Beta-glucano influência a sobrevivência de tilápia-do-nilo após infecção por Francisella orientalis
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Data
2022-02-25
Autores
Quispe, Carlos Humberto Casanova
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Universidade Estadual Paulista (Unesp)
Resumo
O objetivo deste estudo foi avaliar o efeito da suplementação alimentar com β-glucano na sobrevivência de tilápia-do-Nilo desafiada com Francisella orientalis, um patógeno endêmico de grande importância para a aquicultura brasileira e mundial. Considerando que o uso de β-glucano provoca um incremento na proteção frente a patógenos bacterianos em várias espécies de peixes e também exerce efeitos moduladores no sistema imune inato, 240 juvenis de tilápia-do-Nilo foram suplementados com C: 0%, T1: 0.1% e T2: 0.3% de β glucano (Macrogard®) e, posteriormente submetidos ao desafio bacteriano com Francisella orientalis. Os peixes foram alimentados com as dietas experimentais (1,5% do peso vivo) duas vezes ao dia (9h00 e 17h00), por um período de 30 dias. Duas caixas do grupo C e quatro caixas dos grupos T1 e T2 foram inoculados intracelomicamente com 0,1 mL de uma suspensão bacteriana (determinada em ensaio de DL50%) de F. orientalis (1,95 x 10^9 UFC.mL^-1 ). As outras duas caixas do grupo C foram inoculadas com 0,1 mL de tampão fosfato-salino (PBS). As mudanças no comportamento, os sinais clínicos e a mortalidade diária foram avaliadas durante 15 dias após a infecção. Este estudo demonstrou que a suplementação alimentar com 0,3% de β-glucano proporcionou maior sobrevivência nos peixes após o desafio com Francisella orientalis nas condições experimentais testadas.
The aim of this study was to evaluate the effect of dietary supplementation with β-glucan on survival of Nile tilapia challenged with Francisella orientalis, an endemic pathogen of great importance for Brazilian and world aquaculture. Considering that the use of β-glucan causes an increase in protection against bacterial pathogens in several fish species and also exerts modulatory effects on the innate immune system, 240 Nile tilapia juveniles were supplemented with C: 0%, T1: 0.1% and T2: 0.3% of β glucan (Macrogard®) and subsequently submitted to bacterial challenge with Francisella orientalis. Fish were fed the experimental diets (1.5% of live weight) twice a day (9:00 am and 5:00 pm), for a period of 30 days. Two boxes of group C and four boxes from groups T1 and T2 were inoculated intracelomically with 0.1 mL of a bacterial suspension (determined in an LD50 assay) of F. orientalis (1.95 x 10^9 CFU.mL^-1). The other two boxes in group C were inoculated with 0.1 mL of phosphate-buffered saline (PBS). Changes in behavior, clinical signs and mortality daily were evaluated for 15 days after infection. This study demonstrated that the food supplementation with 0.3% of β-glucan provided greater survival in fish after challenge with Francisella orientalis under the experimental conditions tested.
The aim of this study was to evaluate the effect of dietary supplementation with β-glucan on survival of Nile tilapia challenged with Francisella orientalis, an endemic pathogen of great importance for Brazilian and world aquaculture. Considering that the use of β-glucan causes an increase in protection against bacterial pathogens in several fish species and also exerts modulatory effects on the innate immune system, 240 Nile tilapia juveniles were supplemented with C: 0%, T1: 0.1% and T2: 0.3% of β glucan (Macrogard®) and subsequently submitted to bacterial challenge with Francisella orientalis. Fish were fed the experimental diets (1.5% of live weight) twice a day (9:00 am and 5:00 pm), for a period of 30 days. Two boxes of group C and four boxes from groups T1 and T2 were inoculated intracelomically with 0.1 mL of a bacterial suspension (determined in an LD50 assay) of F. orientalis (1.95 x 10^9 CFU.mL^-1). The other two boxes in group C were inoculated with 0.1 mL of phosphate-buffered saline (PBS). Changes in behavior, clinical signs and mortality daily were evaluated for 15 days after infection. This study demonstrated that the food supplementation with 0.3% of β-glucan provided greater survival in fish after challenge with Francisella orientalis under the experimental conditions tested.
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Palavras-chave
Aquicultura, Oreochromis niloticus, Bactéria, Imunomoduladores, Peixe Doenças