ABSTRACT
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.
Subject(s)
Animals , Propolis/administration & dosage , Gram-Negative Bacterial Infections/veterinary , Aeromonas hydrophila/drug effects , Cichlids/microbiology , Fish Diseases/diet therapy , Propolis/therapeutic use , Microbial Sensitivity Tests , Gram-Negative Bacterial Infections/diet therapy , Gram-Negative Bacterial Infections/microbiology , Dietary Supplements , Cichlids/blood , Fish Diseases/microbiology , Immunity, InnateABSTRACT
Este trabalho foi realizado para avaliar rações com dois níveis de proteína bruta (PB) sem e com suplementação de fitase, sobre o desempenho da tilápia do Nilo na terminação, e teve duração de 74 dias. Foram utilizados 60 peixes com peso vivo inicial de 274,39 + ou - 13,50 g, distribuídos em um delineamento em esquema fatorial 2 x 2, com dois níveis de fitase [0 e 500 UF (unidades de fitase)/kg de ração] e dois níveis de PB (25 e 28) em 12 tanques com volume unitário útil de 800 L. Os melhores resultados de ganho de peso, conversão alimentar e taxa de eficiência protéica, rendimento de carcaça, sobrevivência, cálcio e fósforo (P) nos ossos e para os coeficientes de digestibilidade aparente da PB e do P, foram obtidos com a ração contendo 28 PB suplementada com fitase. A suplementação de fitase, independentemente do nível de PB da ração, reduziu a excreção de nitrogênio e P pelos peixes. Concluiu-se que para a tilápia do Nilo na terminação, a ração com 28 de PB suplementada com fitase proporciona os melhores resultados.