ORO-ILEAL DIGESTIBILITY OF HOMOARGININE-LABELED BETA-LACTOGLOBULIN AND CASEIN IN ADULT MINIATURE PIGS

beta-Lactoglobuiin (beta-Lg) binds retinol and may function as a physi ological retinoid carrier-protein. Previous in vitro studies and one i n vivo study suggest a structural and conformational stability of beta -Lg in comparison to casein, reflected by a different digestive pace a nd a reduced prececal digestibility. Eight adult male Gottingen miniat ure pigs were fitted with a permanent T-cannula at the ileum and were then fed meals containing homoarginine-labelled proteins. Absorption o f beta-Lg and casein was estimated based on the disappearance of homoa rginine. Absorption was 97.7 +/- 0.9% for beta-Lg and 97.9 +/- 0.3 % f or casein. If there is a higher proteolytic resistance to beta-Lg then to casein, this does not persist throughout the whole small intestine . If beta-Lg can function as a physiological retinol carrier protein, this would be limited to the stomach and the upper small intestine.