1,122 research outputs found

    Soy protein concentrate as a protein source for Senegalese sole (Solea senegalensis Kaup 1858) diets: Effects on growth and amino acid metabolism of postlarvae

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    The objective of this workwas to evaluate the effect of a dietary amino acid imbalance, originating from the use of a soy protein concentrate (SPC) as the major protein source, on the growth performance and amino acid metabolism of Senegalese sole (Solea senegalensis) postlarvae. Senegalese sole (85.6724.6mg wet weight) were fed one of two experimental diets: one based on fish meal (FM) and another based on SPC. Diet were isonitrogenous (around 56% crude protein) and isoenergetic. Diet acceptability was very good and the growth rate was 6.9%day 1 for sole eating the FM diet and 6.0%day 1 for sole eating the SPC diet. Mass-speci¢c ammonia excretion and the activities of selected amino acid metabolic enzymes (ALAT, ASATand GDH) did not present significant differences between treatments, although this may have been due to the high variability found for these parameters in the SPC treatment. This variability may suggest different capacities of individual fish to adapt to the possible methionine dietary deficiency. The utilization of amino acids as a substrate for lipogenesis does not seem to be affected by the dietary protein source, since NAPDH-generating enzymes (G6PD and ME) had similar activities in both treatments. Amino acid metabolism in Senegalese sole postlarvae seems to be slightly affected by the dietary protein source. Nevertheless, the changes induced by the SPC diet do not seem to impair growth, at least at the high dietary protein level used in this experiment

    Daily oxygen consumption rhythms of Senegalese sole solea senegalensis (Kaup, 1858) juveniles

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    Senegalese sole is known to be a species with pronounced nocturnal feeding behaviour. However, as for most fish species, there is a lack of knowledge concerning the influence of such biological rhythmon metabolic rate. The aim of this study was to determine whether individual variation in routine and fed metabolic rate was affected by daily light–dark rhythms in juveniles of Senegalese sole. The individual oxygen consumption measurements in Senegalese sole juveniles were determined by flow-through respirometry, at fasted conditions and after the fish were fed a single meal, the meal time started at 0930 h and fish fed ad libitum for 30 min. The measurements were made during 22 h, of which 8 h was in the light and 14 h in the dark, and started immediately after transfer to the respiratory chambers at 1100 h. The results suggest an influence of light–dark cycles in routine metabolism. It was observed that oxygen consumption increased during the dark phase in fasted fish (FAST) but was higher during the light phase in fed fish (FEED). However, when feed is provided during the light phase, juveniles are capable of shifting oxygen consumption rhythms to respond to the energetic demands of digestion and growth. These results suggest that routine metabolism varies according to the species natural habits as Senegalese sole is known to be nocturnal. The findings of this study underline the importance of understanding the biological rhythms of the species under study before metabolic data are interpreted

    Do dietary amino acid profiles affect performance of larval gilthead seabream?

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    Live preys commonly used in fish larval rearing seem to be imbalanced in terms of amino acids. Manipulation of their amino acid composition is di fficult, but the use of microencapsulated diets allows this manipulation. This study analysed the effect of amino acid supplementation, in order to compensate for dietary amino acid imbalances, on growth and survival of gilthead seabream ( Sparus aurata ) larvae

    Duality, Quantum Skyrmions and the Stability of an SO(3) Two-Dimensional Quantum Spin-Glass

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    Quantum topological excitations (skyrmions) are analyzed from the point of view of their duality to spin excitations in the different phases of a disordered two-dimensional, short-range interacting, SO(3) quantum magnetic system of Heisenberg type. The phase diagram displays all the phases, which are allowed by the duality relation. We study the large distance behavior of the two-point correlation function of quantum skyrmions in each of these phases and, out of this, extract information about the energy spectrum and non-triviality of these excitations. The skyrmion correlators present a power-law decay in the spin-glass(SG)-phase, indicating that these quantum topological excitations are gapless but nontrivial in this phase. The SG phase is dual to the AF phase, in the sense that topological and spin excitations are respectively gapless in each of them. The Berezinskii-Kosterlitz-Thouless mechanism guarantees the survival of the SG phase at T0T \neq 0, whereas the AF phase is washed out to T=0 by the quantum fluctuations. Our results suggest a new, more symmetric way of characterizing a SG-phase: one for which both the order and disorder parameters vanish, namely =0 = 0 , =0 =0 , where σ\sigma is the spin and μ\mu is the topological excitation operators.Comment: 10 pages, 1 figur

    Nutrition, quality and performance in marine fish larvae

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    O cultivo de larvas de peixes marinhos é caracterizado por altas mortalidades e por problemas de qualidade, nomeadamente malformações esqueléticas. A solução de parte destes problemas passa por uma melhor compreensão dos requisitos nutricionais. Este trabalho pretende fazer uma revisão de trabalhos recentes que demonstram como os aminoácidos, os ácidos gordos e a vitamina K, mas também o regime alimentar, podem influenciar a qualidade e a performance das larvas de peixes marinhos

    Proteomics as a tool to develop molecular indicators of nutritional condition in farmed gilthead seabream

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    Gilthead seabream is the main aquaculture species produced in Portugal, as well as in the Mediterranean. However, the winter disease syndrome, a series of metabolic and immune system disorders caused by low temperatures, affects seabream culture, leading to important industrial losses, either as mortalities or growth decreases during spring. These effects can be minimized through dietary optimisation, either improving diets for the end of summer season, or feeding seabream with a fortified diet during autumn/winter. However, the development of a fortified diet for autumn/winter is hindered by the lack of tools to evaluate fish metabolic and physiological condition. Nevertheless, the recent development of new generation molecular tools provides good perspectives to supply molecular indicators of condition that would support this task

    Produção de mudas de pimenteira-do-reino.

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    Mercado de abacaxi ornamental: uma comparação entre dois grupos de consumidores.

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    A produção e o comércio de abacaxi ornamental emergem como uma alternativa promissora e com grandes potencialidades. Devido à sua diversidade essa fruta ganha destaque no mercado e na preferência do consumidor. O comportamento do consumidor pode ser influenciado por fatores culturais, ambientais, sociais, pessoais e psicológicos. As pessoas provenientes da mesma subcultura, classe social e ocupacional podem levar estilos diferentes de vida. Portanto, a manifestação de grupos consumidores frente aos atributos relevantes no mercado de abacaxi ornamental pode ser diferente. Diante disso este trabalho tem como objetivo comparar os dados obtidos no VI Simpósio Internacional de Abacaxi, realizado em João Pessoa (PB) e na III EXPOFLORES, realizada no município de Cruz das Almas (BA), demonstrando como se comportam diferentes grupos de consumidores, em relação aos atributos de mercado do abacaxi ornamental, como uma estratégia para orientar programas de melhoramento, sistemas de produção e comercialização.PDF 069

    Thermal plasticity of the miRNA transcriptome during Senegalese sole development

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    Several miRNAs are known to control myogenesis in vertebrates. Some of them are specifically expressed in muscle while others have a broader tissue expression but are still involved in establishing the muscle phenotype. In teleosts, water temperature markedly affects embryonic development and larval growth. It has been previously shown that higher embryonic temperatures promoted faster development and increased size of Senegalese sole (Solea senegalensis) larvae relatively to a lower temperature. The role of miRNAs in thermal-plasticity of growth is hitherto unknown. Hence, we have used high-throughput SOLiD sequencing to determine potential changes in the miRNA transcriptome in Senegalese sole embryos that were incubated at 15°C or 21°C until hatching and then reared at a common temperature of 21°C. Results: We have identified 320 conserved miRNAs in Senegalese sole, of which 48 had not been previously described in teleosts. mir-17a-5p, mir-26a, mir-130c, mir-206-3p, mir-181a-5p, mir-181a-3p and mir-199a-5p expression levels were further validated by RT- qPCR. The majority of miRNAs were dynamically expressed during early development, with peaks of expression at pre-metamorphosis or metamorphosis. Also, a higher incubation temperature (21°C) was associated with expression of some miRNAs positively related with growth (e.g., miR-17a, miR-181-5p and miR-206) during segmentation and at hatching. Target prediction revealed that these miRNAs may regulate myogenesis through MAPK and mTOR pathways. Expression of miRNAs involved in lipid metabolism and energy production (e.g., miR-122) also differed between temperatures. A miRNA that can potentially target calpain (miR-181-3p), and therefore negatively regulate myogenesis, was preferentially expressed during segmentation at 15°C compared to 21°C. Conclusions: Temperature has a strong influence on expression of miRNAs during embryonic and larval development in fish. Higher expression levels of miR-17a, miR-181-5p and miR-206-3p and down-regulation of miR-181a-3p at 21°C may promote myogenesis and are in agreement with previous studies in Senegalese sole, which reported enhanced growth at higher embryonic temperatures compared to 15°C. Moreover, miRNAs involved in lipid metabolism and energy production may also contribute to increased larval growth at 21°C compared to 15°C. Taken together, our data indicate that miRNAs may play a role in temperature-induced phenotypic plasticity of growth in teleosts.Peer Reviewe

    Avaliação físico-química e sensorial de variedades melhoradas de mamoeiro.

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    O mamão, oriundo da América Central e do Sul, possui polpa macia, densa, aromática e coloração variável, apresentando alto valor comercial e nutritivo. O presente trabalho teve como objetivo analisar as características físico-químicas e sensoriais de frutos de quatro genótipos melhorados de mamoeiro do grupo Solo (L47-P5, L47-P8, L60, H54.78) e dois do grupo Formosa (L33 e H36.45), sendo as cultivares Sunrise Solo e Tainung nº1 utilizadas como testemunhas do experimento. O genótipo L33 não foi avaliado sensorialmente, pois não estava disponível no campo
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