Abstract
A series of experiments was designed to quantitate the polyuria observed in vitamin A-deficient wethers and to investigate renal function parameters which might be affected. In two trials designed to quantitate changes in urine volume, control wethers excreted only one-half as much urine as vitamin A-deficient wethers. Since control wethers receiving equal amounts of water excreted only 53 % as much urine as did deficient wethers (experiment 2), it was concluded that polydipsia was not a primary causative factor in the observed polyuria. When less minerals and more protein were fed (experiment 3), total volumes decreased one-half for both groups, but the controls still excreted less urine than deficient wethers. Lower osmolality and specific gravity accompanied the increase in urine volume. A marked elevation in inorganic phosphate excretion and a decline in calcium excretion were also observed. When feed and water were withheld (experiment 4), both groups were capable of concentrating urine. Decreased sodium and chloride excretion by the deficient wethers suggested that they were retaining more salt. An alteration in nitrogen metabolism was suggested by increased plasma urea. Increased inorganic phosphate excretion and decreased calcium excretion by the deficient wethers suggested possible alterations in bone metabolism. It was concluded that a deficiency of vitamin A in wethers results in polyuria accompanied by changes in the composition of both the plasma and urine. Copyright © 1968. American Society of Animal Science. Copyright 1968 by American Society of Animal Science