Assimilation of shrimp farm sediment by Holothuria scabra: a coupled fatty acid and stable isotope approach

Deposit-feeding sea cucumbers are efficient nutrient recyclers and have the potential to contribute to the limitation of organic matter load in polyculture or integrated aquaculture systems. Assessing how they assimilate organic matter originating from other farmed species is therefore important for the development of such multi-species farming systems. Here, a coupled stable isotope − fatty acid approach was used to characterize the assimilation of organic matter from shrimp (Penaeus stylirostris) farming by Holothuria scabra in an experimental culture system. H. scabra were reared in mesocosms on shrimp farming-originating sediment with and without additional food sources (maize and fish meals). Although fatty acid results did indicate that shrimp-farming sediment was assimilated by holothurids, we found no evidence of maize waste and fish meal contribution to H. scabra organic carbon (no effect on δ13C, no accumulation of meal-specific fatty acids). However, a strong effect of fish meal on H. scabra δ15N was observed, suggesting that this additional food source could represent an alternative source of nitrogen for holothurids. Finally, this study supports the culture of H. scabra as a perspective to reduce sedimentary organic matter excess associated with shrimp farms, and suggest that the addition of selected food sources might contribute to increasing the content in some nitrogen organic compounds in holothurid tissues

Etude de la spécificité du cardiolipide et des plasmalogènes chez les mollusques bivalves (Apport des méthodes chromatographiques)

Le couplage des méthodes CLHP dites " sans acide " et " avec acide " a permis la séparation des sous-classes PEplasmalogène, PSplasmalogène et PCplasmalogène. Chez les 38 espèces de bivalve analysées, les acides gras NMI, le 20:1(n-11) ou le 22:4(n-9)trans13 sont préférentiellement incorporées dans les plasmalogènes et plus spécifiquement dans la PSplsm et la PEplsm. Cette association semble très caractéristique car ces acides gras sont les rares acides gras biosynthétisés par les bivalves marins. L'importance des aminophospholipides plasmalogènes (PS et PE) vis à vis de la PC indique une localisation préférentielle des plasmalogènes et donc des acides gras biosynthétisés sur la face interne des membranes cellulaires. La présence de l'un ou l'autre de ces acides gras pourrait être liée à l'évolution des bivalves. Concernant les cardiolipides des bivalves marins, la structure moléculaire de cette classe a été confirmée à partir d'analyses chromatographiques et structurales. (RMN et ESI+/MS). Les résultats de l'investigation effectuée sur 38 espèces ont démontré qu'il était possible de regrouper les cardiolipides en trois grands types caractéristiques. Un " type1 " correspondant à une composition contenant presque exclusivement du 22:6(n-3), un " type 2 " caractérisé par la présence conjointe du 22:6(n-3) et du 20 :5(n-3), le " type3 " correspondant à celle conjointe du 22 :6(n-3), du 18 :2(n-6) et du 18 :3(n-3). Ces différences apparaissent comme étant corrélés avec les grands taxons phylogénétiques établis chez les bivalves : les Filibranches Euptèriomorphes (CL de type 1), les Filibranches Ptériomorphes (CL de type 3) et les Eulamellibranches Hérédontes (CL de type 2)BREST-BU Droit-Sciences-Sports (290192103) / SudocPLOUZANE-Bibl.La Pérouse (290195209) / SudocSudocFranceF

Docosahexaenoic and arachidonic acid peroxidation: It's a within molecule cascade.

International audiencePeroxidation is a well-known natural phenomenon associated with both health and disease. We compared the peroxidation kinetics of phosphatidylcholine (PC) molecules with different fatty acid compositions (i.e. 18:0, 18:1n-9, 18:2n-6, 20:4n-6 and 22:6n-3 at the sn-2 and 16:0 at sn-1 position) either as molecules free in solution or formed into liposomes. Fatty acid levels, oxygen consumption plus lipid hydroperoxide and malondialdehyde production were measured from the same incubations, at the same time during maximal elicitable peroxidation. PCs with highly peroxidizable fatty acids (i.e. 20:4n-6 and 22:6n-3) in the same incubation were found to be either fully peroxidized or intact. Rates of peroxidation of PCs with multiple bisallylic groups (i.e. 20:4n-6 and 22:6n-3) peroxidized at 2-3 times the rate per bisallylic bond than the same phospholipid with 18:2n-6. The results suggest that propagation of peroxidation (H-atom transfer) is firstly an intramolecular process that is several-fold faster than intermolecular peroxidation. PCs in solution peroxidized twice as fast as those in liposomes suggesting that only half of the phospholipids in liposomes were available to peroxidize i.e. the outer leaflet. Experiments on liposomes suggest that even after heavy peroxidation of the outer leaflet the inner leaflet is unaffected, indicating how cells may protect themselves from external peroxidation and maintain control over internal peroxidation. Intramolecular peroxidation may produce highly concentrated, localized sites of peroxidation product that together with internal control of peroxidation of the inner leaflet of membranes provide new insights into how cells control peroxidation at the membrane level

Changes in mitochondrial oxidative capacities during thermal acclimation of rainbow trout Oncorhynchus mykiss: roles of membrane proteins, phospholipids and their fatty acid compositions

International audienceChanges in the properties of mitochondria from oxidative muscle of rainbow trout Oncorhynchus mykiss were examined during warm (5 degrees C to 15 degrees C) acclimation. Trout were studied shortly after the initial thermal change and after 8 weeks acclimation to 15 degrees C. To identify potential mechanisms by which oxidative capacities change, the modifications of phospholipid composition, membrane proteins and functional capacities of red muscle mitochondria were examined. Marked functional changes of isolated muscle mitochondria during warm acclimation of rainbow trout were reflected by a host of modifications in phospholipid composition, but by few shifts in protein components. Shortly after transfer of trout from 5 degrees C to 15 degrees C, the maximal oxidative capacity of mitochondria measured at 15 degrees C increased slightly, but rates at both assay temperatures (5 degrees C and 15 degrees C) decreased markedly after warm acclimation. The increase in capacity in short-term warm exposed trout was most pronounced when rates at 15 degrees C were expressed relative to cytochrome a and c(1) levels. Non-phosphorylating (State 4) rates of oxygen uptake increased with short-term warm exposure before returning to initial levels after warm acclimation. Cytochrome c oxidase (CCO) activity in the mitochondrial preparations decreased with warm acclimation. The thermal sensitivity of the ADP affinity was markedly modified during short-term warm exposure, when the ADP/O ratio increased, but warm acclimation returned these values to those observed initially. ADP affinity increased after warm acclimation. Changes in the mitochondrial content of cytochromes and adenine nucleotide translocase (ANT) could not explain these patterns. On the other hand, changes in the proportions of the lipid classes and in the acyl chain composition of certain phospholipid classes mirror the modifications in functional properties. Short-term exposure to 15 degrees C decreased the ratio of diacylphosphatidylethanolamine/diacylphosphatidylcholine (diacylPE/diacylPC), whereas warm acclimation led to restructuring of fatty acids (FA) and to increases of plasmalogen forms of PE and PC. Modification of overall membrane unsaturation did not appear to be the primary aim of restructuring membrane FA during warm acclimation, as total mitochondrial phospholipids and the major phospholipid classes only showed slight shifts of their acyl composition with warm acclimation. On the other hand, natural lysophosphatidylcholine (LysoPC) showed dramatic changes in FA content, as 16:0 and 18:1n-9 doubled whereas 22:6n-3 decreased from around 50% to 32% in warm acclimated trout. Similarly, in cardiolipin (CL), the levels of 16:0 and 18:1n-7 halved while 18:2n-6 increased to over 20% of the FA with warm acclimation. Given the central role of CL in modulating the activity of CCO, F(0)F(1)-ATPase and ANT, these changes suggest that specific compositional changes in CL are important modulators of mitochondrial capacities. The many structural changes in membrane lipids contrast with the limited modifications of the membrane protein components examined and support the concept of lipid structure modulating mitochondrial capacities

Effect of day length on oxidative capacities of mitochondria from red muscle of rainbow trout (Oncorhynchus mykiss)

International audienceIn nature, seasons may be more reliably announced by changes in photoperiod than in temperature. To evaluate the role of day length in setting oxidative capacities of trout muscle mitochondria, we acclimated trout to summer (15 °C, 16L:8D), winter (5 °C, 8L:16D) and mixed conditions (15 °C, 8L:16D). Maximal oxidative capacities of isolated mitochondria at 5 and 15 °C were higher in mixed than summer conditions and higher again in winter conditions. At 5 °C, state 4 rates changed little with acclimation state whereas at 15 °C state 4 rates were lower in summer than in mixed or winter conditions. Using concentrations of the adenylate nucleotide translocase as the denominator for these rates gave much the same conclusions. By using inhibitors to block flux at specific points in the electron transport chain, we found that flux through Complexes II–IV was lowest in summer acclimated trout, increased upon acclimation to mixed and to winter conditions. Flux through complex IV was similar in trout acclimated to summer and mixed conditions, but increased significantly with acclimation to winter conditions. Flux through complex IV was 1.5 fold higher than state 3 rates for summer-acclimated trout but was similar to state 3 rates in trout acclimated to mixed or winter conditions. Our results indicate that a reduction in day length initiates increases in mitochondrial oxidative capacity typically associated with cold acclimation and that acclimation to both cold temperatures and short day lengths enhanced these changes. The overall similarity of the responses of state 3, of flux through complexes II–IV and of flux through complex IV suggests that a generalised mechanism such as changes in the phospholipid composition of the inner mitochondrial membrane may coordinate these changes

cis-4,7,10,trans-13-22∶4 fatty acid distribution in phospholipids of pectinid species Aequipecten opercularis and Pecten maximus

International audienceThe distribution of cis-4,7,10,trans-13-docosate-traenoic (c4,7,10,t13-22∶4), a peculiar FA previously isolated in the glycerophospholipids of some pectinid bivalves, was investigated in glycerophospholipid classes and subclasses of separated organs (gills, mantle, gonads, and muscle) of the queen scallop Aequipecten opercularis and the king scallop Pecten maximus. Plasmalogen (Pls) and diacyl + alkyl (Ptd) forms of serine, ethanolamine, and choline glycerophospholipids were isolated by HPLC and their FA compositions analyzed by GC-FID. Pls and Ptd forms of serine glycerophospholipids (PlsSer and PtdSer), and to a lesser extend the Pls form of ethanolamine glycerophospholipids (PlsEtn), were found to be specifically enriched with c4,7,10,t13-22∶4. This specificity was found to decrease in the tested organs in the following order: gills, mantle, gonad, and muscle. In gills, c4,7,10,t13-22∶4 was shown to be the main unsaturated FA of serine glycerophospholipids in both Pls and Ptd forms (23.8 and 19.4 mol%, respectively, for A. opercularis, and 21.0 and 26.2 mol% for P. maximus). These results represent the first comprehensive report on the FA composition of plasmalogen serine subclass isolated from pectinid bivalves. The specific association of the PlsSer with the c4,7,10,t13-22∶4 for the two pectinid species can be paralleled to the specific association of the PlsSer with the non-methylene interrupted (NMI) FA and 20∶1(n−11) observed in mussels, clams, and oysters (Kraffe, E., Soudant, P., and Marty, Y. (2004) Fatty Acids of Serine, Ethanolamine and Choline Plasmalogens in Some Marine Bivalves, Lipids 39, 59-66.) This, led us to hypothesize a similar functional significance for c4,7,10,t13-22∶4, NMI FA, and 20∶1(n−11) associated with PlsSer subclass of bivalves

Dietary fatty acid composition changes mitochondrial phospholipids and oxidative capacities in rainbow trout red muscle

International audienceDietary conditioning of juvenile trout changed the acyl chain composition of mitochondrial phospholipids and the oxidative capacities of muscle mitochondria. Trout were fed three diets differing only in fatty acid (FA) composition. The highly unsaturated 22:6 n-3 (DHA) accounted for 0.4, 14, and 30% of fatty acids in Diets 1, 2 and 3. After 10 weeks of growth, the dietary groups differed markedly in FA composition of mitochondrial phospholipids, with significant dietary effects for virtually all FA. Mean mitochondrial DHA levels were 19, 40 and 33% in trout fed Diets 1, 2 and 3. Mitochondrial oxidative capacities changed with diet, while mitochondrial concentrations of cytochromes and of the adenylate nucleotide translocase (nmol mg(1) protein) did not. Mitochondria from fish fed Diet 1 had higher non-phosphorylating (state 4) rates at 5 degrees C than those fed other diets. When phosphorylating (state 3) rates differed between dietary groups, rates at 5 and 15 degrees C were higher for fish fed the more unsaturated diets. Stepwise multiple regressions indicated that FA composition could explain much (42-70%) of the variability of state 4 rates, particularly at 5 degrees C. At 15 degrees C, FA composition explained 16-42% of the variability of states 3 and 4 rates. Similar conclusions were obtained for the complete data set (trout fed diets 1, 2 and 3) and for the data from trout achieving similar growth rates (e.g. those fed Diets 1 and 2). Neither general characteristics of membrane FA, such as % saturates, unsaturation index, n-3, n-6 or n-3/n-6 nor levels of abundant unsaturated FA such as DHA or 18:1(n-9 + n-7), were systematically correlated with mitochondrial capacities even though they differed considerably between trout fed the different diets. Relatively minor FA (20:5n-3, 20:0, 18:2n-6, 18:3n-3, 18:0 and 15:0) showed better correlations with mitochondrial oxidative capacities. This supports the concept that acyl chain composition modulates mitochondrial capacities via interactions between membrane proteins and specific FA of particular phospholipid classes in their microenvironment

Occurrence of the cis-4,7,10, trans-13-22:4 Fatty Acid in the Family Pectinidae (Mollusca: Bivalvia)

International audienceThe present study aimed to elucidate the effective phylogenetic specificity of distribution of a cis-4,7,10, trans-13-22:4 (22:4(n-9)Δ13trans) among pectinids. For this purpose, we extended the analysis of membrane glycerophospholipids FA composition to 13 species of scallops, covering 11 genera and 7 tribes representatives of the three subfamilies Chlamydinae, Palliolinae and Pectininae and the subgroup Aequipecten. In species belonging to the subfamily Pectininae and the Aequipecten subgroup, 22:4(n-9)Δ13trans was found in substantial amounts, but it was absent in other species belonging to the subfamilies Chlamydinae and Palliolinae. Homologous non-methylene-interrupted (NMI) FA, also hypothesized to differ along phylogenetic lines in bivalves, were totally absent or present only in trace amounts in representatives of the Aequipecten subgroup but ranged from 0.3 to 4.5% of the total FA in Pectinidae, Chlamydinae, and Palliolinae subfamilies. The species-specific occurrence of NMI and 22:4(n-9)Δ13trans FA in membrane lipids of pectinids agrees with the most recent phylogenies based on shell morphology and molecular characteristics. We examined the potential timing of the appearance of 22:4(n-9)Δ13trans in pectinids on a geologic time scale

Membrane phospholipid composition of hemocytes in the Pacific oyster Crassostrea gigas and the Manila clam Ruditapes philippinarum

International audienceThe detailed sterol (free sterol proportions and compositions) and phospholipid (PL) compositions (relative proportions of PL classes and subclasses and their respective fatty acid (FA) compositions) of hemocyte membranes were investigated in two bivalve mollusks: the Pacific oyster Crassostrea gigas and the Manila clam Ruditapes philippinarum. Hemocyte membrane lipids of both species revealed similar general composition: i) their free sterol/PL ratio was above 0.4 and ii) their PL were predominated by the diacyl + alkyl forms of glycerophosphatidylcholine (PC), the plasmalogen form of glycerophosphatidylethanolamine (PE) and ceramide aminoethylphosphonate (CAEP). Free sterols were predominated by cholesterol in both species. Plasmalogen forms of PE and glycerophosphatidylserine (PS) represented 82-83% and 46-55% of total PE and PS, respectively. When compared to their respective diacyl + alkyl forms, plasmalogen forms of PE and PS were specifically enriched in non-methylene-interrupted (NMI) FA and 20:1n-11, suggesting a functional significance of these PL molecular species in bivalve hemocytes. Lysoglycerophosphatidylcholine (LysoPC) levels were found to be fairly high in hemocytes, accounting for about 8% of the PL Some species-specific features were also found. LysoPC and glycerophosphatidylinositol (PI) FA compositions differed between Ruditapes philippinarum and Crassostrea gigas. CAEP proportion was higher in R. philippinarum than in C. gigas (14.5% and 27.9% of the PL respectively). Hemolymph cell monolayer observations and flow-cytometric analyses revealed species-specific hemocyte morphology and sub-populations which could account for some of the observed species-specific membrane lipid compositions

Lipid composition of the giant lion's-paw scallop (Nodipecten subnodosus) in relation to gametogenesis: I. Fatty acids

cited By 37International audienceSeasonal variations in fatty acid composition in several tissues of a 1-year-old population of giant lion's-paw scallop Nodipecten subnodosus were analyzed during gonad development. Samples were taken bimonthly from December 1999 to June 2000, a period in which gonad development was occurring. Fatty acid accumulation in neutral and polar lipids of the female gonad was concomitant to the gonad development and presented a maximum in June. Among essential fatty acids, a specific accumulation was observed only for 20:5n - 3 in the female gonad, as suggested by an increase in its proportion in the neutral and the polar fractions. However, no specific accumulation was observed for 22:6n - 3, as its proportion remained relatively constant in both fractions. We suggest that a specific increase of 22:6n - 3 is not necessary during gametogenesis because its proportion was high enough for reproductive purposes (20-30%). Although some data suggest a partial mobilization of polyunsaturated fatty acids from the muscle and digestive gland to the female gonad during gonad development, the main supply came directly from the diet. The maximum increase in total and specific fatty acids in the digestive gland occurred in April and was maintained in June. These changes reflect either a higher lipid availability of the food, or the beginning of storage process in the digestive gland. However, in the female gonad, the maximum increase was observed in June, whereas gonad development and spawning were observed from April. It is suggested that different patterns of lipid accumulation in the first (April) and second (June) maturation processes could be related to the reproductive cycle of this species, which exhibits an initial facultative maturation during spring and the main reproductive activity during summer. © 2005 Elsevier B.V. All rights reserved