Levedura, parede celular de levedura e levedura selenizada na saúde e desempenho produtivo de pacu e tilápia-do-Nilo
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Data
2019-02-22
Autores
Silva, Thiago Fernandes Alves [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A expansão da aquicultura baseia-se em cultivos cada vez mais intensivos aumentando a exposição dos animais às elevadas condições de estresse, comprometendo o sistema imunológico e fazendo com que se tornem alvos de patógenos. A utilização de alimentos funcionais apresenta boas perspectivas quanto a melhora no desempenho produtivo e resistência às doenças na aquicultura. Entretanto, seus mecanismos de atuação ainda são pouco conhecidos. Por isto, o presente estudo avaliou o efeito do uso de aditivos derivados de levedura, Saccharomyces cerevisiae, no cultivo de pacus (Piaractus mesopotamicus) e tilápias-do-Nilo (Oreochromis niloticus). Inicialmente foi avaliado o uso de parede celular de levedura e levedura selenizada (fonte de selênio orgânico) no cultivo de pacus. Os animais foram distribuídos em grupos que receberam dietas controle, com parede de levedura, levedura selenizada, levedura selenizada + parede celular de levedura. Neste experimento, os animais que receberam levedura selenizada na dieta mostraram melhores resultados para a atividade respiratória dos leucócitos e lisozima. O uso da parede de levedura elevou o cortisol. Entretanto, o uso de levedura selenizada juntamente com parede celular de levedura manteve elevadas as respostas imunológicas. Um segundo experimento foi realizado com a utilização de parede celular de levedura, levedura selenizada e levedura viva (S. cerevisiae) no cultivo de tilápias-do-Nilo. O uso em conjunto dos imunoestimulantes testados incrementaram o sistema imunológico inato da tilápia, entretanto, concluímos que o uso da parede celular de levedura requer precauções quanto à sua utilização, uma vez que pode elevar o nível de cortisol plasmático no sangue dos peixes.
The expansion of aquaculture is based on increasingly intensive crops increasing the exposure of animals to high stress conditions, compromising the immune system and causing them to become targets of pathogens. The use of functional foods shows good prospects regarding the improvement in productive performance and resistance to diseases in aquaculture. However, their mechanisms of action are still poorly understood. Therefore, the present study evaluated the effect of the use of yeast-derived additives, Saccharomyces cerevisiae, on the cultivation of pacus (Piaractus mesopotamicus) and Nile tilapia (Oreochromis niloticus). Initially, the use of yeast and selenized yeast cell walls (source of organic selenium) in the cultivation of pacus was evaluated. The animals were distributed in groups that received control diets, with yeast wall, selenized yeast, selenized yeast + yeast cell wall. In this experiment, animals that received selenized yeast in the diet showed better results for the respiratory activity of leukocytes and lysozyme. The use of the yeast wall elevated the cortisol. However, the use of selenized yeast along with yeast cell wall maintained high immunological responses. A second experiment was carried out with the use of yeast cell wall, selenized yeast and living yeast (S. cerevisiae) in the cultivation of Nile tilapia. The combined use of the immunostimulants tested increased the innate immune system of the tilapia, however, we concluded that the use of the yeast cell wall requires precautions regarding its use, since it can increase the level of plasma cortisol in the blood of the fish.
The expansion of aquaculture is based on increasingly intensive crops increasing the exposure of animals to high stress conditions, compromising the immune system and causing them to become targets of pathogens. The use of functional foods shows good prospects regarding the improvement in productive performance and resistance to diseases in aquaculture. However, their mechanisms of action are still poorly understood. Therefore, the present study evaluated the effect of the use of yeast-derived additives, Saccharomyces cerevisiae, on the cultivation of pacus (Piaractus mesopotamicus) and Nile tilapia (Oreochromis niloticus). Initially, the use of yeast and selenized yeast cell walls (source of organic selenium) in the cultivation of pacus was evaluated. The animals were distributed in groups that received control diets, with yeast wall, selenized yeast, selenized yeast + yeast cell wall. In this experiment, animals that received selenized yeast in the diet showed better results for the respiratory activity of leukocytes and lysozyme. The use of the yeast wall elevated the cortisol. However, the use of selenized yeast along with yeast cell wall maintained high immunological responses. A second experiment was carried out with the use of yeast cell wall, selenized yeast and living yeast (S. cerevisiae) in the cultivation of Nile tilapia. The combined use of the immunostimulants tested increased the innate immune system of the tilapia, however, we concluded that the use of the yeast cell wall requires precautions regarding its use, since it can increase the level of plasma cortisol in the blood of the fish.
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Palavras-chave
Aquicultura, Selênio-levedura, Alimento funcional, Imunoestimulantes