ABSTRACT
In order to verify possible preferential prey selection by Desmodus rotundus feeding on domestic herbivores in the Municipality of São Pedro (São Paulo, Brazil), vampire bat attacks were surveyed at rural properties where domestic herbivores were being raised and attack frequencies of D. rotundus on the total herd and on different species were calculated. The analysis found that the most frequently attacked herbivores were cattle and horses. The chi-square test (χ2), with a significance level of 5% corroborated the comparative analysis of attack frequency in properties that had these two species. Of the two, horses were attacked more frequently, which could be a sign that D. rotundus exhibits preferential prey selection when attacking domestic herbivores. This evidence is also supported by the Optimal Foraging Theory, in which the net rate of energy consumed is higher for horses than it is for cattle. Additionally, we propose that the thinner integument of horses (relative to that of cattle) may facilitate bites by D. rotundus and thus contribute to the observed prey preference.(AU)
A fim de verificar possível seleção de presa preferencial por Desmodus rotundus alimentando-se em herbívoros domésticos no Município de São Pedro (São Paulo, Brasil), foram pesquisados ataques de morcegos hematófagos em propriedades rurais nas quais os herbívoros domésticos estavam sendo criados e foram calculadas as frequências de ataques por D. rotundus no rebanho total e nas diferentes espécies. A análise mostrou que os herbívoros mais frequentemente atacados eram os bovinos e equinos. O teste do qui-quadrado (χ2) com um nível de significância de 5% corroborou a análise comparativa da frequência de ataque em propriedades que possuíam estas duas espécies. Destas duas, os cavalos foram atacados com maior frequência, o que poderia ser um sinal de que D. rotundus apresenta seleção de presas preferenciais ao atacar herbívoros domésticos. Esta evidência também é apoiada pela Teoria do Forrageamento Ótimo, em que a taxa de energia líquida consumida é maior para cavalos do que para o gado. Além disso, propomos que o tegumento mais fino de cavalos (em relação à de bovinos) pode facilitar a mordidas por D. rotundus e, assim, contribuir para a preferência da presa observada.(AU)
Subject(s)
Animals , Cattle , /physiology , Feeding Behavior/physiology , Brazil , Chiroptera/classification , Horses , Rural PopulationABSTRACT
Objetivos: Comparar las respuestas glucémicas e insulinémicas de dos desayunos, con la prueba estándar de tolerancia a la glucosa oral (PTGO). Métodos: En 14 sujetos sanos se realizó la PTGO, con 75 gr de glucosa. Luego, con un intervalo de una semana, se efectuaron las pruebas de tolerancia con dos tipos de desayunos, elaborados con alimentos de uso común en nuestro medio y cuya principal diferencia fue el tipo de carbohidrato. A los 0, 30, 60 y 120 minutos se cuantificó la concentración de glucosa, por el método de glucosa-oxidasa y la insulina por radioinmunoanálisis. Se calculó el área bajo la curva para la respuesta de glucosa e insulina. Para el análisis estadístico se aplicó un análisis de varianza y las pruebas post-test, para determinar la diferencia entre los grupos. Resultados: Se observó que la respuesta de glucosa con el desayuno 1 fue significativamente menor (p<0,05) a los 30 y 60 minutos y con el desayuno 2 a los 60 minutos (p<0.05) en comparación con la obtenida con la PTGO. El área bajo la curva (ABC) de glucemia no fue diferente entre los 2 tipos de desayunos y fue significativamente menor que con la PTGO. La respuesta de insulina fue significativamente mas baja a los 120 minutos (p<0.05) con el desayuno 1 (arepa) en relación con el desayuno 2 (pan) y con la PTGO. El ABC de insulinemia no fue diferente entre los desayunos y la PTGO. Conclusiones: La respuesta de glucemia postprandial con mezcla de nutrientes es menor que la obtenida con la PTGO, por lo que no debe ser usada con fines diagnósticos.
Objectives: To compare the glycemic and insulinemic responses of two breakfasts with the standard oral glucose tolerance test (OGTT). Methods: In 14 healthy subjects, the OGTT with 75 g of glucose was performed. After an interval of one week, tolerance tests with two types of breakfasts elaborated with common food in our country, and whose main difference was the type of carbohydrate, were carried out. At 0, 30, 60 and 120 minutes, glucose concentration by the glucose oxidase method and insulin by radioimmunoassay were measured. Areas under the curve (AUC) for glucose and insulin response were calculated. An analysis of variance test was applied to determine the difference between the groups. Results: It was noted that the glucose response to breakfast 1 was significantly lower (p <0.05) at 30 and 60 minutes and to breakfast 2 at 60 minutes (p <0.05) compared with that obtained with OGTT. The glucose AUC was not different between the 2 types of breakfasts and was significantly lower than the obtained with OGTT. The insulin response was significantly lower at 120 minutes (p <0.05) with breakfast 1 (arepa) in relation to breakfast 2 (bread) and the OGTT. The insulin AUC was not different between breakfasts and the OGTT. Conclusions: The postprandial blood glucose response to mix of nutrients is lower than that obtained with the OGTT, so it should not be used for diagnostic purposes.