The role of the nasal glands in the survival of ducks (Anas platyrhynchos) exposed to hypertonic saline drinking water

Abstract

The supraorbital nasal glands were removed from the duck (Anas platyrhynchos) 1 week before experimentation. When sham-operated birds were given hypertonic saline drinking water (282 mM NaCl, 6 mM KCl) for 70 h they maintained their body weights and remained in positive water balance. When the ducks lacking nasal glands were similarly treated they became severely dehydrated, lost body weight at the rate of 5.59 ± 1.1 g/h and showed significant increases in the plasma concentrations of Na⁺, Cl⁻, K⁺, and total osmotically active material. When the glandless birds were given hypertonic saline drinking water, the disparity between the measured plasma osmolality and the osmolality calculated on the basis of the Na⁺, Cl⁻, and K⁺ concentrations in plasma increased two-fold. No such change in disparity between the measured and calculated osmolalities of plasma in the sham-operated birds was observed. Forty-eight hours after their return to a diet containing fresh drinking water, the birds without nasal glands regained some of the body weight they had lost and the plasma electrolyte concentrations were restored towards normal. It is concluded that in the absence of nasal glands, the kidney alone is incapable of maintaining positive water balance in ducks fed hypertonic saline as their only source of drinking water.