Metalloproteomic profile determination of muscle samples from nile Tilapia (Oreochromis niloticus) using AAS and ESI-MS/MS after 2D-PAGE separation

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

Anti-androgenic activities of diuron and its metabolites in male Nile tilapia (Oreochromis niloticus)

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

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.

Maternal age influences on reproductive rates in Nile tilapia (Oreochromis niloticus)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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

Ectoparasites of Nile tilapia (Oreochromis niloticus) in cage farming in a hydroelectric reservoir in Brazil

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

Histologia do fígado de tilápia do Nilo (Oreochromis niloticus) alimentados com dietas contendo silagem biológica de pescado

This study aimed to evaluate possible histopathological liver of tilapia fed diets containing fish silage and level protein. Sample of 180 fed with tilapia fingerlings fed with diets containing three protein levels (20, 24 and 28% CP), and Proportions residue fermented silage of tilapia (1/4 and 1/2) of were analyzed during 75 days. The tissue fragments were fixed in Bouin and included in Histosec (R). After that, between 2 to 5 mu m slices were done in a rotation microtome. The methods used for tissue analysis were hematoxilin/eosin and PAS. The histological slices were examined under light microscope (Olympus BX-50). The disarray in the morphology of the liver of fish fed biological silage was influenced by high protein levels, and increased proportions of 1/2 of animal protein diets. It was observed that the variation of hepatocytes is directly related to the type of diet for fish. In fish fed diets containing 28% CP, the liver showed disruption of the structure cordon of hepatocytes, necrosis and shifting points of the core to the periphery. Elevated levels of biological fish silage cause deleterious changes in the liver. The level of protein required to maintain the health of the associated development fish is 24% crude protein.

Identities among actin-encoding cDNAs of the Nile tilapia (Oreochromis niloticus) and other eukaryote species revealed by nucleotide and amino acid sequence analyses

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

Uncaria tomentosa increases growth and immune activity in Oreochromis niloticus challenged with Streptococcus agalactiae

Cat's claw (Uncaria tomentosa) is an Amazon herb using in native cultures in Peru. In mammals, it has been described several effects of this herb. However, this is the first report of its use on the diet of fish. The aim of this study was to determinate the effect of this plant on the growth and immune activity in Oreochromis niloticus. Nile tilapia (81.3 ± 4.5 g) were distributed into 5 groups and supplemented with 0 (non-supplement fish), 75, 150, 300, and 450 mg of U. tomentosa.kg(-1) of diet for a period of 28 days. Fish were inoculated in the swim bladder with inactivated Streptococcus agalactiae and samples were taken at 6, 24, and 48 h post inoculation (HPI). Dose dependent increases were noted in some of the evaluated times of thrombocytes and white blood cells counts (WBC) in blood and exudate, burst respiratory activity, lysozyme activity, melanomacrophage centers count (MMCs), villi length, IgM by immunohistochemistry in splenic tissue, and unexpectedly on growth parameters. However, dietary supplementation of this herb did not affect red blood cells count (RBC), hemoglobin, and there were no observed histological lesions in gills, intestine, spleen, and liver. The current results demonstrate for the first time that U. tomentosa can stimulate fish immunity and improve growth performance in Nile tilapia.

Avaliação da toxicidade da vinhaça tratada quimicamente utilizando Oreochromis niloticus (Perciformes: Cichlidae) como organismo teste

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

Influência de diferentes substratos sobre a composição, a densidade e as interações tróficas do zooplâncton em lagoas de policultivo de camarão-de-água-doce Macrobrachium amazonicum e tilápia-do-nilo Oreochromis niloticus

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo do efeito modulador do macrolídeo tilosina na reação inflamatória aguda de tilápias do Nilo (Oreochromis niloticus), vacinadas e desafiadas com Streptococcus agalactiae

Pós-graduação em Medicina Veterinária - FCAV

Digestibilidade do amido e disponibilidade de ca e p em alimentos energéticos extrusados para a tilápia do nilo (Oreochromis niloticus)

Apparent digestibility coefficients (ADC) of starch and calcium (Ca) and phosphorus (P) apparent availability were evaluated in five cereal grain products and byproducts (corn, wheat meal, rice grain, rice bran and sorghum) for Nile tilapia. Chromic oxide was used as an external digestibility marker. The highest Ca and P apparent availability, respectively, were obtained for rice grain (43.03 and 64.79%), sorghum (39.89 and 58.09%) and corn (22.18 and 19.48%), while rice bran (-31.49 and 3.25%) and wheat meal (5.80 and 1.18%) showed the lowest values. Starch digestibility varied between 99.45 and 95.59% among the evaluated ingredients. This high ADC of starch observed in this study confirms that Nile tilapia is able to efficiently digest and utilize complex carbohydrates.

Vitamin A affects haematology, growth and immune response of Nile tilapia (Oreochromis niloticus, L.), but has no protective effect against bacterial challenge or cold-induced stress

Vitamin A (vitA) is an essential nutrient that acts as an endocrine regulator of several metabolic pathways, modulating normal growth and health status of animals. Although the importance of vitA for normal haematology and immune response is well documented for higher vertebrates, there is limited information on the physiological effects of vitA on fish. Therefore, we designed a 130-day feeding trial to evaluate the effect of vitA supplementation on growth, haematology, immune function and resistance to experimental infection with Aeromonas hydrophila and cold-induced stress. A group of 320 Nile tilapia fingerlings 7.49 ± 0.19 g weight (mean ± SD) were randomly stocked into 40 250 L-aquaria and fed practical diets containing graded levels of vitA (0, 0.06, 0.12, 0.24, 0.48, 0.96, 1.92, 3.84 mg retinol (ROH) kg−1 diet. Growth, haematology, plasma protein profile and immune response were significantly affected by vitA supplementation; however, no clear protective effect of vitA supplementation on disease and cold stress resistance were observed in this study. Clinical signs of vitA deficiency were: resting and abnormal swimming behaviour, exophthalmia, haemorrhages at the base of fins and on skin, serous fluids in abdominal cavity, neutropenia, reduction in red blood cell count, haematocrit and haemoglobin evolving to high mortality rates in a short period of time. A dietary level of vitA around 1.2 mg ROH kg−1 may be required to prevent gross deficiency signs and promote proper growth and health status of Nile tilapia. VitA does not seem to have a pronounced effect on leucocyte differentiation, but clearly plays an important role on maintaining normal erythropoiesis.