Plasma lipoproteins in preruminant calves fed diets containing tallow or soybean oil with and without cholesterol.

Five-week-old, preruminant male calves were fed milk replacer containing tallow or soybean oil (230 g/ kg of dietary DM) with and without cholesterol (10 g/ kg of dietary DM) for 17 d in order to study changes in plasma lipids and lipoproteins. Dietary soybean oil induced higher cholesterolemia 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 lipoproteins were not modified. Addition of cholesterol to diets containing either tallow or soybean oil markedly increased plasma concentrations of intermediate and low density lipoproteins, suggesting partial inhibition 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) lipoproteins. These data indicated that the soybean oil diet, which was rich in linoleic acid, did not reduce the effects of dietary cholesterol on the metabolism of low and high density lipoproteins in the preruminant calf.