Cent Fat Research Articles

The agricultural potential of selected C4 plants in arid environments

Due to the increasing amount of dry lands in the world, C 4 plants which are highly efficient in water use need to be investigated as potential crop species. This study examined the arid-land agricultural potential of several specific C 4 species: Amaranthus hypochondriacus, Amaranthus retroflexus, and Portulaca oleracea. Germination responses of each species to both temperature and moisture were determined in growth chambers and contrasted with the response of two C 3 species, Beta vulgaris var. cicla and Chenopodium album. The growth response of each species to temperature, water availability, and soil salinity was investigated in a series of greenhouse experiments in Tucson, Arizona. The nutritional qualities of both seeds and vegetative matter (per cent moisture, fat, protein, fiber, ash, and amino acid composition) were determined for the experimental species. The C 4 species had higher germination percentages over the entire range of temperatures studied. Differences in photosynthetic pathway had no effect on moisture requirements for germination. Dry weight yields increased linearly with soil moisture for both the C 4 and the C 3 species. However, the water-use efficiencies of the C 4 species were higher at all watering levels investigated when compared with the C 3 species. The photosynthetic pathway of each species had no apparent effect on its productivity in relation to soil salinity. The nutritional values of the C 4 species were generally found to be sufficient but with no outstanding qualities except for consistently high lysine contents. No advantage was found for C 4 plants grown in saline soil. C 4 plants demonstrated a significant potential for arid agriculture and warrant further study.

Validity of the Mellits and Cheek method for body-fat estimation in relation to menstrual cycle status in athletes and non-athletes below 22 per cent fat.

The present experiment tested the hypothesis that 22% body fat based on the Mellits and Cheek (1970) regression equation is a minimum or 'trigger' level of fatness required to maintain regularity of menstrual cycles. The validity of the regression equation was cross-validated against densitometric estimates of body fat in 30 athletes (track, gymnastic, crew) and 30 non-athletes who were below 22% fat. For the total sample, the validity correlation was r = 0.47 between body fat (density) and body fat (regression equation); it was r = 0.75 for athletes and r = 0.47 for non-athletes. For all subjects, 60% had regular menses, 27% were oligomenorrheic and 13% were amenorrheic. The lowest body fat (density) was 12.8% for an athlete with a regular cycle and 12.2% for an oligomenorrheic athlete. The results show that: the Mellits and Cheek (1970) height-weight based regression equation to determine fatness is not valid for women below 22% fat, and 13% body fat (not 22%), should be considered an upper-bound estimate of a minimum level of fatness associated with normal ovulatory cycles.

The normal parathyroid revisited: Percentage of stromal fat

The pathologist must frequently decide, on the basis of a small biopsy specimen, whether a parathyroid gland is normal or abnormal. Most references state that the normal parathyroid contains approximately 50 per cent fat and that a reduction in this fat content is characteristic of hyperplasia. The parathyroid glands of 100 consecutively autopsied patients were evaluated, and the observations were correlated with clinical and laboratory findings. In 90 patients with no clinical, laboratory, or pathologic evidence of parathyroid hyperfunction, we found an average parathyroid fat content of 17 per cent ("percentage fat"). Only one patient had more than 50 per cent fat, and almost one third had less than 10 per cen fat. There was no correlation between percentage fat and age, serum calcium level, or gland weight. The findings of four previous quantitative studies were virtually identical with ours. The normal parathyroid gland contains much less fat than is commonly believed, and the range of values in normal persons is large. Determination of stromal fat has limited usefulness in the evaluation of the functional state of the parathyroid gland.

Body composition of light and heavy rats in a high or low fat diet group

The authors studied the body composition of light and heavy male Wistar rats (approximately 11 and 21 weeks of age) from two diet groups fed a high-fat (HFD, 50 per cent (w/w) fat) and a low-fat diet (LFD, 3 per cent (w/w) fat), respectively. In both age-groups the heavy HFD rats showed a considerably higher fat proportion (as compared with light LFD rats) associated with a correspondingly reduced body water content and an approximately identical body protein concentration. On comparing light and heavy rats (11 and 21 weeks of age) from the same diet group as to their body composition, the authors found greater differences only in the 21-week-old HFD animals; as against light animals, the heavy animals exhibited a highly significant increase in body fat content and a highly significant decrease in body water content. A comparison of LFD and HFD animals of approximately the same weight revealed an increase of the relative body fat content and a decrease of the percentage of body water content in light 11-week-old and also in 21-week-old HFD animals as against heavy LFD animals.

In-vitro and In-vivo Responsiveness of Muscle and Adipose Tissue to Insulin in Rats Rendered Obese by a High-fat Diet

The influence of insulin on [6-14C] glucose metabolism was assessed in vitro and in vivo in epididymal adipose tissue and diaphragm of rats fed either a low-fat (9 per cent fat cal.) or a high-fat diet (72 per cent fat cal.) In vitro, diaphragm of fat-fed rats showed a lower glucose uptake than that of rats fed the low-fat diet, but had identical glycogen labeling and lactic acid production and a strongly reduced 14CO2 production. Responsiveness of these pathways to insulin was unaltered by the fat content of the diet. The adipose tissue of fat-fed rats versus that of rats fed the low-fat diet showed: a higher lactic acid production and more efficient glycerogenesis and glycogenesis, all of these pathways being responsive to insulin; a lower glucose uptake and a strongly depressed fatty acid labeling, these two pathways being unresponsive to insulin. In-vivo labeling of glycogen in diaphragm in both basal and insulin-stimulated conditions was identical in the two groups of rats. In adipose tissue the amount of 14C sequestered in the ghyceride-glycerol moiety was the same in the two groups in basal and insulin-stimulated conditions, whereas the labeling of the fatty acid moiety and its increment with insulin were reduced by more than 99 per cent by the high-fat diet. These results show that alterations in fat content of the diet lead to differences in response to insulin that are pathway- and organ-specific.

The preservation of a Nandi Setaria silage and its feeding value for dairy cows

The process of vacuum ensilage of Setaria Sphacelata (cv. Nandi) (33 per cent DM ; 7 per cent soluble carbohydrates; 1.36 per cent M) was studied, and the resultant silage was evaluated chemically, in milk production trials with dairy cows and in digestion trials with dry cows. The silage was well preserved in a chemical sense (pH 4.5; lactic acid 1.7 per cent, volatile acids 1.2 per cent DM ; volatile bases 9.8 per cent total N) but, because of the structural rigidity of the harvested grass, air could not be completely excluded even from the polythene-covered vacuum stack. The temperature reached 43�C in the first week of storage and considerable surface wastage occurred. The silage (DM digestibility 42 per cent, voluntary DM intake 81 g/kg0.75) was of poorer quality than the grass harvested (DM digestibility 54 per cent, voluntary DM intake 84 g/kg0.75) and, even by feeding concentrates, only a low level of milk production could be sustained in (mainly Jersey) cows in the 5th-9th months of lactation. In silage-fed cows given a protein supplement (cottonseed meal) milk production was lower (3.8 kg day-1) but fat content higher (5.4 per cent) than in those given an energy supplement (sorghum grain) or energy plus protein (4.7 kg day-1 and 4.9 per cent fat). When fed lucerne hay and given the same energy plus protein supplement, cows gave significantly more milk (5.7 kg day-1 and 4.6 per cent fat). The poor nutritive value of the silage is attributed to the nature and composition of the material ensiled rather than to any defect in the ensilage process itself, and may be a feature of most silage made from tropical grasses.

Substrate Interaction in Intravenous Feeding Comparative Effects of Carbohydrate and Fat on Amino Acid Utilization in Fasting Man

Data are presented on the metabolic and endocrine effects of intravenous infusions in normal fasting man observed under highly controlled conditions over a period of six to eight days duration. There are comparative data on a variety of intravenous feeding programs. The data on total starvation are based on studies from the literature, some of which were carried out in this laboratory. The data on low dose glucose, high dose glucose, glycerol, fat emulsion, and amino acids, each given separately, demonstrate changes seen with simple infusion of a single substrate in fasting. These data are now compared with the utilization of amino acid infusions when accompanied by low dose glucose, high dose glucose, glycerol, and fat emulsion. In all, nine experimental intravenous feeding programs are presented, based on data from 35 subjects observed over a total of 370 subject-days. The findings show a strong interaction between glucose or lipid and protein metabolism. In fasting, glucose had protein sparing effect, most evident when given at high dose. Glycerol, in an amount equal to that contained in 2000 ml of ten per cent fat emulsion, had a mild protein sparing effect. Fat emulsion was no more effective. When amino acids were given alone, normal fasting human subjects were always in negative nitrogen balance with the daily nitrogen loss half that seen in starvation alone. Although amino acids given alone have a protein sparing effect, this is accomplished only at the expense of a high nitrogen excretion including an amount equivalent to the entire infusion plus an additional loss from the body's native proteins. The provision of energy yielding non-protein substrates with the amino acids markedly improved nitrogen economy in the following order: glycerol, low dose glucose, fat emulsion and high dose glucose. When caloric provision with glucose approached the isocaloric level for normal diet, the utilization of amino acids was maximized. When given with amino acids, fat emulsion was more effective than the available glycerol alone. THE ACCOMPANYING ENDOCRINE AND BIOCHEMICAL CHANGES SUGGEST THAT THE MILIEU FOR IDEAL UTILIZATION OF INFUSED AMINO ACIDS IS VARIABLE: ketones at low range (carbohydrate) or moderately elevated (fat emulsion); insulin elevated (carbohydrate) or unchanged (fat emulsion). The utilization of the infused amino acids was markedly improved in both endocrine settings, suggesting that it is the provision of energy as substrate as well as the endocrine setting that determines amino acid utilization. There were other changes in plasma intermediates, particularly fatty acids, glucose and urea, all consistent with the concept that when amino acids are given without other substrates, the amino acids must be maximally utilized for gluconeogenesis. When other substrates are provided (particularly glucose at high dose) then this mandate no longer exists and protein synthesis from the amino acids is favored. Several of the plasma amino acid concentrations responded to glucose when added to amino acid infusion. Amino acids alone produced increases in concentration of all the amino acids found in the infusion with the exception of alanine, arginine, and threonine. Many of these increases were abated by the addition of glucose to the amino acid infusion, suggesting an increased utilization rate. Glycerol and fat emulsion, while modulating increases in the plasma amino acid concentration, did so to a lesser extent than did glucose. This lowering of amino acid concentration was unaccompanied by an increase in urinary excretion. The assumption is therefore made that the provision of the added glucose favors the incorporation of amino acid into protein. There is no evidence from these data to suggest that a rising concentration of ketones in the blood favors amino acid utilization or protein synthesis.

In vitro study of deiodination of L-diiodotyrosine and L-thyroxine in liver of dietetically fat rats

Beginning with the fifth week of life, male Wistar rats were fed a diet containing, respectively, 3 and 50 per cent fat (corresponding to, respectively, 7 and 75 per cent fat of total calories). The differences in body weight between the two groups were 64 per cent for 10-week-old rats, and 71 per cent for 6-month-old rats. For these animals, the extent of the enzymatic deiodination of L-diiodotyrosine and L-thyroxin was determined in liver homogenate supernatants. In the 10-week-old rats as well as in the 6-month-old rats on high-fat diet, the deiodination of L-di-iodotyrosine was significantly lower than in the animals on low-fat diet, whereas the diodination of L-thyroxin was significantly higher. It is concluded that the fat content of the diet exerts an inhibiting effect on the deiodination of L-di-iodotyrosine and an enhancing effect on the deiodination of L-thyroxin.

Diätetische Beeinflussung der Dejodierung von L‐Dijodtyrosin und L‐Thyroxin in der Leber bei Ratten

Male Wistar rats of same weight were used to study the effects of diets containing, respectively, 3 and 50 per cent (by weight) fat on the deiodination of L-di-iodotyrosine and L-thyroxin in the liver. For this purpose, liver homogenate supernatants were analysed. The deiodination of L-di-iodotyrosine was significantly lower in the animals on high-fat diet than in those on low-fat diet, whereas the deiodination of L-thyroxin was significantly higher. It is concluded that not the body weight, but the diet influences the extent of deiodination.

Vitamin E adequacy of vegetable oils

Young male rats were fed diets containing 20 per cent fat in the form of soybean oil, corn oil, safflower oil, or hydrogenated shortening, and their vitamin E status was assessed for twenty-seven weeks. On the basis of growth rate, in vitro red cell hemolysis, plasma creatine phosphokinase activity, and testicular development, soybean oil, corn oil, and shortening provided adequate vitamin E. Rats fed safflower oil had slight red cell hemolysis but were normal in other respects. When the tocopherols in corn oil were reduced by half, vitamin E status still appeared normal. Tissue levels of alpha- and gamma-tocopherols were determined in all groups, and the limitations of the dietary E:PUFA ratio are discussed.

Relationships between condition score and carcass composition of pregnant Merino sheep

Body condition scores of approximately 400 Merino ewes and the carcase composition of a sub-sample of ewes were determined by inexperienced operators at the tenth and twentieth weeks of pregnancy. Although the repeatability of estimating condition scores was low on both a within and between operator basis, subjectively assessed condition scores, when averaged for three operators, were positively correlated with the per cent of fat plus muscle in the carcase at both the tenth and twentieth weeks of pregnancy. Ewe liveweight was positively correlated with the per cent fat plus muscle in the carcase at the tenth but not at the twentieth week of pregnancy.

Interlaboratory Variability in Nutrient Analyses: Two Cooperative Studies

Abstract Canned tomato juice and canned peas were analyzed for those nutrients that are mandatory as required by the nutrition labeling regulations. Twenty-four laboratories participated in the studies, using AOAC methods predominately. Results seem to indicate that, with the exception of the fat determination, methods for proximate analyses are satisfactory. Interlaboratory variability as measured by the coefficient of variation was quite large for the fat determination, 60% in tomato juice and 80% in peas. However, at the level present in both products, per cent fat is not significant from a nutrition labeling point of view. Rather significant levels of variability are apparent for most of the vitamin and mineral determinations which would indicate that methods need to be refined and that studies such as this need to be continued for these methods in other products that will be labeled nutritionally.

A LOOK AT NEW ZEALAND DAIRYING

New Zealand has got an excellent climate for prolonged grazing and high output pastures.To exploit this great natural asset fully, all cows are spring calved and manufacturing milk is produced exclusively from grass. The pattern of milk production is completely seasonal with a total shut down of milking sheds and manufacture for a period in the winter.Herds are very large by European standards and there is almost complete standardization of milking sheds and systems and this, allied with almost complete specialization, results in low cost high‐output efficient units.Low feed costs combined with low shed and equipment costs allied with high output/acre,/labour unit and /farm, enables New Zealand dairy farmers to make a relatively good living from milk (4 per cent fat) sold at 10p/gal.

The nutrition of the veal calf 6. The effect of ultra-high (68 per cent) fat milk powders added to liquid skim milk, and a comparison with spray-dried skim milk powder containing 20 per cent margarine fat

SUMMARY1. Fifty-one Jersey, Ayrshire and British Friesian male calves were reared from birth to veal weights on one of three liquid diets.2. Two ultra-high fat milk powders containing 680 g fat, either beef tallow (T) or a mixture of coconut oil and beef tallow (CT)/kg dry matter were prepared and mixed with liquid skim milk (35 g powder/kg) to give diets TLS and CTLS, containing 200 g fat/kg dry matter. A third diet consisted of reconstituted spray-dried skim milk powder containing 200 g margarine fat/kg (MDS).3. The incidence of diarrhoea and of nasal discharge for all breeds, and of a high rectal temperature for the Ayrshire breed was greatest for calves given diet MDS and lowest for those given diet TLS. The incidence of lung lesions at slaughter was 100, 72 and 57% for the Jersey, Friesian and Ayrshire breeds respectively. Severity of lung lesions was lowest for calves given diet TLS.4. Dry-matter intake and live-weight gain, especially for the Ayrshire breed, were greater for calves given diets containing liquid skim milk and the ultra-high fat powders (TLS and CTLS).5. Fat digestibility was lowest on diet TLS. Protein digestibility increased with age. Digestibility of dry matter and lactose, and absorption of ash and calcium decreased with age. Calcium and N retention were lowest on diet MDS.6. Killing-out percentage was highest for the Friesian and lowest for the Jersey breed. Perirenal fat deposition was highest for the Jersey and lowest for the Ayrshire breed. Skin weight/kg0·73was higher for the Ayrshire calves than for the other two breeds.

Effet d'un régime hyperlipidique sur la synthèse in vitro des protéines, du RNA et du ribose-phosphate dans le tissu adipeux épididymaire du rat

Summary In vitro synthesis of nucleic acids, proteins and RNA ribose in epididymal adipose tissue of rats fed either a control diet (T) (3 p. cent fat) or a high fat diet (H) (42 p. cent fat) has been compared. Total protein and nucleic acid synthesis are little modified by the H diet. Yet glucose (U- 14 C) uptake is decreased and the distribution of Glc-6-P between Embden-Meyerhof and pentose pathways is changed, the latter being favoured. Increased pentose recycling may result from the simultaneous inhibition of pentose deshydrogenases and of phosphofructokinase, regression of the latter would be determinant on the fate of Fru-6-P which is recycled through the oxydative pathway working right away at its maximal rate. Thus glyceraldehyde-3-phosphate bypasses phosphofructokinase inhibition, allows increased incorporation of radioactivity from pyruvate (2- 1 4C) into ribose and may play an important role in rats fed a high fat diet, for it allows communication between hexoses, pentoses and triose-phosphate.

The effect of barley supplementation on the liveweight gains of autumn-born calves reared on whole or skimmed milk diets

Forty, Friesian x Jersey bull calves were fed diets comprising factorial combinations of milk, either whole (4.0 per cent fat) or skimmed (0.1 per cent fat) milk, fed at the rate of 4.5 kg day-1 until the calves were ten weeks old, with crushed barley at four levels from two to 18 weeks of age. The four levels of barley were 0, 25, 50 and 75 per cent of the dry matter intake of the calves. The calves had access to hay ad libitum throughout the experiment. The restricted quantities of skimmed milk fed to the calves did not support rapid gains in liveweight, even when supplemented with high levels of barley. The addition of barley to the diet of the calves reared on whole milk produced no response in terms of growth rate (0.54 kg day-1). However, the calves reared on skimmed milk had greater growth rates when their diet contained 25 per cent barley than with no barley, 0.36 kg day-1 and 0.28 kg day-1 respectively. Further additions of barley did not produce additional responses in growth rate.

Analyses of Consumer Responsiveness to Changes in the Price of One Per Cent Fat-Milk in Selected Markets in Western Massachusetts

This pricing study involved fortified one per cent fat milk. The 26 week experiment, September 1, 1969 to February 28, 1970, was in four parts.Part I. September 1 to September 13, 1969. Flavor evaluations were conducted in four stores of a regional chain. A questionnaire was asked of participants. Of the 705 respondents, 662 reacted favorably to the one per cent fat-milk. Consumers were not well informed about the composition of one per cent fat or of regular milk.Part II. September 15 to November 8, 1969. Treatments (price differentials) of −8, −4, 0, and 4 cents below, equal to, and above the price of regular milk were as signed to the price of the one per cent half gallons, in the four stores, under controlled conditions of the Latin square. Treatments lasted two weeks. There were significant differences among treatments at the 10% level. A derived price elasticity of demand coefficient of −1.16 indicates that response to the selected price range for the one per cent fat-milk was relatively elastic.Part III. November 10, 1969 to January 3, 1970. This was a control period to disassociate the bias in sales due to the intervening holidays. The price of the one per cent fat-milk was constant in the four test stores.Part IV. January 5 to February 28, 1970. The same treatments and Latin square design were used as in Part I. There were no significant differences among treatments. The derived price elasticity coefficient of −.91 was attained.The results, although not conclusive, seem to indicate, (when test periods were combined), a slightly elastic demand, −1.03, for one per cent milk at retail.

Somatic and gametic dry matter and protein in gravid females of several amphibian species

1. 1. Specimens of fifteen amphibian species were collected from breeding congregations in the southeast United States during the spring and summer of 1970. 2. 2. Animals were dissected and dry weights of ova and carcasses were obtained. 3. 3. Fat values of ova were estimated by subtracting the percentage of protein and ash from 100 per cent. 4. 4. The proximate composition of eggs was fairly uniform for all species averaging 69·8 per cent protein, 26·6 per cent fat and 4·3 per cent ash. 5. 5. There was considerable intraspecific variation in the amount of protein and dry matter partitioned into ova with an average of about 30 per cent of the total body protein and dry matter.

Hypertriglyceridemia in weanling rats with hypothalamic obesity.

Weanling rats with electrolytic destruction of the ventromedial hypothalamic nuclei (VMN) develop elevated plasma triglyceride and insulin levels despite normal food intake. Triglyceride, insulin and adipose tissue lipoprotein lipase activity (LPL) were studied in VMN and sham-operated (control) rats fed 0, 6 or 25 per cent fat diets. On a 25 per cent fat diet, plasma from VMN rats exhibited the highest triglyceride levels, immobile lipoproteins with trailing from the pre-beta region to the origin on electrophoresis, and visible top particles in polyvinylpyrrolidone columns. On 6 per cent fat, triglyceride levels were lower than on the 25 per cent fat diet but remained greater than those of the controls; immobile lipoproteins and visible top particles were absent but trailing of lipoproteins from the pre-beta region to the origin was still evident on an electrophoretic strip. On a fat-free diet, VMN and control plasma triglycerides were identical but subsequent fasting for forty-eight hours produced elevated triglycerides in VMN rats. The diet-dependent alterations in triglycerides, lipoprotein electrophoretic patterns and polyvinylpyrrolidone columns indicated a combination of endogenous and exogenous hypertriglyceridemia. LPL was increased in VMN rats on all diets but was decreased to levels similar to those of control animals by forty-eight hours of fasting. The exogenous increase in triglycerides which occurred despite the increased adipose tissue LPL was investigated. These studies failed to demonstrate the presence of LPL inhibitors, decreased release of LPL into the circulation or resistance of lipoproteins to hydrolysis but suggested an impaired ability of VMN tissue to take up circulating lipid.

The adrenals and the regulatory nature of running wheel activity

The role of the adrenal cortex in spontaneous running wheel activity was examined. Adrenalectomy reduced activity levels and replacement therapy with corticosterone returned running levels to those of intact animals. Of the physiological measures related to intermediary metabolism which were taken, only the correlation of activity level and per cent fat in the carcass was significant. It was hypothesized that: (1) activity be included in that class of behaviors termed regulatory behaviors; (2) that running serves the organism in the regulation of body fat levels; and (3) that this regulation is, at least in part, accomplished by concomitant variations in the levels of adrenocortical functioning.