Navegando por Assunto "Characidae"

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Acesso aberto (Open Access)
Effects of chromium supplementation on the infrapopulations of Anacanthorus penilabiatus (Monogenoidea) and Piscinoodinium pillulare (Dinoflagellida) parasites of Piaractus mesopotamicus (Characidae)
(2010-08) FUJIMOTO, Rodrigo Yudi; CASTRO, Marcello Pardi de; MARTINS, Maurício Laterça; MORAES, Flávio Ruas de; VARELLA, Jamille Elzira de Almeida; DINIZ, Daniel Guerreiro
This study evaluated the parasitism by Anacanthorus penilabiatus (Monogenoidea) and Piscinoodinium pillulare (Dinoflagellida) in the gills of "pacu", Piaractus mesopotamicus supplemented with chromium in the diet. Randomised delineation by using factorial scheme (4x2x2) for Monogenoidea and 4x2x3 for Dinoflagellate with four levels of chromium (0, 6, 12, 18mg/kg diet), two stocking densities (4kg/m3 and 20kg/m3), two classes of length (higher and lower than 17 cm) for a period of 7, 60 and 90 days, and four replicates was used. The fishes in low density which received 12 and 18mg/kg showed decreased monogeneoidea values, seven days after the experiment begin. Six, 12 and 18 mg/kg caused reduction in the dinoflagellate number in the fishes maintained at 20kg/m3. It was possible that chromium supplementation (12 e 18mg/kg) favoured the fishes health by reducing Monogenoidea and Dinoflagellida number in lower and higher densities, respectively.
Acesso aberto (Open Access)
Estrutura fina do espermatozóide de Acestrorhynchus falcatus Bloch (Teleostei, Characidae) da região norte do Brasil
(2000-09) MATOS, Edilson Rodrigues; MATOS, Patrícia Santos; CORRAL, Laura Felícia Machado; AZEVEDO, Carlos José Correia de
Spermatozoa of amazon fish, Acestrorhynchus falcatus Bloch, 1794 were investigated by optical microscopy (DIC) and electron microscopy (TEM). Spermatozoa have no acrosome, the head is ovoid, and the midpiece region cylindrical, contains spherical mitochondria. The centriolar complex is located at the lateral side of the nucleus, formed by nine peripheral pairs of microtubules and arranged in a right angle to each other. The flagellum consists of nine pairs of peripheral and two central microtubules.
Acesso aberto (Open Access)
A new miniature of Xenurobryconini (Characiformes: Characidae) from the rio Tapajós basin, Brazil
(Universidade Federal do Pará, 2016) MENDONÇA, Marina Barreira; PEIXOTO, Luiz Antônio Wanderley; DUTRA, Guilherme Moreira; NETTO-FERREIRA, André Luiz
A new species of Xenurobrycon isdescribed from tributaries of the rio Tapajós, Pará, Brazil. It is diagnosed from all congeners by the dark color of the posterior half of both caudal-fin lobes, the presence of infraorbitals one, two, and three, the presence of a set of lamellar processes on eighth principal caudal-fin ray of mature males, the presence of bony hooks similar in size or decreasing posteriorly on last unbranched and first 9-12 branched anal-fin rays of mature males, the presence of only conical teeth on both jaws, the lack of the adipose fin and the presence of 15-18 predorsal scales. The description of the new species increases the number of species in Xenurobrycon to six. An updated key to the species of the genus is provided.
Acesso aberto (Open Access)
Seasonality of nematode larvae in Iguanodectes spilurus (Characidae) an ornamental fish from northeastern Para, Brazil
(Instituto Nacional de Pesquisas da Amazônia, 2013-12) FUJIMOTO, Rodrigo Yudi; ANJOS, Ellem Cristina Silva dos; RAMOS, Fabrício Menezes; MARTINS, Maurício Laterça
The current study presents a parasitological survey of larval nematodes from freshwater ornamental fish Iguanodectes spilurus caught in the watercourse of the Caete River, in the northeast region of the State of Para, Brazil. A total of 176 specimens, 1.36±0.75 g weight and 5.53±0.98 cm total length, were analyzed. Nematode larvae were identified as Capillaria sp., Procamallanus sp. and Anisakidae, with prevalence of 70.45% and infection intensity ranging from 1.81 to 4.70 larvae. The highest prevalence 57.38% occurred in the liver, but no seasonality was observed, indicating high infection throughout the year. Seasonality was observed in fish parasitized in the stomach, intestine and caecum, with prevalence and mean intensity of 17.61% and 2.32 parasites, 12.5% and 1.81 parasites, 10.79% and 2.21 parasites, respectively. The highest degree of infection was observed in the rainy season, probably due to increased availability of intermediate hosts or food.