Vitamina E em dietas para reprodutoras de tilápia-do-nilo (Oreochromis niloticus)

Pós-graduação em Aquicultura - FCAV

Caracterização do regime alimentar de Oreochromis niloticus (Linnaeus, 1758) e Tilapia rendalli (Boulenger, 1897) na represa de Barra Bonita, Médio Rio Tietê, SP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Substratos artificiais melhoram a qualidade da água em sistema de cultivo multitróficos e multiespaciais?

Pós-graduação em Aquicultura - FCAV

Stocking densities and feeding strategies in shrimp and tilapia polyculture in tanks

The objective of this work was to evaluate the performance of Pacific marine shrimp (Litopenaeus vannamei) and tilapia (Oreochromis niloticus), in a polyculture in tanks subjected to different stocking densities and feeding strategies, in comparison with monoculture. Two experiments were performed, at the same time, in a completely randomized design with three treatments and four replicates each. Treatments for experiment I were: monoculture with 10 shrimp per m² (10S:0T); polyculture with 10 shrimp and 0.5 tilapia per m² (10S:0.5T); and polyculture with 10 shrimp and 1 tilapia per m² (10S:1T). Shrimp was the main crop, and feed was provided based on shrimp biomass. Treatments for experiment II were: monoculture with 2 tilapia per m² (2T:0S); polyculture with 2 tilapia and 2.5 shrimp per m² (2T:2.5S); and polyculture with 2 tilapia and 5 shrimp per m² (2T:5S). Tilapia was the main crop, and feed was provided based on fish requirements. In the experiment I, tilapia introduction to shrimp culture resulted in lower shrimp growth and poor feed conversion rate. In experiment II, shrimp introduction to tilapia culture did not interfere with fish performance. Polyculture is more efficient with the combination of 2 tilapia and 2.5 or 5 shrimp per m² and feed based on fish requirements.

Temporal and Spatial Variability of Limnological Characteristics in Areas under the Influence of Tilapia Cages in the Chavantes Reservoir, Paranapanema River, Brazil

The influence of tilapia cages on limnological characteristics of the Chavantes Reservoir, Paranapanema River, Brazil, was investigated in March and June 2007. Principal components analysis was used to compare the transparency; dissolved oxygen; temperature; total organic nitrogen, phosphorus, and dissolved solids; chlorophyll aand electrical conductivity of fish farm 1 (239.3m.t.), 2 (461.5m.t.) and areas without cages, in the lacustrine and river-reservoir transition regions. The variables differentiated the regions and areas with and without cages. In March, in the lacustrine region, there was a thermal and chemical stratification, and in the transition region, there was a temperature and oxygen reduction gradient between the surface and bottom that was also observed in June in fish farm 1. The higher transparency confirmed the increased light penetration in the lacustrine region. In the transition region, there were higher turbidity, total dissolved solid, and conductivity values that are likely related to allochthonous material flow and transport. In fish farms, lower oxygen and pH values indicate intense decomposition and respiration. The generally higher total dissolved solid and nutrient values, turbidity, and conductivity and the lower transparency in one or both fish farms indicate their contribution to eutrophication, demonstrating the need for careful monitoring.

Serologic survey of West Nile virus in horses from Central-West, Northeast and Southeast Brazil

Processo FAPESP: 08/50167-6

Redox dysregulation and bioaccumulation of copper in tilapia Oreocromis niloticus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Microbiological quality of whole and filleted shelf-tilapia

Despite fish being a rich source of animal nutrients and having numerous associated health benefits, it is an extremely perishable food, prone to a wide range of hazards. The bacterial load associated with shelf-whole-fish organs (e.g. digestive tracts and skin) or mishandling of fish may be a vehicle of infection and become a risk to public health. The objective of this paper is to evaluate the microbiological quality of whole ungutted and filleted shelf-tilapia, as well as assess the safety for human consumption. For this purpose, in order to investigate the distribution and occurrence of bacterial populations, the count of total and thermotolerant coliforms, coagulase-positive Staphylococcus and presence of Salmonella spp. was determined. This paper shows that all fish organs were contaminated with thermotolerant coliform. Skin and fillet show higher populations and occurrence of all microorganisms analyzed. Lower bacterial populations were recovered from the gut and muscles of whole tilapia. Two samples of fillet were contaminated with coagulase-positive Staphylococcus. It can be concluded that the skin and filleted tilapia are important carriers of food-borne pathogens. In addition, fish might become an important cross and self-contamination source. (C) 2014 Elsevier B.V. All rights reserved.

Polyculture of frogs and tilapia in cages with high feeding frequency

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sugar cane vinasse in water bodies: Impact assessed by liver histopathology in tilapia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A influência do enriquecimento ambiental no comportamento agressivo da tilápia do Congo Tilapia rendalli

O enriquecimento ambiental tem sido proposto como uma prática para melhoria do bem-estar de animais de cativeiro ou de produções zootécnicas. No caso de animais territoriais e agressivos, ao se enriquecer o ambiente, aumenta-se a quantidade de recursos a se defender, bem como o valor do território em disputa, aumentando as interações agressivas. Esse aspecto foi mostrado recentemente para o peixe ciclídeo tilápia-do-Nilo (Oreochromis niloticus). Do ponto de vista comparativo, isso pode ser um fenômeno espécie-específico. Para avaliar isso devemos observar se em condições similares outro peixe ciclídeo sofre a mesma influência do enriquecimento do ambiente. Assim, seguindo a lógica do confronto obtido para tilápia-do-Nilo, aventamos a hipótese de que as atividades agressivas aumentam em função do enriquecimento. Este estudo avaliou essa hipótese para a tilápia do Congo Tilapia rendalli. Como principal resultado, observamos que a latência para iniciar a luta é menor no ambiente enriquecido, mas a frequência de ataques é maior no ambiente não enriquecido (controle). Além disso, observamos clara definição hierárquica por meio da sinalização de submissão (corpo com listras escuras) e dominância (corpo claro sem listras) na condição sem enriquecimento do ambiente. Concluímos que ao contrário da tilápia-do-Nilo, na tilápia do Congo o enriquecimento do ambiente leva a diminuição da agressividade sem clara definição da hierarquia de dominância

Ecological carrying capacity for intensive tilapia (Oreochromis niloticus) cage aquaculture in a large hydroelectrical reservoir in Southeastern Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Isolamento de Streptococcus agalactiae em diferentes órgãos de tilápias do nilo (Oreochromis niloticus) criadas em tanques-rede

Streptococcosis is one of the major causes of mortality in tilapia's creation in Brazil, inducing great economic losses. As soon, the study objectived to determinate the frequency of isolation and identification the Streptococcus agalactiae in organs different of Oreochromis niloticus naturally infected, derived from eight fish farms in the northern region of the state of Parana, that presented clinical signs characteristics of streptococcal disease. However, blood samples and fragments (kidney, liver, spleen, heart and brain) were collected. These all samples were plated on solid medium of brain and heart infusion (BHI) added 5% ovine blood and incubated at 29 degrees C for 7 days in aerophilic conditions. Behind, the bacterial growth and from the macro and microscopic features, colonies compatibles with Streptococcus sp. gender, were selected. The species were identified by PCR reaction and confirmed by sequencing of 16S rDNA gene. The results exhibited that in tilapia of Nile infected with S. agalactiae the isolation is more common in brain, kidney and liver in descending order.

Hematological changes and cytogenotoxicity in the tilapia Oreochromis niloticus caused by sub-chronic exposures to mercury and selenium

Fish bioassays are valuable tools that can be used to elucidate the toxicological potential of numerous substances that are present in the aquatic environment. In this study, we assessed the antagonistic action of selenium (Se) against the toxicity of mercury (Hg) in fish (Oreochromis niloticus). Six experimental groups with six fish each were defined as follows: (1) control, (2) mercury (HgCl2), (3) sodium selenite (Na2Se4O3), (4) sodium selenate (Na2Se6O4), (5) mercury + sodium selenite (HgCl2 + Na2Se4O3), and (6) mercury + sodium selenate (HgCl2 + Na2Se6O4). Hematological parameters [red blood cells (RBC), white blood cells (WBC), and erythroblasts (ERB)] in combination with cytogenotoxicity biomarkers [nuclear abnormalities (NAs) and micronuclei (MN)] were examined after three, seven, ten, and fourteen days. After 7 days of exposure, cytogenotoxic effects and increased erythroblasts caused by mercury, leukocytosis triggered by mercury + sodium selenite, leukopenia associated with sodium selenate, and anemia triggered by mercury + sodium selenate were observed. Positive correlations that were independent of time were observed between WBC and RBC, ERB and MN, and NA and MN. The results suggest that short-term exposure to chemical contaminants elicited changes in blood parameters and produced cytogenotoxic effects. Moreover, NAs are the primary manifestations of MN formation and should be included in a class characterized as NA only. Lastly, the staining techniques used can be applied to both hematological characterization and the measurement of cytogenotoxicity biomarkers.

Genotoxic responses of juvenile tilapia (Oreochromis niloticus) exposed to florfenicol and oxytetracycline

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)