E. Caviedes-vidal et al., Dietary modulation of intestinal enzymes of the house sparrow (Passer domesticus): testing an adaptive hypothesis, COMP BIOC A, 125(1), 2000, pp. 11-24
Citations number
38
Categorie Soggetti
Animal Sciences",Physiology
Journal title
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR AND INTEGRATIVE PHYSIOLOGY
Insectivorous/frugivorous passerine species studied so far lack the ability
to modulate intestinal maltase activity, in contrast to galliformes. We te
sted for dietary modulation of small intestine (SI) enzymes including malta
se in house sparrows to understand whether the difference between the galli
formes on the one hand, and the passerines on the other, reflects a phyloge
netic pattern (maltase modulated in galliformes but not passerines), a diet
ary pattern (maltase modulated in granivores but not insectivore/frugivores
), some other pattern, or chance. We also tested the prediction that intest
inal peptidase activity would be increased on a high protein (HP) diet. Bir
ds were fed three diets high in starch, protein, or lipid for 10 days. For
birds on the HP diet (60.3% protein) we observed the predicted upward modul
ation of aminopeptidase-N activity, as compared with the lower-protein, hig
h starch (HS) (12.8% protein) diet. In contrast, birds eating the HS diet h
ad similar maltase and sucrase activities, and only slightly higher isomalt
ase activity, compared with birds eating the high protein (HP), starch-free
diet. Birds eating high lipid (HL) diet had low activities of both carbohy
drases and peptidase. Considering that the statistical power of our tests w
as adequate, we conclude that house sparrows show little or no increase in
carbohydrases in response to elevated dietary carbohydrate. We cannot rejec
t the hypothesis that maltase lability among avian species has a phylogenet
ic component, or that high dietary fat has a depressing effect on both carb
ohydrase and peptidase activities. (C) 2000 Elsevier Science Inc. All right
s reserved.