Light and electron microscopy of Myxobolus sciades n. sp. (Myxozoa), a parasite of the gills of the Brazilian fish Sciades herzbergii (Block, 1794) (Teleostei: Ariidae)

A myxosporean parasite in the gill lamellae of the freshwater teleost fish, Sciades herzbergii (Ariidae) (Block, 1794), from the Poti River (Northeast of Brazil) was described by light and electron microscopy studies. Polysporic histozoic cyst-like plasmodia containing several life-cycle stages, including mature spores, were observed. The spores were pyriform and uninucleate, measuring 9.15 ± 0.39 μm (n = 50) long, 4.36 ± 0.23 μm (n = 25) wide and 2.61 ± 0.31 μm (n = 25) thick. Elongated pyriform polar capsules (PC) were of equal size (4.44 ± 0.41 μm long and 1.41 ± 0.42 μm in diameter) and each contained a polar filament with 9-10 coils obliquely arranged in relation to the axis of PC. The PC wall was composed of two layers of different electron densities. Histological analysis revealed the close contact of the cyst-like plasmodia with the basal portion of the epithelial gill layer, which exhibited some alterations in the capillary vessels. Based on the morphological and ultrastructural differences, the similarity of the spore features to those of the genus Myxobolus and the specificity of this host to previously described species, we describe a new species named Myxobolus sciades n. sp. in this study.

Acute Toxicity by Water Containing Hexavalent or Trivalent Chromium in Native Brazilian Fish, Piaractus mesopotamicus: Anatomopathological Alterations and Mortality

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Haematological alterations of Leporinus macrocephalus (Osteichtyes: Anostomidae) naturally infected by Goezia leporini (Nematoda: Anisakidae) in fish pond

Estudou-se efeito da infecção por Goezia leporini Martins & Yoshitoshi, 2003 (Nematoda: Anisakidae) sobre as características hematológicas de Leporinus macrocephalus (Osteichthyes:Anostomidae) cultivado. Palidez das brânquias, rins, fígado e coração, pontos negros nos rins e acúmulo de líquido na cavidade visceral, estômago e intestinos foram observados. O conteúdo da vesícula biliar tinha aparência pálida e translúcida. Observaram-se alta e moderada correlações positivas entre número de nematóides e peso do peixe estimadas dentro dos grupos de peixe de 0-100g e 100-200g, respectivamente. As extensões sangüíneas revelaram variações no tamanho (anisocitose) e forma (poiquilocitose) dos eritrócitos, bem como eritrócitos em divisão. Não houve alteração (P>0,05) na contagem total de eritrócitos, de leucócitos, na taxa de hemoglobina e nos percentuais de trombócitos e monócitos. A infecção provocou redução (P<0,05) no percentual de hematócrito, no volume corpuscular médio, na concentração de hemoglobina corpuscular média e no percentual de linfócitos, e aumento (P<0,05) no percentual de neutrófilos e eosinófilos no sangue circulante de peixes infectados. Este é o primeiro relato no Brasil que relaciona hematologia e infecção por nematóides em peixes cultivados.

Genetic conservation of Brazilian fishes - Present state and perspectives

Natural environments have been worldwide affected by the growing impact of anthropogenic actions that promote the reduction or the extinction of several vertebrate species. Aquatic ecosystems represent one of the most affected environments and many fish species and/or populations have been increasingly fragmented distributed due to habitat degradation, predatory fishing, introduction of exotic species, river sedimentation, deforestation, pollution, reduction of food resource, and construction of hydroelectric dams. Actually, more than 150 Brazilian fish species, including freshwater, estuary and coastal species, can be considered threatened. Information on the diversity, conservation biology and population analysis on threatened species or populations, with several DNA markers, can be extremely useful for the success of fish species-recovery and maintenance programs. Although DNA analysis in Neotropical fish species are just beginning, they tend to increase with the widespread attention to the use of molecular approaches to minimize problems related to the risk of extinction. The accumulation of information on biology and pattern of genetic variation of fish species, associated with ecological and demographic data, and also education and respect to the nature, constitutes a crucial task to develop efficient conservation strategies in order to preserve the genetic diversity in aquatic environments.

Composition of Extracellular Polymeric Substances (EPS) produced by Flavobacterium columnare isolated from tropical fish in Brazil

Thirty nine isolates of Flavobacterium columnare from Brazilian fish farms had their carbohydrate composition of EPS evaluated by high efficiency liquid chromatography, using the phenol-sulfuric acid method of EPS. The occurrence of capsules on F. columnare cells was not directly related to biofilm formation, and the predominant monosaccharide is glucose.

Genetic Identification of F1 and Post-F1 Serrasalmid Juvenile Hybrids in Brazilian Aquaculture

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Análise de volatilidade, integração de preços e previsibilidade para o mercado brasileiro de camarão

The present paper has the purpose of investigate the dynamics of the volatility structure in the shrimp prices in the Brazilian fish market. Therefore, a description of the initial aspects of the shrimp price series was made. From this information, statistics tests were made and selected univariate models to be price predictors. Then, it was verified the existence of relationship of long-term equilibrium between the Brazilian and American imported shrimp and if, confirmed the relationship, whether or not there is a causal link between these assets, considering that the two countries had presented trade relations over the years. It is presented as an exploratory research of applied nature with quantitative approach. The database was collected through direct contact with the Companhia de Entrepostos e Armazéns Gerais de São Paulo (CEAGESP) and on the official website of American import, National Marine Fisheries Service - National Oceanic and Atmospheric Administration (NMFS- NOAA). The results showed that the great variability in the active price is directly related with the gain and loss of the market agents. The price series presents a strong seasonal and biannual effect. The average structure of price of shrimp in the last 12 years was R$ 11.58 and external factors besides the production and marketing (U.S. antidumping, floods and pathologies) strongly affected the prices. Among the tested models for predicting prices of shrimp, four were selected, which through the prediction methodologies of one step forward of horizon 12, proved to be statistically more robust. It was found that there is weak evidence of long-term equilibrium between the Brazilian and American shrimp, where equivalently, was not found a causal link between them. We concluded that the dynamic pricing of commodity shrimp is strongly influenced by external productive factors and that these phenomena cause seasonal effects in the prices. There is no relationship of long-term stability between the Brazilian and American shrimp prices, but it is known that Brazil imports USA production inputs, which somehow shows some dependence productive. To the market agents, the risk of interferences of the external prices cointegrated to Brazilian is practically inexistent. Through statistical modeling is possible to minimize the risk and uncertainty embedded in the fish market, thus, the sales and marketing strategies for the Brazilian shrimp can be consolidated and widespread

Nenneguya garavelli n. sp and Myxobolus peculiaris n. sp (Myxozoa : Myxobolidae) in the gills of Cyphocharax nagelli (Osteichthyes : Curimatidae) from Rio do Peixe Reservoir, Sao Jose do Rio Pardo, São Paulo, Brazil

The present work describes myxozoans found in Cyphocharax nagelli (Characiformes: Curimatinae) commonly called saguiru collected from Rio do Peixe Reservoir, Sao Jose do Rio Pardo, São Paulo, Brazil. From a total of 38 examined fish, 24 were infected with Henneguya garavelli n. sp. (63% prevalence) and two with Myxobolus peculiaris n. sp. (5% prevalence) in the gills. Spores were studied by staining and fresh spores were observed by differential interference contrast optics. Henneguya garavelli n. sp. differs from Henneguya iheringi , Henneguya occulta, Henneguya cesarpintoi, Henneguya santae, Henneguya pisciforme, Henneguya amazonica, Henneguya striolata, Henneguya leporinicola and Henneguya chydadea in spore length and from Henneguya travassosi, Henneguya adherens, Henneguya malabarica, Henneguya piaractus and also Henneguya chydadea in polar capsule length and tail length. Myxobolus peculiaris n. sp. was very different when compared to other species of Myxobolus in its morphology and the biggest size of spore body. The authors present tables with comparative measurements of Brazilian myxozoan parasites. (c) 2006 Elsevier B.V. All rights reserved.

Trichodina heterodentata (Ciliophora: Trichodinidae): a new parasite for Piaractus mesopotamicus (Pisces: Characidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Hemolytic activity of alternative complement pathway as an indicator of innate immunity in pacu (Piaractus mesopotamicus)

The objective of this study was to evaluate the methodology to establish the hemolytic activity of alternative complement pathway as an indicator of the innate immunity in Brazilian fish pacu (Piaractus mesopotamicus), in addition to verifying the influence of β-glucan as an immunostimulant. Fish were fed with diets containing 0, 0.1 and 1% β-glucan, during seven days, and then inoculated with Aeromonas hydrophila. Seven days after the challenge, they were bled for serum extraction. The methodology consisted of a kinetic assay that allows calculating the required time for serum proteins of the complement to promote 50% lysis of a rabbit red blood cell suspension. The method developed in mammals was successfully applied for pacu and determined that the hemolytic activity of the proteins of the complement system (alternative pathway) increased after the pathogen challenge, but was not influenced by the β-glucan treatment.

Economic viability of the piaucu Leporinus macrocephalus (Garavello & Britski, 1988) production

Brazilian fish farms presented an accelerated development during the early 90's, mainly because of the increase in fee-fishing operations. To meet the demand of this market, fish production and supply became excessive and, as a consequence, the number of fee-fishing operations, farmers and the final selling price, decreased. This study analyzes the technical aspects, production cost, profitability and economic viability of the production of piaucu (L. macrocephalus) in ponds, based on information from a rural property. Feeding and fingerling costs amount to approximately 47.1 % of the total production cost, representing together with the final selling price the most important factor affecting profitability. The payback period was 8.3 years, the liquid present value US$ 291.07, the internal return margin 9%, and the income-outcome ratio was 1.01, which represents an unattractive investment as a projection based on current conditions. The improvement in productive efficiency enhances the economic valuation index, and that the relative magnitude of cost and income are the most important points for the economic viability of the studied farm.

Alternative treatment for Anacanthorus penilabiatus (Monogenea : Dactylogyridae) infection in cultivated pacu, Piaractus mesopotamicus (Osteichthyes : Characidae) in Brazil and its haematological effects

The present work, studied the effect of 0, 1,000, 1,500 and 2,000 mg of garlic powder/kg dry ration for Piaractus mesopotamicus (Osteichthyes Characidae), weighting 73.6+/-39.4 9 and measuring 15.0+/-2.7 cm, fed for a period of 15, 30 and 45 days. Fifteen days after treatment with 1,000 and 2,000 Prig of garlic/kg dry ration, significant reduction of Anacanthorus penilabiatus (Monogenea: Dactylogyridae) in the gills was related. Nevertheless, the addition of garlic to the ration caused significant increase in the erythrocyte number and in the thrombocyte percentage in the circulating blood. However, a decrease in the lymphocyte percentage was also observed. After 45 days, fish fed with garlic showed significant increase in the erythrocyte number, leucocyte, haemoglobin rate, hematocrit and thrombocyte.

Performance and hematology of pacu fed diets supplemented with vitamins C and/or E

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Innovative molecular approach to the identification of Colossoma macropomum and its hybrids

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efectos del parasitismo sobre el tejido branquial en peces cultivados: estudio parasitologico e histopatologico

One hundred four out of 225 diagnosticated cases were myxosporidian, monogenean, Ichthyophthirius multifiliis Fouquet, 1876 and bacterial diseases in Piaractus mesopotamicus Holmberg, 1887 (pacu), Colossoma macropomum Cuvier, 1818 (tambaqui) and tambacu, at Aquaculture Center, Universidade Estadual Paulista (UNESP), Jaboticabal, São Paulo, Brazil, between 1992 and 1995. The gills were fixed in 10% buffered formalin solution to posterior histologic routine. It was observed Henneguya sp. cysts into the capillaries of the secondary lamellae, encapsulated by the respiratory epithelium cells. It provoked adherence of the adjacent lamellae, hyperplasia, congestion, oedema and epithelium displacement. Monogeneans infestations by Anacanthorus penilabiatus Boeger, Husak & Martins, 1995 and Ancyrocephalinae sub-family caused light inflammatory reaction and hyperplasia. In severe infestations was observed hyperplasia of primary lamellae, necrosis, oedema, respiratory epithelium displacement, ruptured pillar cells and telangiectasis. Response to I. multifiliis was limited to surrounding epithelial cells in young fishes and hyperplasia, necrosis, inflammatory infiltrate and oedema in old fishes. Such lesions iniciate hyperplasic and oedematous process that with inflammation of the parasitic sites, provoked alterations over gases and ions interchange surface and consequently fish metabolism.