ISSN:
1432-136X
Keywords:
Avian osmoregulation
;
Salt gland
;
Saltwater adaptation
;
Maximum secretion capacity
;
Eider duck (Somateria mollissima)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract The function of the supra-orbital salt gland was studied in the common eider duck (Somateria mollissima). The maximum salt-secreting capacity was determined in (1) wild ducks which had been living in a marine environment, (2) ducks reared in captivity on fresh water, and (3) ducks from group 2 adapted to salt water. The maximum secreting capacity was found by infusing a solution of NaCl (1000 mosmol·kg-1) at increasing rates, from 0.691 to 1.671 mosmol·min-1. Freshwater-adapted ducks secreted at a maximum rate of 0.785 mosmol·min-1 (1500 mosmol·kg-1). Adapted to salt water they increased their capacity, and the best duck secreted at a rate of 1215 mosmol·min-1 (1600 mosmol·kg-1). The best wild duck secreted at a rate of 1516 mosmol·min-1. Ducks in group 3 were used to examine the response to a hyperosmotic or an isoosmotic infusion. The amount of salt (NaCl) given per unit time was the same. Given a hyperosmotic solution their salt glands secreted at a high rate: 30 min after the infusion had stopped the ducks had excreted 94% of the sodium infused, 92.9% via the salt gland. Given an isoosmotic solution they secreted at a rate about half the infusion rate: 30 min after cessation of infusion they had excreted 73% of the sodium, 42.9% via the salt gland and the rest by the kidneys.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00367309
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