Evaluation of the efficacy of hydrated sodium aluminosilicate in the prevention of aflatoxin-induced hepatic cancer in rainbow trout / Avaliação da eficácia do aluminosilicato de sódio hidratado na prevenção de câncer hepático induzido por aflatoxina em truta arco-íris

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 percent 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.

Resultados encorajadores têm sido observados com o emprego de aluminosilicatos para descontaminação de ração contendo aflatoxina destinada à avicultura. No entanto, raros estudos têm sido destinados a testar essa substância em aqüicultura. Assim, no presente trabalho, foi investigada a eficácia do aluminosilicato de sódio hidratado (HSAS, 0,5 por cento) em proteger a truta arco-íris dos danos hepáticos causados por ração contaminada com aflatoxina B1. Os grupos experimentais foram alimentados com suas respectivas dietas durante 12 meses, mensalmente cada grupo foi amostrado para análises anatomopatológica e histopatológica para verificação da presença de lesões hepáticas. Apesar da presença de HSAS, todos os grupos que receberam dieta contaminada com aflatoxina B1 apresentaram lesões hepáticas indicativas do processo carcinogênico, sendo que exemplares alimentados com essas dietas por mais longo prazo apresentaram hepatocarcinoma ou colangiocarcinoma. Estes resultados indicaram que a concentração de HSAS usada no presente estudo não foi efetiva em prevenir o desenvolvimento de lesões hepáticas induzidas por aflatoxina B1 em truta arco-íris.

Phylogeny, ultrastructure, histopathology and prevalence of Myxobolus oliveirai sp. nov., a parasite of Brycon hilarii (Characidae) in the Pantanal wetland, Brazil

This paper presents the morphological, histological and ultrastructural characteristics of Myxobolus oliveirai sp. nov., a parasite of the gill filaments in Brycon hilarii from the Brazilian Pantanal. Out of 216 B. hilariispecimens examined (126 wild and 90 cultivated), 38.1 percent of wild specimens (n = 48) were infected. The parasites form elongated plasmodia primarily in the tip of gill filaments, reaching about 3 mm in length. A thorough comparison with all the Myxobolus species described from South American hosts, as well as nearly all the Myxobolus species described so far is provided. Partial sequencing of the 18S rDNA gene revealed a total of 1,527 bp. The Myxobolus species parasite of B. hilarii did not match any of the Myxozoa available in GenBank. In the phylogenetic analysis, M. oliveirai sp. nov. composed a monophyletic group with eight other species: five species of Myxobolus parasites of mugilid fishes, two parasites of pangasiid and one of centrarchid. Infection prevalence values of the parasite revealed no significant differences between wet and dry seasons or between males and females. The importance of the infection to the farming of the host species is emphasized.

Histophatology and ultrastructure of Henneguya caudalongula sp. n. infecting Prochilodus lineatus (Pisces: Prochilodontidae) cultivated in the state of São Paulo, Brazil

The histological and ultrastructural characteristics of a new species of Henneguya and the host reactions to infection by this species are reported. Henneguya caudalongula sp. n. was found in the inter and intralamellar regions of the gills of Prochilodus lineatus (Valenciennes, 1836) cultivated at Center for the Research and Management of Continental Fishing Resources located in the municipality of Pirassununga, state of São Paulo, Brazil. The plasmodia were white and round or ellipsoidal and measured 0.2 to 1 mm in length. The development of the parasite was asynchronous and the mature spores were fusiform, with a total length 71 ± 1.4 æm, body length of 16.6 ± 0.54 æm and width 4.6 ± 0.2 æm. The caudal process was 52.6 ± 1.5 æm long. The polar capsules were elongate (length 6.1 ± 0.19 æm, width 1.6 ± 0.15 æm) and of equal size. The polar filament was coiled in 10-11 turns. The prevalence of the parasite was 48.3 percent and did not vary significantly with the season or host size.

A new species of Henneguya, a gill parasite of Astyanax altiparanae (Pisces: Characidae) from Brazil, with comments on histopathology and seasonality

A new species of Myxosporea, Henneguya chydadea, is described parasitizing the gills of Astyanax altiparanae collected from a lake on Rio das Pedras farm near Campinas, state of Säo Paulo, Brazil. Of the fish examined, 88.3 percent had gills parasitized by myxosporeans. The prevalence of the parasite ranged from 80 percent in the spring and fall, 93 percent in the summer and 100 percent in the winter. The parasite induced the formation of white, oval-shaped cysts measuring 40-64 æm x 64-80 æm which deformed the gill lamellae, compressed the capillaries, and caused retraction of the neighboring lamellae. The mature spores were elongated and had two identical, parallel elongate polar capsules. Each capsule contained a polar filament with 9-10 turns. There was no mucous envelope or iodinophilous vacuole. Morphometric differences between this parasite and other species of the genus Henneguya indicated, that he parasite observed in A. altiparanae is a new species. This is the first report of a myxosporeanparasitizing A. altiparanae

Modificações histológicas das gônadas de manjuba Anchovella lepidentostole (fowler, 1911) (Osteichthyes, engrulidae), durante o ciclo reprodutivo / Gonad histological modifications in manjuba, Anchoviella lepidentostole (Fowler, 1911) (Osteichthyes, Engraulidae), durant the reproductive cycle

Foram utilizados 40 machos e 36 fêmeas de Anchoviella lipidentostole (Fowler, 1911), capturadas no Rio Ribeira de Iguape, Registro - SP, com o objetivo de estudar histologicamente o ciclo reprodutivo desta espécie. As gônadas foram caracterizadas macroscopicamente quanto ao volume, a coloraçäo e a vascularizaçäo superficial. A seguir as gônadas esquerdas foram amostradas em seu terço médio, o qual foi fixado em líquido de Bouin e processado segundo técnicas histológicas de rotina, foram identificados cinco estádios: imaturo, início de maturaçäo , maturaçäo avançada, reproduçäo e esgotado.