Efeito da metionina e do triptofano nas respostas de estresse, sistema imune inato e antioxidante em juvenis de pacu (Piaractus mesopotamicus) Holmberg, 1887
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Data
2023-07-28
Autores
Ribeiro, Raíssa de Cassia Pinheiro
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Universidade Estadual Paulista (Unesp)
Resumo
A presente tese foi desenvolvida em dois experimentos, sendo apresentada em três capítulos. No primeiro capítulo, apresentamos uma introdução geral e referencial teórico sobre os temas que norteiam a tese. Ambos os experimentos contam com análises dos mesmos indicadores: indicadores bioquímicos metabólicos, de estresse, imunidade inata e sistema antioxidante. No primeiro experimento, foram utilizados juvenis de pacu Piaractus mesopotamicus alimentados com dieta comercial suplementada com metionina, nos seguintes tratamentos: Controle – 4 g de Met kg-1 de ração; Tratamento 8 g – 8 g Met kg-1 ração; e Tratamento 12 g – 12 g Met kg-1 ração, durante 15 dias, e submetidos a estressor agudo (EA) de exposição aérea ou injeção de lipopolissacarídeo (LPS) de Escherichia coli. Após o período da dieta experimental, os peixes foram amostrados 1h, 3h, 6h e 24h após o EA. Os resultados mostram que houve elevação das concentrações de cortisol em todos os grupos, independente da condição de estresse, e as concentrações de metionina modularam as respostas de estresse. A glicose foi elevada 1 h e 3 h após o EA e 1 h após o LPS. Em relação aos indicadores imunológicos, o EA e LPS diminuíram a atividade respiratória dos leucócitos. A lisozima foi afetada pelo EA e LPS no tratamento 12 g. Nos grupos sem estressor (SE) e EA, o sistema complemento foi modulado tanto pela suplementação da dieta com 12 g de metionina, quanto pela exposição ao estressor agudo. Nos indicadores metabólicos, as concentrações dos triglicerídeos foram menores nos grupos EA e LPS, as concentrações de lipídeo hepático foram afetadas pelo estressor EA e LPS, e as do lipídeo muscular foram afetadas pelo tratamento 12 g nos Grupos SE e LPS. Nos índices somáticos, o IHS no grupo SE mostrou maior valor. O capítulo 3, correspondente ao segundo experimento, avaliou a inclusão de triptofano nas dietas de juvenis de pacu nas concentrações: Tratamento Controle – 2 g de Trip kg-1 de ração; Tratamento 4 g Trip kg-1 de ração; Tratamento 6 g – 6 g de Trip kg-1 de ração distribuídos em grupos: SE sem estresse; EA estresse agudo; e injeção de LPS. Os resultados mostraram que o cortisol foi elevado após 1 h no grupo EA e LPS e as concentrações do hormônio foram moduladas pela inclusão de triptofano na concentração 6 g. A concentração de glicose foi maior no grupo EA. A atividade de lisozima foi maior no tratamento 4 g 1h após o EA. A atividade do sistema complemento foi menor nos grupos EA e LPS. Nos indicadores bioquímicos, as concentrações de albumina foram maiores nos grupos EA e LPS. A deposição de glicogênio hepático foi afetada pelo EA. Em conjunto, os dados apresentados nos mostram que a metionina e o triptofano tem ações redutora de estresse e imunoestimulante, enquanto o agente estressor afeta negativamente o sistema imunológico e a lipogênese. Em síntese, os resultados nos permitem sugerir a inclusão de ambos os aminoácidos para superar desafios do estresse e reforçar mecanismos de defesa imunológica.
The present thesis was developed in two experiments, being presented in three chapters. In the first chapter, we present a general introduction and theoretical framework on the themes that guide the thesis. Both experiments rely on analysis of the same indicators: stress, innate immunity, biochemical, metabolic and antioxidant indicators. In the first experiment, chapter 2, juveniles of pacu Piaractus mesopotamicus fed a commercial diet supplemented with Methionine were evaluated at the following concentrations: Control – 4 g of Met Kg-1; Treatment 8 g - 8 g Met Kg-1; and Treatment 12 g - 12 g of Met Kg-1, during 15 days and submitted to the acute stress of air exposure and injection of Escherichia coli LPS. After the period of ingestion of the experimental diet, the fish were sampled 1h, 3h, 6h and 24h after the stressor. The results show that was an increase in cortisol concentrations in all groups, regardless of the stress condition, and methionine concentrations modulated the stress responses after the stressor. Glucose was elevated 1 h and 3 h after EA and 1 h after LPS. In the immunological indicators, EA and LPS decreased the respiratory activity of leukocytes. Lysozyme was affected by EA and LPS in the 12 g treatment. In the SE and EA groups, the complement system was modulated both by dietary supplementation with 12 g of methionine and by exposure to an acute stressor. In terms of metabolic indicators, triglycerides were lower in the EA and LPS groups, liver lipid concentrations were affected by the stressor EA and LPS, and muscle lipid was affected by the 12 g treatment in the SE and LPS group. In the somatic indices, the IHS in the SE group showed the highest value. Chapter 3, the second experiment evaluated the inclusion of tryptophan in diets of pacu juveniles in the following concentrations: Control Treatment – 2 g of Trip Kg-1; Treatment 4 g Trip Kg-1; Treatment 6 g – 6 g of Trip Kg-1, divided into groups: SE without stress; Acute stress EA; and LPS injection of lipopolysaccharide Escherichia coli. The results showed that cortisol was elevated after 1 h in the EA and LPS group. The inclusion of tryptophan at 4 g and 6 g concentrations demonstrated to modulate cortisol. Glucose concentration was higher in the EA group. Lysozyme activity was higher in the 4 g treatment 1h after the acute stressor. Complement system activity was lower in EA and LPS groups. In biochemical indicators, albumin was higher in the EA and LPS groups. hepatic glycogen deposition was affected by acute stress. Together, the data presented show us that methionine and tryptophan have stress-reducing and immunostimulating actions. While the stressor negatively affects the immune system and lipogenesis. In summary, it allows us to suggest the inclusion of both amino acids to overcome stress challenges and reinforce immune defense mechanisms.
The present thesis was developed in two experiments, being presented in three chapters. In the first chapter, we present a general introduction and theoretical framework on the themes that guide the thesis. Both experiments rely on analysis of the same indicators: stress, innate immunity, biochemical, metabolic and antioxidant indicators. In the first experiment, chapter 2, juveniles of pacu Piaractus mesopotamicus fed a commercial diet supplemented with Methionine were evaluated at the following concentrations: Control – 4 g of Met Kg-1; Treatment 8 g - 8 g Met Kg-1; and Treatment 12 g - 12 g of Met Kg-1, during 15 days and submitted to the acute stress of air exposure and injection of Escherichia coli LPS. After the period of ingestion of the experimental diet, the fish were sampled 1h, 3h, 6h and 24h after the stressor. The results show that was an increase in cortisol concentrations in all groups, regardless of the stress condition, and methionine concentrations modulated the stress responses after the stressor. Glucose was elevated 1 h and 3 h after EA and 1 h after LPS. In the immunological indicators, EA and LPS decreased the respiratory activity of leukocytes. Lysozyme was affected by EA and LPS in the 12 g treatment. In the SE and EA groups, the complement system was modulated both by dietary supplementation with 12 g of methionine and by exposure to an acute stressor. In terms of metabolic indicators, triglycerides were lower in the EA and LPS groups, liver lipid concentrations were affected by the stressor EA and LPS, and muscle lipid was affected by the 12 g treatment in the SE and LPS group. In the somatic indices, the IHS in the SE group showed the highest value. Chapter 3, the second experiment evaluated the inclusion of tryptophan in diets of pacu juveniles in the following concentrations: Control Treatment – 2 g of Trip Kg-1; Treatment 4 g Trip Kg-1; Treatment 6 g – 6 g of Trip Kg-1, divided into groups: SE without stress; Acute stress EA; and LPS injection of lipopolysaccharide Escherichia coli. The results showed that cortisol was elevated after 1 h in the EA and LPS group. The inclusion of tryptophan at 4 g and 6 g concentrations demonstrated to modulate cortisol. Glucose concentration was higher in the EA group. Lysozyme activity was higher in the 4 g treatment 1h after the acute stressor. Complement system activity was lower in EA and LPS groups. In biochemical indicators, albumin was higher in the EA and LPS groups. hepatic glycogen deposition was affected by acute stress. Together, the data presented show us that methionine and tryptophan have stress-reducing and immunostimulating actions. While the stressor negatively affects the immune system and lipogenesis. In summary, it allows us to suggest the inclusion of both amino acids to overcome stress challenges and reinforce immune defense mechanisms.
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Palavras-chave
Aminoácidos, Imunidade, Metabolismo, Antioxidante, Pacu