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São Paulo, Brazil

Ebert L.A.,Centro Universitario Leonardo da Vinci | Ebert L.A.,Federal University of Sao Carlos | Branco J.O.,Vale do Itajai University | Barbieri E.,Institute Pesca Of Sao Paulo
Pan-American Journal of Aquatic Sciences

The gull Larus dominicanus is one of the most common coastal seabirds of the Brazilian coast, being capable of using several habitats and types of preys. In that context the estuary of Saco da Fazenda is an important feeding area, bathing, cleaning of the feathers and resting. The objective of this work was evaluating the population structure and daily activity of L. dominicanus in the estuary. From February/2004 to January/2005, the gulls were monitored in monthly census in the Saco da Fazenda, with intervals of two hours among the census from the 6:00 am to 8:00 pm. The oscillations observed in the population of L. dominicanus along the year were considered significant, being higher in autumn. The occupation of the estuary started from the first hours of the day, culminating at the 2:00 pm. In the morning, the gulls were observed in feeding activity, following by the bathing, cleaning of the feathers and resting. In the afternoon the abundance reduced significantly, with the dispersion of the gulls to close areas to the Saco da Fazenda. The oscillations found in the abundance of L. dominicanus during this study can be attributed to events of the cycle of life of the gulls and the differences observed in the number of gulls along the day to the period of activity of the fishing fleet. Source

Carraschi S.P.,Sao Paulo State University | Ikefuti C.V.,NEPEAM | Florencio T.,NEPEAM | da Cruz C.,Centro Universitario Da Fundacao Educacional Of Barretos Unifeb | Ranzani-Paiva M.J.T.,Institute Pesca Of Sao Paulo

The use of drugs in aquaculture is necessary to combat pathogens responsible for causing the high rate of mortality in fish farming, such as infection by ectoparasites. The aim of this research was to evaluate the efficacy: (A) of toltrazuril (TOL) treatment against Ichthyophthirius multifiliis, Trichodina heterodentata and Anacanthorus penilabiatus; (B) of thiamethoxam (TH), in treating fish infected by A. penilabiatus and (C) of enrofloxacin (ENR) and florfenicol (FFC) against Aeromonas sp. and Streptococcus sp. The drugs TOL and TH were administered in therapeutic baths while ENR and FFC were mixed with the fish food. The drug concentrations were adjusted according to the experimental conditions (laboratory, microcosm or mesocosm). The drug TOL presented a treatment efficacy rate of 100% against I. multifiliis in microcosm and T. heterodentata in mesocosm. Moreover, ENR presented an efficacy rate of 100% in treating fish infected by Aeromonas sp. and Streptococcus sp. in mesocosm. Finally, TH efficacy rate in controlling A. penilabiatus infection was 81.86% in mesocosm and FFC decreased the overall bacterial load in infected fish. Aeromonas sp. and Streptococcus sp. strains were found in the samples collected for microbiological analysis. In conclusion, TH presented a high efficacy in treating fish against A. penilabiatus infection while TOL was better in controlling T. heterodentata. The antibiotics used in mecoscosm condition presented potential to be used against bacterial infection in aquaculture. © 2013 Elsevier B.V. Source

Vidotti R.M.,Institute Pesca Of Sao Paulo | Pacheco M.T.B.,Institute Tecnologia Of Alimentos | Goncalves G.S.,Institute Pesca Of Sao Paulo
Revista Brasileira de Zootecnia

The objective of this study was to determine the quality and composition of fatty acid in the lipid fraction of silages obtained from the residue of tilapia processing. Stratification of the lipid layer of the silages occurred at different times among the two types of silage (acid and fermented) and the greatest volume of oil was observed in acid silage (8.67% p/p). Although acid silage was more oxidized, it showed lower contents of free fatty acids probably because the degree of hydrolysis of its components is lower than that of fermented silage. Fatty acid composition did not differ among processes inasmuch as level of ω-3 was slightly higher in fermented silage. According to the degree of saturation, monounsaturated fatty acids stood out as the predominant category in acid and fermented silages with values of 39.69% and 33.39%, respectively. The use of antioxidants in the silage is needed because the process of production is carried out at temperatures higher than room temperature. The oil in the silages has excellent nutritional value and contains fatty acids essential for animal feeding. © 2011 Sociedade Brasileira de Zootecnia. Source

Ranzani-Paiva M.J.T.,Institute Pesca Of Sao Paulo | Lombardi J.V.,Institute Pesca Of Sao Paulo | Maiorino F.C.,Laboratory and Vet Diagnostico e Consultoria Ltda | Goncalves A.,CAUNESP | Dias D.C.,Institute Pesca Of Sao Paulo
Boletim do Instituto de Pesca

The aim of this study was to analyze the effects of chronic toxicity of sodium selenite (Na2SeO3 SE4+) on juvenile Nile tilapia Oreochromis niloticus. Therefore, a toxicity test was carried out with three sub-lethal concentrations of that salt (0.4 mgSe L-1, 0.04 mgSe L-1 and 0.01 mgSe L-1), plus a control group. The experiment was carried out for 14 days, sampling six individuals per treatment in intervals of 0, 3, 7, 10 and 14 days. Effects of chronic sublethal concentrations of selenite were evaluated by routine haematological and histopathological analysis. There were significant differences (P<0.05) in the rate of hemoglobin, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) and an increase of the total number of leukocytes, mainly due to the increased number of lymphocytes, monocytes, and neutrophils. Severe gill hyperplasia was found on the fourteenth day. Nephrosis were found in the cephalic kidney, characterized by glomerulonephritis and tubular vacuolar degeneration, which was a result of the necrosis or secondary infection, glomerular atrophy and glomerulosclerosis, proliferative glomerulonephritis, nephrosis, nephrosclerosis, tubular calcification, edema and hemorrhage. It was found that selenite, at the tested concentrations despite being sublethal, caused histological and hematological changes in Nile tilapia. Source

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