An in vivo characterization of colostrum protein uptake in porcine gut during early lactation.

Understanding the bioactive roles of colostrum proteins has gained much attention, and in particular, their potential use in human and veterinary medicine has been extensively studied. However, studies of bioactivity have mainly been conducted in vitro, but it has not yet been well characterized at the individual protein level which colostrum components are internalized by the intestinal tissue of the neonate. The aim of this study was to characterize the in vivo processing of porcine colostrum in the gastrointestinal tract, and describe which of the potential bioactive proteins can be observed in the small intestinal tissue, and therefore may be functionally important. Using 2D-LC-MS/MS analysis we mapped the proteins in porcine colostrum. The colostrum proteins were then traced in the stomach content, as well as in the small intestinal tissue of 5 piglets suckled for 24h. For comparison, we also mapped the proteins present in the intestinal tissue of a newborn piglet that had not received colostrum. This analysis allowed us to identify the colostrum proteins that are internalized and retained in the tissue from the small intestine, indicating their functional importance. Our studies have shown that in early lactation, some colostrum proteins are protected against proteolytic degradation in the stomach. Furthermore, colostrum proteins with immuno-protective, antimicrobial or other bioactive functions are more prone to uptake in the small intestine than the caseins and beta-lactoglobulin, which are amongst the most abundant in colostrum.