Degree Type

Dissertation

Date of Award

1983

Degree Name

Doctor of Philosophy

Department

Animal Science

Abstract

Seventeen preruminant male calves were prepared surgically with lymphatico-venous shunts and/or re-entrant gallbladder to proximal duodenum shunts to evaluate the effects of the degree of saturation of dietary fat upon cholesterol transport in the intestinal lymph and bile and cholesterol transposition from blood capillaries to the intestinal lymph. Liquid diets were formulated to contain 12.5% dried skim milk (SM) or 10.5% SM to which was added 2% soybean oil (SBO), milk fat (MF), beef tallow (T) or a fat plus supplemental cholesterol. Calves received each diet for 3 days at 8% of body weight per day in two equal feedings. Following completion of each three day dietary treatment, total lymph collections were made for 15 min of each hour, 1 h prefeeding and 12 h postfeeding, to determine flow rate, total lipid and cholesterol transport. Total bile collections were made during the same time span to determine flow rate, cholesterol and bile acid transport. Transposition of cholesterol from blood capillaries to intestinal lymph was determined by injection of 100 (mu) Ci 4-('14)C-cholesterol into the blood of calves at feeding time. To avoid recirculation of 4-('14)C-cholesterol via the enterohepatic circulation, bile was diverted and replaced with bile from a donor calf fed an identical diet. For the SM, SBO, T and MF diets, respectively, cholesterol transported in the mesenteric lymph averaged 1.09, 1.92, 2.70, and 2.41 mg/(h x kg body weight); average lipid transport in the mesenteric lymph was 8.94, 32.58, 38.12 and 64.86 mg/(h x kg body weight); cholesterol transposed from capillaries was 44, 61, 48 and 36% of the cholesterol transported in the mesenteric lymph. Source of fat or addition of supplemental cholesterol had no effect on amount of cholesterol or bile acid transported in the bile; however, calves fed SM transported greater quantities of cholesterol in the bile than did calves fed fat or fat plus cholesterol. Our method allows for simultaneous determination of cholesterol absorption and excretion, as well as calculation of intestinal cholesterol synthesis.

DOI

https://doi.org/10.31274/rtd-180813-5046

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Lynn Dale Davis

Language

en

Proquest ID

AAI8316310

File Format

application/pdf

File Size

146 pages

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