RESUMEN
Insufficient or unbalanced food intake typically has a negative impact on immune responses. The understanding of this effect is, however, hampered by the effect that food has on general condition, which, in turn, affects immunity, and the interaction among general condition, immunocompetence, and concurrent infections. The goal of this study was to determine the effects of food restriction and methionine supplementation on immunity in tuco-tucos (Ctenomys talarum). Effects of diet manipulations on nutritional state, inflammatory response to phytohemagglutinin (PHA), and other immune parameters (bacterial killing capacity, natural antibodies, and leukocyte profile) were evaluated. Health and stress parameters and endoparasite loads were assessed to understand more deeply potential effects of treatments on immune status. Individuals under food restriction presented an altered nutritional state as well as increased stress levels (higher N: L ratios) compared with individuals fed ad libitum, and a marked reduction in the inflammatory response to PHA. Supplementation with methionine did not affect any of the parameters analyzed. Endoparasite loads were not affected by treatments. Our results support the idea that food insufficiency can modulate the individual's immune responsiveness through the lack of adequate essential nutrients, metabolic fuel and energetic reserves, or by a detrimental effect of the stress caused by nutrient limitation. We show that the response to PHA previously reported as nonenergetically costly for C. talarum, implies a nutritional cost; an opposite pattern to that previously found for the adaptive antibody response to sheep red blood cells in the same species.
Asunto(s)
Privación de Alimentos , Inflamación/veterinaria , Estado Nutricional/fisiología , Fitohemaglutininas/toxicidad , Roedores/fisiología , Animales , Femenino , Inflamación/inducido químicamente , MasculinoRESUMEN
A traditional approach used to assess whether immune defense is costly is to explore the existence of trade-offs between immunity and other functions; however, quantitative studies of the energetic costs associated with the activation of the immune system are scarce. We assessed the magnitude of a PHA-triggered immune response and the associated energetic costs in 60-day old Ctenomys talarum. We expected that the magnitude of the macroscopic inflammatory response to PHA is lower in young tuco-tucos compared with that of adults, given the allocation of substantial energy to growth, and that the magnitude of the inflammation is lower in male pups compared to females, due to the higher investment in growth of the larger sex. Concomitantly, we expected that the pups challenged with PHA show an increase in oxygen consumption compared to control animals and that a positive association exists between magnitude of the PHA-induced inflammation and oxygen consumption. Contrary to what was expected, young tuco-tucos mounted a higher inflammatory response compared with adults and there were no differences in the magnitude of this response between sexes. The inflammatory response induced by a PHA injection did not represent a significant energetic cost for young tuco-tucos. There were no differences in oxygen consumption between PHA-injected and control animals, and tuco-tucos that mounted a higher inflammatory response to PHA did not show higher oxygen consumption. Energy expenditure, however, is not the only physiological cost involved in trade-offs between immune response and various functions of the organism, and other currencies are discussed.
Asunto(s)
Envejecimiento , Animales Salvajes/fisiología , Metabolismo Energético , Inmunidad Innata , Infecciones/veterinaria , Modelos Biológicos , Roedores/fisiología , Animales , Argentina , Femenino , Pie , Factores Inmunológicos/toxicidad , Infecciones/inmunología , Infecciones/metabolismo , Inflamación/inducido químicamente , Inflamación/inmunología , Inflamación/metabolismo , Inflamación/veterinaria , Masculino , Consumo de Oxígeno , Fitohemaglutininas/toxicidad , Reproducibilidad de los Resultados , Caracteres SexualesRESUMEN
The main objective of this work was to perform a comparative study of the antinutritional and/or toxic properties of phytohemagglutinin and trypsin-chymotrypsin inhibitor extracted from the seed of a commercial cultivar of edible bean used in Brazil. Bean proteins were extracted in acidic salt solution and fractionated by dialysis and centrifugation, then freeze-dried. The total freeze-dried bean extract and the globulin or albumin protein fraction were resuspended in distilled water and heated (100 degrees C, 30 min) for inactivation of hemagglutinin. Diets were prepared with unheated bean protein fractions and heated ones (100% trypsin inhibitor activity, but 0% phytohemagglutinin activity). As a result, the inhibition of growth and poor dietary protein utilization were observed in rats fed diets containing unheated bean protein fractions, but not in rats fed diets containing heated fractions. It was thus assumed that phytohemagglutinin is the main antinutritional and toxic factor that in dry bean (Phaseolus) protein and that trypsin inhibitor (Bowman-Birk type) did not interfere with rat growth.
Asunto(s)
Proteínas en la Dieta/metabolismo , Fabaceae/metabolismo , Fitohemaglutininas/farmacología , Plantas Medicinales , Inhibidor de la Tripsina de Soja de Bowman-Birk/farmacología , Absorción , Animales , Caseínas/metabolismo , Digestión , Fabaceae/química , Liofilización , Calor , Masculino , Nitrógeno/metabolismo , Valor Nutritivo , Fitohemaglutininas/análisis , Fitohemaglutininas/toxicidad , Lectinas de Plantas , Ratas , Ratas Wistar , Aumento de Peso/efectos de los fármacosRESUMEN
Histological studies of the spleen and thymus of rats fed raw black beans (Phaseolus vulgaris) show an atrophy of both lymphoid organs. Decrease in relative thymus weight was most marked. All histological organization of this organ appeared altered. An evident decrease in cell number was also observed in both organs. Proliferative response of splenic cells stimulated in vitro with Concanavalin A was increased as compared to that from animals fed the control diet. It is likely that histological changes observed in the spleen and the thymus are due mainly to a protein caloric deficiency, although the possibility that toxic factors present in the raw diet have an effect on the immune system of the rat can not be overruled.
Asunto(s)
Fabaceae , Manipulación de Alimentos , Síndromes de Inmunodeficiencia/inducido químicamente , Activación de Linfocitos/efectos de los fármacos , Plantas Medicinales , Bazo/efectos de los fármacos , Timo/efectos de los fármacos , Animales , Atrofia , Peso Corporal/efectos de los fármacos , Proteínas en la Dieta/farmacocinética , Proteínas en la Dieta/toxicidad , Inhibidores Enzimáticos/toxicidad , Fabaceae/toxicidad , Calor , Masculino , Tamaño de los Órganos/efectos de los fármacos , Fitohemaglutininas/toxicidad , Lectinas de Plantas , Proteínas de Plantas/farmacocinética , Proteínas de Plantas/toxicidad , Ratas , Ratas Sprague-Dawley , Bazo/patología , Taninos/toxicidad , Timo/patologíaRESUMEN
Histological studies of the spleen and thymus of rats fed raw black beans (Phaseolus vulgaris) show an atrophy of both lymphoid organs. Decrease in relative thymus weight was most marked. All histological organization of this organ appeared altered. An evident decrease in cell number was also observed in both organs. Proliferative response of splenic cells stimulated in vitro with Concanavalin A was increased as compared to that from animals fed the control diet. It is likely that histological changes observed in the spleen and the thymus are due mainly to a protein caloric deficiency, although the possibility that toxic factors present in the raw diet have an effect on the immune system of the rat can not be overruled
Asunto(s)
Animales , Masculino , Fabaceae , Manipulación de Alimentos , Síndromes de Inmunodeficiencia/inducido químicamente , Activación de Linfocitos/efectos de los fármacos , Bazo/efectos de los fármacos , Timo/efectos de los fármacos , Atrofia , Peso Corporal/efectos de los fármacos , Proteínas en la Dieta/farmacocinética , Proteínas en la Dieta/toxicidad , Inhibidores Enzimáticos/toxicidad , Calor , Fabaceae/toxicidad , Tamaño de los Órganos/efectos de los fármacos , Fitohemaglutininas/toxicidad , Proteínas de Plantas/farmacocinética , Proteínas de Plantas/toxicidad , Ratas , Ratas Sprague-Dawley , Bazo/patología , Taninos/toxicidad , Timo/patologíaRESUMEN
Wistar rats were submitted to the action of active lectins from common dry beans (Phaseolus vulgaris) and from jack beans (Canavalia ensiformis, DC). Raw common bean was offered to the rats in an otherwise balanced diet to make 10% protein as the sole protein source. A single dose of 20 mg of jack bean lectin (concanavalin A) was given by gastric intubation. Half of the rats receiving raw bean died within 22 days of experiment. Histological findings showed ulceration and necrosis of the intestinal villi in the surviving rats. In some cases the lesions reached also the submucosa. Gastric intubation of concanavalin A caused intense scaling off in the apical portion of the villi.