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1.
Protein utilization of the diet was tested in relation to different levels of magnesium and zinc in rats. The experimental diets contained either a low (0.14 g Mg or 10 mg Zn/kg) or adequate (0.45 g Mg or 40 mg Zn/kg) level of Mg or Zn and two different quality protein sources: casein or wheat gluten. Net protein utilization and net protein radio indexes in case of casein were significantly lower for the diet containing a low level of Mg or Zn. For gluten diets, such differences were not observed. Digestibility of protein measured in rats fed a low Mg or Zn casein diet was the same as for the diets with an adequate content of these minerals. Rats fed low Mg or Zn casein diets showed a significantly lower plasma Mg or Zn and a lower liver DNA content in comparison to the rats on adequate Mg or Zn diets. The results indicate that the utilization of protein is affected by Mg and Zn content of the diet and that this relationship depends on the quality of protein.  相似文献   

2.
Maternal blood alcohol levels, weight gain during pregnancy, parturition time, perinatal mortality, and postnatal growth of offspring were compared in groups of pregnant rats fed one of three ethanol-containing liquid diets (Kahn's formula = BSA diet, Revised Wiener's = RA6 diet, and Lieber-DeCarli's high protein 82C diet = LDA diet). The three ethanol diets all contained the same amount of ethanol-derived energy (36% of total energy), but differed in the amount of energy contributed by protein (17, 30, and 25%), fat (36, 24, and 13%), and carbohydrate (12, 10, and 27%), respectively. The experimental design also included dams that were pair-fed isocaloric ethanol-free versions of the three ethanol diets (designated BSP, RP6, and LDA, respectively) and a group of dams fed a pelleted casein-based solid diet (PC diet). All experimental diets were fed ad libitum from gestational day 7 to delivery. The effect of ethanol exposure in utero was most severe in mothers and offspring fed the BSA diet. The feed efficiency ratio (maternal weight gain/total dietary energy consumed) of this low-protein ethanol diet was less than that of RA6 or LDA diets. The feed efficiency ratio calculated for RA6 and LDA diets was not different from that of PC diet. Compared with rats fed RA6 and LDA diets, the rats that were fed BSA diet exhibited deficient maternal weight gain, greater parturition delay, impaired fetal growth, and increased perinatal mortality among the offspring. BSA dams had the highest blood ethanol levels of all groups fed ethanol diets, and exhibited the least difference in blood ethanol concentrations between the day (2 PM) and night (9 PM) periods of the diurnal cycle.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

3.
Young Wistar rats developed a fulminant infection when inoculated with the rodent malaria parasite Plasmodium berghei. Rats that died during the infection exhibited a progressive paralysis of the extremities, a rapidly decreasing body temperature and minute haemorrhages in the brain. Increasing the level of protein in the diet from 4 to 8 and 16% was accompanied by an increase in morbidity and mortality from 15 to 40 and 90% respectively on day 6 of the infection. Increasing the level of dietary protein also increased the reticulocyte count of the peripheral blood in infected and non-infected rats. The attenuation of the cerebral syndrome in rats fed a diet low in protein may be related to changes in erythropoiesis or to changes in immune reactivity.  相似文献   

4.
Feeding of wistar albino rats on low protein and energy diet (4% protein) caused suppression of parasitaemia when infected with Plasmodium berghei besides causing a depressed immune response. The refeeding of protein energy deficient rats on normal protein and energy diet (18% protein) for four weeks resulted in the normal course of parasitaemia after P. berghei infection. The present study was carried out to find the cause of suppression of malaria in protein energy deficient rats. The experiments revealed re-elevation of malaria parasitaemia when rats were fed on low protein diets supplemented with p-amino-benzoic acid (PABA). Moreover, the parasite persisted at subpatent levels in tissues in protein energy deficient rats and resulted in the development of antimalarial antibodies. Low protein energy diet could cause deficiency of certain essential nutrients required for the parasite, PABA being one of them, and hence suppresses the parasitaemia to subpatent levels. As a result, sufficient antigenic stimulus is provided to the host so that the host develops an immune response which might in turn help in further suppression of parasitaemia to subpatent levels.  相似文献   

5.
Dietary protein: a trigger of insulin-dependent diabetes in the BB rat?   总被引:5,自引:1,他引:5  
Summary Animals from a colony of spontaneously diabetic insulin-dependent BB rats were fed from weaning with semisynthetic diets in which natural proteins were replaced by l-amino acids with or without the addition of either milk or wheat proteins. The normal 50% incidence of diabetes in the colony was reduced to 15% in rats fed the basic semi-synthetic diet, while it was 35% and 52% when supplemented with gluten or milk, respectively. Thus, dietary factors might precipitate the expression of the disease.  相似文献   

6.
Summary Recently, we demonstrated a reduction in the diabetogenic action of streptozotocin (STZ) in rats previously adapted to a high protein (HP) diet. These data suggested that amelioration of diabetes resulted from the combination of two effects of the HP diet: initial protection against the diabetogenic action of the drug at the time of exposure and subsequent improvement of the induced diabetic condition. The present study evaluated the effects of a HP diet on the evolution of the metabolic condition in rats with STZ-induced or spontaneous diabetes (BB Wistar rats). Two days after STZ injection, the animals were given isocaloric HP (70% protein, 8% fat) or control (66% carbohydrate, 16% protein, 8% fat) diets for 15 days. After 13 days, the STZ-treated rats fed HP diet showed an impressive decrease in severity of diabetes, as judged by rate of body weight change, plasma glucose, urine volume and glycosuria, serum and pancreatic insulin. The BB Wistar rats, already diabetic for 5 weeks before being transferred to the HP or control diet, were treated with daily injections of insulin. After 31 days on the HP diet, the BB rats showed reduced insulin requirement, reduced blood and urinary glucose levels, but no difference in body weight gain or pancreatic insulin content. The data show that short-term use of HP diets can greatly improve the diabetic condition in STZ-treated animals, but that the beneficial effects of the diet are much less marked in rats with chronic spontaneous diabetes. These data suggest that the ameliorating effect of HP diet is fully manifested only when the diabetic rats have a sufficient number of residual functioning B-cells.  相似文献   

7.
J F Bruno  J F Song  M Berelowitz 《Endocrinology》1991,129(3):1226-1232
To further evaluate nutrient regulation of GRF synthesis, we measured hypothalamic preproGRF messenger (m) RNA in food-deprived rats refed diets varying in nutrient composition by nuclease protection analysis. Adult male Sprague-Dawley rats were allowed free access to food (Fed), food deprived for 72 h (72-h FD), or 72 h FD then refed for 72 h with either a normal (NF) diet or isocaloric diets containing no protein (PF), carbohydrate (CF), or fat (FF). Seventy-two-hour FD rats displayed the expected 80% reduction in hypothalamic preproGRF mRNA. Upon refeeding, levels were normalized in rats refed NF, CF, or FF diets. In contrast, preproGRF mRNA in rats refed a PF diet was similar to that in 72-h FD rats. Rats refed a PF diet failed to gain weight and consumed less food than animals refed NF, CF, or FF diets. However, the lack of the GRF response to the PF diet was due to protein deprivation rather than caloric restriction, since hypothalamic preproGRF mRNA returned to 66% of Fed values in rats refed an equivalent amount (grams per day) of a NF diet. In 72-h FD rats refed isocaloric diets containing 4%, 8%, or 12% protein, preproGRF mRNA was restored to Fed values in a protein concentration-dependent manner being completely restored by the 12% diet. A lack of dietary protein was sufficient to regulate hypothalamic preproGRF mRNA since feeding rats a PF diet without prior food deprivation resulted in 70% reduction in preproGRF mRNA, whereas CF and FF diets were without effect. These data indicate that decreased hypothalamic preproGRF mRNA expression in 72-h FD rats occurs as a result of dietary protein deprivation.  相似文献   

8.
S ummary . The effects were examined of dietary protein concentration and quality on the response of polycythaemic hypertransfused rats to 6 units of human urinary erythropoietin. Rats were either starved or fed one of 14 different diets. Four protein sources were used, having a quality gradient from 100 to about 24. Two proteins—casein and wheat gluten—were used at five different levels of concentration (5–25%) in the diet. The response of rats maintained on the standard diet (Purina rat chow, 23.4% protein/g) was taken as the normal standard. The response to erythropoietin was 25% of normal in starved rats and 35% of normal in rats put on a protein-free diet. When 10% protein in the diet was obtained by using high biological value proteins (egg yolk or casein) the response to erythropoietin was normal. When the same concentration was achieved by using low biological value proteins (wheat gluten or corn protein) the response to erythropoietin was undistinguishable from that of rats put on the protein-free diet. When rats were maintained on diets with different concentrations of casein (5–25%) a normal response was observed when protein concentration was 10% with no further changes at higher concentrations. When rats were fed diets with different wheat gluten concentrations (5–25%) the response to erythropoietin was subnormal. These data suggest that the ability of rats to respond normally to erythropoietin is dependent on a continuous dietary intake of proteins at levels which are dependent on their biological values.  相似文献   

9.
Previous studies demonstrated that a whole-grain diet attenuated sodium-dependent hypertension and renal disease in Dahl salt-sensitive rats from the colony at the Medical College of Wisconsin (Dahl SS/Mcw rats) compared with rats maintained on a purified AIN-76A diet. The present experiments determined which component(s) of the grain diet prevented renal and cardiovascular disease. Male SS/Mcw rats were maintained on isocaloric diets identical to AIN-76A, except the source of protein (wheat gluten for casein), carbohydrate (wheat flour for sucrose), or fat (soybean oil for corn oil) was substituted in separate diets. Rats were maintained on the different diets from weaning and studied after 3 weeks on a high-salt (4.0% NaCl) diet. Substitution of the carbohydrate in the diet did not affect body weight, arterial pressure, or renal disease. Replacement of casein with wheat gluten significantly reduced body weight (258+/-7 versus 353+/-3 grams), mean arterial pressure (133+/-2 versus 153+/-2 mm Hg), and albumin excretion (9+/-1 versus 50+/-7 mg/d) to levels of rats fed the whole-grain diet (n=7 to 16/group). Replacement of the fat in the diet increased arterial pressure without affecting body weight or albumin excretion. The results of the present study indicate that dietary components other than sodium play an important role in the development of hypertension and renal disease in the Dahl SS/Mcw rat.  相似文献   

10.
Administration of a chemically defined, elemental diet to rats given 20 mg/kg of methotrexate intraperitoneally has consistently resulted in a 100% mortality from severe enteritis within 156 h. This study examined the importance of specific dietary components in the etiology of this enhanced toxicity. Rats were given their respective diets for 7 days, whereupon methotrexate (20 mg/kg) was given intraperitoneally, and percent of survivors was recorded. Varying the concentration of carbohydrate as polysaccharide (0%, 50%, 100%) (n = 30) had no effect on survival. An increase in the percent of protein as polypeptide (0%, 25%, 50%, 75%, 100%) (n = 50) in the elemental diet resulted in a progressively significant increase in percent survival. Addition of either fat or bulk to this elemental diet had no effect on survivorship. Serum and bile methotrexate levels of rats fed an elemental liquid diet (whether or not all of the protein was provided as polypeptide) were significantly increased from 12 to 72 h (p less than 0.03) compared with rats fed a regular Chow diet. When the protein content of the elemental liquid diet was provided as 100% polypeptide, serum and bile methotrexate levels were significantly lower at 48 h compared with the elemental diet group given 100% of protein as amino acid. Administration of methotrexate to rats fed an elemental liquid diet in which all of the protein is provided as amino acids is extremely toxic to the gastrointestinal tract, probably as a result of delayed clearance of the drug from the systemic circulation and from bile. This toxicity is alleviated by the provision of protein as polypeptide in the elemental diet. No toxicity to the drug is seen at this dose in rats fed a regular Chow diet. If these results are applicable to humans, the use of elemental liquid diets as the only source of enteral nutrition would appear contraindicated in patients receiving methotrexate.  相似文献   

11.
A relationship was assessed between the amino acid composition of 9 protein sources or of their in vitro digestion products and total serum cholesterol in rats. Three animal proteins (casein, beef, fish) and 6 vegetable proteins (soy, pea, peanut meal, rapeseed, oatmeal, wheat gluten) were tested. The intact protein sources were submitted to an enzymatic proteolysis according to a new in vitro digestion method. Each protein source was hydrolyzed for 30 min with pepsin at pH 1.9, then with 10 mg pancreatin at basic pH in a dialysis cell. The digestion products diffused through the dialysis membrane of the cell and were collected by a circulating sodium phosphate buffer over a 6-h period. They were likely to correspond to end products luminal in vivo digestion. The aromatic and the basic amino acids were present in higher proportions in the digestion products than in the intact protein sources, reflecting the specificity of the proteolytic enzymes. Total serum cholesterol was measured on male Sprague-Dawley rats fed cholesterol-free or cholesterol-enriched (1% cholesterol, 0.5% cholic acid) semipurified diets containing protein sources. Total serum cholesterol ranged from 70 mg/dl with the pea diet to 98 mg/dl with the peanut meal diet in rats fed cholesterol-free diets and from 163 mg/dl with the wheat gluten diet to 313 mg/dl with the casein diet in rats fed the cholesterol-enriched diets. These results suggested no specific effect of protein from animal or vegetable origin on total serum cholesterol in rats. In rats fed cholesterol-enriched diets, significant correlations were observed between total serum cholesterol and tyrosine content or leucine/isoleucine ratio of digestion products. These correlations were stronger than those observed with intact protein sources.  相似文献   

12.
Hypocholesterolemic effect of vegetable protein in a hypocaloric diet   总被引:2,自引:0,他引:2  
Eleven obese volunteers took part in a 12-week study during 8 weeks of which 2 meals of their control 1000 kcal diets were replaced by a soya based liquid formula (1 month) or a milk based liquid formula (1 month). The mean weight loss per month was 2.5 kg (P less than 0.05). On the soya formula total and LDL cholesterol levels were reduced significantly over the month by 10.0 +/- 2.7% (P less than 0.01) and 17.5 +/- 5.6% (P less than 0.02), respectively. Neither the milk based formula or the control low calorie diet lowered serum cholesterol significantly over the diet period. No change was seen in serum triglycerides on any of the 3 diets. No difference was seen between treatments in 24-h urinary C-peptide excretion. The results indicated that use of a vegetable protein supplement in a weight loss program which induced moderate weight loss was associated with a reduction in blood lipids, whereas moderate weight loss on a control low calorie diet or milk based formula was not.  相似文献   

13.
The effects of protein levels and types of fat in the diet on the metabolism of lean and obese Zucker rats were studied. For 40 days the rats were fed ad libitum one of four diets: two "usual protein" diets (19% protein by weight) with 19.4% triacylglycerols, either long chain (UP-LCT diet) or medium chain (UP-MCT diet); and two high protein (64% protein), carbohydrate-free diets, again with 19.4% triacylglycerols (HP-LCT and HP-MCT diets, respectively). The energy intakes of the obese rats decreased about equally on the HP-LCT, UP-MCT, and HP-MCT diets. The daily weight gain, which was high in the UP-LCT rats, was lower when carbohydrates were replaced by proteins, or when LCTs were replaced by MCTs; furthermore, when these two changes were made together, their beneficial effects on body weight were additive. The lipid gain, too, was high with the UP-LCT diet and lower both with the high protein diets and with the MCT diets; again combining the two amplified the two individual effects, so much that the final lipid concentration in the body was lowered, whereas the concentration of water increased. Hepatic acetyl CoA carboxylase activity was low when the diet supplied plenty of LCTs, but replacing carbohydrates with proteins in such a diet produced an additional decrease in this enzymatic activity. When either a normal protein or a high protein diet supplied MCTs in place of LCTs, acetyl CoA carboxylase activity was high and similar to that found with a high carbohydrate diet.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

14.
Summary Groups of diabetic rats (65 mg/kg streptozotocin SC) were fed ad lib on three different dietary regimens for 43 weeks: a standard control diet (68% of calories as carbohydrate, 20% as protein, and 12% as fat), a low carbohydrate high protein diet (6% carbohydrate, 63% protein, 31% fat) or a low carbohydrate-high fat diet (5% carbohydrate, 75% fat, 20% protein). The high fat diet resulted in a fall of blood glucose from 700 to 350 mg/100 ml. Rats fed the high protein diet showed a similar initial decrease in blood glucose concentration, and a further improvement was evident from the 28th week on. After 43 weeks blood glucose levels were below 180 mg/100 ml and glycosuria below 100 mg/24 h in all rats fed the high protein diet. When rats exhibiting blood glucose levels below 180 mg/dl were transferred temporarily to standard diet blood glucose levels increased and marked glycosuria was observed. Rats on the standard diet maintained blood glucose concentrations greater than 500 mg/100 ml and glycosuria of about 16 g/24 h throughout the experiment. The pancreatic insulin content at death of rats fed the standard diet or the high fat diet was 1% of normal rats, whereas the values for the rats on the high protein diet were increased to 9%. Animals fed the low carbohydrate diets showed greater weight gain. In the high fat diet group there was a marked rise after 43 weeks in plasma triglycerides, free fatty acids, 3-hydroxybutyrate and acetoacetate in the plasma. Urea excretion was raised in the animals on the high protein diet. Thus, treatment with low carbohydrate diets for 10 months regardless of fat and protein content markedly improved the diabetic state of rats.  相似文献   

15.
Altered protein diets and circadian rhythms of gastrin and cholecystokinin (CCK) were investigated in 126 male and 126 female Sprague-Dawley rats acclimated for two weeks to a 1212 hr lightdark cycle. Rats were divided equally and fed low-protein (8%), high-protein (64%) or normal protein (27%) diets for four weeks. All animals were fasted for 24 hr prior to blood collections. Blood samples were collected at 4-hr intervals for 24 hr for determination of plasma gastrin and CCK using specific radioimmunoassays. A significant rhythm for gastrin was detected in males on normal and lowprotein diets (P < 0.03) and in females on lowprotein diets (P < .02). A significant rhythm for CCK was detected (P < 0.05) in rats of both sexes fed normal and highprotein diets. Mean plasma levels of both peptides were lower in females than males. In a separate study, food intake and body weight were monitored in male rats receiving the three diets over 21 days. Animals on the lowprotein diet exhibited reduced food intake and body weight compared to rats fed the normal or high-protein diets.Presented in part at the Eighteenth International Conference on Chronobiology, Leiden, The Netherlands, July 12–17, 1987.Supported by a grant from the National Institutes of Health PO1 DK35608.  相似文献   

16.
ABSTRACT

Epidemiological studies in man suggest that blood pressures tend to be higher in persons with low calcium (Ca) intakes. Previous studies in normal rats have shown that severe Ca restriction raises blood pressure. The chronic effect of moderate Ca restriction is not known. We evaluated the effect upon systolic blood pressure of rearing young Wistar rats on a diet marginally adequate in Ca. Male weanling Wistar rats (8 rats per group) were placed on one of four diets containing 0.5% Ca (control diet), 0.4% Ca, 0.3% Ca, or 0.2% Ca. The three experimental diets were made up by replacing CaHPO4 in the salt mix with (NH4)H2PO4. Content of PO4 and electrolytes other than Ca was the same for all 4 diets. Sodium (Na) content was 0.1%. Diets were fed for 19 weeks. Rats did not grow normally on the 0.2% Ca diet, but growth was normal on the other three diets. There was no overall statistically significant effect of diet upon systolic pressure. During the first nine weeks of study there were no significant differences between groups and no consistent trends. During the last seven weeks, however, there was a consistent trend toward higher systolic pressures as Ca intake decreased. The mean change in blood pressure during the last five weeks of study from the baseline value at 4 weeks of age was significantly greater in rats consuming 0.2% Ca and tended to be greater in rats consuming 0.3 and 0.4% Ca than in controls. On several occasions, group mean systolic pressures were significantly greater in rats on the experimental diets than in controls. Systolic pressures for individual rats, averaged over the last seven blood pressure measurements, varied over a wider range in the experimental groups than in rats eating the control diet, and the distribution in the experimental groups was shifted toward higher systolic pressures. The results suggest that rearing normal rats on a diet marginally adequate in Ca may lead to a modest elevation in the blood pressures of some, but not all rats. The effect, however, is of much smaller magnitude than that observed with severe Ca restriction.  相似文献   

17.
Groups of rats were fed diets containing 15% protein from arhar dal (Cajanus cajan), bengal gram dal (Cicer arietinum), urad dal (Phaseolus mungo) and also isolated proteins from casein, egg, soya bean, gluten and gelatin for a period of 10 days. Rats maintained on the casein diet had the highest liver arginase activity and those having egg the lowest. All the leguminous proteins gave similar levels of arginase activity, the values falling between the casein and egg groups. Serum arginase level was found to be low only in rats on egg and gluten diets. Liver ornithine transcarbamylase (OTC) activity was significantly higher when legumes provided the protein as compared with the diet containing egg. Serum OTC level was lowest in the egg and arhar dal groups. Though the levels of urea cycle enzymes were altered by the quality of dietary proteins, no simple relationship could be established between them.  相似文献   

18.
The pregnant rat fed a low-protein diet has become widely used as a model system in the study of the prenatal programming of adult metabolism and disease. When pregnant rats of the hooded Lister strain were fed semisynthetic diets containing 18% or 9% casein supplemented with 0.5% dl-methionine, there was significant postnatal mortality in the group fed the low-protein diet. In a second experiment, dams were fed diets containing 9% casein supplemented with varying concentrations of dl-methionine up to 0.4% (w/w) and compared with a group fed a diet containing 18% casein supplemented with 0.5% dl-methionine. At birth, the pups from dams fed the low-protein diets supplemented with 0.2% dl-methionine or greater were significantly smaller than those of the dams fed the diet containing 18% protein. By 25 weeks of age, the body weight of the offspring of dams fed the low-protein diet supplemented with 0.2% or 0.3% dl-methionine were approximately 10% lower than those in the control group of offspring from dams fed 18% protein supplemented with 0.5% dl-methionine. There were corresponding changes in the weights of the major organs. These data suggest that increasing the dl-methionine supplement in the low-protein diet retards the growth of the fetus and affects the mature adult body weight. In contrast to the findings of other studies that used different formulas of the low-protein diet, the glucose tolerance in the offspring was unaffected by the protein content of the maternal diet at all levels of dl-methionine supplementation. These results suggest that the changes in metabolism of the offspring result from interactions between protein, lipids, and carbohydrates in the maternal diet, rather than a consequence of postnatal growth retardation per se and highlight the importance of considering all components of the maternal diet in the programming mechanism.  相似文献   

19.
Previous studies of dietary protein intake and calcium balance demonstrate decreased fecal calcium excretion with high-protein diets. To determine whether a duodenal or ileal calcium transport response could account for these findings, we examined calcium transport by these two segments directly byin situ perfusion. Weight-matched growing rats were pair-fed isocaloric diets for 6–8 days containing 89% protein (casein), 39% protein, or 0% protein. Sucrose was substituted for the decreased casein in the 39% and 0% protein diets. Each diet also contained 5% fat, a mineral mix, and vitamins. Calcium content of all diets was 0.5%. Body weight was maintained by the 39% protein group; weight loss was 5% for the 89% protein group and 18% for the 0% protein group. Smallintestinal weight as a percentage of body weight was the same for the three groups. For both the duodenum and the ileum, mucosal dry weight per centimeter was greater in the 39% protein group than either the 89% protein or 0% protein group. Calcium absorption per gram dry weight of mucosa (absorptive specific activity) was the same for all diet groups, but because of the greater mucosal weight per unit length in the 39% protein group, absorption per centimeter was increased in this group. In conclusion, although we found no direct relation between dietary protein and mucosal absorptive specific activity for calcium, calcium absorption was determined by the amount of mucosa which was dependent on protein intake and reflected the nutritional status of the body.  相似文献   

20.
Breast milk is the natural nutrition for infants, but in the second half of the first year of life, complementary feeding is needed. Many complementary foods contain gluten, but gluten exposure is associated with the risk of developing celiac disease (CD). CD is a disease with considerable morbidity and mortality. Although CD is associated with certain genetic features, carrying the human leukocyte antigen haplotypes DQ2 or DQ8 (a prerequisite for CD development) cannot fully explain who will or who will not develop CD. Potential risk factors for CD include perinatal events and infant feeding practice. With the exception that children who are breastfed at and beyond gluten introduction into the diet probably may be at a lower risk of developing CD, and that heavy gluten load early in life may increase the risk of future CD, data on the impact of infant feeding are inconsistent.  相似文献   

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