Resposta fenotípica integrada do morcego frugívoro Artibeus lituratus (Chiroptera, phyllostomidae) frente à redução da qualidade da dieta
Arquivos
Data
2006-08-18
Autores
Otani, Lye [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Apesar das inúmeras vantagens da endotermia, os animais endotérmicos necessitam do constante aporte de energia. As variações na qualidade da dieta são tidas como um dos principais agentes seletivos envolvidos na evolução de padrões comportamentais, morfológicos e fisiológicos de endotérmicos. O presente trabalho procurou analisar os mecanismos ingestórios e digestórios utilizados por Artibeus lituratus quando deparado com a queda na qualidade da dieta, e seus efeitos sobre o metabolismo basal (TMB) e a capacidade termogênica (CT). Após 7, 30 e 90 dias de aclimatação a dietas artificiais com diferentes teores de fibras, foram quantificadas a eficiência digestória, a TMB, a CT, a condição corpórea e massa dos órgãos viscerais. A. lituratus sob dieta de baixa qualidade apresentaram maiores digestibilidade de matéria seca e energia, com um maior aporte de energia metabolizável ingerida. No entanto, nenhuma alteração foi observada nos órgãos viscerais, com exceção dos rins. A hipertrofia desse órgão pode ter sido conseqüência da maior ingestão de proteínas. A ausência de flexibilidade fenotípica na massa dos órgãos pode ser devida a uma combinação de fatores, incluindo o uso de ajustes comportamentais (produção de ejetas) e/ou a utilização de reservas energéticas. A TMB e a CT apresentaram-se maiores para os morcegos sob dieta de baixa qualidade. Como não houve alteração na massa dos órgãos em função da qualidade da dieta, e tampouco correlação entre massa dos órgãos e TMB, os mecanismos responsáveis pelo maior gasto energético basal de morcegos expostos à dieta de baixa qualidade são incertos, mas podem estar relacionados a uma maior atividade enzimática dos órgãos viscerais. A maior CT de morcegos expostos à dieta de baixa qualidade não pode ser explicada pelo modelo clássico da capacidade aeróbica. A CT foi influenciada...
Although endothermy has innumerous advantages, endothermic animals need constant energy ingestion. Variations on diet composition are among the most important selective determinant factors of behavior, morphologic and physiologic aspects of evolution of endothermic animals. In spite of the numerous advantages of endothermy, such animals require constant energy income. This study aims to analyze ingestion and digestion mechanisms employed by Artibeus lituratus when facing a decrease in food quality, and the influence of this on its basal metabolism (BMR) and thermogenic capacity (TC). Past 7, 30 and 90 days of acclimation to diets containing different fiber concentrations, we quantified the digestive efficiency, BMR and TC of the bats, and also recorded their body condition and visceral organs masses. The species presented higher dry matter and energy digestibility, and also high metabolizable energy intake under low quality diet condition, but there were no observed morphological alterations on their internal organs, with the exception of their kidneys, which were unusually increased. This could have been due to higher protein ingestion. The lack of phenotypic variation in the visceral mass could have been caused by a myriad of factors, including behavioral adjustments (i.e. ejecta production), or utilization of energetic reserves. There was an increase of the BMR and TC of bats under low quality food conditions. As there were no alterations on the internal organs mass neither any detected correlation between this mass and the BMR of the bats, perhaps the greater energy expenses responsible mechanisms could be involved with a greater enzymatic activity of the internal organs. The observed greater TC of the bats fed on low quality food is not explainable through the classical aerobic capacity model. TC was influenced by fat mass, independently of diet quality and acclimation time. However... (Complete abstract click electronic access below)
Although endothermy has innumerous advantages, endothermic animals need constant energy ingestion. Variations on diet composition are among the most important selective determinant factors of behavior, morphologic and physiologic aspects of evolution of endothermic animals. In spite of the numerous advantages of endothermy, such animals require constant energy income. This study aims to analyze ingestion and digestion mechanisms employed by Artibeus lituratus when facing a decrease in food quality, and the influence of this on its basal metabolism (BMR) and thermogenic capacity (TC). Past 7, 30 and 90 days of acclimation to diets containing different fiber concentrations, we quantified the digestive efficiency, BMR and TC of the bats, and also recorded their body condition and visceral organs masses. The species presented higher dry matter and energy digestibility, and also high metabolizable energy intake under low quality diet condition, but there were no observed morphological alterations on their internal organs, with the exception of their kidneys, which were unusually increased. This could have been due to higher protein ingestion. The lack of phenotypic variation in the visceral mass could have been caused by a myriad of factors, including behavioral adjustments (i.e. ejecta production), or utilization of energetic reserves. There was an increase of the BMR and TC of bats under low quality food conditions. As there were no alterations on the internal organs mass neither any detected correlation between this mass and the BMR of the bats, perhaps the greater energy expenses responsible mechanisms could be involved with a greater enzymatic activity of the internal organs. The observed greater TC of the bats fed on low quality food is not explainable through the classical aerobic capacity model. TC was influenced by fat mass, independently of diet quality and acclimation time. However... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Morcego, Artibeus lituratus, Metabolismo energético
Como citar
OTANI, Lye. Resposta fenotípica integrada do morcego frugívoro Artibeus lituratus (Chiroptera, phyllostomidae) frente à redução da qualidade da dieta. 2006. iv, 127 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências de Rio Claro, 2006.