawaiian strains. Finally the database Stylog is exploited in view of discriminating “good” from “bad” rearings on the basis of relevant indicators.
Les études de faisabilité de l'aquaculture de crevettes ont débuté en Nouvelle-Calédonie dans les années soixante dix. Aujourd'hui environ 2000 tonnes de Litopenaeus stylirostris, introduite en 1978, sont produites chaque année de façon semi-intensive. Depuis quinze ans la production a été impactée par deux vibrioses : le syndrome d'été provoqué par Vibrio nigripulchritudo en relation avec la qualité de la tranche d'eau et des fonds de bassins et le syndrome d'hiver provoqué par Vibrio penaeicida en relation avec des chutes rapides de température. Dans le but d'élucider les processus entrainant des mortalités dans les élevages, Ifremer a conduit un programme de recherche depuis 2003 dans le cadre du projet DESANS (2003-2006) puis du présent projet DEDUCTION co-financé par les provinces Nord et Sud et le Gouvernement de la Nouvelle-Calédonie. Ce programme se construit dans une démarche multidisciplinaire intégrant les origines supposées multifactorielles des mortalités de crevettes. La qualité environnementale dans les bassins (les fonds et la colonne d'eau) joue un rôle majeur dans l'état physiologique des animaux, influençant leur sensibilité aux pathogènes. DEDUCTION se focalise sur une meilleure compréhension de la composition phytoplanctonique et des flux bio-géochimiques à l'interface eau/sédiment dans les bassins.L'impact des rejets des fermes est également étudié. En outre, un travail plus fondamental est conduit pour connaître les mécanismes de pathogénicité de ces deux espèces de Vibrio mais aussi pour prévenir les occurences d'infections virales par des approches ARN Interférence. Des marqueurs de l'état physiologique des oeufs, larves, post-larves et animaux en élevage, tels que les enzymes du stress oxydant sont utilisés.Les gains de performance (résistance aux pathogènes et croissance) sont obtenus sur des hybrides issus du croisement de la souche locale avec une souche hawaienne. Finalement la base de données STYLOG est exploitée dans le but de distinguer les bonnes des mauvaises pratiques sur la base d'indicateurs fiables.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00143/25438/23591.pdf
http://archimer.ifremer.fr/doc/00143/25438/

Résumé : L’objectif de ce travail est la définition d’une méthode d’incubation des oeufs de platax orbicularis garantissant une estimation plus précise et plus sûre du nombre d’animaux réalisée au démarrage des élevages larvaires Afin de pouvoir améliorer la précision de la répartition, nous avons fait l’hypothèse qu’il est préférable de mettre en place une incubation des oeufs directement dans les bassins d’élevage. En effet les oeufs sont plus facilement manipulables que les larves, ce qui présente un avantage important lors de leur comptage. Cette méthode faciliterait aussi la conduite de certains protocoles d’élevage larvaire, notamment la production de familles. Un gain de qualité des larves est aussi attendu découlant du fait que les larves ne sont plus manipulées après l’éclosion. Mais cette méthode présente l’inconvénient de ne pas pouvoir connaître directement le taux d’éclosion et l’effectif post-éclosion présent dans les bassins. Il est donc nécessaire de mettre en place en parallèle une méthode d’incubation témoin. Les résultats de comptage montrent qu’il est plus sur de compté des oeufs que des larves et six prélèvements de 5ml sont suffisant pour avoir une précision de 8 % et cela de façon reproductible. La mise en place d’éclosion témoin en incubateur de 50 litres a permis d’estimer l’éclosion avec un intervalle de confiance de 3 %. Ce qui a permis la mise en place de la méthode « directe » engendrant un gain de précision dans la répartition de l’ordre de 40 %. Au final, il serait préférable de compter les oeufs, puis de les répartir par volumétrie dans les bassins d’élevage. Il est préférable d’utiliser en parallèle des incubateurs de 50 litres pour conduire une incubation témoin précise et sûre. Les taux d’éclosion de ces témoins seront appliqués aux bassins larvaires et permettront de connaître la population de chaque bassin.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00128/23877/21812.pdf
http://archimer.ifremer.fr/doc/00128/23877/

Éditeur(s) : Elsevier Science Bv
Résumé : The euryhaline white shrimp Litopenaeus vannamei lives in both coastal and oceanic areas through ontogeny. Its osmoregulation pattern and variations in its tolerance to salinity are partially known from several studies under different experimental conditions (developmental stages, salinities and acclimation procedures). Although L. vannamei is recognized as one of the most euryhaline penaeid species, with adults and juveniles exhibiting an hyper-hypo-osmoregulatory pattern and being able to tolerate a wide salinity range, little is known on larval and early postlarval strategies to cope with salinity fluctuations. In order to establish their euryhalinity range and to fully understand the ontogenetic changes in L. vannamei osmoregulatory pattern, we evaluated the effect of six salinities (5, 10, 20, 32, 45 and 60 psu) on 17 developmental stages by directly exposing them to experimental salinities and conducting observations during the next 48 hours. At 5 hours post osmotic shock (hps), all developmental stages survived (> 20%) in 20, 32 and 45 psu. The euryhalinity and osmoregulation pattern changed at some developmental stages of L. vannamei. The hyper-hypo osmoregulatory pattern exhibited by Juvenile and Adult appears to be established early in the first post-larval stage PL1 (ontogenetic osmoregulation pattern type 3), with higher tolerance to salinity variations observed in PL2, PL4 and PL22 suggesting that L. vannamei shows a progressive increase in the efficiency of osmoregulatory mechanism following last metamorphosis.
Aquaculture (0044-8486) (Elsevier Science Bv), 2014-02 , Vol. 422 , P. 261-267

Droits : 2013 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00169/28068/26283.pdf
DOI:10.1016/j.aquaculture.2013.11.034
http://archimer.ifremer.fr/doc/00169/28068/

Éditeur(s) : Proceedings of the 9th International Pectinid Workshop, Canada
Résumé : The influence of density on Patinopecten yessoensis larval development was studied during production of an F2 generation. Setting behaviour of P. yessoensis on PVC removable spat collectors, previously tested with Pecten maximus, was determined. Poor larval growth of P. yessoensis was observed at a larval density of 7 ·ml·1 and post larval settlement occurred mainly on the bottom of the baskets, as has been observed with the king scallop, P. maximus. The PVC collector is not suitable for either species of scallop.

Droits : 1994 Ifremer
http://archimer.ifremer.fr/doc/00090/20163/17816.pdf
http://archimer.ifremer.fr/doc/00090/20163/

Éditeur(s) : Office Int Epizooties
Résumé : The tremendous development of penaeid shrimp culture across the world over the past twenty years has led to international trade in eggs, larvae and spawners of the best shrimp species for aquaculture. Trade has involved, in particular, the following species: - Penaeus japonicus from Japan to Europe, the Pacific Islands and South America - P. monodon from South-East Asia to almost all tropical countries - P. vannamei and P. stylirostris from countries along the Pacific coast of South and Central America to the United States of America, the islands of the South Pacific, countries along the Atlantic coast of the Americas and certain countries in Africa. In the 1980s, research conducted by American and French teams enabled the breeding of stocks of spawners in captivity. This resulted in the establishment of lines of captive broodstock outside natural areas of distribution, and the development of new breeding farms in previously unproductive regions. Trade related to movements of these species is facilitated by the absence of legislation in most countries; even when such legislation does exist, it is not always applied These practices have led to the rapid development of world shrimp production, but have also contributed to the dissemination of pathogens. In recent years, the occurrence of serious epizootics - occasioning heavy losses world-wide - has led to a more cautious approach involving trade of post-larvae obtained from captive broodstock in which thorough control measures have been implemented for known diseases. Trade in wild shrimp will probably be abandoned progressively, to avoid the risk of introducing new pathogens. The main challenges for research in the near future are the development of diagnostic tools, to enable continuous control of captive broodstock, and the selection of strains which are resistant to the principal pathogens affecting these species.
Revue Scientifique Et Technique-office International Des Epizooties (0253-1933) (Office Int Epizooties), 1996-06 , Vol. 15 , N. 2 , P. 499-515

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00091/20231/17883.pdf
http://archimer.ifremer.fr/doc/00091/20231/