A comparative study of milk serum proteins in camel (Camelus dromedarius) and bovine colostrum.

Introduction

In bovine whey, there are five major protein fractions with defined molecular weights, ic., im- munoglobulins (1gs), mainly immunoglobulin G (IgG), bovine serum albumin (BSA), «-lactalbumin (a-la), B-lactoglobulin (B-Ig) and proteose peptones (Whitney, 1977; Eigel et al., 1984). Serum proteins that were identified in camel milk include a-la, serum albumin, lactophorin A, lactoferrin, lac toperoxidase and Igs. Three other fractions include whey acidic protein (WAP), peptidoglycan recogni- tion protein (PGRP) and blood serum albumin (Beg et al., 1985, 1986, 1987; Conti et al., 1985; Farah, 1993; Kappeler, 1998). It appears that most of the whey proteins in camel milk resemble those of bovine whey proteins, except for the lack of B-lg (Ochirkhuyag et al., 1998). Nevertheless, proteins of molecular weight around 23 and 43 kDa were reported to be bands of bovine B-lg (Farah, 1986). Colostrum differs in composition from regular milk, especially in its high content of fat, protein, ash and whey proteins. The latter contain the immuno- globulins (Ig), which are needed to provide the newborn with immunity and are passed to the calf in the colostrum (Schmidt, 1971; Jenness, 1985). In the present work, camel colostrum was studied in comparison to bovine colostrum, to determine the composition of the serum protein fractions and their changes immediately postpartum, using size exclu-