Éditeur(s) : Elsevier
Résumé : The effect of ambient ammonia and molt stage on the physiological response of the blue shrimp Litopenaeus stylirostris was studied. Shrimps were submitted to 54.6 mg l(-1) ammonia-N (1.76 mg l(-1) NH3-N) for 24 h. Only shrimps in stages C, D-0, D-1 and D-2 were used for the analysis. Haemolymph was assayed for osmoregulatory capacity (OC), magnesium ion (Mg ion), total proteins, oxyhaemocyanin, lactate and glucose. Molt stage had an effect on OC, Mg ion and total proteins in control shrimps, and on OC, Mg ion and lactate in treated animals. Ammonia treatment decreased OC and lactate, and increase Mg ion concentration in haemolymph, for all molt stages. It decreased significantly total proteins and oxyhaemocyanin for stages D-1 and D-2, and increased glucose concentration for stages C and Do. There was a combined effect of treatment and molt stage only on total proteins concentration. The effects of an external factor (ammonia), an internal one (molt stage) and the combination of both, and the usefulness of using physiological parameters measured in this study as tools to detect stress, are discussed. (C) 2004 Elsevier B.V. All rights reserved.
Journal of Experimental Marine Biology and Ecology (0022-0981) (Elsevier), 2004-09 , Vol. 309 , N. 1 , P. 35-46

Droits : 2004 Elsevier B.V. All rights reserved
http://archimer.ifremer.fr/doc/2004/publication-371.pdf
DOI:10.1016/j.jembe.2004.03.008
http://archimer.ifremer.fr/doc/00000/371/

Éditeur(s) : Elsevier
Résumé : A field survey was conducted on two intensive shrimp farms using similar technical practices: one (DF) historically affected by a vibriosis, the other (HC) in which the pathogen has been observed although no mortality event has occurred. Because historical data suggest that eutrophication process may directly or indirectly play a role in the disease outbreak, we focussed our research on its dynamics. A higher variability of the phytoplanktonic compartment linked to an imbalance in the molar N:P ratio was observed in farm DF compared to farm HC, implying a modification on the linkage between the bacteria and phytoplankton compartments at DF. The beginning of the mortality outbreak at DF followed a shift from picoto nanophytoplankton. The organic matter mineralization process at the water-sediment interface may explain the disturbance observed in the water column during eutrophication. The consequences of this disturbance on shrimps' health status and pathogen ecology are discussed. (C) 2009 Elsevier Ltd. All rights reserved.
Marine Pollution Bulletin (0025-326X) (Elsevier), 2010-03 , Vol. 60 , N. 3 , P. 402-411

Droits : 2010 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00002/11368/8119.pdf
DOI:10.1016/j.marpolbul.2009.10.012
http://archimer.ifremer.fr/doc/00002/11368/

Éditeur(s) : Elsevier
Résumé : The effect of ambient ammonia, hypoxia and combination of both on survival and the physiological and immunological response of the blue shrimp Litopenaeus stylirostris in relation to molt stage was studied. Shrimp were submitted to 44.0-71.5 mg 1(-1) total ammonia-N corresponding to 2.0 mg 1(-1) unionized ammonia NH3-N and/or to 1.5 mg O-2 1(-1) (4.3 kPa) for 24 hours. Survival was recorded and the molt stages of both dead and surviving shrimp determined. Only shrimp in intermolt and premolt stages were sampled for analysis of haemolymph. Haemolymph was assayed for osmoregulatory capacity (OC), magnesium ion (Mg2+), calcium ion (Ca2+), total proteins, oxyhaemocyanin, lactate, glucose and total haemocyte count (THC). Low mortalities were recorded for shrimp submitted independently to ammonia or hypoxia. Seventy five percent of dead shrimp were in early post molt (stage A) in ammonia treatment, while hypoxia affected mainly late premolt animals (stage D-2). A synergic effect of ammonia and hypoxia combination (A+ O-2 treatment) on mortality was observed, affecting nearly exclusively shrimp in late premolt stage D-2. Analysis of molt stage repartition at the end of the experiment suggests that ammonia treatment may have accelerated molting. The common physiological response of shrimp to the different treatments was characterized by a reduced OC and an increase in Ca2+. Increase in Mg2+ could not be validated by the statistical analysis, as well as glycaemia variations. Plasmatic lactate level increased and THC decreased in shrimp submitted to hypoxia and the combination of hypoxia and ammonia. Total proteins concentration was reduced in ammonia and A+O-2 treatments. The effect was more pronounced in late premolt shrimp than in intermolt shrimp. Combination of ammonia and hypoxia led to a physiological response stronger than this observed for ammonia-alone and/or hypoxia-alone treatments, except for oxyhaemocyanin. The effects of each external factor (ammonia, hypoxia) and the combination of both, and internal one (molt stage) are discussed. (c) 2007 Elsevier B.V All rights reserved.
Aquaculture (0044-8486) (Elsevier), 2008-02 , Vol. 274 , N. 2-4 , P. 398-407

Droits : 2008 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2008/publication-4092.pdf
DOI:10.1016/j.aquaculture.2007.11.033
http://archimer.ifremer.fr/doc/00000/4092/

Éditeur(s) : Elsevier
Résumé : The blue shrimp Litopenaeus stylirostris was exposed to pond sediment for 48 h and its physiological response was studied in relation to molt stage. Shrimp were maintained in cages within a semi-intensive pond after 4 months of rearing. Hypoosmoregulatory capacity (hypo-OC), magnesium ions (Mg ions), glucose, total proteins and oxyhaemocyanin were assayed in haemolymph. An increase of 370% to 500% in Mg ions concentration and 200% to 266% in glucose concentration, and a decrease in hypo-OC in shrimp maintained close to the centre of the pond indicated a short-term stress response in all molt stages. Indicators of water and sediment pore water quality were within normal operating limits, however this area was characterized by high water content and relatively high total ammonia nitrogen in pore water of sediment. To a lesser extent, shrimp maintained in two other stations also presented a stress response. Physiological response of shrimp in molt stage D, compared to C/D-0 and D-2 seems to indicate that shrimp were more sensitive to environment at this stage. The use and choice of physiological parameters to detect shrimp stress in a pond are discussed.
Aquaculture (0044-8486) (Elsevier), 2006-03 , Vol. 253 , N. 1-4 , P. 703-711

Droits : 2005 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2006/publication-1675.pdf
DOI:10.1016/j.aquaculture.2005.09.008
http://archimer.ifremer.fr/doc/00000/1675/

Résumé : The New-Caledonian shrimp industry is based on the controlled reproduction of the shrimp Litopenaeus stylirostris, a species which was introduced in the 80s. The major difficulty to which the industry has been faced for 10 years is the occurrence of the "syndrome 93", which corresponds to mortality phases when the temperature falls down in April-May-June. This mortality is associated to the pathogenic bacteria Vibrio penaecida and is expressed at different levels which are variable from year ta year and from pond to pond. No resistance to this pathology has been developed spontaneously. This is likely due to the protocole used to rear spawners, which does not allow to implement an efficient selective pressure at each generation An experimental selection on the criteria of survival after picks of syndrome 93 has been conducted at the Laboratoire Aquacole de Calédonie. The 3rd selected generation demonstrates survival rates improved by 20% during experimental infections with V. penaeicida in comparison with a non selected control population of same genetic origin. The comparison of the correlated responses on the level of expression of 5 genes which are potentially implicated in immunity phenomena (Peneidins, lysozyme, transglutaminase. profiline, annexine) shows that the selected population has a level of expression in lyzozyme twice higher than the control population. This result suggests that the lysozyme could be a genetic marker which could be used in a selective breeding program to he developed in relation with the private hatcheries.
La filière crevette de Nouvelle-Calédonie repose sur la maîtrise de la reproduction contrôlée de la crevette Litopenaeus stylirostris, espèce introduite dans les années 80. La difficulté majeure que rencontre la filière depuis une dizaine d'années est la récurrence du « syndrome 93 », qui correspond à des épisodes de mortalités lors des baisses de température en avril-mai-juin. Ces mortalités sont associées à la bactérie pathogène Vibrio penaeicida et s'expriment à des niveaux d'intensité variable d'une année à l'autre et d'un bassin à l'autre. Aucune résistance vis-à-vis de cette pathologie ne s'est développée spontanément. Ceci est vraisemblablement lié au protocole employé pour l'élevage des géniteurs qui ne permet pas d'exercer une pression de sélection efficace à chaque génération. Une expérience de sélection sur un critère de survie à des épisodes de syndrome 93 a été menée au Laboratoire Aquacole de Calédonie. La 3ème génération sélectionnée montre des survies améliorées de l'ordre de 20% lors d'infections expérimentales à V. penaeicida par rapport à une population témoin non sélectionnée de même origine génétique. La comparaison des réponses corrélées sur le niveau d'expression de 5 gènes potentiellement impliqués dans les phénomènes de défense immunitaire (penaeidine, lysozyme, transglutaminase, profiline, annexine) montre que la population sélectionnée a un niveau d'expression en lysozyme deux fois plus élevé que la population témoin. Ce résultat suggère que le lysozyme pourrait être un marqueur génétique utilisable dans un programme de sélection à développer en relation avec les écloseries de production.

Droits : 2003 Ifremer
http://archimer.ifremer.fr/doc/00109/22020/19643.pdf
http://archimer.ifremer.fr/doc/00109/22020/

Éditeur(s) : Pergamon-elsevier Science Ltd
Résumé : The present work aimed at better understanding metal and metalloid bioaccumulation in the edible Pacific blue shrimp Litopenaeus stylirostris, using both laboratory and field approaches. In the laboratory, the bioaccumulation kinetics of Ag, Cd, Co, Cr, and Zn have been investigated in shrimp exposed via seawater and food, using the corresponding gamma-emitting radiotracers (Ag-110m, Cd-109, Co-57, Cr-51, and Zn-65) and highly sensitive nuclear detection techniques. Results showed that hepatopancreas and intestine concentrated the metals to the highest extent among the blue shrimp organs and tissues. Moulting was found to play a non negligible detoxification role for Co, Cr and, to a lesser extent, Zn. Metal retention by L stylirostris widely varied (from a few days to several months), according to the element and exposure pathway considered (a given metal was usually less strongly retained when ingested with food than when it was taken up from the dissolved phase). In the field study, Ag, As, Cd, Co, Cr, Cu, Mn, Ni, and Zn were analysed in shrimp collected from a New Caledonian aquaculture pond. Metal concentrations in the shrimp muscles were generally relatively low and results confirmed the role played by the digestive organs and tissues in the bioaccumulation/storage/detoxification of metals in the Pacific blue shrimp. Preliminary risk considerations indicate that consumption of the shrimp farmed in New Caledonia is not of particular concern for human health. (C) 2010 Elsevier Ltd. All rights reserved.
Marine Pollution Bulletin (0025-326X) (Pergamon-elsevier Science Ltd), 2010 , Vol. 61 , N. 7-12 , P. 576-584

Droits : 2010 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/00014/12528/9869.pdf
DOI:10.1016/j.marpolbul.2010.06.035
http://archimer.ifremer.fr/doc/00014/12528/

Éditeur(s) : Elsevier
Résumé : The effect of different levels of dissolved oxygen (DO) and a decreased temperature combined with severe hypoxia were studied in the blue shrimp Litopenaeus stylirostris in relation to molt stage. In the first experiment, shrimps were submitted to DO concentrations of 5 to 1 mg l(-1). Osmoregulatory capacity (OC) was measured in shrimps at molt stage C after 6, 24, or 48 h of exposure. No mortality was recorded but a significant negative effect of DO concentration on hypo-OC was observed for DO concentrations below 3 mg l(-1). Osmoregulation improved after 48 h exposure, compared to 6 and 24 h exposure. In a second experiment, temperature was decreased from 28 to 22 degreesC in 24 h, before a severe hypoxia of 0.5+/-0.1 mg O-2 l(-1) was applied. Mortality and OC were studied in relation to molt stages. Half of the shrimps died after respectively 100 min at 0.5 mg O-2 l(-1) at 28 degreesC and 153 min at 0.4 mg O-2 l(-1) at 22degreesC. Mortality was significantly higher in stages D-2 and B compared to stages C and Do. Control shrimps in stage D2 had a lower hypo-OC than shrimps in stages C and Do both at 28 and 22 degreesC. Temperature decrease had no effect on hypo-OC. Hypoxia reduced hypo-OC for all stages, whatever the temperature, but the effect was greater in stage C at 27 degreesC (68% decrease) compared to 22 degreesC (49%) and stage D-2 at both temperatures (respectively, 43% and 58% at 27 and 22 degreesC). Combination of temperature and hypoxia had a significant effect on hypo-OC. Low temperature reduced the effect of hypoxia presumably by slowing down the metabolism. Results are discussed in relation to pond observation. (C) 2004 Elsevier B.V. All rights reserved.
Aquaculture (0044-8486) (Elsevier), 2005-02 , Vol. 244 , N. 1-4 , P. 315-322

Droits : 2004 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2005/publication-372.pdf
DOI:10.1016/j.aquaculture.2004.11.010
http://archimer.ifremer.fr/doc/00000/372/

Éditeur(s) : Elsevier Science Bv
Résumé : Shrimp aquaculture in New Caledonia is subject to seasonal mortalities during grow-out due to highly virulent Vibrio nigripulchritudo (Vn). To understand the mechanisms affecting shrimp resistance and leading to significant mortality, a shrimp ecophysiology and immunology survey was conducted on two farms, the first considered as a "control" farm (HC), the second affected by the disease (DF). Mortality observed during the survey at DF started 50 days after stocking and was typical of this disease. The main observations regarding shrimp were: (a) growth was not affected by the disease and was faster in the DF than in the HC pond; (b) disease did not affect one sex more than the other, or a specific part of the population in terms of weight; (c) the physical condition of shrimp did not specifically allow us to foresee disease outbreak; (d) shrimp at late premolt stage D-2 and early postmolt stage A appeared to be at some points of the mortalities - but not continuously - the most sensitive to disease; (e) physiological, immunological and nutritional parameters of uninfected shrimp in the DF pond were altered, suggesting that environmental stress occurred just before the first mortalities; (f) data suggest that Vn-infected shrimp are more stressed than the presumed healthy shrimp. Combined with pathological and environmental knowledge gained in parallel during this survey, a conceptual model is proposed. Results suggest that an unstable environment induced conditions (i) stressful for the shrimp, increasing their susceptibility to bacterial infections and (ii) favoring the proliferation of the pathogen in the pond. The combination of these two processes could lead to significant mortality.
Aquaculture (0044-8486) (Elsevier Science Bv), 2013-04 , Vol. 388 , P. 105-114

Droits : 2013 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00176/28764/27567.pdf
DOI:10.1016/j.aquaculture.2013.01.010
http://archimer.ifremer.fr/doc/00176/28764/

Éditeur(s) : Elsevier
Résumé : Understanding of antimicrobial defence mechanisms of penaeid shrimp should help in the design of efficient strategies for the management and disease control in aquaculture. In this study, we have specifically analysed the expression in circulating hemocytes of antimicrobial peptides (AMPs) encoding genes, such as PEN2 and PEN3, ALF, crustin, lysozyme and a putative cysteine-rich peptide. We evidenced a relationship between the level of expression of some AMPs and the successful response of the shrimp, Litopenaeus stylirostris, to circumvent a pathogenic Vibrio penaeicida infection. Additionally, significant differences in some AMP transcript amounts are evidenced between control, non-selected shrimp line and the third generation breeding of shrimp selected for their survival to natural V. penaeicida infections. On the basis of these results, it will now be of great interest to determine if these AMPs are directly involved in the resistance of shrimp to infection or if they only reflect other acquired defence mechanisms which can confer a resistance. (C) 2008 Elsevier Ltd. All rights reserved.
Molecular Immunology (0161-5890) (Elsevier), 2008-07 , Vol. 45 , N. 12 , P. 3438-3445

Droits : 2008 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/2008/publication-4524.pdf
DOI:10.1016/j.molimm.2008.04.002
http://archimer.ifremer.fr/doc/00000/4524/