N.L. Jacobson

MODE OF CHOLESTEROL INGESTION AND ATHEROSCLEROSIS IN THE YOUNG BOVINE

SUMMARY Varying degrees of atherosclerosis were noted in aortas and coronary arteries of calves fed high-cholesterol diets for 25 weeks. Intimal lipid was more extensive in aortas and circumflex coronary arteries from nonruminating calves fed cholesterol in a highfat, liquid (milk) diet than in arteries from ruminating calves fed cholesterol in low-fat (grain) diet. Cholesterol deposition was coextensive with the intimal lipid. Plasma and liver cholesterol levels were higher in calves fed cholesterol in the high-fat, liquid diet but variation in animal response was substantial. Digestibility data indicated that the low amount of fat in the diet of the calves receiving primarily grain depressed absorption of cholesterol. Moreover, exposure of cholesterol to digesta of the ruminoreticulum, as would occur in grain feeding, was shown by in vitro and in vivo observations to enhance degradation of cholesterol.

The effects of supplemental dietary cholesterol and exercise on blood cholesterol and atherosclerosis in the goat.

The objective of this experiment was to determine the effects of supplemental dietary cholesterol and treadmill exercise on blood plasma cholesterol and development of atherosclerosis in young goats. Eighteen two-week-old goats, assigned to four groups for 22 weeks, were fed 100 g whole milk and, after 14 weeks, 50 g corn and cob meal daily/kg body weight. The four groups received, respectively, 250, 175, 100 and 25 mg cholesterol/kg body weight daily in the milk. From week 10 to week 22 of the experiment half of the goats in each group were exercised on a motorized treadmill at a rate of 6.4 km/h for 15 min daily, five days per week. Addition of cholesterol to the diet increased the mean plasma cholesterol in each of the four groups, but between-group comparisons were statistically significant for only the 250-mg group versus the 25-mg group. Exercise had no effect on plasma cholesterol. Analysis of serial blood samples of 16 of the goats during one day of the experiment indicated no significant diurnal variations. Six males, three exercised and three nonexercised, were sacrificed; all had extensive aortic sudanophilia. Histological preparations from sudanophilic areas of all aortas showed areas of intimal thickening composed of foam cells. These same areas stained strongly for lipid with Oil Red 0. No histological evidence of calcium deposition or fibrous plaques was found.

Effect of soy versus beef diets on blood and tissue cholesterol and body composition of growing swine

Abstract Growing pigs were fed diets, similar in protein and fat content, based on soy protein isolate and soybean oil (soy) or ground beef containing 21% fat (beef). Ground corn, vitamins and minerals completed the diets. Egg yolk was added to balance the intake of cholesterol. No significant differences were seen in total plasma cholesterol or liver cholesterol concentrations. Soy-fed pigs had significantly greater concentrations of cholesterol in the viscera excluding the liver (p Our data show that the soy diet, as compared to the beef diet, increased the proportion of fat in the carcass and increased tissue cholesterol deposition.

Blood plasma lipoprotein and tissue cholesterol of calves fed soybean oil, corn oil, vegetable shortening or tallow☆

The objective of this study was to determine cholesterol content of blood plasma, blood plasma lipoproteins and tissues of calves fed fats of differing compositions. Groups of 2-week-old calves were fed one of the following fats in a reconstituted milk formula: soybean oil, corn oil, vegetable shortening or tallow. The diets contained no dry feed or added cholesterol. Blood plasma cholesterol concentrations increased with time for all groups. After 15 weeks, cholesterol concentrations were greater in the blood, liver and fat of the groups fed soybean oil and corn oil than in those of the groups fed vegetable shortening and tallow. Low density lipoprotein was identified as the carrier of the increased amounts of cholesterol noted in the blood.

Cholesterol transport and uptake in miniature swine fed vegetable and animal fats and proteis. 1. Plasma lipoproteins and LDL clearance

In a 2×2 factorial arrangement, miniature pigs were fed four diets containing vegetable protein/fat (soybean) and animal protein (egg white)/fat (beef tallow) to demonstrate the effects of protein and fat source on total plasma cholesterol, lipoprotein distribution, low density lipoprotein (LDL) composition, and plasma clearance of LDL-cholesterol and protein. Beef tallow consumption resulted in greater plasma cholesterol concentration, decreased LDL-cholesterol concentration, and a lower LDL-cholesterol to LDL-protein ratio than did consumption of soybean oil. High density lipoprotein (HDL)-cholesterol concentration was increased by beef tallow consumption. Cholesterol percentage by weight in LDL was significantly greater in pigs consuming soybean oil than those consuming beef tallow. Percentages by weight of protein, triglyceride and phospholipid in LDL were not significantly different in any group. Dietary protein source had no significant effect on total plasma cholesterol concentration, lipoprotein concentration or LDL composition. Egg white consumption decreased fractional catabolic rate and irreversible loss of LDL-cholesterol and LDL-protein when compared with consumption of soy protein. Dietary fat source had no consistent effect on LDL clearance from plasma. Dietary fat and protein seemed to influence lipoprotein metabolism by different mechanisms. Fat source altered lipoprotein concentration and LDL composition, whereas protein source affected the removal rate of LDL from plasma.

Effect of type and amount of dietary fat on concentration of cholesterol in blood plasma and tissues of rabbits

Abstract Rabbits were fed skim milk-based diets containing by weight either 14% soybean oil, 28% soybean oil, 14% tallow or 28% tallow. A control group was fed a commerical stock diet. Plasma cholesterol concentration was monitored for 10 weeks, after which cholesterol concentrations of liver, skeletal muscle, adipose tissue, brain, heart, aorta, kidney, skin and intestinal mucosa were determined. Feeding soybean oil diets (relatively high content of polyunsaturated fat by acids) resulted in lesser concentrations of cholesterol in blood plasma than did feeding tallow diets (greater content of saturated fatty acids). Conversely, cholesterol contents were greater in skeletal muscle, adipose tissue, heart, aorta, kidney, skin and intestinal mucosa of rabbits fed soybean oil diets. Cholesterol contents of liver and brain were unaffected by type of dietary fat. Our results demonstrate that the degree of saturation of fat in a milk-based diet of rabbits will influence the partitioning of cholesterol between the blood and several other tissues and organs.

The domestic goat: A useful model to determine effects of diet and exercise on cholesterol accumulation in the body☆

1. Young goats were used to study factors contributing to atherosclerosis. 2. Cholesterol in egg yolk affected plasma cholesterol concentration more than did a similar amount of crystalline cholesterol in the diet. 3. Goats fed high fat diets developed fatty lesions in their aortas. 4. Cholesterol concentration in low-density lipoprotein was greatest in goats fed restricted-calorie diets without exercise, but least in goats fed liberally and exercised. 5. Cholesterol concentration in liver and fat deposition in aorta were greatest in the restricted-calorie, no exercise regime.

Cholesterol transport and uptake in miniature swine fed vegetable and animal fats and proteins. 2. LDL uptake and cholesterol distribution in tissues

In a 2×2 factorial arrangement, miniature pigs were fed four diets containing vegetable protein/fat (soybean) and animal protein (egg white)/fat (beef tallow) to demonstrate the effects of protein and fat source on tissue cholesterol concentrations, uptake of intact low density lipoproteins (LDL) and free cholesterol exchange from LDL to tissues. Soybean oil feeding, compared with beef tallow feeding, resulted in greater concentrations of cholesterol in aorta, heart, and large and small intestines. Similar trends were seen in liver, adipose tissue and skeletal muscle. Dietary protein source had little or no effect on tissue cholesterol concentrations. Uptake of intact LDL, as measured by using [14C]sucrose-LDL, tended to be greater in pigs fed soybean oil or soy protein. Net exchange of free cholesterol from LDL, as measured with [3H]cholesterol, tended to be greater when vegetable products were fed. Relative contributions of whole tissues to total uptake by either mechanism were not influenced by diet. Mechanisms in addition to uptake of cholesterol from LDL seem to be involved in the greater accumulation of tissue cholesterol resulting from polyunsaturated fat feeding.

Effects of sources of dietary fat and protein on tissue cholesterol

Abstract Dietary variables were soy oil, beef tallow, soy protein, and casein. Dietary combinations were soy oil-soy protein, soy-oil casein, beef tallow-soy protein, and beef tallow-casein, and 96 rats were allotted randomly to the four isocaloric diets. [Crystalline cholesterol was added to standardize each diet at 0.2%.] Two randomly selected rats from each dietary group were killed at 0, 7, 9, 11, 13, 15, 18, 22, 30, 36, 42, and 48 days on experiment to determine the effects of sources (plant versus animal) of dietary fat and protein on tissue cholesterol concentrations and on cholesterogenesis in liver and small intestine. Feeding soy oil, a polyunsaturated fat, resulted in lower blood cholesterol concentrations, higher liver cholesterol concentrations, and lower intestinal cholesterogenesis than did feeding beef tallow, a saturated fat. Feeding soy protein, a plant protein, resulted in lower blood and liver cholesterol concentrations and less intestinal cholesterogenesis than did feeding casein, an animal protein. Hepatic cholesterogenesis and intestinal tissue cholesterol levels were not affected significantly by diet. Eight rats killed at day 0 had, on the average, lesser plasma cholesterol concentrations and greater rates of intestinal cholesterogenesis than rats fed experimental diets. Our results demonstrate that the hypocholesterolemic action of soy oil and soy protein fed to rats may be related to decreased intestinal cholesterogenesis. In addition, soy oil, a polyunsaturated fat caused a redistribution of cholesterol from plasma to liver.