The effect of ingested NACL on body temperature in two avian species : the domestic fowl and the glaucous-winged gull

The relative effects of ingested sodium chloride (NaCl) on body temperature were examined in two avian species; the domestic fowl (Gallus domesticus), a terrestrial bird which excretes NaCl renally, and the Glaucous-winged gull (Larus qlaucescens), a marine bird which excretes NaCl both renally and extrarenally. Plasma sodium ([Na⁺]pl), potassium ([K⁺]pl), chloride ([Cl⁻]pl, ionized ([Ca²⁺]pl) and total calcium ([Ca]pl) concentrations, plasma osmolality (Osmolpl), body temperature, evaporative water loss (EWL), total body water (TBW), respiratory frequency (f), minute ventilation (VE) , and panting thresholds were determined in roosters and gulls exposed to increasing dietary NaCl levels. High dietary NaCl significantly raised gull resting body temperature (40.4°C ± 0 . 4°C) to 41. 0°C ± 0 .5°C (P<0.05) but did not alter rooster body temperature (41.0°C ± 0.2°C) significantly. [Na⁺]pl increased by 5.4% (P<0.01) in gulls and by 3.7% (P<0.01) in roosters, and was correlated with body temperature in gulls (r = 0.497, n = 25) . . [Ca²⁺]pl increased (roosters, 5.5%, P<0.01; gulls, 11.8%, P<0.01) when [Na⁺]pl was high. Plasma sodium to calcium ratios were not altered and were unrelated to body temperature in both species. High dietary NaCl elevated the internal threshold for panting in roosters from 41.95 ± 0.41°C to 42.35 ±0.3 6°C (P<0.05), and the increase was associated with an increase in Osmolpl (303.6 ± 4.0 mosmol/kg to 319.5 ± 4.3 mosmol/kg, P