Iron trends in rat serum related to dietary fish oils under protein malnutrition

The iron trend in the serum of male rats fed a low wheat gluten (5% level) diet containing several fish oils for 2 to 4 wk was investigated. The body weight in every experimental group decreased during the first 3 d and thereafter their body weights dropped gradually until the 4th week. At the end of the experimental period, the weights of the spleens from the rats in the cod liver oil (CLO) and sardine oil (SO) groups were significantly heavier than those of the corn oil (control: CO) group. The iron concentrations in the serum of all dietary groups at the 4th week had a tendency to decrease compared to that of the control (CO) group. Ferritin in serum in the 4th week was significantly increased compared to that of the 2nd week for both the CO and CLO groups. However, that of the SO group remained at a low level similar to that measured in the 2nd week. The unsaturated iron binding capacity (UIBC) of the SO group in the 2nd week was significantly higher than that of the control (CO) group. In the 2nd week, the non-heme iron content in the liver was almost equal to the standard value. In the 4th week, however, the non-heme iron in the liver tissues of all dietary groups was significantly increased compared to those of the corresponding groups in the 2nd week. These findings suggest that iron accumulates in the liver.