ABSTRACT The present study proposes to characterize the parasites isolated during the initial phase of production in fish farms located in Mato Grosso do Sul in the central-western region of Brazil, using histopathology analysis and molecular techniques. A total of 340 hybrid surubim fish (Pseudoplatystoma reticulatum × P. corruscans) from four farms were examined during the co-feeding phase. Histopathology analysis showed that 10.9% (n = 37) of the fish were infected with parasites. Branchitis, lifting epithelium, hypertrophy of epithelial cells, lamellar fusion, aneurisms and infection in the bone tissue of the gill filament was observed. The parasite species was determined by amplification of the 18S rRNA gene followed by sequencing. The phylogenetic analysis of nucleotide sequences indicates a close relationship (99.6%) with Henneguya pseudoplatystoma reported to be infecting the hybrid Pseudoplatystoma. This study demonstrates the occurrence of H. pseudoplatystoma in hybrid surubim (P. reticulatum × P. corruscans) during the co-feeding phase in fish farms in Mato Grosso do Sul. Also, molecular techniques provide a faster and sensitive method to identify fish parasites, and may assist in the development of new management techniques aimed at improving the sanitary conditions contributing to the reduction of mortality rates in these animals.

O filo Protozoa reúne diversos organismos evolutivamente distintos que podem atuar como ecto ou endoparasitos de peixes em todo o mundo, sendo responsáveis por doenças as quais, por sua vez, podem ocasionar impactos econômico e social nos diferentes países. Apesar dos recentes avanços no campo de diagnóstico de doenças em peixes no Brasil, ainda pouco se conhece sobre a fauna de protozoários parasitos de peixes e suas relações com o ambiente e hospedeiro. Esta revisão apresenta os mais importantes protozoários parasitos encontrados em peixes cultivados no Brasil, não apenas com ênfase no seu diagnóstico, biologia, transmissão e relação hospedeiro-parasito, mas também algumas informações que podem ser úteis para pesquisadores para o correto diagnóstico em pisciculturas.

The Phylum Protozoa brings together several organisms evolutionarily different that may act as ecto or endoparasites of fishes over the world being responsible for diseases, which, in turn, may lead to economical and social impacts in different countries. Apart from the recent advances for the diagnosis of fish diseases in Brazil, little is known on the protozoan parasites and their relationship with environment and host. This revision presents the most important protozoan parasites found in farmed fish from Brazil, not only with emphasis on its diagnosis, biology, transmission and host-parasite relationship, but also on some information that may be useful to researchers in determining the correct diagnosis in fish farms.

O objetivo deste trabalho foi descrever a fauna parasitária de cachara (Pseudoplatystoma reticulatum) cultivado em tanque-rede, no rio Paraguai. Dez peixes com peso médio de 598,0±81,3 g e comprimento total médio de 38,6±1,6 cm foram examinados. Todos os peixes necropsiados apresentaram infestação por pelo menos duas espécies de parasitos. Entre os parasitos, foram encontrados Ichthyophthirius multifiliis (Ciliophora), Myxobolus sp. e Henneguya sp. (Myxozoa), Monogenoidea, Choanoscolex abscissus e Nominoscolex sudobim (Cestoda), Dolops carvalhoi (Crustacea) e Digenea. O protozoário Ichthyophthirius multifiliis foi o parasito com maior prevalência.

The objective of this work was to describe the parasitic fauna of cachara (Pseudoplatystoma reticulatum) cultured in a net-cage in the Paraguai River, Brazil. Ten fish with mean weight of 598.0±81.3 g and total length of 38.6±1.6 cm were examined. All necropsied fish were parasitized by at least two species. Among them, Ichthyophthirius multifiliis (Ciliophora), Myxobolus sp. and Henneguya sp. (Myxozoa), Monogenoidea, Choanoscolex abscissus and Nominoscolex sudobim (Cestoda), Dolops carvalhoi (Crustacea), and Digenea were diagnosed. The protozoan Ichthyophthirius multifiliis was the most prevalent parasite.

O objetivo desse trabalho foi registrar a primeira ocorrência sazonal do acantocefala Quadrigyrus nickoliSchmidt & Hugghins, 1973(Quadrigyridae) no peixe “Mato Grosso”,Hyphessobrycon eques Steindachner, 1882 (Characidae), capturados no Rio Chumucuí, região Bragantina, Pará, Brasil. Os peixes foram coletados no período de julho∕2006 a junho∕2007 e examinados com técnica padrão para detecção de parasitas. Um total de 75 parasitas foram encontrados no estômago e intestino. Dos 83 peixes capturados (50 na estação seca e 33 na chuvosa), 22 estavam parasitados por cistacantos de Quadrigyrus nickoli. No presente trabalho discute-se a importância do H. eques como hospedeiro paratênico para Quadrigyrus nickoli. Os presentes dados constituem o primeiro estudo sobre a biologia e a infecção de Q. nickoli na Amazônia oriental.

The objective of this work was to report the first seasonal occurrence of the acanthocephalan Quadrigyrus nickoliSchmidt & Hugghins, 1973(Quadrigyridae), in the “Mato Grosso”Hyphessobrycon eques (Characidae) (Steindachner, 1882), collected from the Chumucuí River, state of Pará, Brazil. The fish were collected between July 2006 (rainy season) and June 2007 (dry season) and were examined for parasites using pattern techniques. A total of 75 parasites were found in the stomach and intestine. Among 83 fish examined (50 in the dry season and 33 in the rainy season), 22 were parasitized by cystacanths of Q. nickoli. The importance of H. eques as a paratenic host for Q. nickoli is discussed. This is the first study on the biology of and infection by Q. nickoli occurring in the eastern Amazon region.

The aim of this study was to evaluate the immune response of hybrid surubim vaccinated by intraperitoneal injection and by immersion against Aeromonas hydrophila. Vaccine was prepared with formalin-inactivated A. hydrophila. Forty eight fishes (47±9g) were distributed in 12 tanks (4 fish / tank) in the following treatments (4 tanks / treatment): unvaccinated fish, vaccinated intraperitoneally and vaccinated by immersion. After 21 days, intraperitoneally vaccinated fishes showed the highest values of total protein and immunoglobulins, agglutination titer and serum antimicrobial activity. Lysozyme concentration in the serum was higher in the fishes vaccinated by immersion than unvaccinated fishes. Intraperitoneal vaccination induced the highest immune response and could be used to improve the fish resistance against motile Aeromonas.

O objetivo deste trabalho foi selecionar reprodutores de Litopenaeus vannamei sobreviventes de um surto do vírus da síndrome da mancha-branca (WSSV), adaptados às condições locais e diagnosticados negativamente para WSSV e para o vírus da necrose infecciosa hipodermal e hematopoiética (IHHNV), e avaliar se esta extratégia é uma alternativa viável para produção em Santa Catarina. Foram selecionados fenotipicamente 800 machos e 800 fêmeas, de um viveiro. Análises de nested-PCR de 487 fêmeas e de 231 machos, sexualmente maduros, mostraram que 63% das fêmeas e 55% dos machos estavam infectados com IHHNV. Os animais livres de IHHNV foram testados para WSSV, e os considerados duplo negativos destinados à reprodução. As pós-larvas produzidas foram estocadas em nove berçários, para análise. Das 45 amostras, com 50 pós-larvas cada, apenas duas foram positivas para IHHNV e nenhuma para WSSV. Os lotes de pós-larvas diagnosticadas livres de vírus por nested-PCR foram encaminhados para seis fazendas. Foi realizada análise comparativa em viveiros de engorda, entre pós-larvas locais e pós-larvas do Nordeste do Brasil. Também foram analisados caranguejos (Chasmagnathus granulata), siris (Callinectes sapidus) e lebres do mar (Aplysia brasiliana), que são possíveis vetores dos vírus. A média de sobrevivência foi de 55% para as pós-larvas locais e de 23,4% para as pós-larvas do Nordeste. As lebres do mar apresentaram prevalência de 50% e os caranguejos de 67% de WSSV.

The objective of this work was to select surviving breeders of Litopenaeus vannamei from white spot syndrome virus (WSSV) outbreak, adapted to local climatic conditions and negatively diagnosed for WSSV and infectious hypodermal and hematopoietic necrosis virus (IHHNV), and to evaluate if this strategy is a viable alternative for production in Santa Catarina, Brazil. A total of 800 males and 800 females were phenotypically selected in a farm pond. Nested-PCR analyses of 487 sexually mature females and 231 sexually mature males showed that 63% of the females and 55% of the males were infected with IHHNV. Animals free of IHHNV were tested for WSSV, and those considered double negative were used for breeding. The post-larvae produced were stocked in nine nursery tanks for analysis. From the 45 samples, with 50 post-larvae each, only two were positive for IHHNV and none for WSSV. Batches of larvae diagnosed free of virus by nested-PCR were sent to six farms. A comparative analysis was carried out in growth ponds, between local post-larvae and post-larvae from Northeast Brazil. Crabs (Chasmagnathus granulata), blue crabs (Callinectes sapidus), and sea hares (Aplysia brasiliana), which are possible vectors of these viruses, were also evaluated. The mean survival was 55% for local post-larvae against 23.4% for post-larvae from the Northeast. Sea hares showed prevalence of 50% and crabs of 67% of WSSV.