Webb

Polyuria in Vitamin A-Deficient Sheep K. E. Webb, Jr., G. E. Mitchell, Jr., C. O. Little and G. H. Schmitt J Anim Sci 1968. 27:1657-1662.

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POLYURIA IN VITAMIN

A-DEFICIENT

SHEEP1

K. E. WEBB, JR., G. E. MITCHELL, JR., C. O. LITTLE ANn G. H. SCHMITT2 University o/ Kentucky, Lexington head was fed daily to the control wethers during all experiments. Stanchion-type metabolism crates were used min A deficiency to renal function in rumi- in all experiments to facilitate urine collection nants involved either autopsy findings (Hart every 12 hr. In the third and fourthexperiand Guilbert, 1937; Sutton et al., 1940; ments it was collected under toluene. Specific Langham et al., 1941 ; Eveleth et al., 1949) or gravity and pH were determined on aliquot studies of urinary calculi (Schmidt, 1941; samples immediately and samples were then Beeson et al., 1943; Lindley et al., 1953; frozen for later analysis of other constituents. Swingle and Marsh, 1956) until Woelfel etal. Heparinized blood samples were taken by jug(1965) reported marked changes in volume ular puncture and the plasma was removed and osmolality of urine excreted by vitamin after centrifugation and frozen for later analyA-deficient heifers. The experiments reported sis. Sodium and potassium concentrations of here continued this area of investigation in sheep with the following specific objectives:plasma and urine were determined by flame (1) to quantitate the polyuria in vitamin A- photometry (Seligson, 1958). Plasma and deficient wethers; (2) to study relationships urine chloride, inorganic phosphate and urea between polydipsia and the polyuria; (3) to were determined by the procedures of Zall et study the influence of vitamin A deficiency on al. (1956), Fiske and Subbarow (1925) and theability of the kidneys to concentrate urine Skeggs ( 1957), respectively. Calcium was deduring feed and water deprivation; and (4) to termined by atomic absorption spectrophostudy alterations in plasma and urine composi- tometry. Creatinine in plasma and urine samples was determined by the F01in and Wu tion which may be related to polyuria. procedure taken from Hawk, Oser and Summerson (1954). Theprocedures for chloride, Procedures inorganic phosphate, urea and creatinine were General Procedures. Four mature wethers modified for application to automated analytiwith chronic vitamin A deficiency and four cal equipment. The pH, specific gravity and controls were used in these experiments. Clas- osmolality of urine and osmolality of plasma sic signs of vitamin A deficiency including weredetermined by standard procedures. night blindness and convulsions were present. Analysis of variance procedures described Only traces of vitamin A were found in biopsy by Snedecor (1959) were used to evaluate the samples of livers of the deficient wethers data. (Tucker et at., 1967). Levels of vitamin A Experiment 1. Experiment 1 was composed detected in plasma of the wethers during each of two 7-daytrials, each being one-half of a experiment are presented in table 1. Vitamin switch-back metabolism study with two levels A was extracted by the method of Kimble of protein (diets 1 and 2, table 2). A d libitum (1939) and the color developed by the triflu- water intake of each animal was recorded. oroacetic acid method described by Dugan Experiment 2. Each animal was offered only (1964). 750 ml.of water after each feeding (1,500 ml. The carotene-deficient diets fed during these per day). Diet 2 (table 2) was fed. Urine was experiments (table 2) were composed of collected daily throughout the 7-day experiground corn cobs, ground milo, soybean meal ment. and glucose with minerals added. Experiment 3. Each animal was fed 454 gln. Each wether was fed 454 gin. twice daily. A of diet 3...