Artículo
Activity of intestinal carbohydrases responds to multiple dietary signals in nestling House sparrows
Fecha de publicación:
06/2013
Editorial:
Company of Biologists
Revista:
Journal of Experimental Biology
ISSN:
0022-0949
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
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.
Palabras clave:
Phenotypic Flexibility
,
Digestive Enzymes
,
House Sparrows
,
Ontogeny
Archivos asociados
Licencia
Identificadores
Colecciones
Articulos(CCT - SAN LUIS)
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - SAN LUIS
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - SAN LUIS
Articulos(IMIBIO-SL)
Articulos de INST. MULTIDICIPLINARIO DE INV. BIO. DE SAN LUIS
Articulos de INST. MULTIDICIPLINARIO DE INV. BIO. DE SAN LUIS
Citación
Brzek, Pawel; Kohl, Kevin D.; Caviedes Vidal, Enrique Juan Raul; Karasov, William H.; Activity of intestinal carbohydrases responds to multiple dietary signals in nestling House sparrows; Company of Biologists; Journal of Experimental Biology; 216; 6-2013; 3981-3987
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