Proteome Analysis of Human and Goat Colostrum: A closer look at whey fractions

Background: Human colostrum, the first form of milk produced by mammary glands, is crucial for newborn development. Nowadays, there is a great interest in finding alternative colostrum from different species to replace the extremely scarce human colostrum. In this study, we investigated the proteomic profiles of whey fractions of human and goat colostrum samples to understand the proteomic differences and gain insight into the potential functions of these proteins. Methods: Proteomic profiles of human (n=6) and goat (n=6) colostrum that were collected at the early stages of lactation were investigated using two-dimensional difference gel electrophoresis (DIGE). Spot intensity differences were detected and spots were identified by MALDI-TOF/TOF mass spectrometry. Functional annotation analyses were performed. Results: In total, 533 spots were detected and identified in human and goat colostrum samples. Immunoglobulin, casein, lactoferrin, lactoglobulin, albumin, lactotransferrin, and lactalbumin proteins were found to be abundant. Low abundance proteins such as α1-antitrypsin, cathelicidin, galectin-3-binding protein, lactadherin, tenascin, and apolipoprotein J were also detected. Functional annotation analysis showed that human colostrum proteins were commonly involved in the phagosome, complement and coagulation pathways, and disease-related pathways. Conclusion: Our results provide a preliminary proteomic comparison between human and goat colostrum samples. The proteins detected in the whey fractions of human and goat colostrum showed a remarkable number of common proteins. Moreover, human colostrum showed disease-related pathway enrichments and further suggests the role of passive immunization that might protect the newborn from diseases.