EFFECTS OF INTESTINAL RESECTION, CHOLECALCIFEROL AND ASCORBIC-ACID ONIRON-METABOLISM IN RATS

The effect of dietary supplementation with ascorbic acid or cholecalci ferol on Fe utilization was studied using the metabolic balance techni que, in rats in which 50% of the distal small intestine was removed, o r in which the mid small intestine was transected and reanastomosed (c ontrols). Three different diets were used. The first (basal diet) cont ained (g/kg dry wt): protein (casein + 50 mg D,L-methionine/g) 120 and fat (medium-chain triacylglycerols, olive oil and sunflower oil, in e qual parts) 40. The other diets were obtained by adding ascorbic acid (150 mg/kg diet) or cholecalciferol (0 . 4 mg/kg diet) to the basal di et. Apparent digestibility coefficient (ADC) and Fe retention were sig nificantly lower in resected animals than in their respective control groups (transected rats). However, the addition of ascorbic acid or ch olecalciferol to the basal diet increased the ADC and Fe retention in both transected and resected rats. Five weeks after surgery, resection also resulted in a reduced concentration of Fe in the sternum, but di d not reduce the concentration of haemoglobin or serum Fe total Fe-bin ding capacity or the concentration of Fe in liver, testes, femur or mu scle (longissimus dorsi). Supplementation with ascorbic acid increased serum Fe concentration, while the concentration of Fe in muscle was r educed by supplementation with both ascorbic acid and cholecalciferol. Neither supplementation had any effect on the Fe concentration in oth er tissues, on haemoglobin concentration or plasma total Fe-binding ca pacity. Thus, supplementation with ascorbic acid or with cholecalcifer ol increased Fe absorption and reduced the concentration of Fe in musc le.