RESUMEN
ABSTRACT The effect of the ethanolic extract of propolis (EEP) on Aeromonas hydrophila was analyzed by determination of minimum inhibitory concentration (MIC). Then, the effects of crude propolis powder (CPP) on growth, hemato-immune parameters of the Nile tilapia, as well as its effects on resistance to A. hydrophila challenge were investigated. The CPP (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0%) was added to the diet of 280 Nile tilapia (50.0 ± 5.7 g fish-1). Hemato-immune parameters were analyzed before and after the bacterial challenge. Red blood cell, hematocrit, hemoglobin, mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), and hydrogen peroxide (H2O2) and nitric oxide (NO) were evaluated. The MIC of the EEP was 13% (v/v) with a bactericidal effect after 24 hours. Growth performance was significantly lower for those fish fed diets containing 2.5 and 3% of CPP compared to the control diet. Differences in CPP levels affected fish hemoglobin, neutrophils number and NO following the bacterial challenge. For others parameters no significant differences were observed. Our results show that although propolis has bactericidal properties in vitro, the addition of crude propolis powder to Nile tilapia extruded diets does not necessarily lead to an improvement of fish health.
Asunto(s)
Animales , Própolis/administración & dosificación , Infecciones por Bacterias Gramnegativas/veterinaria , Aeromonas hydrophila/efectos de los fármacos , Cíclidos/microbiología , Enfermedades de los Peces/dietoterapia , Própolis/uso terapéutico , Pruebas de Sensibilidad Microbiana , Infecciones por Bacterias Gramnegativas/dietoterapia , Infecciones por Bacterias Gramnegativas/microbiología , Suplementos Dietéticos , Cíclidos/sangre , Enfermedades de los Peces/microbiología , Inmunidad InnataRESUMEN
The effect of the ethanolic extract of propolis (EEP) on Aeromonas hydrophila was analyzed by determination of minimum inhibitory concentration (MIC). Then, the effects of crude propolis powder (CPP) on growth, hemato-immune parameters of the Nile tilapia, as well as its effects on resistance to A. hydrophila challenge were investigated. The CPP (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0%) was added to the diet of 280 Nile tilapia (50.0 ± 5.7 g fish-1). Hemato-immune parameters were analyzed before and after the bacterial challenge. Red blood cell, hematocrit, hemoglobin, mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), and hydrogen peroxide (H2O2) and nitric oxide (NO) were evaluated. The MIC of the EEP was 13% (v/v) with a bactericidal effect after 24 hours. Growth performance was significantly lower for those fish fed diets containing 2.5 and 3% of CPP compared to the control diet. Differences in CPP levels affected fish hemoglobin, neutrophils number and NO following the bacterial challenge. For others parameters no significant differences were observed. Our results show that although propolis has bactericidal properties in vitro, the addition of crude propolis powder to Nile tilapia extruded diets does not necessarily lead to an improvement of fish health.
Asunto(s)
Aeromonas hydrophila/efectos de los fármacos , Cíclidos/microbiología , Enfermedades de los Peces/dietoterapia , Infecciones por Bacterias Gramnegativas/veterinaria , Própolis/administración & dosificación , Animales , Cíclidos/sangre , Suplementos Dietéticos , Enfermedades de los Peces/microbiología , Infecciones por Bacterias Gramnegativas/dietoterapia , Infecciones por Bacterias Gramnegativas/microbiología , Inmunidad Innata , Pruebas de Sensibilidad Microbiana , Própolis/uso terapéuticoRESUMEN
The purpose of this work was to determine the concentration of copper in samples of farmed Nile tilapia (Oreochromis niloticus L.) fillets purchased in the city of Botucatu (São Paulo, Brazil) and in fillet and liver samples of Tilapia fed diets supplemented with different concentrations of Cu from the Laboratory of Aquatic Organism Nutrition/FMVZ-UNESP (Botucatu, Brazil). The fillet samples were prepared by lyophilisation and cryogenic grinding into particles smaller than 60 µm, and copper was extracted ultrasonically using 0.10 mol l(-1) HCl as extraction solution. Copper determination was performed by graphite furnace atomic absorption spectrometry (GFAAS) with optimised temperatures of drying, pyrolysis, atomisation and cleaning. Palladium nitrate was injected into the samples as a chemical modifier and tungsten as a permanent modifier. Copper concentrations of 0.70-1.60 mg kg(-1) were found, which are in line with Brazilian regulations. The accuracy and precision of the copper concentrations determined in this study were evaluated using certified standard Lake Michigan fish tissue (NIST SRM 1947).
Asunto(s)
Cobre/análisis , Tilapia , Animales , Brasil , Espectrofotometría AtómicaRESUMEN
This paper presents a simple, fast and sensitive method to determine selenium in samples of feces and of fish feed by graphite furnace atomic absorption spectrometry (GFAAS) through the direct introduction of slurries of the samples into the spectrometer's graphite tube. The limits of detection (LOD) and quantification (LOQ) calculated for 20 readings of the blank of the standard slurries (0.50% m/v of feces or feed devoid of selenium) were 0.31 microg l(-1) and 1.03 microg l(-1), respectively, for the standard feces slurries and 0.35 microg l(-1) and 1.16 microg l(-1), respectively, for the standard feed slurries. The proposed method was applied in studies of bioavailability of selenium in different fish feeds and the results proved consistent with that obtained from samples mineralized by acid digestion using the microwave oven.