Trypsin-inhibitor activity in colostrum - an overview

The crucial role of colostrum for the neonatal immune system is well recognized. Following ingestion, proteins and especially immunoglobulins must pass the gastrointestinal tract and its proteolytic enzymes intact in order to be absorbed into the neonatal blood circulation. For this reason colostrum exhibits trypsin-inhibitor activity. This activity is not exerted by a single molecule but represents a general characteristic of the first colostrum. In artiodactyl species, high-level trypsin inhibition has been demonstrated along with a rapid decrease during the first days of lactation. In equine colostrum, trypsin-inhibitor activity has also been detected. Its importance is however controversially discussed in the literature due to the fact that the anti-trypsin activity is less pronounced in comparison to artiodactyl species and exhibits reduced stability in acidic environment. In the colostrum of carnivores, anti-trypsin activity has also been proven, this however is less prominent than in ungulates. The presented overview of the literature aims at summarizing the current understanding of trypsin inhibition in the colostrum of different species.