252 resultados para teleost macrograzers
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Augmentation of vertebrate growth by growth hormone (GH) is primarily due to its regulation of insulin-like growth factor I (IGF I) and IGF II levels. To characterize the effect of GH on the levels of IGF I and IGF II mRNA in a teleost, 10 micrograms of bovine GH (bGH) per g of body weight was administered to juvenile rainbow trout (Oncorhynchus mykiss) through i.p. injection. The levels of IGF I and IGF II mRNA were determined simultaneously, by using RNase protection assays, in the liver, pyloric ceca, kidney, and gill at 0, 1, 3, 6, 12, 24, 48, and 72 hr after injection. In the liver, IGF I mRNA levels were significantly elevated at 6 and 12 hr (approximately 2- to 3-fold, P < or = 0.01), while IGF II mRNA levels were significantly elevated at 3 and 6 hr (approximately 3-fold, P < or = 0.01). In the pyloric ceca, IGF II mRNA levels were significantly elevated at 12, 24, and 48 hr (approximately 3-fold, P < or = 0.01), while IGF I mRNA was below the limits of assay accuracy. GH-dependent IGF mRNA appearance was not detected in the gill and kidney. Serum bGH levels, determined by using a radioimmunoassay, were significantly elevated at 3 and 6 hr (P < 0.005). In primary hepatocyte culture, IGF I and IGF II mRNA levels increased in a bGH dose-dependent fashion, with ED50 values of approximately 45 and approximately 6 ng of bGH per ml, respectively. The GH-dependent appearance of IGF II mRNA in the liver and pyloric ceca suggests important roles for this peptide hormone exclusive of IGF I.
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Prosorhynchoides apogonis n. sp. (Digenea: Bucephalidae) is described from the intestine of the apogonid Cheilodipterus macrodon on the southern Great Barrier Reef, Australia. The new species is differentiated from other species of Prosorhynchoides Dollfus, 1929 by the configuration of its digestive system, shape and distribution of its vitelline follicles, and the shape and extent of its uterus. This is the first bucephalid to be described from the teleost family Apogonidae, and our records suggest that this species is strongly host-specific, at least to the genus Cheilodipterus. The host family is consistent with the pattern of Prosorhynchoides being reported from a very wide range of piscivorous fish families. As a result of comparisons made in the description of this species, 18 species formerly included in Bucephaloides Hopkins, 1954, Bucephalopsis Diesing, 1855 and Neobucephalopsis Dayal, 1948 are transferred to Prosorhynchoides, 16 as new combinations and two as replacement names to prevent secondary homonymy.
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Understanding the factors that influence the distribution and abundance of predators, including sharks, is important for predicting the impacts of human changes to the environment. Such studies are particularly important in Florida Bay, USA where there are planned large-scale changes to patterns of freshwater input from the Everglades ecosystem. Studies of many marine predators suggest that links between predator and prey habitat use may vary with spatial scale, but there have been few studies of the role of prey distribution in shaping habitat use and abundance of sharks. We used longline catches of sharks and trawls for potential teleost prey to determine the influence of teleost abundance on shark abundance at the scale of regions and habitats in Florida Bay. We found that shark catch per unit effort (CPUE) was not linked to CPUE ofteleosts at the scale of sampling sites, but shark CPUE was positively correlated with the mean CPUE for teleosts within a region. Although there does not appear to be a strong match between the abundance of teleosts and sharks at small spatial scales, regional shark abundance is likely driven, at least partially, by the availability of prey. Management strategies that influence teleost abundance will have cascading effects to higher trophic levels in Florida Bay.
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We would like to thank Lucia Gonzalez and Maria Sanz for technical assistance. Professor Øystein Evensen is also acknowledged for providing us with the inactivated IPNV. This work was supported by the European Research Council (ERC Starting Grant 2011 280469) and by the European Commission under the 7th Framework Programme for Research and Technological Development (FP7) of the European Union (Grant Agreement 311993 TARGETFISH). T. W. received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference HR09011).
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Tese de dout. em Química, Faculdade de Ciências do Mar e do Ambiente, Univ. do Algarve, 2002
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Tese de dout. em Biologia, especialidade de Biologia Molecular, Unidade de Ciências e Tecnologias dos Recursos Aquáticos, Univ. do Algarve
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A adição de sal à água tem sido utilizada para a mitigação de estresse e aumento da taxa de sobrevivência em peixes. O presente estudo avaliou o efeito do cloreto de sódio (0,0; 1,0; 3,0 e 6.0 g/l) nas concentrações de cortisol plasmático, glicemia, triglicerídios, proteínas total plasmática, hematócrito, hemoglobina, número de eritrócitos, glicogênio e lipídio hepáticos, e lipídio muscular em matrinxã Brycon amazonicum adultos após quatro horas de transporte e durante período de recuperação de 96 h. Amostras foram coletadas antes e depois do transporte, bem como 24 e 96 h após a chegada. O nível de cortisol plasmático estava mais elevado logo após o transporte quando comparado à condição inicial (pré-transporte), exceto para os peixes transportados com sal nas concentrações 3,0 e 6,0 g/l. Comportamento semelhante foi observado para a glicemia, porém os peixes dos tratamentos 0,0, 1,0 e 3,0 g/l necessitaram de período superior a 24 h para recuperar a condição inicial. Foram registrados níveis mais baixos de glicogênio hepático em peixes do tratamento controle (0,0 g/l). Os parâmetros hemoglobina, número de eritrócitos, proteína plasmática total e lipídio hepático não apresentaram alterações durante o período experimental. Os valores de hematócrito diminuíram logo após o transporte em todos os tratamentos, retornando aos níveis iniciais após 24 h. Todos os tratamentos apresentaram redução nos níveis de lipídio muscular e triglicerídios durante o período de recuperação. Os resultados sugerem que a adição de 6,0 g/l de sal na água de transporte reduz as alterações fisiológicas de estresse e que é necessário período de 96 h após o transporte para a recuperação da condição inicial de matrinxãs transportados sem a adição de sal.
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The effects of parasitic infections in condition factor, hematocrit, hemoglobin, mean corpuscular hemoglobin concentration (MCHC), and leucocytes and thrombocytes distribution in Piaractus mesopotamicus, Leporinus macrocephalus, hybrid tambacu (P. mesopotamicus x Colossoma macropomum and Brycon amazonicus collected in feefishing from Franca, São Paulo, Brazil were evaluated. Parasitized tambacu and L. macrocephalus had higher (p<0.05) condition factor than unparasitized fish. However, the contrary occurred in P. mesopotamicus and B. amazonicus. Changes in the hematocrit, hemoglobin and MCHC were not related to parasitism. Parasitic infections did not cause effect on leucocytes and thrombocytes percentage (p>0.05) of tambacu. In P. mesopotamicus parasitized by Monogenea Anacanthorus penilabiatus and dinoflagellate Piscinoodinium pillulare, increase in monocytes and decrease in thrombocytes percentage (p<0.05) were found. However, the same parasitic association in L. macrocephalus caused a decrease in lymphocytes percentage accompanied by increase in neutrophils percentage (p<0.05). In B. amazonicus, infection by Ichthyophthirius multifiliis, P. pillulare and monogeneans caused increase in neutrophils percentage.
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São apresentadas novas informações sobre a distribuição geográfica de algumas espécies de peixes teleósteos que ocorrem na costa brasileira, incluindo duas espécies que nunca haviam sido registradas em nossas águas. Os serranídeos Pseudogramma gregoryi (assinalado da Flórida à Venezuela) e Plectranthias garrupellus (registrado da Carolina do Norte ao Caribe) foram encontrados, respectivamente, na costa do Ceará e na costa sudeste-sul do Brasil. São aqui mencionados e discutidos os dois primeiros registros do gênero Caristius (Caristiidae) no Brasil, bem como os primeiros registros na costa sudeste-sul do Brasil das espécies Enchelycore carychroa (Muraenidae), e Chilomycterus antillarum (Diodontidae), e da espécie Neobythites brasiliensis(Bythitidae) no nordeste do Brasil. É também assinalada a ocorrência mais setentrional do pargo Calamus mu (Sparidae), uma espécie até então circunscrita à região entre o Espírito Santo e São Paulo, e são discutidos os registros adicionais de Bascanichthys paulensis (Ophichthidae), Nezumia aequalis (Macrouridae), Antigonia combatia (Caproidae) e Notolycodes schmidti (Zoarcidae) na costa brasileira.
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The use of aluminum silicates for decontaminating animal feed containing aflatoxins has yielded encouraging results in chicken and turkey poults. In contrast, very few studies have tested these substances in aquaculture. In this work, we investigated the efficacy of a trout diet containing 0.5% hydrated sodium aluminosilicate (HSAS) in protecting against contamination with aflatoxin B1. Trout were reared on these diets for one year and the experimental groups were examined monthly for hepatic presumptive preneoplastic and neoplastic lesions. Regardless of the presence of HSAS, all of the fish that received aflatoxin in their diet have shown hepatic lesions indicative of a carcinogenic process, presenting also the development of cancer in some fish. The concentration of HSAS used in this study was ineffective in preventing the onset of hepatic lesions induced by aflatoxin B1 in rainbow trout.