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El Puerto de Santa María, Spain

Cruzado I.H.,Institute Investigacion Y Formacion Agraria Y Pesquera Of Andalucia Ifapa | Cruzado I.H.,Centro El Toruno | Rodriguez E.,University of La Laguna | Herrera M.,Institute Investigacion Y Formacion Agraria Y Pesquera Of Andalucia Ifapa | And 2 more authors.
Aquaculture Research

Brill (Scophthalmus rhombus L.) is a flatfish considered of special interest for aquaculture diversification, but the high mortality observed during the early larval rearing is the main obstacle to commercial culture. The objective of this study was to contribute to the knowledge of nutrient utilization of early-hatched larvae, characterizing the changes in lipid and protein contents during embryogenesis and the yolk-sac larval stage of S. rhombus. Total lipid, lipid classes and fatty acid contents remained constant during embryogenesis and yolk-sac larval development, except for phosphatidylethanolamine and phosphatidylinositol, which increased in quantity during the yolk-sac larval stage. On the other hand, total protein (including non-protein nitrogen) and amino acids decreased their contents in both periods, especially at hatching. The decrease only in the serine, glutamic acid, proline and lysine contents during embryogenesis suggests a selective use of amino acids during this phase. Unlike embryogenesis, amino acids loss during hatching appears to be non-selective, and almost all amino acids (essential and non-essential) decreased. Our results suggest that there is higher catabolism of protein vs. lipid during embryogenesis and the yolk-sac larval stage of S. rhombus. © 2012 John Wiley & Sons Ltd. Source

Melian C.J.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | Melian C.J.,National Center for Ecological Analysis And Synthesis | Baldo F.,Spanish Institute of Oceanography | Baldo F.,Institute Ciencias Marinas Of Andalucia Csir | And 6 more authors.
Advances in Ecological Research

In recent years, there has been a renewed interest in the ecological consequences of individual trait variation within populations. Given that individual variability arises from evolutionary dynamics, to fully understand eco-evolutionary feedback loops, we need to pay special attention to how standing trait variability affects ecological dynamics. There is mounting empirical evidence that intra-specific phenotypic variation can exceed species-level means, but theoretical models of multi-trophic species coexistence typically neglect individual-level trait variability. What is needed are multispecies datasets that are resolved at the individual level that can be used to discriminate among alternative models of resource selection and species coexistence in food webs. Here, using one the largest individual-based datasets of a food web compiled to date, along with an individual trait-based stochastic model that incorporates Approximate Bayesian computation methods, we document intra-population variation in the strength of prey selection by different classes or predator phenotypes which could potentially alter the diversity and coexistence patterns of food webs. In particular, we found that strongly connected individual predators preferentially consumed common prey, whereas weakly connected predators preferentially selected rare prey. Such patterns suggest that food web diversity may be governed by the distribution of predator connectivity and individual trait variation in prey selection. We discuss the consequences of intra-specific variation in prey selection to assess fitness differences among predator classes (or phenotypes) and track longer term food web patterns of coexistence accounting for several phenotypes within each prey and predator species. © 2014 Elsevier Ltd. Source

Araujo C.V.M.,University of Cadiz | Tornero V.,University of Cadiz | Lubian L.M.,University of Cadiz | Blasco J.,University of Cadiz | And 12 more authors.
Science of the Total Environment

This work presents the results of an interlaboratory proficiency exercise for whole-sediment toxicity assays with the benthic marine diatom Cylindrotheca closterium. An assay protocol was established and followed by all participating laboratories. Cell growth after 72 h exposure was the endpoint used. Four sediment samples of unknown toxicity were assayed. The main problem encountered during this exercise was the differences in the cell growth of algae exposed to reference sediment. Those differences may be associated with changes in the physiological status of the initial culture due to temperature changes during transport to the other laboratories. In general, the method proposed presented good replicability (precision between replicates) and reproducibility (interlaboratory precision). Around 80% (17 out of 21) of results obtained were classified as satisfactory (Z-scores < 2). The whole-sediment assay with C. closterium presented here can be considered sufficiently successful for possible use as a standard toxicity test. The assay is simple to perform, the proposed species is ecologically relevant as an integral component of microphytobenthos, and is widely distributed around the world. These positive factors suggest that the whole-sediment assay with the benthic marine diatom C. closterium can be used as a reliable tool in marine sediment quality assessment. © 2009 Elsevier B.V. All rights reserved. Source

Catanese G.,Centro El Toruno | Manchado M.,Centro El Toruno | Fernandez-Trujillo A.,University of Malaga | Infante C.,Centro El Toruno
Food Chemistry

In this study, we have developed a novel multiplex-PCR assay for the authentication of mackerels of the genus Scomber in processed food. The method consists of two novel Scomber japonicus- (104 bp) and Scomber australasicus-specific (143 bp) amplicons, respectively, corresponding to the mitochondrial control region. It also includes the previously described Scomber colias-specific product (159 bp) corresponding to the 5S ribosomal DNA, the Scomber scombrus-specific fragment (123 bp) from the mitochondrial NADH dehydrogenase subunit 5, and finally a positive amplification control corresponding to the small 12S rRNA subunit (188 bp). The system was assayed in fresh samples as well as in a total of 40 commercial samples including 28 different canned products and 12 unprocessed fresh fillets. A positive identification was observed in all cases according to their commercial labelling. Overall, this methodology reveals as a potential molecular tool for direct application in the authentication of Scomber mackerels in the seafood industry. © 2010 Elsevier Ltd. All rights reserved. Source

Van Bergeijk S.A.,Centro El Toruno | Paullada Salmeron J.A.,Centro El Toruno | Lopez Perez A.I.,University of Seville | Moreno J.,University of Seville | And 2 more authors.
Aquaculture Research

Rotifers, used in aquaculture as feed for early larval stages, are poor in carotenoids compared with copepods, the natural most common prey item of marine fish larvae. A minimal sufficient level of carotenoids in fish larvae may be essential for a correct development. The freshwater microalga Muriellopsis sp. has been identified as a potential source of the carotenoid lutein with possible application in aquaculture. Lutein is a potent antioxidant, with potentially beneficial effects as a carotenoid for fish larvae. This study describes the lutein enrichment of the rotifer Brachionus sp. when incubated with homogeneously dispersed suspensions of freeze-dried, lutein-rich Muriellopsis sp. in seawater. A short enrichment time (2 or 2.5 h) resulted in a higher lutein content of the rotifers than a long enrichment time (13.5 or 24 h). Although the concentration of lutein in enriched rotifers, 0.06-0.16 mg (g dry weight)-1 was low compared with its content in Muriellopsis sp. [about 3 mg (g dry weight)-1], it was in the range reported for natural copepod populations. Therefore, we conclude that freeze-dried biomass of Muriellopsis sp. can be used to enrich rotifers with lutein, providing an adequate level of this carotenoid for marine fish larvae. © 2012 John Wiley & Sons Ltd. Source

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