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M Krajcovicová

Publications and source records attributed to M Krajcovicová.

At least 19 recordsLinked to original sources
PubMed1985

Determination of physiological casein and wheat gluten protein requirements of adult rats aged 75-89 days.

Mounting doses of casein and wheat gluten protein (from 0% to 40% in the diet) were given to adult male rats aged 75-89 days for 14 days. The optimum physiological daily dose, determined from changes in body nitrogen, body water and body weight, was 2.76 g/d for casein protein (corresponding to a 10% casein protein diet) and 3.67 g/d for wheat gluten protein (corresponding to a 15% gluten protein diet). Determined from body weight changes, the daily maintaining dose of casein or wheat gluten protein was 1.054 and 1.511 mg/d respectively, from body nitrogen changes 970 and 1.514 mg/d and from body water changes 1.124 and 1.637 mg/d. Compared with newly weaned animals aged 35-49 days, the optimum physiological daily dietary protein doses for adult animals fall, while the maintaining doses rise.

Animals↗
PubMed1984

Physiological casein and gluten protein requirements of growing rats.

Using mounting casein and wheat gluten protein values (0-40%) in the animals' diet, the optimum and minimum physiological daily doses were determined in 49-day-old growing rats from changes in their body water, body nitrogen and protein intake. The optimum physiological doses were identical with the peak of linearity of the given parameters, which coincided with a 15% casein protein and a 20% gluten protein concentration in the diet. This was also confirmed by the maximum body amino acid values, which were found in animals given a 15% casein or 20% gluten protein diet. It was further confirmed by the finding of significantly elevated alanine aminotransferase and aspartate aminotransferase activity in the liver of animals with a higher intake of the above protein sources. The minimum physiological dose of the given protein was determined from the equations of the regression curves in the presence of zero changes in the body nitrogen or body water content. The optimum physiological daily doses of casein and wheat gluten protein were 3.25 g and 4.05 g respectively. The minimum physiological daily doses of casein protein were 268 mg (from body nitrogen changes) and 371 mg (from body water changes) and the minimum physiological daily doses of gluten protein were 892 mg (from body nitrogen changes) and 1,000 mg (from body water changes). The above indicators demonstrate, in the presence of higher and high dietary concentrations, that an intake of the given proteins over and above the optimum physiological daily dose is at the very least uneconomical (gluten), if not harmful (casein), making this a highly topical problem for further study.

Aging↗
PubMed1983

Determination of the optimum proportion of saccharides in the diet of adult rats.

SPF male Wistar rats weighing 250-260 g and aged 90 days were fed 14 days on diets with a constant 10% protein (casein) content, a constant 11% fat (margarine) content and mounting saccharide (rice starch: sugar: potato starch - 6.4: 1.2: 1) contents of 31, 36, 41, 46, 51, 56, 61 and 66%. Protein intake and the body and liver nitrogen values were used to determine the utilization parameters of protein biological value, i.e. NPU (body) and LPU (liver), for the individual diets. Liver gluconeogenesis was also studied by measuring specific phosphoenolpyruvate carboxykinase (PEPCK) and fructose-1.6-diphosphatase (FDP-ase) activity. On the basis of linearity between the growth parameter NPR and protein and saccharide intake we determined the reciprocal relationship of the intake of the two nutrients and used it to compute the optimum saccharide concentration for the diet. The 51% saccharide diet gave the best protein utilization (the maximum (net) protein utilization value) in the 90-day-old rat organism. This was confirmed by the course of gluconeogenesis, which was significantly activated in the presence of 31-46% saccharide diets. By substituting the optimum protein intake in the reciprocal saccharide-protein intake relationship we obtained the optimum saccharide intake, which corresponded to a 49% concentration in the diet. With its use of a biological, biochemical and computation method, the study is a contribution to the determination of optimum nutrient values.

Animals↗
PubMed1982

Determination of the optimum dose of fats in the food of rats of different ages.

Over a 14-day period, male SPF Wistar rats with an initial weight of 60, 200 and 250 g (ages 30, 75 and 90 days) were given diets with a constant protein content (10% casein) and a mounting fat content (10, 15, 20, 25, 30, 40 and 50% margarine, at the expense of the saccharides in the standard diet). The utilization parameter of protein biological value (NPU) for the various diets was determined from protein intake and the body nitrogen values. The reciprocal relation of the intake of the two nutrients was determined on the basis of linearity between th growth parameter NPR and protein and fat intake and, after substituting the optimum protein intake, was used to compute the optimum fat content of the diet. From the aspect of the maximum NPU value the optimum fat contents were 30% for 30-day-old, 15% for 75-day-old and 10% for 90-day-old animals. In all three age groups (according to the growth curve for the standard Larsen diet animals with an equal growth rate of 3 g/day), protein utilization under optimum nutritional conditions was the same. The optimum fat content of the diet computed from the reciprocal relationship of fat and protein intake is in agreement with the value obtained by the biological method - 29.4% (49.5 energy %) for 30-day-old animals, 15,8% (30.4% of the total energy value of the diet) for 75-day-old animals and 11.83% (23.7% of total energy) for 90-day-old rats. By using a biological and a mathematical method, this study contributes to the determination of optimum physiological doses of nutrients.

Aging↗
PubMed1982

Minimum and optimum physiological doses of egg albumin and mutton protein in newly weaned rats.

Using diets with a mounting egg albumin and mutton protein concentration, the authors determined the optimum physiological doses, which are identical with the maximum of linearity of the given parameters, from changes in body nitrogen, body weight and body water. The regression equations of the lines from these parameters were used to determine the minimum physiological doses for newly weaned rats. The optimum and minimum physiological doses of the amino acids in the relevant dietary proteins were also determined by analysing the source for its nitrogen content and other components and for the amino acid spectrum. The optimum dose of egg albumin protein for newly weaned rats was 1.69 g/day (on a 15% protein diet) and of mutton protein 2.56 g/day (on a 12.5% protein diet), with daily amounts of 60 mg methionine, 93 mg phenylalanine, 112 mg valine and 60 mg tyrosine for both proteins. The minimum doses of egg albumin and mutton protein, determined from changes in body nitrogen were 282 mg and 213 mg/day respectively [methionine 10.4 (4.7) mg/day, phenylalanine 16.1 (7.5) mg/day, valine 19.1 (9.2) mg/day and tyrosine 9.8 (5.2) mg/day)].

Amino Acids↗
PubMed1982

[Utilization of proteins in rats with different fat and saccharide intakes].

For 14-day periods, 30-day-old and 90-day-old male rats were fed ad libitum the diets with a constant protein content (casein) of 10 p. c. and with an increased fat content (margarine) of 10, 20. 30, 40 and 50 p.c. (first experiment) and then the diets with a constant protein content (casein) of 10 p. c. and with a constant fat content (margarine) of 30 p. c. (30-day rats) and of 11 p. c. (90-day rats) and with an increasing saccharide content of 31, 36, 41, 46 and 51 p. c. (90-day rats were further fed by 56, 61 and 66 p. c.) composed of rice starch, sugar and potato starch at a ratio of 6.4 : 1.2 :1 (second experiment). Net protein utilization (NPU) was determined on the basis of body nitrogen content and protein intake. The animal liver was examined for the gluconeogenesis by measuring the specific activity of phosphoenolpyruvate carboxykinase (PEPCK). The highest NPU value can be achieved as follows: in 30-day animals by administration of the feeds containing 30 p. c. of fat, 36 p. c. of saccharides; in 90-day animals by 10 p. c. of fat and 51 p. c. of saccharides. Under the optimum nutrition conditions, both age groups utilize protein in the same way. The extreme nutrition conditions are better tolerated by the just weaned animals than by 90-day animals. The results of this biological method were also proved by the course of gluconeogenesis (activated at 40 and 50 p. c. fat content and 31 p. c. saccharide content in the diet fed to 30-day animals; in 90-day animals the activation occurred beginning 20 p. c. fat content and at 31 to 46 p. c. saccharide content). This paper contributes to the determination of optimum physiological nutrient rates by biological and biochemical methods.

Animals↗
PubMed1981

[Utilization of proteins as related to protein and fat intake].

Low-protein (5%) and high-protein (40%) diets as well as low-fat (5%) and high-fat (40%) diets were fed to weanling rats in a 14-day experiment, the standard diet containing 10% of protein and 10% of fat. The net protein utilization of casein, the liver protein utilization and the activity of the key enzyme of gluconeogenesis in the liver, phosphoenol pyruvate carboxykinase, were determined. The utilization of proteins by the organism was adversely affected by a high intake of proteins and also of fats. This fact and the observed stimulation of gluconeogenesis testify to the physiological and economical unsuitableness of diets containing excessive amounts of proteins and fats. A low fat intake was less detrimental to the utilization of proteins than a high fat intake; a low intake of proteins seemed to improve the utilization, but other parameters evidenced that it is not sufficient. The application of diets with closely graded contents in wide ranges for various times will yield biochemical indicators being of importance as supplementary factors in the determination of the physiological value of nutrients under different conditions.

Animals↗
PubMed1981

Determination of optimum fat intake.

In a 14-day experiment, adult rats weighting 250-260 g were given ad libitum diets with a constant protein content [casein - 10 %] and a mounting fat content [margarine - 0, 10, 20, 30 and 40 % - added at the expense of carbohydrates]. The growth parameters of protein biological value - PER and NPR - were determined and together with weight increments in correlation to protein an fat intake [a linear correlation] they were used on the basis of their regression equations to calculate the reciprocal relationships of fat and protein intake [for equality y]. By substituting the optimum protein intake [43.3 g/14 days - according to NPU], the optimum fat intake for adult rats was found to correspond to dietary fat concentrations of 9.72 % [y = weight increments], 12,82 % [y = PER] and 11.83 % [y = NPR]. These results wee verified in a biological experiment in which adult animals, for 14 days, were given a limited amount [31 g/animal per day] of diets containing 10 % protein [casein] an d9, 10, 11, 12, and 13 % fat [margarine - at the expense of carbohydrates] with the aim of studying the effect of a mounting fat intake on optimum protein intake [43.4 g/14 days]. The correctness of the mathematical method for determining the optimum fat intake was verified by a biological method [the optimum net protein utilization , NPU, which is highest in diets containing 11 % fats, i.e. 22.5 % of the total energy value of the diet]. It was also found that this method, both along and in conjunction with other methods [especially the one using the NPR parameter], was suitable for the determination of optimum nutrient values.

Animals↗
PubMed1981

Effect of a high fat intake on protein utilization during ontogenetic development.

Male rats (Wistar strain, Velaz, Prague) aged 30, 90 and 150 days were fed 14 days ad libitum on a high fat diet (containing 40% margarine) and their growth (PER, NPR) and utilization (NPU, LPU) parameters of protein (casein) biological value were compared with those of animals given a standard gel containing 10% margarine (the diets were isoenergetic). The course of gluconeogenesis in their liver was also determined by measuring phosphoenolpyruvate carboxykinase (PEPCK) activity. A high fat intake had a negative effect on the growth parameters of protein biological value, PER and NPR, in all three age groups and on the utilization parameters NPU and LPU in 30- and 90-day-old rats. The nonsignificant increase in NPU and LPU in the oldest animals was evidently related to the equal protein intake compared with the control, indicating that proteins need to be utilized more economically in the presence of a raised fat intake; owing to their far lower fat intake compared with 90-day-old animals on a high fat diet, the fat had a less negative effect on their protein utilization than in the younger age group. The negative effect of a high fat intake was confirmed by high activation of gluconeogenesis in 30- and 90-day-old animals and by raised phosphoenolpyruvate carboxykinase activity in 150-day-old rats, in which the supposition that gluconeogenesis would be highly activated if the diet were administered for a period other than 14 days cannot be ignored. The biological and biochemical methods employed in this study can be used with a wider perceptual range of dietary nutrients to determine optimum nutrient values under different conditions.

Aging↗