Cholesterol concentration and lipoprotein pattern in the serum of veal calves fed milk replacers with various levels of cholesterol.

Veal calves, aged about 1 week, were fed for 146 days milk replacement diets supplemented with various levels of cholesterol. Four groups consisting of 11 or 12 animals received diets to which 0, 0.19, 0.56 or 0.93% (on the basis of air-dry matter) cholesterol was added at the expense of fat. Cholesterol feeding significantly increased the level of serum cholesterol. This increase was either linear or S-shaped over the entire range of cholesterol feeding, depending on the time during which the calves were fed the diets. In the calves fed cholesterol, the ratio of free to esterified cholesterol in the serum was significantly increased. The ingestion of cholesterol markedly increased the cholesterol content of the VLDL, IDL and LDL fractions in the serum. When compared to the 0.56%-cholesterol diet, the inclusion of 0.93% cholesterol in the diet did not further increase the cholesterol concentrations in the IDL and LDL fractions. Upon density gradient ultracentrifugation of serum prestained for lipid with Sudan Black, it was observed that dietary cholesterol caused the HDL1 particles (1.063 less than d less than 1.092) to to shift towards a lower density range. Cholesterol feeding effected an increase in the level of serum triglycerides, the increase being already maximal with 0.19% cholesterol in the diet. Dietary cholesterol induced elevated concentrations of serum phospholipids, the elevation being proportional to the amount of cholesterol in the diet.