Ocimum basilicum essential oil in pacu Piaractus mesopotamicus: anesthetic efficacy, distribution, and depletion in different tissues.

This study aimed to evaluate the anesthetic activity of Ocimum basilicum essential oil and the distribution and depletion of its major compounds in different tissues of the pacu, Piaractus mesopotamicus. Juveniles (319.08 ± 9.14 g) were individually anesthetized with six concentrations of essential oil from O. basilicum (150, 180, 210, 240, 270, and 300 mg L-1), while in a second experiment, fish (492.39 ± 51.51 g) were subjected to a 10 min immersion bath with essential oil from O. basilicum (300 mg L-1). After anesthetic recovery, blood and tissue samples of the brain, gills, liver, spleen, and white muscle were collected at 0, 0.5, 1.0, 3.0, 6.0, 12.0, and 24 h. A 300 mg L-1 concentration induced anesthesia in the shortest time (193.11 ± 9.31), while at 270 and 300 mg L-1 concentrations, the anesthetic recovery period was the longest (244.33 ± 12.44) Methyl chavicol and linalool were quantified in all tissue samples. The plasma concentrations of methyl chavicol differed (p < 0.05) at all evaluated times. Linalool decreased (p < 0.05) from 0 to 1 h and decreased again only after 12 h. Reduction percentages in 24 h were 92.9% for methyl chavicol, and 97.2% for linalool. Elimination of the compounds methyl chavicol and linalool is slower in the gills, where lower elimination constants (0.03 and 0.15 per h) and longer half-lives (25.84 and 4.53 h), respectively, are noted. In general, essential oil from O. basilicum compounds was readily eliminated, showing promising potential for use as an anesthetic in aquaculture.

Parasitological assessment in hybrids Serrasalmidae fish farmed in Brazil.

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.

Parasitological assessment in hybrids Serrasalmidae fish farmed in Brazil / Avaliação parasitológica em híbridos de peixes Serrasalmidae cultivados no Brasil

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.

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.

Influences of Sex and Age on the Hematological Profile of the Jundiá (Silver Catfish) Rhamdia quelen.

In this study, sex and age influenced the hematological profiles of Jundiá (Silver Catfish) Rhamdia quelen. Females showed lower levels of hemoglobin, young fish increased lymphocyte counts, and older fish increased hematocrit values. These results indicate that, depending on age and sex, the fish have disparate hematological profiles. For this reason, it is important to consider the sex and age of an R. quelen when examining the impact of environmental and management factors on this species in terms of their hematological profiles. Received May 24, 2015; accepted March 24, 2016.

Histopathology from liver of tuvira ( Gymnotus spp.) parasitized by larvae of nematodes / Histopatologia de fígado de tuvira parasitado por larvas de nematoides

ABSTRACT: The aim of this study was to evaluate the histological changes in the liver of thirty-five Gymnotusspp. parasitized by endohelminths collected between April 2012 to October 2013 in commercial bait fish farming of Pantanal basin. Histological cuts of 7µm were stained with hematoxylin-eosin for parasites research and liver changes and have also been submitted to the Perls histochemical method for evaluation of hemosiderosis (Fe+++) based on the incidence degree and severity of change (Grade I, II and III) and tests for the presence of central melanomacrophages. Parasites identified were: Brevimulticaecumsp. with a prevalence of 22,9%, Eustrongylidessp 17,1%, Contracaecumtype I 68,7%, Contracaecumtype II 5,7%, Contracaecumtype III 5,7% and larvae of Anisakidae11,4%. Histological analysis showed intense disorganization of hepatic parenchyma with degenerate hepatocytes due to high parasitic infection, changes that can be deleterious and compromise the organism functioning, being harmful to the health of evaluated animals. Also evidencing normal tissue interleaved with different stages of Fe+++ deposit in grades II and III, injuring or destroing the cell. Histopathological changes in the tuvira's liver suggested a chronic response and the development of a balance relation between tuvira and parasitism by endohelminth identified in this study. There are also a testimony to the health condition of commercial bait fish farming on current ecosystem conditions.

RESUMO: O objetivo deste estudo foi avaliar as alterações histológicas do fígado de trinta e cinco Gymnotusspp. parasitados por endohelmintos, coletados entre abril de 2012 a outubro de 2013, em isqueiros da bacia do Pantanal. Cortes histológicos de 7µm foram corados com hematoxilina-eosina para pesquisa de parasitos e de alterações hepáticas; também foram submetidos ao método histoquímico de Perls para avaliação de hemossiderose (Fe+++) com base no grau de incidência e severidade da alteração (Grau I, II e III) e pesquisa da presença de centro de melanomacrófagos. Os parasitos identificados foram: Brevimulticaecumsp., com prevalência de 22,9%, Eustrongylidessp. 17,1%, Contracaecumtipo I 68,7%, Contracaecumtipo II 5,7%, Contracaecumtipo III 5,7% e larvas de Anisakidae11,4%. A análise histológica revelou intensa desorganização do parênquima hepático, com hepatócitos degenerados devido à alta infecção parasitária. Essas alterações podem ser deletérias e comprometer o funcionamento do organismo, sendo prejudicial à saúde dos animais avaliados; também evidenciou tecido normal intercalado com estágios diferenciados de depósito de Fe+++ nos Graus II e III, podendo lesionar ou destruir a célula. As alterações histopatológicas do fígado das tuviras sugerem uma resposta crônica e o desenvolvimento de uma relação de equilíbrio entre a tuvira e o parasitismo pelos endohelmintos identificados neste estudo. Elas também são um testemunho da condição de saúde dos peixes dos isqueiros nas condições atuais do ecossistema.

Parasitological assessment in the hybrid surubim (Pseudoplatystoma reticulatum x P. corruscans), with uncommon occurrence of Monogenea parasites.

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.

Parasitological assessment in the hybrid surubim (Pseudoplatystoma reticulatum x P. corruscans), with uncommon occurrence of Monogenea parasites / Avaliação parasitológica no híbrido surubim (Pseudoplatystoma reticulatum x P. corruscans), com ocorrência incomum de parasitos Monogenea

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.

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.

Brazilian catfish parasitized by Epistylis sp. (Ciliophora, Epistylididae), with description of parasite intensity score.

The determination of mean intensity of parasitism for colony-forming sessile protozoan such as Epistylis has been a great problem in parasitological studies. Some alternatives have been proposed by researchers for laboratory and field conditions. This study describes the criteria to establish the parasitic intensity score for epistylidid infestation in fish. Parasite distribution and the host-parasite relationship in four species of Brazilian cultured catfish and their hybrids are discussed. The highest prevalence rates were found in the hybrid jundiara, Leiarius marmoratus male × Pseudoplatystoma reticulatum female (96.4 %), followed by jurupoca, Hemisorubim platyrhynchos (60 %), and the hybrid surubim, Pseudoplatystoma corruscans male × P. reticulatum female (52.7 %). Positive correlation between parasitic intensity score and the fish size, weight, and relative condition factor were also observed. These findings indicate that Epistylis infestation in Brazilian catfish is an emerging disease in cultured fish.