Adaptation of intestinal epithelial hydrolysis and absorption of dietary carbohydrate and protein in mammals and birds

The small intestine of mammals and birds exhibits fascinating variation across taxa, body size, and life history features such as locomotion and diet. In the intestine's brush border membrane (BBM), hydrolases are more abundant than transporters in both mammals and birds, but there are differences among the groups in abundance of certain hydrolases and possibly in transporters. For example, mammals express two α-glucosidases, sucrase-isomaltase (SI) and maltase glucoamylase (MGAM), whereas songbirds we studied have only SI, and the chicken expresses SI plus another α-glucosidase that functions similarly to MGAM but is not a true ortholog. For intestinal absorption of sugars and amino acids, small fliers rely on a paracellular pathway to a greater extent than do nonflying mammals, which rely more on transporters. Possibly having evolved in fliers as compensation for lower intestinal nominal surface area (NSA), the fliers' reliance on paracellular absorption is supported by their greater villous surface enlargement that leads to more (per cm2 NSA) tight junctions and greater clearance of passively absorbed compounds. To match digestive capacity to nutrient load, a positive relationship is often observed between dietary intake of macronutrients and intestinal activity of the enzymes and transporters of their respective constituents. In enterocytes, rapid, fine-tuned adjustment to high dietary carbohydrate and protein involves rapid, specific correlated increase in activity and abundance of hydrolases and transporters in the BBM and increases in their mRNA.Fil: Karasov, William. University of Wisconsin; Estados UnidosFil: Caviedes Vidal, Enrique Juan Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. University of Wisconsin; Estados Unido

Activity of digestive enzymes in chicken's small intestine and caeca: Effect of dietary protein and carbohydrate content

Digestion is a mediating factor between the animals and their environment, one of the variables related to the efficiency in extracting energy from nutrients is rate of hydrolysis. Phylogenetical and functional hypothesis has been proposed linking dietary flexibility and enzyme lability. Species belong to Parvclass Galloanserae, studied until now, did not modulate aminopeptidase-N activity but they did modulate disaccharidases activities. Additionally, peptide hydrolysis has been demonstrated in avian caeca, but not in chickens. Finally, dietary proteins are essential for chicken growth in the first stages of development, but little information is available in chickens beyond 42 days of life. Chickens beyond that age were fed for 15 days either a high protein (DHP = 49.72% protein and 11.92% carbohydrates) or a high starch diet (DHS = 52.82% carbohydrates and 10.49% protein). Aminopeptidase-N, maltase and sucrase, were assessed in chicken’s small intestines and caeca. Body mass of DHP birds was 37.5% higher than body mass of DHS birds, at the end of the trial. Aminopeptidase-N and sucrase did not change, but maltase exhibited higher activity in DHS than in DHP birds. The lack of aminopeptidase-N modulation and its relatively high activity in caeca, together with a modulation of maltase, contribute and give apparent support to the functional hypothesis. Surprisingly, a high quantity of protein resulted important for growth in chickens after 42 days of life. Also it is important to notice that a casein diet has been demonstrated as a high digestible meal for chickens, so the last data may be of interest for poultry industry.Fil: Ciminari, María E.. Universidad Nacional de San Luis. Facultad de Ciencias Humanas. Laboratorio de Biología "Profesor Enrique Cavides Codelia"; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Caviedes Vidal, Enrique Juan Raul. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Ciencias Humanas. Laboratorio de Biología "Profesor Enrique Cavides Codelia"; ArgentinaFil: Chediack, Juan Gabriel. Universidad Nacional de San Luis. Facultad de Ciencias Humanas. Laboratorio de Biología "profesor Enrique Cavides Codelia"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; Argentin

Isolation of epithelial cells, villi and crypts from small intestine of pigeons (Columba livia)

The isolation of viable enterocytes, villi and crypts from the small intestine of a feral bird (Columba livia) is important for performing physiological experiments in ecologically relevant processes of membrane transport. The effectiveness of mechanical disruption, enzymatic digestion and chelating agents were compared. The objectives were to isolate enterocytes, villi and crypts from the small intestine of young pigeons; to evaluate the viability of the isolated intestinal epithelial cells isolated; and to verify the integrity of enterocytes by biochemical features. Enzymatic and mechanical methods yielded both elongated columnar and spherical cells. With the chelating method villi and crypts were obtained. All methods produced a high yield of intestinal epithelial cells with about 50 % viability. Brush border enzymes (sucrase-isomaltase and alkaline phosphatase) activities were high and, as reported in chickens, they did not differ along the intestinal villus-crypt axis. Although the three methods have good viabilities, the enzymatic technique gives the best yield in cell number, while the chelating method provides the highest populations of morphologically distinctive villi and crypts.Fil: Mac Donal, Oscar. Universidad Nacional de San Luis. Facultad de Ciencias Humanas; ArgentinaFil: Chediack, Juan Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Caviedes Vidal, Enrique Juan Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentin

Primer registro del Suirirí Amarillo (Satrapa icterophrys) en la Provincia de San Luis, Argentina

El 19 de enero de 2001, se registraron dos ejemplares adultos de suirirí amarillo (Satrapa icterophrys) en el Embalse La Florida (33°07’S-66°02’W, departamento Coronel Pringles, provincia de San Luis, Argentina) el primero a las 10:00 y el segundo, minutos más tarde. Ambos individuos fueron encontrados en las cercanías de la costa del embalse (aproximadamente a 20 m), en un ambiente abierto compuesto por dos estratos vegetales: uno arbóreo (Prosopis caldenia) y otro constituido, mayoritariamente, por pata de perdiz (Cynodondactylon). Se observaron a una distancia menor de 8 metros, posados sobre árboles de P. caldenia a unos 3 a 4 metros de altura. Durante el periodo de observación presentaron un comportamiento muy confiado y permanecieron en el lugar por un tiempo aproximado de 2 minutos. Es importante destacar que fue la primera y única vez que se observaron en muestreos realizados durante enero de 2001 (17 días de observación, con muestreos matinales y vespertinos en 5 estaciones de muestreo). La presente contribución, constituye el primer registro de S. icterophrys en la provincia de San Luis (ver Nellar Romanella, 1993; Nores, 1995).Fil: Cid, Fabricio Damian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Caviedes Vidal, Enrique Juan Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentin

Daily expression of sodium-dependent glucose cotransporter-1protein in jejunum during rat ontogeny

It is widely known that intestinal capacities such as the enzymatic hydrolysis of carbohydrates, lipids and proteins, and the subsequent absorption of the hydrolyzed products, are evolutionary matched to dietary loads and feeding behaviors. In this study, we demonstrate that the protein expression of apically located sodium-dependent glucose cotransporter-1 (SGLT-1) throughout rat ontogeny is daily adjusted to afford glucose uptake when the load of this metabolically essential monosaccharide in the intestinal lumen is maximum. The jejunal expression of SGLT-1 protein in 14 one-day-old suckling pups was found to increase at dark and early light phase (P < 0.05), when they have a better access to mother milk. In weaning 21-d-old and juvenile 28-d-old rats, the cotransporter expression was high throughout the entire day (P < 0.05). Finally, adult 90-d-old rats showed a well-developed circadian rhythm for SGLT-1 protein (P < 0.05), whose expression increased at late light and dark phase when the highest intestinal glucose load was achieved. To our knowledge, these results are the first reporting the daily profile of SGLT-1 expression during rat early developmental stage and may contribute to understand the biological significance of a well-established molecular capacity to deal with the crucial increase of glucose load in the diet during the weaning process.Fil: Baston, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Cid, Fabricio Damian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Caviedes Vidal, Enrique Juan Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Chediack, Juan Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentin

Is diet-shifting facilitated by modulation of pancreatic enzymes? Test of an adaptational hypothesis in Yellow-rumped Warblers

Many birds exhibit seasonal switches in diet and thus alter nutrients predominating their food intake. We tested for dietary modulation of pancreatic enzymes in Yellow-rumped Warblers (Dendroica coronata), a species for which such dietary changes are documented. Birds were fed three diets formulated from either fruit, insect, or seed. We predicted that pancreatic carbohydrase amylase, and the proteases trypsin and chymotrypsin, would be modulated in direct correlation with relative levels of dietary carbohydrate and protein, respectively. In contrast to the prediction, there was no significant dietary effect on activities of amylase and chymotrypsin, and a significant change in trypsin activity (highest on seed diet) occurred in the wrong direction with regard to the prediction. Considering the statistical power of our tests, we conclude that Yellow-rumped Warblers represent a case of only modest ability, at best, to modulate pancreatic enzymes. For some diets, especially high-starch diets that they digest relatively poorly and on which they tend to lose body mass, they may lack sufficient enzyme and hence are constrained in their dietary niche.Fil: Ciminari, María Eugenia. Universidad Nacional de San Luis; ArgentinaFil: Afik, Daniel. University of Haifa at Oranim; IsraelFil: Karasov, William. University of Wisconsin; Estados UnidosFil: Caviedes Vidal, Enrique Juan Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentin

Chronic cannulation in the small intestine of feral pigeons (Columba livia) to assess bioavailability

We improved a method of chronic duodenal cannulation to study intestinal transport of solutes in an in vivo model (pigeon, Columba livia). A hypoallergenic cannula was inserted into the proximal part of the small intestine of pigeons and used for solution administration. Recovery from surgery was extremely rapid and animals started eating and drinking within a day. After surgery, the body mass of cannulated pigeons was stable, and no adverse effects in the weight could be detected. The method is simple, economical and useful to determine intestinal bioavailability of solutes, for nutritional and ecological studies, in intact animals without influence of anesthesia.Fil: Chediack, Juan Gabriel. Universidad Nacional de San Luis. Facultad de Ciencias Humanas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; ArgentinaFil: Cid, Fabricio Damian. Universidad Nacional de San Luis. Facultad de Ciencias Humanas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; ArgentinaFil: Fasulo, S. V.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Ciencias Humanas; ArgentinaFil: Caviedes Vidal, Enrique Juan Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Ciencias Humanas; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; Argentin

Activity of intestinal carbohydrases responds to multiple dietary signals in nestling House sparrows

The ‘adaptive modulation hypothesis’ predicts that activity of digestive enzymes should match the amount of their substrates in diet. Interestingly, many passerine birds do not adjust the activity of intestinal carbohydrases to dietary carbohydrate content. It is difficult to assess the generality of this rule, because in some studies passerines fed on low-carbohydrate and high-lipid diet showed reduced activity of intestinal carbohydrases. However, as carbohydrase activity may be inhibited by high dietary lipid content, it is unclear whether observed effects reflected lack of induction by the low carbohydrate levels or suppression by the high lipid levels. Here, we isolated the specific effects of dietary carbohydrate and lipid on carbohydrases. We hand-fed house sparrow nestlings on diets with 25% starch and 8% lipid (diet HS), no starch and 20% lipid (HL), or 25% starch and 20% lipid (HSL). Our results show that activity of intestinal carbohydrases is simultaneously induced by dietary carbohydrates and decreased by dietary lipid, although the latter effect seems stronger. Activities of maltase and sucrase summed over the total intestine decreased in the order HS>HSL>HL. We observed a complex interaction between diet composition and intestinal position for mass-specific activity of these enzymes, suggesting site-specific responses to changes in digesta composition along the intestines caused by digestion and absorption. We re-interpret results of earlier studies and conclude that there is no unequivocal example of adaptive modulation of intestinal carbohydrases by dietary carbohydrate in adult passerine birds, whereas the present experiment confirms that nestlings of at least some species possess such capacity.Fil: Brzek, Pawel. University of Wisconsin. Department of Forest and Wildlife Ecology; Estados UnidosFil: Kohl, Kevin D.. University of Wisconsin. Department of Forest and Wildlife Ecology; Estados UnidosFil: Caviedes Vidal, Enrique Juan Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. University of Wisconsin. Department of Forest and Wildlife Ecology; Estados Unidos. Universidad Nacional de San Luis. Facultad de Ciencias Humanas. Laboratorio de Biología "Profesor Enrique Cavides Codelia"; ArgentinaFil: Karasov, William H.. University of Wisconsin. Department of Forest and Wildlife Ecology; Estados Unido

Fully reversible phenotypic plasticity of digestive physiology in young house sparrows: lack of long-term effect of early diet composition

Feeding conditions during the nestling period may significantly affect whole-life fitness in altricial birds but little is known about the physiological mechanisms responsible for these effects. Permanent changes (irreversible developmental plasticity) in digestive physiology caused by the neonatal diet may form such a mechanism. We previously showed that the lack of starch in the diet of house sparrow (Passer domesticus) nestlings between 3 and 12 days post-hatching significantly decreased the activity of intestinal maltase, an enzyme essential for starch digestion. To check whether diet-induced variation in maltase activity in young house sparrows is reversible, we raised them under laboratory conditions from 3 until 30 days of age on diets with either 0% starch or 25% starch, with some individuals experiencing a switch in their assigned diet at 12 days of age. We found evidence for the presence of an internal, presumably genetic, program for changes in the activity of maltase and sucrase, which was, however, significantly affected by diet composition (i.e. environmental factor). Digestive enzyme activity in 30 day old birds was not influenced by diet composition prior to day 12 but instead depended only on diet that was fed between days 12 and 30. We conclude that plasticity in the activity of intestinal disaccharidases in house sparrow nestlings represents completely reversible phenotypic flexibility that can help young sparrows to cope with unpredictable variation in food composition during ontogeny without long-term effects on their digestive system. However, comparison with other species suggests that the magnitude of digestive flexibility in young passerines may be evolutionarily matched to species-specific variation in feeding conditions.Fil: Brzęk, Pawel. University of Wisconsin; Estados Unidos. University of Bialystok; PoloniaFil: Kohl, Kevin D.. University of Wisconsin; Estados Unidos. University of Utah; Estados UnidosFil: Caviedes Vidal, Enrique Juan Raul. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Karasov, William H.. University of Wisconsin; Estados Unido

Rapid and parallel changes in activity and mRNA of intestinal peptidase to match altered dietary protein levels in juvenile house sparrows (Passer domesticus)

Although dietary flexibility in digestive enzyme activity (i.e. reaction rate) is widespread in vertebrates, mechanisms are poorly understood. When laboratory rats are switched to a higher protein diet, the activities of apical intestinal peptidases increase within 15 h, in some cases by rapid increase in enzyme transcription followed by rapid translation and translocation to the intestine's apical, brushborder membrane (BBM). Focusing on aminopeptidase-N (APN), we studied intestinal digestive enzyme flexibility in birds, relying on activity and mRNA data from the same animals. Our model was nestling house sparrows (Passer domesticus), already known to modulate intestinal peptidase activity when switching between lower and higher protein diets. Twenty-four hours after a switch from an adequate, lower protein diet to a higher protein diet, APN activity was increased in both whole intestinal tissue homogenates and in isolated BBM, but not at 12 h post-diet switch. Twenty-four hours after a reverse switch back to the lower protein diet, APN activity was decreased, but not at 12 h post-diet switch. Changes in APN activity in both diet switch experiments were associated with parallel changes in APN mRNA. Although transcriptional changes seem to be an important mechanism underlying dietary modulation of intestinal peptidase in both nestling house sparrows and laboratory rodents, the time course for modulation in nestlings seemed slower (taking approximately twice as long) compared with laboratory rodents. It may be ecologically advantageous if nestlings biochemically restructure their gut in response to a sustained increase in insects and protein intake rather than one or a few lucky insect meals.Fil: Brun, Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Luis; Argentina. University of Wisconsin; Estados UnidosFil: Magallanes Alba, Melisa Eliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Karasov, William. University of Wisconsin; Estados UnidosFil: Caviedes Vidal, Enrique Juan Raul. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Luis; Argentina. University of Wisconsin; Estados Unido