Osmoregulatory and metabolic costs of salt excretion in the Rufous-collared sparrow Zonotrichia capensis.
Comp Biochem Physiol A Mol Integr Physiol
; 164(2): 314-8, 2013 Feb.
Article
em En
| MEDLINE
| ID: mdl-23103672
ABSTRACT
Recent experiments on shorebirds have demonstrated that maintaining an active osmoregulatory machinery is energetically expensive. This may, in part, explain diet and habitat selection in birds with salt glands. However little is known about the osmoregulatory costs in birds lacking functional salt glands. In these birds, osmotic work is done almost exclusively by the kidneys. We investigated the osmoregulatory cost in a bird species lacking functional salt glands, the passerine Zonotrichia capensis. After 20 days of acclimation to fresh water (FW) and salt water (200 mM NaCl, SW), SW birds tended to be heavier than FW birds. However, this difference was not statistically significant. Total basal metabolic rate was higher in SW birds as compared with FW birds. Renal and heart masses were also higher in the SW group. We also found greater medullary development and an increase in urine osmolality in the SW group. In spite of Z. capensis' ability to tolerate a moderate salt load in the laboratory, we hypothesize that increased cost of maintenance produced by salt consumption may significantly affect energy budget, dietary, and habitat choices in the field.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Glândula de Sal
/
Equilíbrio Hidroeletrolítico
/
Pardais
Tipo de estudo:
Health_economic_evaluation
Limite:
Animals
Idioma:
En
Revista:
Comp Biochem Physiol A Mol Integr Physiol
Assunto da revista:
BIOLOGIA MOLECULAR
/
FISIOLOGIA
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Chile