PLASMA-LIPOPROTEINS IN PRERUMINANT CALVES FED DIETS CONTAINING TALLOWOR SOYBEAN OIL WITH AND WITHOUT CHOLESTEROL

Five-week-old, preruminant male calves were fed milk replacer containi ng tallow or soybean oil (230 g/kg of dietary DM) with and without cho lesterol (10 g/kg of dietary DM) for 17 d in order to study changes in plasma lipids and lipoproteins. Dietary soybean oil induced higher ch olesterolemia than did tallow because of a specific increase in plasma concentrations of large high density lipoproteins of type 1 (1.026 to 1.060 g/ml), but plasma concentrations of low and very low density li poproteins were not modified. Addition of cholesterol to diets contain ing either tallow or soybean oil markedly increased plasma concentrati ons of intermediate and low density lipoproteins, suggesting partial i nhibition of the low density lipoprotein receptor activity in tissue. By contrast, dietary cholesterol added to the diet containing soybean oil led to an increase in plasma concentrations of type 1 high density lipoproteins and of light high density (1.060 to 1.091 g/ml) lipoprot eins. These data indicated that the soybean oil diet, which was rich i n linoleic acid, did not reduce the effects of dietary cholesterol on the metabolism of low and high density lipoproteins in the preruminant calf.