title: Effect of calcium supplements to a maize-soya diet on the bioavailability of minerals and trace elements and the accumulation of heavy metals in growing rats.
abstract: Thirty-five (five groups with seven animals each) male albino rats (initial average weight = 44 g) were fed phytate-rich diets (analysed phytic acid concentration = 6.9 g/kg) based on maize and soy bean meal (5 g Ca, 3 g P, 1.2 g Mg, 23 mg Zn, 10 mg Pb, 5 mg Cd/kg diet). Experimental diets were supplemented with 0, 2, 4, 6 and 8 g calcium from CaCO3 per kg. The supplementation of increasing amounts of calcium resulted in a dose-dependent decrease in the apparent absorption of phosphorus. Furthermore, apparent zinc absorption and femur zinc concentration were moderately decreased due to the calcium supplementation. Kidney Cd concentration was significantly lower in rats that were fed the high calcium diets in comparison with the control animals. Femur lead concentration and hepatic delta-aminolevulinic acid dehydratase, which are known to be sensitive parameters of lead accumulation remained unchanged by the different dietary treatments. Magnesium absorption as well as liver and plasma zinc concentration and activity of plasma alkaline phosphatase were also unaffected. Although calcium supplementation may lead to a decrease in the accumulation of certain heavy metals such as cadmium, the carry-over of lead was not affected under the given experimental conditions. Furthermore, calcium-phytate-zinc interactions may adversely affect zinc bioavailability in growing rats.
authors.affiliation: Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-University, Giessen, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Walter
authors.forename: G
authors.initials: G
authors.lastname: Rimbach
authors.forename: E
authors.initials: E
authors.lastname: Most
authors.forename: J
authors.initials: J
authors.lastname: Pallauf
mesh_terms: D000469:Alkaline Phosphatase / Q000097:blood; D000622:Aminolevulinic Acid / Q000097:blood; D000821:Animal Feed; D000818:Animals; D002104:Cadmium / Q000032:analysis; D002118:Calcium / Q000032:analysis; D002136:Calcium, Dietary / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D019587:Dietary Supplements / Q000009:adverse effects*; D005269:Femur / Q000737:chemistry; D006454:Hemoglobins / Q000032:analysis; D007668:Kidney / Q000737:chemistry; D007854:Lead / Q000032:analysis; D008099:Liver / Q000737:chemistry; D008274:Magnesium / Q000032:analysis; D008297:Male; D010758:Phosphorus / Q000032:analysis; D010833:Phytic Acid / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D015032:Zinc / Q000032:analysis
chemical_list: D002136:Calcium, Dietary; D006454:Hemoglobins; D002104:Cadmium; D010758:Phosphorus; D007854:Lead; D010833:Phytic Acid; D000622:Aminolevulinic Acid; D000469:Alkaline Phosphatase; D008274:Magnesium; D015032:Zinc; D002118:Calcium