Iron and Copper Utilization in Rabbits as Affected by Diet and Germfree Status

Abstract

Germfree rabbits maintained with steam-sterilized diets containing moderate amounts of iron and copper from natural ingredients but relatively high amounts of these minerals as supplemental salts, showed low hemoglobin, hematocrit and plasma iron levels, and high plasma total iron-binding capacity (TIBC) values. Plasma copper values were normal. Either conventionalization of these germfree rabbits or transfer to a steam-sterilized diet which contained more iron from natural ingredients (soybean meal) but less total amount of this mineral alleviated all symptoms of iron deficiency anemia within 4 weeks. The effect of feeding this last diet to germfree and conventional rabbits from weaning was then investigated. After the diet had been fed for 8 weeks, plasma copper, iron, TIBC, and percentage saturation of iron-binding protein levels were similar in germfree and conventional rabbits. Hemoglobin and hematocrit values were slightly lower but within normal range in germfree rabbits. The iron content of liver, spleen and kidney was lower in germfree rabbits than in conventional rabbits. There was no difference between the copper content in these organs. It is concluded that germfree rabbits utilized iron more efficiently from a natural source than from the usual mineral suuplement.