Resumo O objetivo deste trabalho foi investigar as ocorrências de parasitos e determinar as taxas de infestação/infecção parasitária em juvenis de Arapaima gigas de sete pisciculturas do Estado do Amazonas, relacionando às características dessas pisciculturas. Dos 70 A. gigas avaliados, 43 estavam infestados/infectados, com um total de 133 parasitos coletados. As pisciculturas 2, 4 e 6 apresentaram os maiores níveis de prevalência de parasitas (100%, 70%, 70%), intensidade média (4,1±2,6, 8,1±9,2 e 2,1±1,3) e abundância média (4,1±2,6, 5,7±8,1 e 1,5±1,5), respectivamente. A prevalência variou de 30% a 100%, intensidade média de 1,0 a 8,1 e abundância média de 0,3 a 5,7. Monogenea, Digenea, Nematoda (Hysterothylacium sp. e Spirocamallanus sp.) e Acanthocephala (Neoechinorhynchus sp. e Polyacanthorhynchus sp.) foram identificados. Os parasitas Hysterothylacium sp. e Neoechinorhynchus sp. foram os mais prevalentes com 31,43% e 15,71%, respectivamente. Os peixes apresentaram alometria negativa no crescimento e fator de condição constante. Foram discutidas as medidas de prevenção e controle das doenças parasitárias diagnosticadas, assim como práticas profiláticas que contribuam para a biossegurança das fazendas.

Abstract The objective of this study was to investigate the parasites occurrences and to determine the rates of infestation/parasitic infection in juvenile Arapaima gigas from seven fish farms in the state of Amazonas, relating to the characteristics of these fish farms. Of the 70 A. gigas evaluated, 43 were infested/infected, with a total of 133 parasites collected. Three fish farms (2, 4, 6) showed the highest levels of prevalence of parasites (100%, 70%, 70%), mean intensity (4.1±2.6, 8.1±9.2, and 2.1±1.3), and mean abundance (4.1±2.6, 5.7±8.1, and 1.5±1.5), respectively. Prevalence ranged from 30% to 100%, mean intensity from 1.0 to 8.1 and mean abundance from 0.3 to 5.7. Monogenea, Digenea, Nematoda (Hysterothylacium sp. and Spirocamallanus sp.) and Acanthocephala (Neoechinorhynchus sp. and Polyacanthorhynchus sp.) were identified. The parasites Hysterothylacium sp. and Neoechinorhynchus sp. were the most prevalent parasites with 31.43% and 15.71%, respectively. The fish presented negative allometry in growth and constant condition factor. Measures to prevent and control the parasitic diseases diagnosed are discussed as well prophylactic practices that contribute to the biosecurity of the farms.

Resumo As infecções influenciam negativamente a produção de tambaqui e, no norte do Brasil, a ampla distribuição dessa doença parasitária tem gerado preocupação entre os piscicultores. O objetivo deste estudo foi revisar a literatura publicada sobre esse patógeno. Seis principais bancos de dados de pesquisa on-line foram investigados usando-se as palavras-chave “Neoechinorhynchus buttnerae”, “acantocefalose” e “acantocéfalos de peixe”. Com base em um conjunto de critérios predeterminados, 39 publicações foram selecionadas para esta revisão. O mecanismo de ação patogênica de N. buttnerae está relacionado ao grau de penetração da probóscide. A infecção resulta em alterações histopatológicas e morfológicas no hospedeiro. A recorrência do parasito na região Norte foi maior, doze anos após sua primeira ocorrência. A falta de legislação específica sobre produtos veterinários para animais aquáticos, combinada com a negligência de boas práticas de manejo e com a ausência de um plano de contingência para o controle de infecções por acantocéfalos, contribuíram para a atual situação sanitária em Colossoma macropomum na região Norte do Brasil. Informações adicionais sobre a ocorrência da doença, patogenicidade e controle de infecções por acantocéfalos são imprescindíveis para o desenvolvimento de um plano de contingência de doenças na região e pesquisas para resolvê-las devem ser incentivadas pelo setor.

Abstract Infections negatively influence the production of tambaqui, and in north Brazil, the wide distribution of this parasitic disease has generated concern among fish farmers. The objective of this study was to review published literature on this pathogen. Six main online research databases were searched using the keywords “Neoechinorhynchus buttnerae”, “acantocefalose”, and “acanthocephalan fish”. Based on a set of predetermined criteria, 39 publications were selected for this review. The mechanism of pathogenic action of N. buttnerae is related to the degree of penetration of the proboscis. Infection results in histopathological and morphological changes in the host. The recurrence of the parasite in the northern region was greater twelve years after their first occurrence. The lack of specific legislation on veterinary products for aquatic animals, combined with the neglect of good management practices, and the absence of a contingency plan for the control of acanthocephalan infections have contributed to the current health situation of Colossoma macropomum northern Brazil. Additional information about the occurrence of the disease, pathogenicity, and control of acanthocephalan infections are imperative for developing a disease contingency plan in the region and research to address these should be encouraged by the sector.

Resumo Este estudo avaliou a fauna parasitária de híbridos tambacu (Colossoma macropomum × Piaractus mesopotamicus) e patinga (P. mesopotamicus × Piaractus brachypomus) e a interação hospedeiro-parasito-ambiente durante as estações quente e fria em duas pisciculturas localizadas no estado de Mato Grosso do Sul, Brasil, América do Sul. Foram examinados um total de 120 peixes, sendo 60 peixes por espécie. A qualidade da água foi mensurada semanalmente para avaliar a interação entre condições ambientais e parasitismo. Foram encontradas quinze espécies de parasitos: Ichthyophthirius multifiliis, Chilodonella hexasticha e Trichodina sp. (Protozoa); Henneguya piaractus, Myxobolus colossomatis e Myxobolus cuneus (Myxozoa), Anacanthorus penilabiatus, Mymarothecium boegeri, Mymarothecium viatorum e Notozothecium janauachensis (Monogenoidea), Goezia spinulosa e Goezia sp. (Nematoda), Echinorhynchus jucundus (Acanthocephala), Dolops carvalhoi eLernaea cyprinacea (Crustacea). O protozoário ciliado I. multifiliis e helmintos monogenoides foram os parasitos mais prevalentes nas estações fria e quente para ambos os híbridos nos diferentes sistemas de cultivo, produção intensiva comercial e pesca esportiva. Observou-se que os híbridos de serrasalmídeos são mais suscetíveis aos parasitos e abrigam alta diversidade parasitária em relação às espécies parentais, C. macropomum, P. mesopotamicus e P. brachypomus em ambiente de cultivo com predominância de ectoparasitos.

Abstract This study evaluated the parasitic fauna of hybrids tambacu (Colossoma macropomum × Piaractus mesopotamicus) and patinga (P. mesopotamicus × Piaractus brachypomus) and their host-parasite-environment interaction during the warm and cold seasons in two fish farms located in the State of Mato Grosso do Sul, Brazil, South America. A total of 120 fish, being 60 fish for species (30 in the warm season and 30 in the cold season) were examined. Water quality was measured weekly to evaluate the interaction between environmental conditions and parasitism. Fifteen species of parasites were found: Ichthyophthirius multifiliis, Chilodonella hexasticha e Trichodina sp. (Protozoa), Henneguya piaractus, Myxobolus colossomatis and Myxobolus cuneus (Myxozoa); Anacanthorus penilabiatus, Mymarothecium boegeri, Mymarothecium viatorum, and Notozothecium janauachensis (Monogenoidea), Goezia spinulosa and Goezia sp. (Nematoda), Echinorhynchus jucundus (Acanthocephala), and Dolops carvalhoi, Lernaea cyprinacea (Crustacea). The ciliate protozoan I. multifiliis and monogenoids were the most prevalent parasites in the cold and warm seasons for both hybrids in the different culture systems intensive production and sportive fishing. It was observed that the serrasalmid hybrids are more susceptible to parasites and harbor high diversity of parasites in relation to the parental species C. macropomum, P. mesopotamicus and P. brachypomus, with a predominance of ectoparasites.

ABSTRACT This study aimed to evaluate the hematological profile and relative condition factor of naturally parasitized Nile tilapia from 12 fish farms in southern Brazil. A total of 240 fish were collected from four regions of the state of Santa Catarina. They were anesthetized, and the blood was collected by puncturing the caudal vein. Subsequently, the fish were necropsied for parasitological analysis. The results were compared with the Kruskal-Wallis test, and the correlations were verified with the Spearman test (P ˂ 0.05). The parasitological analysis revealed high infestations by Ichthyophthirius multifiliis on the fish gills of the south and west regions. The presence of Trichodina magna and Trichodina compacta was observed in low intensity on the body surface of fish from all facilities. Trichodina spp. was found in high intensity parasitizing the fish gills of northern, Itajaí valley and western regions, nonetheless, in those regions, the presence of Monogenea, Cichlidogyrus sclerosus, and Cichlidogyrus halli, on fish gills was observed. The hematological profile presented altered parameters, featuring monocytosis and thrombocytopenia, possibly associated with high parasitic intensities. The observed correlations suggest that neutrophils and monocytes are directly involved in an organic defense against parasites. Monocytes are mainly targeted in the defense against I. multifiliis.

Resumo A infecção pelo acantocéfalo Neoechinorhynchus buttnerae é considerada uma das preocupações mais importantes para produção de tambaqui (Colossoma macropomum). Estratégias de tratamento têm sido o foco de vários estudos in vivo ; entretanto, poucos estudos foram realizados em protocolos in vitro para manutenção do parasito. O objetivo deste estudo foi desenvolver a melhor condição de cultura in vitro para N. buttnerae para garantir sua sobrevivência e adaptação fora do hospedeiro, a ser utilizado para teste com substâncias no controle do parasito. Para isso, os parasitos foram coletados de peixes naturalmente infectados e distribuídos em placas de cultura de 6 poços sob os seguintes tratamentos em triplicata: 0.9% NaCl, água estéril do tanque, meio de cultura L-15 Leibovitz, meio de cultura L-15 Leibovitz + ágar 2%, meio de cultura RPMI 1640, e meio de cultura RPMI 1640 + ágar 2%. As placas contendo os parasitos foram mantidos a 24 °C, 28 °C, e 32 °C. O meio de cultura RPMI 1640 + ágar 2% apresentou a melhor sobrevivência de 24 dias a 24 °C. Nenhuma alteração corporal tais como inchaço dos parasitos, deformação corporal, desidratação e endurecimento foram observados no meio de cultura RPMI 1640 + ágar 2%.

Abstract Infection by the acantocephalan Neoechinorhynchus buttnerae is considered one of most important concerns for tambaqui fish (Colossoma macropomum ) production. Treatment strategies have been the focus of several in vivo studies; however, few studies have been undertaken on in vitro protocols for parasite maintenance. The aim of the present study was to develop the best in vitro culture condition for N. buttnerae to ensure its survival and adaptation out of the host to allow for the testing of substances to be used to control the parasite. To achieve this, parasites were collected from naturally infected fish and distributed in 6-well culture plates under the following treatments in triplicate: 0.9% NaCl, sterile tank water, L-15 Leibovitz culture medium, L-15 Leibovitz + agar 2% culture medium, RPMI 1640 culture medium, and RPMI 1640 + agar 2% culture medium. The plates containing the parasites were maintained at 24 °C, 28 °C, and 32 °C. The RPMI 1640 + agar 2% culture medium showed the best survival of 24 days at 24 °C. No body alterations such as swollen parasites, body deformation, dehydration and hardening were observed in the RPMI 1640 + 2% culture medium.

Resumo O objetivo deste estudo foi avaliar o impacto do parasitismo por metazoários sobre os parâmetros hematológicos, bioquímicos e fator de condição relativo de tambaquis (Colossoma macropomum) cultivados na região Norte do Brasil. Foram coletados 32 tambaquis em fase de engorda numa piscicultura comercial no município de Rio Preto da Eva, estado do Amazonas, Brasil. A prevalência de parasitos foi de 100% para Anacanthorus spathulatus, Mymarothecium boegeri e Notozothecium janauachensis, 100% para Neoechinorhynchus buttnerae e 53,13% para Dolops geayi. A maior intensidade média foi de acantocéfalos, seguida por monogenéticos e branquiúros. Correlação negativa significativa foi observada entre abundância de N. buttnerae e os parâmetros de hematócrito, concentração de hemoglobina, trombócitos totais e glicose, bem como entre a abundância de monogenéticos e glicose. A infecção por parasitos metazoários foi capaz de debilitar os tambaquis como observado por meio das alterações hematológicas; sendo este quadro de anemia hipocrômica e trombocitopenia importante para ser utilizado no diagnóstico destas parasitoses. Este estudo foi o primeiro registro da ocorrência de Dolops geayi em tambaquis cultivados na Amazônia.

Abstract The aim of this study was to evaluate the impacts of metazoan parasites on hematological and biochemical parameters and relative condition factor of tambaqui (Colossoma macropomum ) farmed in northern Brazil. A total of 32 juvenile fish were captured from a commercial fish farm located in the municipality of Rio Preto da Eva, Amazonas state, Brazil. Parasite prevalence was 100% for Anacanthorus spathulatus, Mymarothecium boegeri and Notozothecium janauachensis, 100% for Neoechinorhynchus buttnerae and 53.13% for Dolops geayi. The greatest mean parasite intensity was found in acantocephalans followed by monogeneans and branchiuran crustaceans. A negative correlation was observed between abundance of N. buttnerae and hematocrit percentage, hemoglobin concentration, total thrombocyte count and glucose and between abundance of the monogenean and glucose concentration. Parasitic infections caused damage in tambaqui in terms of the observed hematological parameters that were characterized by hypochromic anemia and thrombocytopenia, which are important parameters to be used in parasitic diagnosis. This study is the first record of the occurrence of Dolops geayi in farmed tambaqui in the Amazon.

ABSTRACT This study aimed to characterize the metazoan parasitic fauna associated with freshwater farmed ornamental fish in Southern Brazil. Between July 2014 and January 2015, a total of 423 fish belonging to nine species were examined: Pterophylum scalare, Betta splendens, two varieties of Carassius auratus, Danio rerio, Xiphophorus helleri, two varieties of Xiphophorus maculatus, Poecilia sphenops, Tanichthys albonubes and Puntius sachsii. In each fish collection, the water quality parameters were measured. Specimens were obtained from three ornamental fish farms located in three micro-regions in the State of Santa Catarina (Araquari, Biguaçu and Camboriú). Parasitological indexes were obtained after qualitative and quantitative parasitological analysis. Monogenean parasites, nematodes, and cestodes were found in all facilities. Nevertheless, nematodes and monogeneans presented 100% of prevalence in P. scalare from Araquari. From the analyzed species, P. scalare showed the highest parasite richness.

ABSTRACT The ornamental fish aquaculture represents a consolidated market worldwide. In Brazil, the major volume of commercialized freshwater ornamental fish is originated from fish farms managed by small and midsized farmers. The aim of this study was to characterize the metazoan parasitic fauna associated with the main freshwater ornamental fish farmed in Southern Brazil. Between July 2014 and January 2015, 423 fishes belonging to nine freshwater species were examined: angelfish Pterophylum scalare, siamese fighting fish Betta splendens, telescope and comet goldfish Carassius auratus, zebrafish Danio rerio, blood red swordtail Xiphophorus helleri, caramel and wagtail platy fish Xiphophorus maculatus, black molly Poecilia sphenops, white cloud mountain minnow Tanichthys albonubes and goldfinned barb Puntius sachsii. Water quality was measured in fishponds from each facility. Specimens were obtained from three ornamental fish farms located in three micro-regions in the State of Santa Catarina (Biguaçu, Camboriú e Joinville). Parasitological indexes were obtained after parasitological analysis of mucus, gills, and eyes. Trichodinids, Piscinoodinium pillulare, and Ichthyophthirius multifiliis were found in all fish farms analyzed. However, P. pillulare showed the greatest prevalence and mean intensity, compared to the other protozoa analyzed. 75% prevalence and mean intensity 57.5 were observed in the gills of P. scalare from fish farm Araquari. This study showed that fish farm Biguaçu, was the facility presenting the greatest parasite diversity. P. scalare and C. auratus were the most parasitized fish species presenting the higher richness when compared to another species. These ornamental species are widely traded and require greater care in cultivation because it is essential to produce healthy fish with attractive features accepted by the market.

Resumo Este estudo avaliou a fauna de parasitos do surubim híbrido cultivado (Pseudoplatystoma reticulatum x P. corruscans) e a relação hospedeiro-parasito-ambiente em duas pisciculturas localizadas no Estado do Mato Grosso do Sul, região Centro-Oeste, Brasil. Um total de 120 híbridos de duas fazendas, 60 em cada estação (30 na estação quente e 30 na fria), foram examinados durante um ano. A qualidade da água foi medida semanalmente para avaliar a interação entre as condições ambientais e o parasitismo. Histopatologia foi usada para observar os efeitos dos parasitos e do ambiente nas brânquias dos peixes. O protozoário ciliado Ichthyophthirius multifiliis e Monogenea (Ameloblastella sp., Amphocleithrium paraguayensis, Vancleaveus ciccinus, V. fungulus e V. janacauensis) foram os parasitos mais prevalentes detectados em ambas estações nas duas fazendas, com prevalências acima de 80%. Observou-se que os parasitos não causaram danos ao estado de saúde do surubim híbrido. Esses resultados estão relacionados às boas práticas de manejo e qualidade ambiental implementada pelos produtores. É discutida a presença incomum de Monogenea para esse híbrido, comparado com seus progenitores, podendo causar preocupação ambiental e ecológica.

Abstract This study evaluated the parasite fauna of farmed hybrid surubim (Pseudoplatystoma reticulatum x P. corruscans) and the host-parasite-environment relationship in two fish farms located in Mato Grosso do Sul, Central Brazil, South America. A total of 120 hybrids from two different farms, 60 in each season (30 in the hot and 30 in cold season) were examined during a year. Water quality was weekly measured to evaluate the interaction among environmental conditions and parasitism. Histopathology was used to observe the effects of the parasites and environment on the fish gills. The ciliate protozoan Ichthyophthirius multifiliis and the monogeneans (Ameloblastella sp., Amphocleithrium paraguayensis, Vancleaveus ciccinus, V. fungulus and V. janacauensis) were the most prevalent parasites detected in both seasons in both farms, with prevalence above 80%. It was stated that parasites did not cause important damage in the health status of the hybrid surubim. These results might be related to general good management practices and environmental quality implemented by the fish farmers. The presence of uncommon monogenean parasites to this hybrid compared to their parents causing an environmental and ecological concern is here discussed.

Este estudo avaliou a correlação dos parâmetros hematológicos com a abundância média de helmintos monogenea Rhabdosynochus rhabdosynochus em robalo-flecha, Centropomus undecimalis, cultivado em diferentes temperaturas e salinidades. As condições experimentais foram: 28 °C/0 ‰; 28 °C/15 ‰; 28 °C/32 ‰; 25 °C/0 ‰; 25 °C/15 ‰; 25 °C/32 ‰. A prevalência (P) foi de 100,0% nos peixes de 28 °C/15 ‰, 28 °C/32 ‰, 25 °C/15 ‰ significativamente diferente (p<0,05) dos peixes de 25 °C/32 ‰ (P=75,0%). O número de eritrócitos, hematócrito e leucócitos totais foram significativamente maiores nos peixes mantidos a 28 °C/15 ‰ e 28 °C/32 ‰. A abundância média de R. rhabdosynochus, hematócrito e número de eritrócitos mostraram correlação positiva (p<0,05) com a temperatura (ρ = 0,3908; ρ = 0,4771 e ρ = 0,2812, respectivamente). Houve correlação negativa da abundância média com a hemoglobina (ρ = -0,3567) e a concentração de hemoglobina corpuscular média (CHCM) (ρ = -0,2684). Não houve correlação entre a abundância e a salinidade entre os tratamentos (ρ = -0,0204). O baixo número de Monogenea registrado (mín: 1 e máx: 33) justifica as poucas alterações na saúde dos animais avaliados. Isso sugere que essas condições experimentais de cultivo podem ser recomendadas para um futuro desenvolvimento do cultivo de C. undecimalis no Brasil, sem que haja influência e perdas econômicas associadas a mortalidades, por parasitos R. rhabdosynochus.

This study evaluated the correlation of hematological parameters with the mean abundance of the monogenean helminth Rhabdosynochus rhabdosynochus in Centropomus undecimalis reared at different temperatures and salinities. The experimental conditions were: 28 °C/0 ppt (parts per thousand); 28 °C/15 ppt; 28 °C/32 ppt; 25 °C/0 ppt; 25 °C/15 ppt; and 25 °C/32 ppt. The prevalence was 100.0% in fish at 28 °C/15 ppt, 28 °C/32 ppt and 25 °C/15 ppt, which was significantly different (p < 0.05) from those at 25 °C/32 ppt. The red blood cell (RBC) count, hematocrit and total leukocyte (WBC) count were significantly higher in fish at 28 °C/15 ppt and 28 °C/32 ppt. The mean abundance of R. rhabdosynochus, hematocrit and RBC showed positive correlations (P < 0.05) with temperature (ρ= 0.3908; ρ= 0.4771 and ρ = 0.2812). Mean abundance showed negative correlations with hemoglobin (ρ= -0.3567) and mean corpuscular hemoglobin concentration (MCHC) (ρ = -0.2684). No correlation between abundance and salinity was detected among the experimental conditions (ρ = -0.0204). The low numbers of monogeneans recorded (min -1 and max -33) explain the few changes to fish health. This suggests that these experimental conditions may be recommended for development of rearing of C. undecimalis in Brazil, without any influence or economic losses from R. rhabdosynochus.

This study evaluated the haematological parameters of the hybrid surubim (Pseudoplatystoma corruscans x P. reticulatum) farmed in intensive and semi intensive system. A total of 240 fish were examined, 120 from fish farm and 120 from a semi-intensive for comparison between the hot and cold season. The water quality was weekly measured to evaluate the influence of environmental conditions on the haematology. Fish from intensive system showed hematocrit and white blood cell count (WBC) higher in hot season while the total plasmatic protein, hemoglobin concentration, mean corpuscular hemoglobin concentration (MCHC) and mean corpuscular volume (MCV) were higher in cold season. In fish from semi intensive system, the red blood cells count (RBC) and total thrombocyte number was higher in hot season while the MCHC and MCV were higher in cold season. There was no alterations in the numbers of lymphocytes, neutrophils, basophils, eosinophils and PAS - positive granular leukocyte (PAS-LG). The results showed the influence of seasonality on the hematological parameters of the hybrid surubim kept under normal farming conditions. Regarding water quality, hot season was directly related to increased water temperature and decreased dissolved oxygen while the opposite was found in cold season.

O objetivo deste trabalho foi avaliar a fauna parasitária dos peixes híbridos cachapinta (Pseudoplatystoma corruscans macho x P. reticulatum fêmea) e jundiara (Leiarius marmoratus macho x P. reticulatum fêmea) no período de larvicultura. Um total de 315 animais, 126 híbridos jundiara e 189 híbridos cachapinta, foram examinados de acordo com o estágio de desenvolvimento: larvas, pós-larvas e alevinos. Larvas e pós-larvas foram prensadas entre lâmina e lamínula e observadas sob microscopia óptica. Os alevinos foram observados externamente em estereomicroscópio e necropsiados para avaliação interna dos órgãos. Foram aferidos os parâmetros de qualidade de água em todas as fases de cultivo. O exame parasitológico revelou a presença dos protozoários Epistylis sp. e Trichodina sp., no tegumento e nas brânquias, Ichthyophthirius multifiliis no tegumento, dos helmintos Monogenea nas brânquias, e das metacercárias de digenéticos em brânquias, baço, rins, fígado e intestino, em ambos os híbridos analisados. Os parasitos Epystilis sp., Trichodina sp. e metacercária de digenéticos ocorrem com maior frequência nos dois híbridos, nas fases de pós-larvas e alevinos. Há maior prevalência e diversidade de parasitos na fase de alevinagem dos híbridos estudados.

The objective of this work was to evaluate the parasitic fauna of the hybrid fish cachapinta (Pseudoplatystoma corruscans male x P. reticulatum female) and jundiara (Leiarius marmoratus male x P. reticulatum female) at the hatchery stages. A total of 315 animals, 126 hybrids of jundiara and 189 hybrids of cachapinta were examined according to their development stage: larvae, post-larvae, and fingerlings. Larvae and post-larvae were pressed between a slide and a cover slip and were observed under optical microscopy. Fingerlings were externally observed in a stereomicroscope and dissected for internal evaluation of organs. Water quality parameters were measured in all cultivation phases. The parasitological exam showed the presence of the protozoa Epistylis sp. and Trichodina sp., on integument and gills, and Ichthyophthirius multifiliis on integument, of the helminth Monogenea on gills, and of digenean metacercariae on gills, spleen, kidneys, liver, and intestines in both hybrid fish evaluated. The parasites Epistylis sp., Trichodina sp., and digenean metacercariae occur most frequently in the two hybrids at the stages of post-larvae and fingerlings. There is a higher prevalence and diversity of parasites in the fingerling phase of the studied hybrids.

Tricodinídeos são protozoários ciliados móveis com ampla distribuição mundial; são considerados um dos agentes parasitários que mais acometem peixes cultivados. No Brasil, a maioria dos tricodinídeos que parasitam importantes espécies de peixes cultivados são desconhecidos, o que requer mais estudos taxonômicos com esse grupo de parasitos. Este estudo caracteriza morfologicamente Trichodina colisae Asmat & Sultana, 2005 de pacu (Piaractus mesopotamicus) e do híbrido patinga (P. mesopotamicus × P. brachypomus) cultivados, respectivamente, no Centro-Oeste e Sudeste do Brasil. Foram feitas montagens a fresco do raspado de muco da pele, nadadeiras e brânquias, fixados com metanol e, posteriormente, impregnados com nitrato de prata e coradas com Giemsa para avaliação em microscopia óptica. O presente estudo relata não só a segunda ocorrência de T. colisae no mundo, mas também a primeira ocorrência na América do Sul.

Family Trichodinidae comprises ciliate protozoa distributed worldwide; they are considered some of the main parasitological agents infecting cultivated fish. However, the trichodinidae parasitizing important fish species cultured in Brazil are unknown, and more taxonomic studies on this group of parasites are required. This research morphologically characterizes Trichodina colisae Asmat & Sultana, (2005) of pacu (Piaractus mesopotamicus) and patinga hybrid (P. mesopotamicus × P. brachypomus) cultivated in the central and southeast regions of the country. Fresh assemblies were made from mucus scraped from the skin, fins and gills, fixed with methanol and, subsequently, impregnated with silver nitrate and stained with Giemsa for assessment under light microscopy. This research reports not only the second occurrence of T. colisae in the world, but also its first occurrence in South America.

O objetivo do presente estudo foi reportar a infecção por Trypanosoma sp. em tuviras (Gymnotus aff. inaequilabiatus) oriundas do Pantanal Sul-mato-grossense, Brasil. Dez peixes provenientes do rio Paraguai, Pantanal Sul-mato-grossense, foram avaliados quanto à presença de hemoflagelados. Tripomastigotas de Trypanosoma sp. foram observados nas extensões sanguíneas de três peixes (30% de prevalência), e algumas formas encontravam-se em divisão. Por meio do exame a fresco e da centrifugação do sangue em capilar de hematócrito como métodos para diagnóstico, a taxa de prevalência foi de 80%. Esse é o primeiro relato de Trypanosoma sp. em tuviras no Brasil.

The blood infection by Trypanosoma sp. in tuvira (Gymnotus aff. inaequilabiatus) from the Pantanal wetland was reported in this study. Ten fish from the Paraguay River in the Pantanal were evaluated for the presence of hemoflagellates. Trypomastigotes of Trypanosoma sp. were observed in blood smears from three fish (30% prevalence) and some forms were seen to be undergoing division. Using the diagnostic methods of fresh examination and blood centrifugation in hematocrit capillary tubes, the prevalence rate was 80%. This is the first report of Trypanosoma sp. in tuvira in Brazil.

Este estudo avaliou o efeito da heparina 100UI e do Na2EDTA nas concentrações de 3, 5 e 10% sobre a coagulação sanguínea e os parâmetros hematológicos de surubim híbrido. Foram utilizados 10 peixes, com peso médio de 386,7±24,3g e comprimento total médio de 38,7±6,4cm, para colheita das amostras sanguíneas e determinação do percentual do hematócrito, teor de proteínas plasmáticas totais e teste de fragilidade osmótica dos eritrócitos (FOE). Os dados foram submetidos à análise de variância, e as médias foram comparadas pelo teste de Tukey, a 5% de probabilidade. A coagulação foi eficientemente inibida quando utilizado o Na2EDTA; já as amostras com heparina coagularam 10 horas após a coleta. Houve aumento na fragilidade osmótica dos eritrócitos (P<0,01), especialmente quando utilizado o Na2EDTA 10 e 5%, não havendo diferença entre o controle e a heparina. No hematócrito e teor de proteínas plasmáticas totais, não foram verificadas diferenças significativas. O Na2EDTA 3% é seguro e eficiente como anticoagulante para surubim híbrido, prevenindo a coagulação por mais de 10h e ocasionando discreto efeito sobre a fragilidade osmótica dos eritrócitos.

The effect of heparin 100IU and Na2EDTA in concentration of 3%, 5% and 10% on the blood coagulation and hematological parameters of hybrid surubim catfish were evaluated. We used ten fish weighing 386,7±24,3g and average length of 38,7±6,4cm for collection of blood samples and determination of the percentage of hematocrit, plasma total protein content and osmotic fragility erythrocytes test (OFE). Data were submitted to analysis of variance and averages compared by Tukey test at 5% probability. Coagulation was efficiently inhibited when used the Na2EDTA, while the samples with heparin coagulate ten hours after collection. There was an increase in osmotic fragility of erythrocytes (P<0.01), especially when using Na2EDTA 10% and 5%, with no difference between control and heparin. In hematocrit and total plasma protein content were not observed statistical differences. The Na2EDTA 3% is safe and effective anticoagulant for hybrid surubim catfish, preventing clotting for more than 10 hours causing slight effect on the osmotic fragility of erythrocytes.