Data/hora: 10/06/2024 18:08:08

Provedor de dados: 	Revista Chilena de Historia Natural	
País: 	Chile	
Título: 	Osmoregulatory responses to dietary protein and water intake in the granivorous Zonotrichia capensis (Passerine, Emberizidae)	
Autores: 	ALDEA,PATRICIA; SABAT,PABLO.	
Data: 	2007-01-01	
Ano: 	2007	
Palavras-chave: 	Granivory; Kidney; Nitrogenous waste; Osmoregulation; Passerines.	
Resumo: 	We studied the osmoregulatory responses of the granivore Zonotrichia capensis, acclimated to high- and low-protein diets as well as two levels of water intake. We tested whether Z. capensis has the ability to modify the proportion of nitrogenous waste in the excreta when protein intake and water intake varies. After 21 days of acclimation, plasma osmolality was not significantly affected by dietary treatment; however, excreta osmolality was higher in the high-protein group compared to the low-protein group. Nitrogenous wastes in Z. capensis are excreted mainly in the form of uric acid. The proportion of kidney devoted to medullary tissue was 40 % higher in dehydrated birds than in hydrated birds. Excreta osmolality was higher in dehydrated birds, and in all cases higher than plasma concentration by more than 300 mOsm kg"¹. Our data do not support the hypothesis that Z. capensis can switch nitrogen excretion pathways. We hypothesize that the low water content of the seed-base diet, the comparatively low water intake, and the large difference between urine and plasma concentrations may minimize the retrograde flux of urine to the lower intestinal tract, thereby reducing the potential for post-renal urine modification	
Tipo: 	Journal article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2007000400006	
Editor: 	Sociedad de Biología de Chile	
Formato: 	text/html	
Fonte: 	Revista chilena de historia natural  v.80 n.4 2007