LAUSR

BACKGROUND Iron supplements is always limited by its poor absorption and low efficacy. Circadian feeding schedule would affect the circadian rhythm and improve nutrient metabolism. In this study, eighteen iron deficiency piglets were randomly assigned into three groups: control group receiving a constant diet with mid-iron (MI), HL group receiving a high-iron (HI) diet at 8:00 h and a low-iron (LI) diet at 18:00, and LH group receiving a LI diet at 8:00 and a HI diet at 18:00. The effects of circadian iron administration on iron absorption, iron status and biological rhythm in iron-deficient piglets were investigated. RESULTS Serum iron and hemoglobin were significantly improved (P<0.05) but not significantly differed in the piglets in circadian iron-feeding groups (P>0.05). Iron concentrations in the liver and spleen were significantly higher in LH group than that of HL group (P<0.05). Furthermore, mRNA expressions of Divalent Metal Transport 1 (DMT1), Cytochrome B (CYBRD1) and Ferroportin (FPN) genes in the duodenum were significantly elevated in LH group (P<0.05). The clock-related genes showed differential expressions in the duodenum, with greater mRNA expressions of Period (Per2) and Cryptochrome (Cry1 and Cry2) in LH group (P<0.05). CONCLUSION Circadian iron administration affected iron absorption and iron stores in pigs. Iron supplementation in the evening might be a more effective pattern for iron utilize and the rhythmic system in the intestine driven by the time played an important role in this process. This article is protected by copyright. All rights reserved.