Evaluation of Dietary Salt Levels for Swine II. Effect on Blood and Excretory Patterns2,3

Abstract

Six experiments utilizing 81 growing crossbred barrows were designed to study the effect of salt (NaCl) supplementation on blood and excretory measurements. The measurements studied were: packed cell volume (PCV), sodium and potassium excretion, and urinary and fecal nitrogen excretion. Conventional corn-soybean meal diets with varying amounts of supplemental salt were fed along with deionized drinking water. Supplemental salt levels studied ranged from .00 to .39% salt, added as sodium chloride. The PCV values initially decreased with increased salt intake (P<05) until a stabilization point was reached below .14% added salt. The negative correlation between salt intake and PCV was highly significant and up to 31% of the variability in PCV can be accounted for by salt addition. Urinary potassium and nitrogen excretion and fecal nitrogen excretion were not altered by level of salt intake. Total daily urinary and fecal sodium excretion were not increased (P<01) until the salt level was greater than .14% added salt. Sodium excretion primarily, and to a lesser extent PCV, can be used as predictors of physiological salt needs. The close agreement between the results obtained via the two measurements is encouraging. Copyright © 1976. American Society of Animal Science . Copyright 1976 by American Society of Animal Science.