Transport of Colostral Macromolecules into the Cerebrospinal Fluid via Plasma in Newborn Calves

Abstract

The objective of this study was to investigate the transfer of bovine colostral macromolecules especially the lactoferrin (Lf), transferrin (Tf), immunoglobulin G (IgG), and epidermal growth factor (EGF) from the gastrointestinal tract to the cerebrospinal fluid (CSF) via systemic circulation in newborn calves. Cannulae were placed into the jugular vein and cisterna magna to collect blood and CSF, respectively at various time points. The colostrum, plasma, and CSF were analyzed by ELISA, SDS-PAGE, two-dimensional PAGE, and Western blotting. The concentration of total protein, Lf, Tf, and IgG in plasma averaged 47mg, 204ng, 101μg and 15μg/ml before colostrum feeding and increased to the peak values of 64mg, 2413ng, 820μg, and 4608μg/ml 8h after feeding, respectively. Before colostral feeding CSF, total protein, Lf, Tf, and IgG averaged 0.44mg, 10.3ng, 0.31μg, and 0.11μg/ml, but peak values after feeding averaged 2.0mg, 173ng, 71μg and 72μg/ml after 10h, respectively. Immunologically, six EGF-positive protein bands were detected in colostrum as well as in three bands higher density in plasma and CSF after colostral feeding. This study revealed that the colostral macromolecules were not only absorbed into the systemic circulation, but also some of them including Lf, Tf, IgG, and EGF-like proteins were transported into the CSF in a time-dependent manner through blood-CSF or blood-brain barrier of the newborn calves.