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Olhão, Portugal

Navarro-Guillen C.,Institute Ciencias Marinas Of Andalucia Icman Csic | Engrola S.,University of Algarve | Castanheira F.,University of Algarve | Bandarra N.,IPMA | And 4 more authors.
Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology | Year: 2013

Lipid nutrition of marine fish larvae has focused on supplying essential fatty acids (EFA) at high levels to meet requirements for survival, growth and development. However, some deleterious effects have been reported suggesting that excessive supply of EFA might result in insufficient supply of energy substrates, particularly in species with lower EFA requirements such as Senegalese sole (Solea senegalensis). This study addressed how the balance between EFA and non-EFA (better energy sources) affects larval performance, body composition and metabolism and retention of DHA, by formulating enrichment emulsions containing two different vegetable oil sources (olive oil or soybean oil) and three DHA levels. DHA positively affected growth and survival, independent of oil source, confirming that for sole post-larvae it is advantageous to base enrichments on vegetable oils supplying higher levels of energy, and supplement these with a DHA-rich oil. In addition, body DHA levels were generally comparable considering the large differences in their dietary supply, suggesting that the previously reported {increment}4 fatty acyl desaturase (fad) operates in vivo and that DHA was synthesized at physiologically significant rates through a mechanism involving transcriptional up-regulation of {increment}4fad, which was significantly up-regulated in the low DHA treatments. Furthermore, data suggested that DHA biosynthesis may be regulated by an interaction between dietary n-. 3 and n-. 6 PUFA, as well as by levels of LC-PUFA, and this may, under certain nutritional conditions, lead to DHA production from C18 precursors. The molecular basis of putative fatty acyl {increment}5 and {increment}6 desaturation activities remains to be fully determined as thorough searches have found only a single ({increment}4) Fads2-type transcript. Therefore, further studies are required but this might represent a unique activity described within vertebrate fads. © 2013 Elsevier Inc.

Morais S.,IRTA - Institute of Agricultural-Alimentary Research and Technology | Mendes A.C.,IPMA | Castanheira M.F.,University of Algarve | Coutinho J.,IPMA | And 6 more authors.
Aquaculture | Year: 2014

Senegalese sole is considered a species with high interest for aquaculture diversification in the South of Europe whose production has shown an important increase in recent years. However, broodstock nutrition of this species is still based on a diet of fresh feeds, which poses important sanitary risks, has variable supply and nutritional composition and contributes to the deterioration of water quality. This study was performed to test two new specifically formulated semi-moist diets for Solea senegalensis broodstock: a control diet (CTR) formulated with high quality ingredients and a further supplemented diet (PLUS), fortified with lipids, vitamins and long-chain polyunsaturated fatty acids (LC-PUFA), mainly DHA. Larvae originating from simultaneous spawns of both broodstock groups were reared in the same standard conditions up to 67. days post-hatching (dph) and effects were assessed on early ontogeny (up to first-feeding), larval (up to 17. dph) and juvenile performance. Both diets led to the production of eggs with good viability, hatching rate and fatty acid composition. The fatty acid profile reflected differences in the experimental diets, with eggs from the PLUS group presenting higher levels of both EPA and DHA, although more markedly for EPA. Furthermore, significant differences in the percentage of EPA were maintained until 7. dph, while DHA was only significantly higher in eggs and 0. dph larvae from the PLUS treatment. The expression of enzymes of the LC-PUFA biosynthesis pathway was assessed in parallel and results show that transcript levels of elovl5 and δ4fad in eggs and newly hatched larvae were affected by broodstock diet and that DHA biosynthesis capacity of Senegalese sole larvae may have been up-regulated at hatching in the CTR treatment. Further nutrient supplementation in the PLUS diet did not enhance larval survival and performance and larvae originating from this treatment were significantly smaller than their CTR counterparts at hatching and 3. dph and had lower growth up to 17. dph, probably reflecting variations in egg size between batches. However, after metamorphosis, post-larvae from the PLUS treatment quickly caught-up and after complete weaning were significantly larger than juveniles originating from the CTR broodstock. Furthermore, juveniles from the PLUS treatment had a much lower incidence of tail fin deformity. These results were surprising and should be further investigated as, although we cannot exclude a genetic effect, the results could also indicate a nutritional programming effect of broodstock diet in sole juvenile growth and quality. In addition, the results suggest that Senegalese sole larvae are capable of regulating DHA biosynthesis as early as at hatching to counterbalance lower levels of DHA in eggs. Finally, we demonstrate that the current feeding protocol of sole broodstock can be replaced by a safer formulated semi moist diet with good results. © 2014 Elsevier B.V.

Gutscher M.-A.,French National Center for Scientific Research | Dominguez S.,Montpellier University | Westbrook G.K.,University of Birmingham | Le Roy P.,French National Center for Scientific Research | And 8 more authors.
Tectonophysics | Year: 2012

The Gibraltar arc, spans a complex portion of the Africa-Eurasia plate boundary marked by slow oblique convergence and intermediate and deep focus seismicity. The seemingly contradictory observations of a young extensional marine basin surrounded by an arcuate fold-and-thrust belt, have led to competing geodynamic models (delamination and subduction). Geophysical data acquired in the past decade provide a test for these models and support a narrow east-dipping, subduction zone. Seismic refraction studies indicate oceanic crust below the western Gulf of Cadiz. Tomography of the upper mantle reveals a steep, east-dipping high P-wave velocity body, beneath Gibraltar. The anisotropic mantle fabric from SKS splitting shows arc-parallel "fast directions", consistent with toroidal flow around a narrow, westward retreating subducting slab. The accompanying WSW advance of the Rif-Betic mountain belt has constructed a thick pile of deformed sediments, an accretionary wedge, characterized by west-vergent thrust anticlines. Bathymetric swath-mapping images an asymmetric embayment at the deformation front where a 2. km high basement ridge has collided. Subduction has slowed significantly since 5. Ma, but deformation of recent sediments and abundant mud volcanoes suggest ongoing activity in the accretionary wedge. Three possible origins for this deformation are discussed; gravitational spreading, overall NW-SE convergence between Africa and Iberia and finally a WSW tectonic push from slow, but ongoing roll-back subduction. In the absence of arc volcanism and shallow dipping thrust type earthquakes, evidence in favor of present-day subduction can only be indirect and remains the object of debate. Continued activity of the subduction offers a possible explanation for great (M. >. 8.5) earthquakes known to affect the area, like the famous 1755 Great Lisbon earthquake. Recent GPS studies show SW motion of stations in N Morocco at velocities of 3-6. mm/yr indicating the presence of an independent block, a "Rif-Betic-Alboran" microplate, situated between Iberia and Africa. © 2012 Elsevier B.V.

Mattiucci S.,University of Rome La Sapienza | Garcia A.,IPMA | Cipriani P.,University of Rome La Sapienza | Santos M.N.,IPMA | And 2 more authors.
Parasite | Year: 2014

Thirteen parasite taxa were identified in the Mediterranean swordfish by morphological and genetic/molecular methods. The comparison of the identified parasite taxa and parasitic infection values observed in the Mediterranean swordfish showed statistically significant differences with respect to those reported for its Atlantic populations. A stepwise Linear Discriminant Analysis of the individual fish examined showed a separation among three groups: one including fish from the Mediterranean Sea (CTS, STS, and IOS); one consisting of fish from the Central South (CS), Eastern Tropical (ET), and Equatorial (TEQ) Atlantic; and a third comprising the fish sampled from the North-West Atlantic (NW); the CN Atlantic sample was more similar to the first group rather than to the other Atlantic ones. The nematodes Hysterothylacium petteri and Anisakis pegreffii were the species that contributed most to the characterization of the Mediterranean swordfish samples with respect to these Atlantic ones. Anisakis brevispiculata, A. physeteris, A. paggiae, Anisakis sp. 2, Hysterothylacium incurvum, Hepatoxylon trichiuri, Sphyriocephalus viridis, and their high infection levels were associated with the swordfish from the Central and the Southern Atlantic areas. Finally, H. corrugatum, A. simplex (s.s.), Rhadinorhynchus pristis, and Bolbosoma vasculosum were related to the fish from the North-West (NW) Atlantic area. These results indicate that some parasites, particularly Anisakis spp. larvae identified by genetic markers, could be used as "biological tags" and support the existence of a Mediterranean swordfish stock. © S. Mattiucci et al., published by EDP Sciences, 2014.

Ramalho Ribeiro A.,University of Algarve | Goncalves A.,IPMA | Goncalves A.,University of Porto | Colen R.,University of Algarve | And 4 more authors.
Aquaculture | Year: 2015

Marine fish are a rich source of iodine in the human diet. Exogenous feeding under captivity opens the possibility of tailoring fish composition with health valuable nutrients, such as iodine, and establishing it as a functional food. A study was undertaken to test the efficacy of various dietary iodine supplemental forms on the growth performance of gilthead seabream and assess the effects on sensory attributes and nutritional value of fillets. Duplicate groups of 35 seabream (IBW: 252g) were fed over 118days: a) control diet (CTRL) with 3mgIkg-1, supplied as potassium iodide; b) this same control diet supplemented with potassium iodide (diet KI: 26mgI·kg-1) or with ethylenediamine dihydroiodide (diet EDDI; 22mgI·kg-1); c) a fourth diet with 10% of Laminaria digitata, an iodine-rich macroalgae (diet LAM). At the end of the trial, fish doubled their initial weight, but irrespective of the iodine form used, the elevation of dietary iodine level had no effect (P>0.05) on feed intake, growth rate, feed conversion, nutrient utilization or whole-body composition. Dietary iodine supplementation led to a significant increase (P<0.05) of the iodine content in seabream fillets. In comparison to the CTRL treatment (0.13mg·kg-1), seabream fed KI and EDDI supplemented diets showed a significant enhancement (P<0.05) of their fillet iodine content (0.17mg·kg-1). Feeding seabream with the iodine-rich brown algae L. digitata resulted in a significant (P<0.05) 6.5-fold increase (0.84mg·kg-1 fillet) of fillet iodine content over the levels found in the CTRL treatment. Overall sensory difference between CTRL and fish fed supplemented diets was significant (P<0.05) only for fish fed the EDDI diet. Steam-cooking elicited 13-20% losses of the iodine content of seabream fillets. Iodine supplementation had no effect (P>0.05) on the fatty acid profile of seabream muscle. Dietary iodine-rich macroalgae was an effective and natural strategy to fortify muscle with iodine, showing that a 160g portion of steam-cooked seabream fillets could cover approximately 80% of the Daily Recommended Intake for iodine and 370% of the Daily Adequate Intake of EPA+DHA for enhanced cardiovascular health in adults. © 2014 Elsevier B.V.

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