R. Y. Fujimoto

Haematological alterations of Leporinus macrocephalus (Osteichtyes: Anostomidae) naturally infected by Goezia leporini (Nematoda: Anisakidae) in fish pond

The effect of Goezia leporini Martins & Yoshitoshi, 2003 (Nematoda: Anisakidae) infection on the haematological characteristics of cultivated Leporinus macrocephalus (Osteichthyes:Anostomidae) was studied. Paleness of gills, kidneys, liver and heart, black spots on the kidney and accumulation of fluid in the visceral cavity, stomach and intestines were observed. Gall bladder content had pale and translucent aspect. Strong and slight positive correlations between number of nematodes and fish weight were estimated within the 0-100g and 100-200g fish weight group, respectively. Blood smears from infected fish showed variation in erythrocyte size (anisocytosis) and shape (poikilocytosis), and also dividing erythrocytes. No significant alteration (P>0.05) was shown as to erythrocyte, leukocyte count, haemoglobin concentration and thrombocyte and monocyte percentage. Parasite infection provoked significant reduction (P<0.05) in hematocrit, mean corpuscular volume, mean corpuscular haemoglobin concentration and lymphocyte percentage. On the other hand, significant increase (P<0.05) in neutrophil and eosinophil percentage in circulating blood of infected fish was observed. This is the first report regarding haematology of nematode infected freshwater cultivated fish in Brazil.

Characterization of the acute inflammatory response in the hybrid tambacu (Piaractus mesopotamicus male × Colossoma macropomum female) (Osteichthyes)

This work evaluated the acute inflammatory response induced by injections of 0.5 mL saline solution (control), 500 microg carrageenin and 0.5 mL thioglycollate 3% in the swim bladder of juvenile tambacu hybrid. Fish were distributed in three treatments, three replications and acclimated for a period of 10 days before assay. The cell characterization from the inflammatory exudate was performed in Giemsa and PAS stained smears. Carrageenin, injected in fish, showed an increase on the total number of cells in the inflammatory exudate when compared to saline and thioglycollate injected. Whereas, for carrageenin-injected fish, the percentage of thrombocyte was higher than thioglycollate. On the other hand, granulocyte percentage in thioglycollate-injected fish was higher than the ones injected using carrageenin. Carrageenin provoked the highest migration of macrophage to the inflammatory site. The PAS method confirmed the presence of three types of granulocytes: eosinophilic granular cell (EGC) type 1 with the characteristics of a special granulocytic cell commonly found in the circulating blood; EGC type 2 shorter than the last one and neutrophil. This study contributes to a better understanding of the inflammatory response and infectious processes in native fish.

Protozoan parasites of Xiphophorus spp. (Poeciliidae) and their relation with water characteristics

This work investigated the relationship between water characteristics and infestation of protozoan parasites, Icthyophthirius multifiliis and Trichodina sp., in swordtails (Xiphophorus helleri) and platy (Xiphophorus maculates) collected in an ornamental fish farm in Sao Paulo, Brazil. Fish were monthly collected from ponds and tanks for one year. The prevalence rates in fish from tanks and ponds were, respectively, 34.2% and 22.5% for I. multifiliis, and 13% and 54.2% for Trichodina sp. Increased electric conductivity and pH provoked reduction of I. multifiliis infestation. Low oxygen concentration increased Trichodina sp. infestation. The use of salt to increase the electric conductivity of water was a method to control I. multifiliis. Low dissolved oxygen and the addition of organic fertilizer favored the reproduction of Trichodina sp.

Effects of chromium supplementation on the infrapopulations of Anacanthorus penilabiatus (Monogenoidea) and Piscinoodinium pillulare (Dinoflagellida) parasites of Piaractus mesopotamicus (Characidae)

O objetivo do trabalho foi avaliar a intensidade de parasitismo por monogenoide Anacanthorus penilabiatus e pelo dinoflagelado Piscinoodinium pillulare em pacus Piaractus mesopotamicus, cuja dieta foi suplementada com cromo. Foram utilizados dois delineamentos em esquema fatorial, consistindo de 4 niveis de cromo (0, 6, 12, 18 mgCQC/kg), duas densidades de estocagem (4 kg/m3 e 20 kg/m3) e duas classes de tamanho para monogenoide (maiores e menores de 17cm) e/ou 3 periodos de coleta (7, 60 e 90 dias), com quatro repeticoes. Os peixes que receberam 12 e 18mg CQC/kg apresentaram diminuicao de monogenoides apos 7 dias de alimentacao na menor densidade. Nos peixes na maior densidade, os niveis de 6, 12 e 18 mgCQC/kg ocasionou reducao de dinoflagelados. Os resultados demonstraram que a suplementacao com cromo (12 e 18 mgCQC/kg) promoveu uma melhora na saude dos peixes na menor e na maior densidade, respectivamente.

Controle alternativo de helmintos de Astyanax cf. zonatus utilizando fitoterapia com sementes de abóbora (Cucurbita maxima) e mamão (Carica papaya)

The objective of this study was to evaluate the effectiveness of an alternative method with pumpkin and papaya seeds, dried and ground, for control of helminth parasites of Astyanax cf. zonatus. Sixty fish were distributed into twelve containers, with one fish/liter. The experiment consisted of four treatments and three replications: TJ = fish in fasting; TRC = fish fed with commercial diet; TSA = fish fed ad libitum with pumpkin seed, and TSM = fish fed ad libitum with papaya seeds. After seven days of feeding, all fish were weighed and blood was taken for blood smears. Efficacy was determined by checking the presence of parasites in the gills, stomach and intestine, in 40% of fishes per treatment (n=6). TJ and TSM showed 39% and 25% of weight loss respectively. The TSA showed better efficacy against the nematode in intestine and stomach (95.26% and 92.48%). The TSM promoted 72% of efficiency on monogeneans control. Hematology revealed an increase of monocyte values to treatment TSM. A decrease of eosinophil values was observed in treatments TSA, TSM and TRC. Thus, feeding fishes with pumpkin is a effective alternative method of low cost for control of nematodes in Astianax cf. zonatus.

A note on the occurrence of praniza larvae of Gnathiidae (Crustacea, Isopoda) on fishes from Northeast of Pará, Brazil

The infection of the estuarine teleost fishes Mugil gaimardianus Desmarest, 1831 (Mugilidae), Arius phrygiatus Valenciennes, 1839 (Ariidae), Conodon nobilis Linnaeus, 1759 (Haemulidae), Cetengraulis edentulus Cuvier, 1829 (Engraulidae), and Anableps anableps Linnaeus, 1758 (Anablepidae) by praniza larvae of Gnathiidae (Crustacea, Isopoda) was studied in specimens fished off the Atlantic Ocean in Northeast of Pará State, near Bragança, Brazil. The highest infection prevalence value was found in Anableps anableps (42.3%) and the lowest in Conodon nobilis (9.1%). The mean intensity varied from 1 parasitein Conodon nobilis to 19.5 in Arius phrygiatus. A description of the larvae is provided. The morphology of the mouthparts is related to the blood sucking activity, and is compared with the characteristics of other gnathiidae species.

Composição corporal e eficiência de utilização de nutrientes por pacus alimentados com ração suplementada com cromo trivalente

The objective of this work was to evaluate body composition as well as nutrient efficiency use by pacus fed on diet supplemented with chromium at two stocking densities. The experimental design was completely randomized with 24 treatments, in factorial scheme: four levels of chromium in the diet (0, 6, 12, and 18 mg kg -1 ), two stocking densities (4 and 20 kg m -3 ) and three periods (30, 60 and 90 days). Increases in efficiency of crude protein retention and in percentage of crude protein and decrease in efficiency of fat retention and smaller values of fat percentage in the carcass were observed. In the smallest density, the level of 6 mg kg -1 of chromium was enough to make possible the higher accumulation of protein and smaller fat concentration in the carcass. In the density of 20 kg m -3 , the need of chromium was higher, 12 mg kg -1 , to obtain similar results. Pacus fed on diet supplement with chromium present lean meat, with smaller fat concentration, until 60 days of experiment.

Experimental infection in Notodiaptomus sp. (Crustacea: Calanoida) with larvae of Camallanus sp. (Nematoda: Camallanidae)

A viabilidade da infeccao experimental com larvas do nematoide Camallanus sp. em Notodiaptomus sp., crustaceo com potencial para hospedeiro intermediario foi avaliada. Femeas adultas do nematoide foram extraidas de Xiphophorus maculatus (Osteichthyes: Poeciliidae), provenientes de piscicultura de peixes ornamentais no estado de Sao Paulo. As femeas foram ligeiramente pressionadas para liberar as larvas, coletadas com pipeta Pasteur e separadas em placas de Petri contendo 9ml de agua filtrada a 28,1oC do proprio cultivo de zooplâncton. Os tratamentos consistiram de placas contendo 60 e 105 copepodes onde se adicionou 120, 150 e 210 larvas de nematoides em quatro repeticoes. Nos tempos de 24 e 36h apos a exposicao as larvas, os copepodes foram fixados em alcool 70% para quantificacao de larvas. Apos 24h de exposicao, o grupo com 60 copepodes na presenca de 120 larvas apresentou maior prevalencia (46,5%) do que 105 copepodes com 120 larvas (33,2%). Sugere-se que 120 larvas foram suficientes para o sucesso da infeccao. A infeccao experimental mostrou-se viavel, servindo de modelo para o estudo do ciclo de vida de camalanideos e testes de susceptibilidade de hospedeiros.