Biomedical subjects

N L Jacobson

Publications and source records attributed to N L Jacobson.

At least 19 recordsLinked to original sources

PubMed1990

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.

Animals↗

PubMed1989

Effects of dietary beef and soy protein on tissue composition and low density lipoprotein uptake in young pigs.

To study effects of dietary protein source on plasma cholesterol homeostasis, six littermate pairs of 8-wk-old, castrated male pigs were assigned randomly to high fat diets containing either lean beef or soy protein isolate, with beef tallow as the major fat source in both diets. Diets were fed for 6 wk, with blood samples taken weekly and analyzed for lipid composition. At 6 wk, each pig was injected with [3H]cholesterol- and [14C]sucrose-labeled low density lipoproteins, and serial blood samples were taken. Pigs were then killed, and several tissues were sampled. Results show that dietary beef or soy protein, when fed with beef tallow as a fat source, has differential effects on rates of uptake of intact LDL by heart, M. sartorius muscle and subcutaneous adipose tissue, and on rates of uptake of LDL cholesterol by net free cholesterol exchange in subcutaneous and perirenal adipose tissues. Dietary protein source affected the composition of only two tissues analyzed. Pigs fed the beef-based diet had greater lipid concentrations in M. sartorius muscle, whereas pigs fed the soy protein-based diet had greater lipid concentrations in heart. Source of dietary protein did not influence in vivo kinetics of LDL cholesterol removal from blood plasma.

Animals↗

PubMed1987

Effect of animal and vegetable fats and proteins on distribution of cholesterol in plasma and organs of young growing pigs.

Young, growing pigs were fed for 8 wk diets containing either soy protein isolate or ground beef as the main protein source and soybean oil or beef tallow as the main fat source to examine effects of types of dietary protein and fat on cholesterol distribution between blood plasma, plasma lipoproteins and body organs. Type of dietary protein did not influence concentrations of a) cholesterol in plasma, b) low-density-lipoprotein (LDL) cholesterol, c) high-density-lipoprotein (HDL) cholesterol or d) cholesterol in several organs of pigs. Pigs fed tallow had greater concentrations of plasma cholesterol and LDL and HDL cholesterol than did pigs fed soybean oil. Ratios of HDL to LDL were not altered by dietary fat. Cholesterol concentrations were greater in heart, skeletal muscle and viscera of pigs fed soybean oil than in those fed tallow. Plasma cholesterol varied reciprocally with cholesterol in several tissues. Thus, dietary beef and soy protein isolate had similar effects on cholesterol concentrations in plasma, LDL, HDL and organs, whether pigs consumed soybean oil or beef tallow as a major fat source. Soybean oil, however, exerted a hypocholesterolemic effect, irrespective of major source of dietary protein.

Animals↗

PubMed1986

Plasma, tissue and fecal cholesterol of young pigs fed restricted or liberal amounts of beef, soy or conventional diets.

Cholesterol disposition (tissue deposition + fecal excretion) was determined in young pigs fed restricted (trial 1) or liberal (trial 2) amounts of beef-based, soy-based or conventional swine diets. Cholesterol content of diet is greater than average United States consumption per kilogram body weight but is very similar on a per-kilocalorie intake basis. Both beef and soy diets contained more cholesterol (0.09% by weight vs. 0%) and fat (40-50% of calories vs. 8-9%) than did conventional diets. Dried egg yolk was the source of cholesterol in the soy diets. Beef- and soy-fed pigs had greater plasma, HDL and LDL cholesterol concentrations than did conventionally fed pigs; beef-fed pigs had greater plasma, HDL and LDL cholesterol concentrations than did soy-fed pigs in trial 2 only. Final HDL-to-LDL cholesterol ratios did not differ. Neutral steroid and bile acid excretion was twofold greater in soy-fed than in conventionally or beef-fed pigs in trial 2 only. Differences in cholesterol concentrations were found in liver (soy, beef greater than conventional) and heart (soy greater than beef, conventional) in trial 1 and in liver (soy, beef greater than conventional), adipose tissue (soy greater than conventional greater than beef) and aorta and other viscera (conventional greater than soy, beef) in trial 2. In both trials, soy-fed pigs had greatest whole-body cholesterol concentrations. Thus, in both trials, disposition of cholesterol was similar in conventionally fed and beef-fed pigs, despite greater cholesterol intake in the latter, but was greater soy-fed pigs.

Adipose Tissue↗

PubMed1986

Vitamin D3 and D3 metabolites in young goats fed varying amounts of calcium and vitamin D3.

Twenty-four male goats, 2 to 4 wk of age, were allotted to four dietary treatments in a 2 X 2 factorial design and, for 20 wk, were fed a milk diet at 12.5% body weight. Treatments varied in amounts of supplemental calcium and vitamin D3. Daily allowances per kilogram body weight were: 9.4 IU vitamin D3 (basal), 9.4 IU vitamin D3 plus 406 mg calcium carbonate (basal plus Ca), 940 IU vitamin D3 (basal plus D3), and 940 IU vitamin D3 plus 406 mg calcium carbonate (basal plus Ca plus D3). At the end of wk 7, a corn supplement was added to all diets at 1% body weight daily. Addition of vitamin D3 to the diet resulted in a dramatic increase in plasma concentrations of vitamin D3. Goats in the basal plus D3 and basal plus Ca plus D3 groups had nearly 100 X greater concentrations of vitamin D3 than goats in the basal and basal plus Ca groups. When greater amounts of vitamin D3 were fed, dietary calcium interacted to decrease plasma vitamin D3 concentrations. Plasma concentrations of 25-hydroxyvitamin D3 were unaffected by additional dietary calcium but were increased by dietary vitamin D3, increasing sixfold to seven-fold in the basal plus D3 and basal plus Ca plus D3 groups. Supplemental calcium resulted in decreased plasma 1,25-dihydroxyvitamin D3. No signs of vitamin D toxicity were noted. The physiological responses reported implicate the goat as a potential animal model for vitamin D research in dairy cattle.

Animals↗

PubMed1986

Effects of dietary calcium, vitamin D3, and corn supplementation on growth performance and mineral metabolism in young goats fed whole milk diets.

Twenty-four male goats, approximately 2 to 4 wk of age, were allotted to four dietary treatments in a 2 X 2 factorial design and were fed a basal milk diet at 12.5% body weight for 20 wk. Vitamin D3 was added to the milk in two different amounts with and without supplemental CaCO3. At the end of wk 7, corn was added to all diets at 1% body weight. Over 20 wk, average daily gain was unaltered by addition of Ca or vitamin D3 to the diet. When corn was added to the diet, gains increased from 48 to 180 g/d. Plasma Ca concentrations were not affected by dietary treatment. Supplemental Ca decreased plasma Mg concentrations. Corn supplementation curtailed a depression in plasma Mg and seemed to prevent a whole milk-induced hypomagnesemia. Fecal excretion of all minerals measured was increased in goats fed supplemental Ca. Dietary Ca increased urinary Ca but decreased urinary Mg. Percentage of apparent absorption of Ca, Mg, and total ash was lower in Ca-supplemented goats, as was apparent retention of Ca and Mg. The physiological responses reported suggest the goat as a potential research model for mineral metabolism studies in other ruminants.

Animals↗

PubMed1985

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

In a 2 X 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.

Animals↗

PubMed1985

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 X 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.

Animals↗

PubMed1985

Dietary calcium and vitamin D: risk factors in the development of atherosclerosis in young goats.

Effects of supplemental dietary calcium and vitamin D on lipid distribution and aortic mineralization were examined in young goats. Twenty-four goats, 2-4 wk of age, were allotted one of four dietary treatments for a 20-wk period and fed a basal milk diet (Basal), a calcium-supplemented diet (Basal + Ca), a cholecalciferol-enriched diet (Basal + D3) or a diet with both calcium and cholecalciferol (Basal + Ca + D3). Goats in the Basal + Ca group had plasma cholesterol concentrations that were 16.6% of those of the Basal group. Percentage absorption and fecal excretion of total lipids were unaffected by dietary treatment. Generally, total lipid and cholesterol concentrations were unaltered in liver, other viscera and carcass tissues. Dietary cholecalciferol increased concentrations of cholesterol and total lipid in aortas, whereas dietary calcium decreased total lipids in aortas. Concentrations of calcium, magnesium and total ash were increased in aortas by dietary treatment, with a marked increase observed in the Basal + Ca + D3 group. Sudan IV and gross calcium staining in aortas revealed both lipid and mineral deposition that confirmed composition data. A high intake of vitamin D accompanied by excessive intake of calcium seems to accelerate the development of atherosclerosis. Supplemental calcium with normal amounts of vitamin D, however, is hypocholesterolemic and seems protective against the atherogenic process.

Animals↗

PubMed1985

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 X kg body weight), and cholesterol transport averaged 1.09, 1.92, 2.41 and 2.70 mg/(h X kg body weight). Lipid and cholesterol transport in lymph was less (P less than 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.

Animals↗

PubMed1985

Cholesterol transport in mesenteric lymph of the preruminant calf: contribution of cholesterol transposition from blood to lymph.

Eight preruminant male calves were prepared surgically with lymphatico-venous shunts and re-entrant gallbladder to proximal duodenum shunts. 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) or beef tallow (T). Two calves were assigned to each dietary treatment. Transposition of cholesterol from blood capillaries to intestinal lymph was determined by injection of 100 microCi [4-14C]-cholesterol into the blood of calves at feeding time. To avoid recirculation of [4-14C]-cholesterol via the enterohepatic circulation, bile was diverted and replaced with bile from a donor calf fed an identical diet. For the SM, SBO, MF and T diets, respectively, cholesterol transposed from capillaries was 44, 61, 36 and 48% of the cholesterol transported in the mesenteric lymph. When cholesterol synthesis in response to test diets was calculated, we found that intestinal cholesterol synthesis is less when calves are fed SM or SBO than when fed T or MF.

Absorption↗

PubMed1985

Effects of beef, soy and conventional diets on body composition and plasma lipids of young pigs fed restricted or liberal amounts of diet.

Effects were determined of restricted and liberal feeding of beef-based, soy-based and conventional diets on growth rate, nutrient absorption, body composition and plasma lipid and urea concentrations of young pigs. Beef and soy diets contained more fat (40-50% of calories vs. 8-9%) and cholesterol (0.09 vs. 0%) than did conventional diets; calorie and protein intakes were equal across diets. Beef-fed pigs had greater average daily gain and absorption of fat and gross energy than did conventionally fed pigs; soy-fed pigs had intermediate growth rates but the greatest absorption of fat and gross energy. With restricted intakes, percentage of body fat was greater in soy-fed pigs than in pigs fed a conventional diet or beef and with liberal feeding, greater in soy- and beef-fed pigs than in pigs provided with a conventional diet. Plasma free fatty acid, triglyceride and cholesterol concentrations were greater in soy- and beef-fed pigs than in conventionally fed pigs. These results indicate that absorption and subsequent partitioning of nutrients toward body fat are influenced by composition as well as the amount of diet consumed. Our results also demonstrate that the pig can successfully be fed diets resembling human diets (i.e., high fat) and because of its physiological similarities to humans our understanding of nutrition and lipid metabolism of humans may be advanced.

Absorption↗

PubMed1984

Effects of dietary calcium and fat on cholesterol in tissues and feces of young goats.

To examine the effects of amount of calcium and type of fat in the diet on distribution of cholesterol in plasma, several tissues and feces, 4-week-old goats (6 females and 18 males) were fed isocaloric diets consisting of goat milk supplemented with cholesterol and 1) soybean oil, 2) tallow, 3) soybean oil and CaCO3 or 4) tallow and CaCO3 for 20 weeks. Plasma cholesterol increased initially in all animals; plasma and lipoprotein cholesterol concentrations, however, were not affected by dietary fat or calcium. Goats fed CaCO3 excreted more calcium and ash in their feces and had greater cholesterol and fat concentrations in their livers. Neutral steroid, but not bile acid, excretion was greater in soybean oil-fed goats than in goats fed tallow. Soybean oil-fed goats had greater cholesterol concentrations in the viscera (minus liver) and tended to have greater cholesterol concentrations in the carcass and whole body. Aortas of soybean oil-fed goats exhibited greater fat deposition. In summary, dietary fat, but not calcium, significantly altered cholesterol disposition in young goats by affecting cholesterol deposition in tissues and excretion in feces, without a concomitant change in plasma cholesterol.

Absorption↗

PubMed1983

Effects of dietary fat on amounts of cholesterol transported by mesenteric lymph in calves fed milk.

Five nonruminating male calves were prepared surgically with shunts from mesenteric lymph duct to posterior vena cava and sequentially were fed diets of reconstituted skim milk and skim milk plus supplemental cholesterol plus soybean oil, beef tallow, or milk fat. Calves received skim milk for 2 days, followed by the other diets for 4 days each in a predetermined order. On the 2nd and 4th day each diet was fed, lymph was collected hourly for 8 h, starting 1 h before the morning feeding. Cholesterol transported in lymph increased markedly in the hour after feeding and then declined rapidly but to quantities still greater than pre-feeding. Average cholesterol in lymph was 1.7, 2.8, 3.7, and 4.2 mg/(h X kg body weight) for the skim milk, soybean oil, tallow, and milk fat diets. No difference was significant between 2nd and 4th day totals for each diet. Because cholesterol rate of flow quickly responded to new diets and stabilized within 2 days, this technique permitted evaluation of effects of dissimilar dietary fats upon amounts of cholesterol and triglyceride transported by mesenteric lymph.

Animals↗

PubMed1980

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.

Adipose Tissue↗

PubMed1980

Effect of type of dietary fat on plasma and tissue cholesterol of calves.

Two experiments were conducted to examine the effects of liquid milk diets with varying proportions of beef tallow (T) and soybean oil (SBO), with and without dry feed, on cholesterol concentrations in blood and other tissues of nonruminating calves. In experiment 1, 4--10-day-old male Holstein calves were fed for 15 weeks a reconstituted milk containing 9% ot 12% dried skim milk and 2% SBO, 2% T or 3.5% T. Plasma cholesterol and cholesterol content (% of dry matter) of muscle, liver, omental fat and perirenal fat were greater (P less than 0.05) for calves fed the 2% SBO diet. No significant differences were observed in cholesterol concentrations of the aorta, coronary arteries, brain or spleen. Experiment 2 used 4--10-day-old male Holstein calves to study the effect of 2% fat diets formulated in ratios of SBO 2/3:T 1/3 and SBO 1/3:T 2/3 and to observe the effect of dry feed added to 2% T and 2% SBO diets. Tallow and SBO fed in weighted combinations affected plasma and tissue cholesterol concentrations like the predominant fat fed alone. The greatest increases in plasma and tissue cholesterol concentrations occurred in calves fed SBO diets. Dry feed supplementation decreased body cholesterol concentrations of calves fed either fat. Body weight gain of calves fed SBO was less in both experiments.

Adipose Tissue↗

PubMed1978

Effect of various triglycerides on blood and tissue cholesterol of calves.

Blood and tissue cholesterol responses were measured in six groups of four calves each fed for 24 weeks reconstituted nonfat dry fat milk in which 30% of calories was derived from one of the following: soybean oil (SBO), beef tallow (T), medium-chain triglycerides (MCT), and 1:1 soybean-oil tallow (SBO/T) combination. Two groups of four calves each also were fed SBO-milk plus dry feed and T-milk plus dry feed, respectively. Blood cholesterol concentration was significantly greater in SBO-fed calves than in T-fed calves. Calves fed MCT-milk had significantly lower blood cholesterol than calves fed T- or SBO-milk. Significant differences in cholesterol concentration were noted for the liver, perianal fat, and for omental fat.

Adipose Tissue↗

PubMed1977

Type and amount of dietary fat affect relative concentration of cholesterol in blood and other tissues of calves.

Sixteen male Holstein calves consumed by nipple a reconstituted milk containing nonfat dry milk and either soybean oil or tallow for 24 weeks. Calves fed milk in this manner (with no dry feed) are functionally nonruminants because the milk bypasses the ruminoreticulum. The fat in these diets contributed about 30% of total dietary calories. The calves consuming soybean oil milk had significantly greater amounts of cholesterol in blood plasma and adipose tissue than did the calves consuming tallow milk.

Animals↗