Belgrade rats inherit microcytic, hypochromic anemia as an autosomal r
ecessive trait (gene symbol b), Erythrocytes and tissue are iron defic
ient in the face of elevated TIBC (total iron binding capacity) and pe
rcent iron saturation; iron injections increased the number of erythro
cytes but their appearance remained abnormal. We have investigated iro
n supplements to improve husbandry of b/b rats and to learn more about
the underlying defect and its tissue distribution, Weekly IM (intramu
scular) injections of iron-dextran (Imferon at 30 mg kg(-1)) improved
the anemia but did not alter the red cell morphology. Certain diets al
so improved the health of b/b rats when compared to standard rat chows
by the criteria of weight, survival to adulthood, hematology and repr
oduction, The critical nutritional factor turned out to be iron bioava
ilability, with ferrous iron added to the diet improving the health of
Belgrade rats without affecting the underlying erythroid defect, Tiss
ue iron measurements after dietary or parenteral supplementation confi
rmed the iron deficient status of untreated b/b rats and established t
hat dietary ferrous iron partially relieved this deficiency, with inje
ctions leading to greater amounts of tissue iron, Serum iron and TIBC
were also found to be elevated in untreated b/b rats, with dietary sup
plementation decreasing but not eliminating the elevation in TIBC, The
se studies indicate that iron supplements can improve the health of b/
b rats without altering the underlying defect and also suggest that th
e mutation could alter iron uptake in the GI (gastrointestinal) tract.