Effect Of Dietary Fat Level Research Articles

Effect of Dietary Fat on X-Ray-Induced Mammary Cancer in Sprague-Dawley Rats<xref ref-type="fn" rid="FN2">2</xref><xref ref-type="fn" rid="FN3">3</xref>

We studied the effect of dietary fat levels on the induction of mammary cancer by 350 rads total-body X-radiation given to noninbred albino Sprague-Dawley rats at 50 days of age. Compared to rats on a low-fat (LF) diet (5% lard), rats on a high-fat (HF) diet (20% lard) from 30 days of age had more tumors, with a higher multiplicity of carcinomas per rat. LF-fed groups exhibited a longer median tumor latency period thatn did HF-fed groups. A similar trend toward more tumors with an earlier time of death was seen in rats given single iv doses of 50 mg 1-methyl-1-nitrosourea/kg and fed an HF diet as compared to an LF diet.

The Effect of Dietary Corn Oil and Cholesterol Level on the Neutral Steroid Composition in the Large Intestinal Contents of the Rat

The influence of dietary cholesterol and fat on the com position of neutral steroids within the large intestinal contents of rats was investigated. Concentrations and total amounts of cholesterol and its me tabolites, coprostanol and coprostanone, were determined in the cecum and colon, initially and after being fed experimental diets for 3, 6 and 9 months. Eight week old rats were fed one of four semipurified diets: 5% corn oil, no cholesterol; 5% corn oil, 1% cholesterol; 20% corn oil, no cholesterol; 20% corn oil, \% cholesterol. Rats were killed at 2, 5, 8 and 11 months of age corresponding to feeding experimental diets 0, 3, 6 and 9 months. The large intestinal total neutral steroid content slightly decreased with time or rat age, but fraction of cholesterol degradation did not change. A greater concentration of all three neutral steroids was found in the colon contents but a greater total amount in the cecal contents. Fraction of cholesterol degradation was the same in both locations. When cholesterol was fed, more neutral steroids were found in the large intestine. Fraction of cholesterol degradation decreased but a greater absolute amount of cholesterol metab olites was present. The effect of dietary fat levels was complicated by inter action with cholesterol feeding. Without cholesterol feeding a greater con centration of neutral steroids was present in the large intestine of rats fed the higher level of fat. With cholesterol feeding a greater amount of neutral steroid was found in the large intestine of rats fed the 5% fat diet. Fraction of cholesterol degradation was greatest when the 5% fat diet without sup plemental cholesterol was fed. Increasing dietary fat to 20% decreased fraction of cholesterol degradation and feeding cholesterol decreased it more. The fraction of cholesterol degradation value was the same regardless of dietary fat level when cholesterol was fed. J. Nutr. 209: 1730-1738, 1979.

Effect of Dietary Fat Level on Growth and Lipogenesis in the Colostrum Deprived Neonatal Pig

Thirty male neonatal pigs were obtained by cesarean section and randomly allotted from littermate groups to three diets containing 2%, 17%, and 32% fat on a dry matter basis. Butterfat was used to replace glucose in the isoenergetic liquid, semipurified diets. Each pig was placed in a sterile isolator and fed ad libitum five times daily. After 14 days, pigs were weighed, killed, and samples of liver and backfat were obtained. The carcass of each pig was ground and samples obtained for determination of total body fat and protein. An increase in the level of dietary fat resulted in a significant increase in 14 day weight gain and a tendency for improved feed efficiency. These results demonstrate not only that the neonatal pig can utilize semipurified liquid diets high in butterfat content, but also that energy from butterfat appears to be used as efficiently as energy from glucose from growth purposes. Increasing dietary fat level decreased the activity of fatty acid synthetase and citrate cleavage enzyme in adipose tissue and liver, and decreased the activity of malic enzyme in adipose tissue. The specific activities of these three enzymes were higher in adipose tissue than in liver.

Effects of dietary fat level and dimethylhydrazine on fecal acid and neutral sterol excretion and colon carcinogenesis in rats.

Effects of dietary fat level and dimethylhydrazine on fecal acid and neutral sterol excretion and colon carcinogenesis in rats.

The Effect of Dietary Fat Level on Heat Prostration of Broilers

Three trials were conducted to study the effect of dietary fat level on mortality that was due to heat prostration in 8-week-old male broilers. The four diets contained 1, 3, 7 and 10 percent added animal fat and were fed ad libitum for the 4- to 8-week experimental period. At 8 weeks of age, the dry-bulb temperature was increased from 21.1° C. with a dew point temperature of 10.0° C. to 40.6° C. over 6 hours, with a dewpoint temperature of 23.9° C. The temperature was held at 40.6° C. for 2 hours, then decreased to 26.7° C. over 30 minutes. Mortality that was due to heat prostration was recorded at 30-minute intervals during the stress test.The results obtained indicate that the dietary level of animal fat did not affect mortality due to heat prostration. This finding is significant since more concentrated rations are sometimes fed to commercial broilers during the summer in an attempt to improve growth and feed utilization.

Effects of Dietary Fat Level on Pantothenate Depletion and Liver Fatty Acid Composition in the Rat

Weanling male rats were fed a 6% or an 18% cottonseed oil diet, lacking pantothenate or supplemented with graded levels of pantothenate, to determine whether a high fat diet would accelerate the development of pantothenate deficiency or increase the pantothenate requirement for growth. The fatty acid composition of liver lipid fractions was also determined. Increasing the level of fat did not increase the pantothenate requirement for maximal growth or accelerate the development of the deficiency as indicated by body weight, adrenal weight, or onset and incidence of greying. Pantothenate deficiency with either the 6% fat or the 18% fat diet significantly lowered the relative proportions of phospholipid arachidonate and stearate. Liver CoA values in both the control and deficient groups fed the 18% fat diet were significantly lower than in the rats fed the 6% fat diet.

Metabolism of Glucose and Acetate in Obese Rats

To determine the mechanism leading to obesity when Osborne-Mendel rats are fed a high fat diet, the effect of dietary fat level on glucose and acetate metabolism was studied. Metabolism was followed at 3- or 6-week intervals by measurement of 14C in expired carbon dioxide after intraperitoneal administration of 2 µc of glucose-1-14C, glucose-6-14C, or sodium acetate-1-14C. Differences between the groups fed at the 2 levels of fat were observed, but showed no trends which might explain the obesity of rats fed the high fat diet, although at 15 and 21 weeks after weaning this group excreted less of the dose of acetate-1-14C than did rats fed the 5% fat diet. The percentage of dose of glucose-1-14C expired as CO2 decreased sharply between 1 and 6 weeks in both diet groups. This decrease was also noted after administration of glucose-6-14C to rats fed the 60% fat diet, and the decrease continued until 21 weeks. The percentage of dose expired after administration of sodium acetate-1-14C did not change with increasing age in either diet group. However, the rats fed the 60% fat diet excreted carbon dioxide of lower specific activity than those fed the 5% fat diet at 9, 15, and 21 weeks after weaning.

Effect of Dietary Fat Level on Apparent Nutrient Digestibility by Growing Swine

Effect of Dietary Fat Level on Apparent Nutrient Digestibility by Growing Swine

The Effect of Dietary Fat Level on the Rate of Mortality in Caged Layers

ALTHOUGH the advantages of fat supplementation of broiler rations have been amply demonstrated, the value of thus increasing the energy level of laying rations is questionable. It has been reported by Weiss and Fisher (1957) and Donaldson and Gordon (1960) that rations containing high levels of fat fed to laying birds may result in obesity and fatty livers leading to a high rate of mortality.The present paper summarizes the data on mortality obtained in an experiment in which birds were kept in cages and fed diets supplemented with different levels of fat from day-old to 3 years of age. EXPERIMENTALStarting, growing and laying rations were formulated according to Table 1. The rations were calculated to contain 20, 16.5 and 15 percent protein respectively. Each type of ration was adjusted to contain 2.5, 7.5 and 12.5 percent of fat. The two higher levels of fat were attained by the …

The serum protein and lipoprotein response to tuberculosis in chicks fed various levels of dietary fat.

In mammals, the serum proteins and constituent fractions, separated by electrophoresis, are significantly altered by a wide variety of physiologic and pathologic factors. Among these, the effects of experimental infection with 111 ycobacterium tuberculosis have been studied in the rabbit (1), the guinea pig (2), the mouse (3), and the rat (4). Although the serum proteins of birds have been the subject of several investigations by free (5-7) and zone (8) electrophoresis, these studies have dealt primarily with factors other than pathologic states. Reports are available concerning the effects of vitamin E deficiency (9) and of erythroblastosis (10) on the electrophoretic distribution of serum proteins in the chick. Since dietary fat level has been reported (11) to influence resistance to experimental infection with M. tuberculosis in mice, the present investigation was designed to study the serum protein response in the chick to infection with avian tubercle bacilli; and to assess the possible effects of dietary fat level on this response. Data regarding mortality and tissue reactions to infection are the subjects of other reports (12); those presented here concern the serum protein and lipoprotein responses to infection studied by paper electrophoresis.

The Effect of Dietary Fat Level on Thyroid Activity in the Growing Chick

ABSTRACT SINGH and Shaffner (1950) found that increasing the calorie content of the diet appeared to raise metabolic rate in the chick. Mellen, Hill and Dukes (1954) reported that the fasting oxygen consumption of male chickens reared on a diet containing 975 Calories per pound was higher than that of similar chicks fed a diet containing only 505 Calories per pound. In the above experiments the diets at the lower energy level were suboptimal in energy and consequently may be considered to represent a low plane of nutrition. There do not, however, appear to be data regarding the effect of high energy levels on the basal metabolic rate of chickens. There have been studies on rats in which the effects of different levels of fat were investigated. Panos and Finerty (1953 Panos and Finerty (1954) found a relative decrease in the weight of the thyroid glands in rats fed fat-deficient diets, and other investigators . . .

Fat Studies in Poultry: 6. Utilization of Fats of Different Melting Points

DUCKWORTH, Naftalin and Dalgarno (1950) found that the difference in digestibility between low and high melting point fats reported for other animals exists also for the chick. Carver et al. (1955) and Sunde (1956) reported that hydrogenated fat is poorly utilized by the chick. The following experiments were conducted to study the nutritive value for the growing chick of fats of different saturation. The effect of dietary fat level and of feeding surface active agents on the utilization of fat has been studied. Since there is little data available regarding the form in which fatty acids are excreted by the chick, the ratio of split to unsplit fat excreted has been determined. EXPERIMENTALExperiment 1. The composition of the rations used in the first experiment is shown in Table 1. The basal ration included 12 percent cerelose. In the rations in which fat was included, cerelose was replaced on a …

Fat Studies in Poultry: 5. The Effect of Dietary Fat Level on the Choline Requirement of the Chick

KUMMEROW, Weaver and Honstead (1949) found that the addition of high levels of fat to the diet increased the requirement of the chick for choline. Siedler and Schweigert (1953), on the other hand, observed no gain from choline supplementation of diets containing from 2 to 8 percent of added fat. Frazer (1946) and Tidwell (1950) reported that choline accelerated absorption of fat in the rat. The data in the literature indicate that choline requirement is not always raised by increasing the dietary fat level; nevertheless, there is often an effect in this direction. Because of the recognized interrelationship among choline, folacin, vitamin B12 and methionine, it seemed possible that contradictory evidence regarding the effect of dietary fat on choline requirement may be the result of differences in the composition of the experimental diets.Schaefer, Salmon, Strength and Copeland (1950) and Strength, Schaefer and Salmon (1951) demonstrated an interrelationship between the …

Effects of Diet on Blood Lipids In Man

Abstract 1. Lipids exist in the blood serum as emulsions ("chylomicrons") and as solutions of lipoprotein containing proteins, cholesterol, and other lipids. Interest in relation to atherosclerosis is centered on the cholesterol and the beta lipoproteins which contain most of the cholesterol. 2. The diet influences the blood lipids in man and animals but great quantitative differences between species makes it essential to study man himself to discover the effects of the diet on the blood lipids in man. 3. The amount of lipid in the chylomicron form in the serum is practically independent of the concentration of cholesterol and lipoproteins in the serum. The correlation between the concentrations of alpha and beta lipoproteins is very low. 4. Experiments on man show that dietary cholesterol per Se, even in large amount, has no important influence on the serum cholesterol concentration but that the latter is markedly affected by the total fat content of the diet. 5. Calorie intake per se has little influence on the blood lipids. Such effect as it has may be secondary to fat metabolism differences commonly associated with differences in calorie intakes. 6. Studies on population samples of healthy men show a marked direct relationship between the content or proportion of fat in the diet on the one hand and the concentration of total cholesterol and of beta lipoproteins in the serum on the other. The effect of the diet tends to be greater in middle-aged men than in younger men. 7. The average concentration of cholesterol in the serum of men in areas where the diets are very high in fats (of the order of 40 per cent of calories), is 25 to 50 per cent greater than the average in areas where the diets are low in fats (of the order of 20 per cent, or less, of calories). 8. A significant effect of dietary fat level on the serum cholesterol concentration is evident in man in a few weeks on a changed diet. The effect tends to increase very slowly with time thereafter and it is most pronounced when comparison is made between populations habitually subsisting on different diets. 9. It is not known how the dietary fat intake exerts its controlling influence on the blood lipids of man but the mechanisms must be complex.