Suplementação dietética com vitamina E: respostas de estresse, da imunidade inata e do sistema antioxidante de juvenis de pacu (Piaractus mesopotamicus, Holmberg, 1887)
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Data
2019-03-01
Autores
Souza, Aurea Veras Barbosa de
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Universidade Estadual Paulista (Unesp)
Resumo
Manejos inerentes da piscicultura intensiva afetam a condição fisiológica e o sistema imune, desencadeando respostas de estresse nos animais, podendo aumentar a susceptibilidade a infecções, causando queda da produtividade. Para contornar este problema, o uso de nutrientes moduladores do sistema imunológico na dieta vem sendo utilizado como medida profilática para assegurarem uma maior sobrevivência e consequentemente a produtividade. A vitamina E é um importante antioxidante e tem sido muito utilizado na aquicultura pelo seu efeito imunoestimulante. Porém, é pouco investigado o seu efeito direto sobre a resposta clássica de estresse. Neste contexto, o presente estudo avaliou, em juvenis de pacu (Piaractus mesopotamicus), o uso oral de vitamina E na dieta com 0,150 e 500 mg kg-1 administrados por 30 dias, onde em cada condição alimentar metade dos peixes foram manipulados (submetidos a estresse por perseguição (estresse crônico). Após o período experimental, foram amostrados para respostas de estresse, do sistema imune e sistema antioxidante de peixes submetidos a estressores crônico e agudo. Avaliamos como indicadores da resposta de estresse, a concentração de cortisol e glicose plasmáticos; como indicadores do sistema imune inato, a atividade respiratória de leucócitos, a atividade hemolítica do sistema complemento e a atividade de lisozima; como indicadores do sistema antioxidante/estresse oxidativo, as atividades das enzimas hepáticas da glutationa-S-transferase (GST), da glutationa reduzida (GSH) e da catalase (CAT). A vitamina E influenciou na glicose ao longo das amostragens, e em peixes não manipulados a elevação foi maior nos que receberam alimentação com 150mg de vitamina. A atividade respiratória de leucócitos teve elevação reduzida nos peixes que receberam a ração suplementada. A concentração sérica da lisozima não diferiu em ambas as condições, tanto nos peixes com estresse crônico quanto os que sofreram estresse agudo e a atividade hemolítica do sistema complemento aumentou 24h depois do estressor agudo em todos os grupos, nas duas condições. Nossos resultados mostram que a vitamina E estimula o sistema imunológico, e também o sistema antioxidante de ambas as condições de estresse.
Inherent management of intensive fish farming affects the physiological condition and immune system, triggering stress responses in animals, which may increase susceptibility to infections, causing a drop of the productivity. To solve/reduce this problem, the use of nutritional modulators of the immune system in the diet has been considered as a prophylactic measure to ensure better survival and consequently productivity. Vitamin E is an important antioxidant that has been widely used in aquaculture also as an immunostimulant. However, its direct effect on the classic stress response is little investigated. In this context, the present study evaluated the oral use of vitamin E in the diet with 0.150 and 500 mg kg-1 administered for 30 days, in which half of the fish were handled during the whole period (Chronic Stress) and the other half was not disturbed and only handled acutely after the 30-day period (Acute stress). After the experimental period, both fish groups were sampled for the assessment of indicators of stress, innate immune system and the antioxidant system. We evaluated the concentration of cortisol and glucose, the respiratory activity of leukocytes, the hemolytic activity of the complement system and the activity of lysozyme, and the activity of hepatic enzymes glutathione-S-transferase (GST) and catalase (CAT), and the reduced glutathione (GSH). Vitamin E influenced glucose throughout the samplings, and non-fish manipulated the elevation was higher in those fed with 150mg vitamin. The leukocyte respiratory activity had a reduced elevation in the fish that received the supplemented feed. The serum concentration of lysozyme did not differ in both conditions, both in fish with chronic stress and those who suffered acute stress and the hemolytic activity of the complement system increased 24 hours after the acute stressor in all groups, under both conditions. Our results show that vitamin E stimulates the immune system, and also the antioxidant system of both stress conditions.
Inherent management of intensive fish farming affects the physiological condition and immune system, triggering stress responses in animals, which may increase susceptibility to infections, causing a drop of the productivity. To solve/reduce this problem, the use of nutritional modulators of the immune system in the diet has been considered as a prophylactic measure to ensure better survival and consequently productivity. Vitamin E is an important antioxidant that has been widely used in aquaculture also as an immunostimulant. However, its direct effect on the classic stress response is little investigated. In this context, the present study evaluated the oral use of vitamin E in the diet with 0.150 and 500 mg kg-1 administered for 30 days, in which half of the fish were handled during the whole period (Chronic Stress) and the other half was not disturbed and only handled acutely after the 30-day period (Acute stress). After the experimental period, both fish groups were sampled for the assessment of indicators of stress, innate immune system and the antioxidant system. We evaluated the concentration of cortisol and glucose, the respiratory activity of leukocytes, the hemolytic activity of the complement system and the activity of lysozyme, and the activity of hepatic enzymes glutathione-S-transferase (GST) and catalase (CAT), and the reduced glutathione (GSH). Vitamin E influenced glucose throughout the samplings, and non-fish manipulated the elevation was higher in those fed with 150mg vitamin. The leukocyte respiratory activity had a reduced elevation in the fish that received the supplemented feed. The serum concentration of lysozyme did not differ in both conditions, both in fish with chronic stress and those who suffered acute stress and the hemolytic activity of the complement system increased 24 hours after the acute stressor in all groups, under both conditions. Our results show that vitamin E stimulates the immune system, and also the antioxidant system of both stress conditions.
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Palavras-chave
Estresse em peixes, Imunonutriente, Piscicultura, Sistema antioxidante, Sistema imune, Tocoferol