Binding of porcine milk lactoferrin to piglet intestinal lactoferrin receptor

Abstract

The saturation kinetics, the competitive binding studies and the Scatchard plots clearly demonstrate the presence of a specific lactoferrin receptor in piglet's small intestine. Like in mice, humans and rhesus monkeys, the intestinal porcine lactoferrin receptor is a low affinity receptor. Because of the high lactoferrin concentration in the milk of these species, a physiological role of the receptor can be assumed. There are reasons to suggest that only a small amount of milk casein is digested in the stomach of a suckling piglet. In species with milk high in casein (e.g., sow's milk), this will result in a relatively high concentration of incompletely digested casein causing immobilization and decreased availability of iron at the site where it is most efficiently absorbed (duodenum). The presence of lactoferrin receptors in the jejunum and ileum may facilitate absorption of iron, gradually being released from partly digested casein in the distal parts of the small intestine. Our results indicate that the isolated piglet enterocyte might be a suitable model for further studies on the interaction between the enterocyte and species specific lactoferrin.