Liet Chim

In recent years the biological control of diseases by environmental friendly methods such as probiotics has become an important subject of investigation in aquaculture research. Probiotics are live microorganisms which when administrated in adequate amounts confer a health benefit on the host . In the last 4 years, IFREMER in collaboration with Lallemand company, have carried out researchs in New Caledonia with the aim to assess the probiotic strain P. acidilactici MA 18/5M on farmed shrimp Litopenaeus stylirostris.This project started in 2005 demonstrated the beneficial effects of the probiotic Pediococcus acidilactici dietary supplementation on the nutrition and the health status of peneid shrimps and highlighted that its use as probiotic can be part of the natural solutions proposed to face the challenge of today’s shrimp farming industry.

Il s’agit d’un article presentant l’institut, son historique, sa presence et les projets qu’il mene en Nouvelle-Caledonie. Apres une premiere partie de presentation generale de l’organisme un focus est place sur le renforcement de la presence de l’Ifremer en Nouvelle-Caledonie. 3 questions sont posees a L. Loubersac sur l’organisation en interne, la strategie et des exemples de travaux realises dans le cadre du chantier lagons. Puis un coup de projecteur est porte sur 3 projets : Deduction 2 qui vise a optimiser les performances de la filiere crevetticole (T. Laugier), AMICAL qui se focalise sur la culture de micro-algues (L. Chim) et AMBIO axe sur le suivi et la definition d’indicateurs de performance des modes de gestion des Aires Marines protegees et des zones Inscrites au Patrimoine Mondial (D. Pelletier). La synthese de cet article est realisee par S. Chopot de la revue Environnement Nouvelle-Caledonie.

Probiotics are increasingly documented to confer health and performance benefits across farmed animals. The aim of this study was to assess the effect of a constant daily intake of the single-strain probiotic Pedicococcus acidilactici MA18/5M (4 × 108 CFU.day−1.kg−1 shrimp) fed over fixed, restricted ration sizes (1% to 6% biomass.day−1) on the nutritional performance and metabolism of adult penaeid shrimp Litopenaeus stylirostris (initial body-weight, BWi = 10.9 ± 1.8 g). The probiotic significantly increased the relative daily growth rate (RGR) across all ration size s tested (Mean-RGR of 0.45 ± 0.08 and 0.61 ± 0.07% BWi.day−1 for the control and probiotic groups, respectively) and decreased the maintenance ration (Rm) and the optimal ration (Ropt) by 18.6% and 11.3%, respectively. Accordingly, the probiotic group exhibited a significantly higher gross (K1) and net (K2) feed conversion efficiency with average improvement of 35% and 30%, respectively. Enhanced nutritional performan...

A study of the sexual physiology of penaeid prawns essentially based upon Penaeus japonicus is performed in both descriptive and experimental ways, using the controlled rearings conducted at the Centre Oceanologique de Bretagne (CNEXO-COB), Brest. Sexual morphogenesis is described. This preliminary study enables definition of simple criteria for determination of the stage of genital development of the prawns during their growth. The neuroendocrine control of the genital system development is studied, using eyestalks ablations and male eyestalks extracts injection in prawns belonging to the same sex. A biochemical criterion as a test of the effect of eyestalks extract injections on the genital system development is discussed. The evolution of the specific activity of aspartate transcarbamylase (ATC) has been followed and results are discussed.

Aquaculture diversification has been set as a major policy by New Caledonia public authorities. This has been set up to carry by ADECAL Technopole which carries projects in view of developing cultivation marine species native from Caledonian waters. In this context, the development of micro-algal cultures has been identified as a priority. The study presented has been co-funded by Glencore company in New Caledonia and achieved under the program entitled Aquaculture of MIcro-algae in new-CALedonia (AMICAL) and has two objectives: (i) designing a device to bring dissolved CO2 into micro-algae cultures with a minimum release in atmosphere of this green-house gas and (ii) to assess this device by carrying out carbon budget of micro-algae cultures in microcosm. Our study has been carried out in comparison with traditional system of CO2 input by bubbling. We thus designed a laboratory scale and pilot scale simple device called “dissolved CO2 concentrator” with a capacity to produce enrich...

The study of the antioxidant status and oxidative stress in shrimp L. stylirostris make it possible to assess risk factors (temperature, shrimp size, pathogen, ..) associated with shrimp farming. From a practical view, this research should lead to zootechnical and/or nutritional recommendations to improve the antioxidant status of the shrimp during their growout stage in farm.

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...

AMICAL is a partnership program of research and innovation between ADECAL TECHNOPOLE (New Caledonia innovation and technology park) and IFREMER to initiate the development of a microalgae industry in New Caledonia, based on selected local strains. This French oversea territory, located in south Pacific, features many competitive advantages for the development of a blue economy industry (climate, biodiversity hotspot, well developed aquaculture sector...). The project relies on two laboratories (Figure 1) owned and managed by ADECAL TECHNOPOLE with the scientific support of IFREMER: • the Laboratory for MicroAlgae study (LEMA), whose scientific direction is provided by the laboratory of Physiology and Biotechnology of Algae (PBA, IFREMER, Nantes), dedicated to microalgae applied studies at laboratory scale. The LEMA is set up in Noumea and has been in operation since May 2013 • The Laboratory for MicroAlgae Technology (LTMA) with pilot scale production facilities.. The LTMA, located ...

Mass selection studies with a domesticated strain of Penaeus stylirostris to improve growth rate have been carried out since 1992 at IFREMER-Tahiti in French Polynesia. The selected line was graded once or twice by generation, with a selection rate ranging from 4% to 18% in the successive generations (Figure 1) while a nonselected line was maintained as a control. At the fourth generation growth improvements became statistically significant, with an 18% growth improvement compared to the control line. At the sixth generation, additional experiments were conducted in order to characterize differences between the selected and the control lines on several traits (FCR, osmoregulation capacity, and others) that could have been affected by selecting only for growth.

References Agard, J.B.R., 1999. A four-dimensional response surface analysis of the ontogeny of physiological adaptation to salinity and temperature in larvae of the palaemonid shrimp Macrobrachium rosenbergii (de Man).. Involvement of the superoxyde anion radical in the auto oxidation of pyrogallol and a convenient assay for superoxyde dismutase. Eur. kit evaluated for determining plasma and lipoprotein fractions that react with thiobarbituric acid. Clin. Chem. 38:704-709. Conclusion These first results show that the antioxidant defences and the response of the shrimp to an "oxidative stress" evolve during the embryonic development. These preliminary observations indicate that nauplius and zoea stages could be more subject to oxidative stress. Further analysis must be assessed to confirm these results. This research should allow to identify the main risk factors and thus prevent from oxidative stress in larval commercial production. From a practical angle, some zootechnic...

Fish processing is an important activity in the Pacific, but it generates a lot of by-products that are not used in a way that maximises their economic potential. There is opportunity to turn fish processing by-products into food, fish meal, fertiliser, pharmaceutical and other marketable products. The problem is that fish processors operate to extract the most value from their primary products, with little attention being dedicated to extracting value from by-products. This results in missed economic return from this secondary resource due to underinvestment in technologies that add value to by-products. In addition to this missed opportunity, disposal of by-products often has a direct financial and environmental cost. In some Pacific sland countries and territories, fish processors are already extracting value and creating employment by processing by-products, but more value can be extracted. A first step in assessing the potential to add more value to fish processing by-products ...

The underlying physiological mechanisms explaining why the adult penaeid prawn Litopenaeus stylirostris cannot successfully face heavy stressful events on the low edge of its thermopreferendum (20–22°C) were studied during the austral winter. Prawns were studied during recovery from net fishing and rapid transfer from outdoor earthen ponds into indoor facilities. This was assimilated to a predator–prey interaction. O2-consumption, hemolymph osmotic pressure (OPh), arterial O2 partial pressure (PO2), a–v O2-capacitance and mortality rates were analysed. Data were compared to similar challenges performed at 28°C during the austral summer. At 20–22°C, mortality of up to 70% was observed after 2 days whereas at 28°C, maximum mortality was 3–5%. Mortality occurred when OPh shifted towards equilibrium with seawater, the resting O2-consumption, the a–v O2-capacitance and the arterial PO2 went down to minimal values. These events can be counterbalanced by transiently hyper-oxygenating the hemolymph or by blocking the OPh shift in isosmotic water (Wabete et al. in Aquaculture 260:181–193, 2006): both led to a dramatic decrease in mortality. It is concluded that in penaeid prawns L. stylirostris, a mismatch between O2-demand and O2-supply contributes to setting the geographical limits for this animal species through an impairment of their hemolymph O2-carrying capacity during heavy stressful events like chasing by predators.