scholarly journals Effect of varying energy and protein intake on nitrogen balance in adults engaged in heavy manual labour

1979 ◽  
Vol 41 (1) ◽  
pp. 19-25 ◽  
Author(s):  
A. Iyengar ◽  
B. S. Narasinga Rao
Keyword(s):  
Urinary Excretion ◽  
Nitrogen Balance ◽  
Dietary Protein ◽  
Protein Level ◽  
Protein Intake ◽  
Energy Levels ◽  
Adult Men ◽  
Dietary Protein Level ◽  
Low Protein ◽  
Manual Labour

1. The effect of varying energy and protein intake on nitrogen balance in adult men engaged in heavy manual labour was investigated.2. Low protein and energy levels resulted in negative N balance and urea index (Waterlow, 1963) was decreased.3. Urinary excretion of hydroxyproline was found to be sensitive to dietary protein level, but not to energy.

scholarly journals Fractional catabolic rates of myosin and actin estimated by urinary excretion of NT-methylhistidine: the effect of dietary protein level on catabolic rates under conditions of restricted food intake

1977 ◽  
Vol 37 (3) ◽  
pp. 345-353 ◽  
Author(s):  
N. Nishizawa ◽  
M. Shimbo ◽  
S. Hareyama ◽  
R. Funabiki
Keyword(s):  
Skeletal Muscle ◽  
Urinary Excretion ◽  
Dietary Protein ◽  
Protein Level ◽  
Protein Intake ◽  
The Body ◽  
Dietary Protein Intake ◽  
Adult Rats ◽  
Critical Studies ◽  
Dietary Protein Level

1. Critical studies on the distribution of NT-methylhistidine (3-methylhistidine; Me-His) among organs and tissues in adult rats are reported. Adult rats contained 46.5 ± 3.6 mg Me-His/kg body-weight. Almost 90% of the Me-His in the body was recovered from skeletal muscle. These results support the hypothesis that fractional catabolic rates of myosin and actin in skeletal muscle can be estimated by measuring urinary excretion of Me-His.2. Dietary protein level did not affect the total amount of Me-His in the body. However, urinary excretion of Me-His increased as dietary protein intake was increased.3. From these results it was concluded that fractional catabolic rates of myosin and actin increase as dietary protein intake increases.

scholarly journals Effect of feeding pattern on the energy metabolism of rats given low-protein diets

1975 ◽  
Vol 33 (2) ◽  
pp. 277-289 ◽  
Author(s):  
K. J. McCracken
Keyword(s):  
G Protein ◽  
Energy Intake ◽  
Dietary Protein ◽  
Protein Level ◽  
Dry Matter ◽  
Dietary Protein Level ◽  
Low Protein ◽  
Gastric Intubation ◽  
Energy Retention ◽  
Protein Diets

1. The deposition of fat and protein and the utilization of energy by growing rats offered diets ad lib. or in controlled amounts by gastric intubation has been investigated. Diets contained 50, 75, 100 or 200 g protein/kg, mainly as caseinGain of body-weight and protein increased with increasing dietary protein concentration when animals received the same energy intake, although the reverse was true for fat deposition. However, the differences in live-weight gain were almost entirely due to changes in body water. The dry-matter content of the gain in animals given low-protein diets was 770 g/kg compared to 360 g/kg in those given the control diet2. Energy retention was unaffected by dietary protein level in groups given the same energy intake by gastric intubation. In Expt 1 daily heat production increased significantly (P < 0·05) with increasing protein level (50, 75 and 200 g protein/kg diet) when energy intake was constant, but in Expt 2 there was no significant effect of protein level (50, 100 and 200 g protein/kg diet). Problems arose in the selection of a suitable basis for comparison of heat production between groups because of the differences in body-weight and body composition3. The energy requirement for zero energy balance was approximately 10% lower for the low-protein groups than for those given the diet containing 200 g protein/kg when food intake was just above the maintenance level. When the requirement was expressed per unit metabolic body size (W0·75 kg) dietary protein level had no significant effect. The mean values for Expts 1 and 2 were 452 and 436 kJ respectively4. The energy cost of weight gain increased as dietary protein level decreased in pairs of groups gaining at the same rate. The extra energy ingested by the animals given the lower protein level was converted to body tissue with an efficiency of at least 0·705. Striking differences were observed in body composition and energy retention of the two pairs of groups used for the comparison of tube-feeding and ad lib. feeding. With the diet containing 50 g protein/kg, tube-fed rats gained significantly more weight (P < 0·01) and more fat, dry matter and energy (P < 0·001) than their ad lib. counterparts given an iso-energetic intake6. The results demonstrate that dietary protein level has little or no effect on the utilization of energy by growing rats when the pattern of intake is controlled by gastric intubation.

THE EFFECT OF DIETARY FAT AND PROTEIN LEVELS UPON THYROID ACTIVITY IN THE CHICK

1964 ◽  
Vol 42 (3) ◽  
pp. 333-339 ◽  
Author(s):  
B. E. March ◽  
Jacob Biely
Keyword(s):  
Dietary Fat ◽  
Dietary Protein ◽  
Protein Level ◽  
High Protein Diet ◽  
Protein Diet ◽  
Thyroid Activity ◽  
Protein Levels ◽  
Dietary Protein Level ◽  
Low Protein ◽  
Fat Diets

The effects on thyroid activity of dietary protein level and of dietary fat level were studied. Diets containing 18 and 26% of protein were fed with and without 8% of supplementary fat. Thyroid weights and thyroidal uptake of I131 of chicks fed the diets were determined. The chicks fed the higher dietary protein level had consistently greater thyroid weights. The effect of supplementary fat on thyroid weight was variable. Total thyroidal uptake of I131 in chicks fed the fat-supplemented diets was greater when the diets contained 26% of protein. With the low-fat diets, protein level did not significantly affect uptake of I131. Supplementary fat decreased I131 uptake in chicks fed the low-protein diet and increased I131 uptake in chicks fed the high-protein diet. Thus, although it is evident that diet affects thyroid activity, conclusions regarding the effect of diet will depend upon the parameter used as a measure of thyroid activity.

scholarly journals Nitrogen balance response to varying levels of dietary protein in slow-growing Windsnyer pigs

2021 ◽  
Vol 50 (5) ◽  
Author(s):  
V.A. Hlatini ◽  
C.N. Ncobela ◽  
M. Chimonyo
Keyword(s):  
Linear Relationship ◽  
Total Nitrogen ◽  
Nitrogen Balance ◽  
Dietary Protein ◽  
Protein Level ◽  
Growing Pigs ◽  
Nitrogen Utilization ◽  
Dietary Protein Level ◽  
Quadratic Relationship ◽  
Slow Growing

Protein requirements for slow-growing pigs have not been defined. The study was designed to determine the relationship between the level of dietary protein and nitrogen balance in slow-growing Windsnyer pigs. Thirty Windsnyer pigs with an initial bodyweight of 34.7 (SD = 0.85) kg were randomly assigned to six experimental diets containing 193, 174, 154, 135, 117, and 97 g/kg of crude protein (CP). Pigs were penned individually. There were five pigs in each diet. The faecal nitrogen output (NFO) showed a decreasing quadratic relationship with protein level. A linear relationship between protein level and urinary nitrogen excretion was observed (P =0.0001). The total nitrogen excreted showed a significant quadratic relationship to decreasing levels of CP in the diets (P =0.0001). The apparent digestibility of nitrogen had a linear relationship with dietary CP level (P =0.0005). A quadratic relationship between dietary protein level and N utilization was observed (P =0.0001). The optimum protein level for total nitrogen excreted, nitrogen utilization and biological value of feed protein were attained at 135 g/kg protein level. The efficiency of nitrogen utilization supports the low protein diet. The present results suggest reducing the dietary protein level for Windsnyer pigs to decrease amount of excreted N that is deposited into the environment.Protein requirements for slow-growing pigs have not been defined. The study was designed to determine the relationship between the level of dietary protein and nitrogen balance in slow-growing Windsnyer pigs. Thirty Windsnyer pigs with an initial bodyweight of 34.7 (SD = 0.85) kg were randomly assigned to six experimental diets containing 193, 174, 154, 135, 117, and 97 g/kg of crude protein (CP). Pigs were penned individually. There were five pigs in each diet. The faecal nitrogen output (NFO) showed a decreasing quadratic relationship with protein level. A linear relationship between protein level and urinary nitrogen excretion was observed (P =0.0001). The total nitrogen excreted showed a significant quadratic relationship to decreasing levels of CP in the diets (P =0.0001). The apparent digestibility of nitrogen had a linear relationship with dietary CP level (P =0.0005). A quadratic relationship between dietary protein level and N utilization was served (P =0.0001). The optimum protein level for total nitrogen excreted, nitrogen utilization and biological value of feed protein were attained at 135 g/kg protein level. The efficiency of nitrogen utilization supports the low protein diet. The present results suggest reducing the dietary protein level for Windsnyer pigs to decrease amount of excreted N that is deposited into the ironment. Keywords: apparent nitrogen digestibility, ideal protein level, nitrogen retention, excreted nitrogen, nitrogen utilization

On the variation of urinary excretion of creatinine and purine derivatives in pregnant and lactating ewes given diets with different protein contents

1999 ◽  
Vol 68 (3) ◽  
pp. 555-566 ◽  
Author(s):  
C. Dapoza ◽  
C. Castrillo ◽  
J. Balcells ◽  
S. Martín-Orúe ◽  
J. A. Guada
Keyword(s):  
Organic Matter ◽  
Plasma Concentration ◽  
Urinary Excretion ◽  
Dietary Protein ◽  
Protein Level ◽  
Fish Meal ◽  
Physiological State ◽  
Purine Derivatives ◽  
Creatinine Excretion ◽  
Dietary Protein Level

AbstractThe effect of the physiological state and dietary protein level on urinary excretion of creatinine (C) and purine derivatives (PD) was studied in two experiments carried out with pregnant and lactating ewes to evaluate whether the PD/C ratio in urine can he confidently used as an index of PD excretion. In both experiments ewes were given ammonia-treated straw and concentrates including different levels of fish meal and the excretion in urine and milk and the plasma concentration of C, allantoin (AL), xanthine, hypoxanthine and uric acid was measured.Creatinine excretion (in urine and milk) was higher in pregnant ewes than in those lactating (492 and 420 (s.e. 10.0) μmol/kg maternal live weight0.75) and no significant differences were found due to number of foetuses and dietary protein level. The coefficient of variation was 0·10 in both pregnancy and lactation and individual variation accounted for proportionately 0·78 and 0·93 of total variation. The AL/C ratio in urine was highly correlated with daily AL excretion (r = 0·90 and 0·78 in pregnant and lactating ewes, respectively). Changes in PD excretion with experimental treatments were mainly reflected in AL, as the main component (0-83) of total PD. Most of the variation in AL excretion was explained by differences in rumen fermentable organic matter intake (RFOMI) (R2 = 0·79) and AL excretion did not differ between treatments when expressed per kg of RFOMI. In contrast to this the ratio AL/digestible organic matter intake decreased with increasing levels of fish meal in the diet. Urinary PD excretion was better related to estimated PD kidney tubular load (r = 0·76) than to PD plasma concentration (r = 0·64).The results suggest that creatinine excretion is scarcely affected by the number of foetuses in pregnancy and dietary protein level but if the AL/С in urine is used instead of total collection as an index of purines absorbed in the duodenum, differences in urinary creatinine excretion due to physiological state must be accounted for.

Voluntary intake of low-protein diets by ruminants: II. Intake of food by sheep

1967 ◽  
Vol 69 (3) ◽  
pp. 383-390 ◽  
Author(s):  
R. C. Elliott
Keyword(s):  
Dietary Protein ◽  
Protein Level ◽  
Nutritive Value ◽  
Latin Square ◽  
Dietary Protein Level ◽  
Low Protein ◽  
Total Food ◽  
Separate Treatment ◽  
Voluntary Intake ◽  
Protein Diets

1. A study was made of the voluntary intake of hay of low nutritive value by sheep when given four different amounts of concentrate foods (9, 18, 27 and 36 g/kg W0.73/day) each providing three levels of protein (1·3, 2·6 and 3·9 g DCP/kg W0.73/day). Hay alone was offered as a separate treatment. The trial was designed as an incomplete Latin square with thirteen treatments, thirteen sheep and four replicates.2. Voluntary intake of low-protein hay by sheep was invariably lowered when they were given increasing amounts of concentrates. Hay consumption was also affected by level of supplementary protein; intakes increasing sharply from the lowest level provided (1·3 g DCP/kg metabolic body weight) to maximal intakes when about 3 g DCP/kg W0.73 were given to the sheep.3. Total food and digestible energy (DE) intakes were similarly affected by changes in dietary protein level. Successive increments in concentrate allowances, except at the highest level of concentrate input, caused corresponding reductions in hay intake so that total food consumption remained similar (when protein level was kept constant). In consequence, DE intakes rose to maxima when approximately 30 g concentrate/kg W0.73/day were fed to the sheep.

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