A Preparation of Cow's Late Colostrum Fraction Containing αs1-Casein Promoted the Proliferation of Cultured Rat Intestinal IEC-6 Epithelial Cells

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Colostrum is a complex mixture of bioactives that promotes neonate growth. Recently, we have found by in vivo study that skimmed, sterilized, and concentrated bovine late colostrum (SCBLC), obtained from a Holstein herd on days 6–7 after parturition, had an ability to maintain intestinal integrity. In the present study we investigated effects of SCBLC on rat intestinal IEC–6 cell proliferation in vitro. A fraction containing αs1–casein was found to have a robust stimulation effect as compared to other protein fractions from SCBLC and even the αs1–casein fraction from milk from other Holstein herds. Furthermore, the SCBLC αs1–casein molecule demonstrated not only slightly slower mobility on both SDS– and native–PAGE than other bovine milk αs1–caseins, but also a peculiar conformation reminiscent of moltenglobule in the circular dichroism spectrum. These findings may be of relevant to the competence of SCBLC to preserve intestinal integrity.