Iron absorption in nursing piglets.

Forty-two piglets on days 3 and 12 of age were used to determine the rate of intestinal absorption of iron by the red cell radioiron method and to evaluate the effect of age on intestinal absorption of iron. s9 Fe-labelled ferric citrate in a dose of 1 2 /aci per kilogram weight was administered with carrier ferric citrate in 5% fructose solution by stomach tube after 1-hr fast. Two levels of carrier dose (8 and 24 mg iron) were assigned. After s 9 Fe dosing, all piglets were daily administered ferric citrate of the same level as carrier dose. Although uptake of s 9 Fe by red cells was markedly lower from the ingested dose than from the intravenous injection, the incorporation into red cells of the ingested s9 Fe reached a plateau 6-days post-dose, suggesting ready incorporation into hemoglobin. The red cell utilization of ingested iron by nursing piglets, dosed with 8 mg iron, ranged broadly from 44 to 85% with mean 59%. Only a small amount of s9 Fe was detected in nonheme iron in the liver at the end of experiment. The uptake of s 9 Fe into red cells for the 24 mg dose was markedly depressed as compared with the 8 mg dose. However, since the amount of S9Fe in nonheme iron in the liver was increased with the elevated dosage, it seems likely that iron absorption from the intestine of the nursing pigs is not largely affected by the elevated dose. Iron depletion prior to initiation of s 9 Fe dosing did not enhance the percentage absorption of iron from the intestine significantly over that of the group receiving 8 mg per os daily. Although hematological parameters did not change with the level of iron dose, nonheme iron in the liver was significantly increased with the elevated dose. Thus, it seems likely that the great physiological iron need for hemoglobin synthesis associated with extremely rapid growth is a major factor responsible for