Quantitation of Fat and Cholesterol Transport in the Mesenteric Lymph and Bile of the Preruminant Calf

Nine preruminant male calves were prepared surgically with lymphatico-venous shunts and/or re-entrant gallbladder to proximal duodenum shunts to evaluate the effects of degree of saturation of dietary fat on cholesterol transport in intestinal lymph and bile. Liquid diets were formulated to contain 12.5% dried skim milk (SM) or 10.5% SM to which 2% soybean oil (SBO), milk fat (MF), beef tallow (T) or one of these fats plus supplemental cholesterol was added. After 3-d dietary treatments, total lymph collections were made to determine flow rate, total lipid and cholesterol transport. Total bile collections were made to determine flow rate and cholesterol and bile acid transport. For SM, SBO, MF and T diets, respectively, average lipid transport in mesenteric lymph was 8.94, 32.58, 64.86 and 38.12 mg/(h · kg body weight), and cholesterol transport averaged 1.09, 1.92, 2.41 and 2.70 mg/(h · kg body weight). Lipid and cholesterol transport in lymph was less (P < 0.05) in SM-fed calves than in fat-fed calves. Source of fat or supplemental cholesterol had no statistically significant effect on amount of cholesterol or bile acid transported in bile; however, calves fed SM transported greater quantities of cholesterol in bile than did calves fed fat or fat plus cholesterol.