Feasibility studies in rats fed heavy metals as multiple nutrient markers
Luckey, T.D.; Kotb, A.; Vogt, J.R.; Hutcheson, D.P.
Journal of Nutrition 105(6): 660-669
1975
ISSN/ISBN: 0022-3166 PMID: 1170285 Document Number: 88017
The nitrates of 5 metals, Ce, Tb, Yb, Lu and Ir, were given by mouth to adult male Sprague-Dawley rats in apparent digestibility studies. Faecal recovery of a single dose was completed within 72 h. When the salts were mixed into the diet, 48 to 96 h were required to establish a steady state concentration of markers in faeces. The diurnal variation of Ce in faeces was considerably when it was given twice daily as a single dose before each feeding. When incorporated into the diet, negligible diurnal variation in faecal concentration was noted with Lu, and small variation was seen with other metals. In nutrient apparent digestibility studies, good agreement was generally found between direct and indirect multiple marker methods. Experiments with a daily intake marker suggested that Ce was not satisfactory as a multiple marker when neutron activation analysis was the method of estimation.