THE RELATION OF DIETARY PROTEIN LEVEL TO LIVER ENZYME ACTIVITIES IN COLD-EXPOSED RATS

1963 ◽  
Vol 41 (9) ◽  
pp. 1871-1877 ◽  
Author(s):  
John R. Beaton
Keyword(s):  
Cold Exposure ◽  
Dietary Protein ◽  
Protein Level ◽  
Liver Enzymes ◽  
Albino Rats ◽  
Protein Levels ◽  
Dietary Protein Level ◽  
Phosphate Activated Glutaminase ◽  
Relationship Of ◽  
Environmental Temperatures

Male, albino rats were fed diets containing 5%, 20%, and 40% casein by weight for 7 days at environmental temperatures of 22 °C and 2–3 °C. In one experiment, food was provided ad libitum; in a second experiment, all groups were provided with equal amounts of food. At 22 °C, the activities in liver of alanine-glutamic transaminase, phosphate-activated glutaminase, and arginase increased with increasing dietary protein level. At 2–3 °C, activities of the last two enzymes increased with increasing dietary protein level from 5% to 20% but not from 20% to 40% whereas transaminase activities increased throughout the dietary protein range 5% to 40%. No relationship of glucose-6-phosphatase activity to dietary protein level was evident at either environmental temperature. Cold exposure per se increased the activities of alanine-glutamic transaminase and glucose-6-phosphatase in all dietary protein groups but increased the activities of arginase and phosphate-activated glutaminase only in rats fed the 5% and 20% protein diets. It is postulated that increased activities of these liver enzymes during cold exposure result from augmented catabolism of substrates to meet increased energy requirements. As previously observed with respect to other metabolic alterations, it is apparent that cold exposure modifies the response of liver enzymes to changing dietary protein levels.

THE RELATION OF DIETARY PROTEIN LEVEL TO LIVER ENZYME ACTIVITIES IN COLD-EXPOSED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 1871-1877
Author(s):  
John R. Beaton
Keyword(s):  
Cold Exposure ◽  
Dietary Protein ◽  
Protein Level ◽  
Liver Enzymes ◽  
Albino Rats ◽  
Protein Levels ◽  
Dietary Protein Level ◽  
Phosphate Activated Glutaminase ◽  
Relationship Of ◽  
Environmental Temperatures

Male, albino rats were fed diets containing 5%, 20%, and 40% casein by weight for 7 days at environmental temperatures of 22 °C and 2–3 °C. In one experiment, food was provided ad libitum; in a second experiment, all groups were provided with equal amounts of food. At 22 °C, the activities in liver of alanine-glutamic transaminase, phosphate-activated glutaminase, and arginase increased with increasing dietary protein level. At 2–3 °C, activities of the last two enzymes increased with increasing dietary protein level from 5% to 20% but not from 20% to 40% whereas transaminase activities increased throughout the dietary protein range 5% to 40%. No relationship of glucose-6-phosphatase activity to dietary protein level was evident at either environmental temperature. Cold exposure per se increased the activities of alanine-glutamic transaminase and glucose-6-phosphatase in all dietary protein groups but increased the activities of arginase and phosphate-activated glutaminase only in rats fed the 5% and 20% protein diets. It is postulated that increased activities of these liver enzymes during cold exposure result from augmented catabolism of substrates to meet increased energy requirements. As previously observed with respect to other metabolic alterations, it is apparent that cold exposure modifies the response of liver enzymes to changing dietary protein levels.

METABOLIC EFFECTS OF DIETARY PROTEIN LEVEL WITH CALORIC RESTRICTION IN COLD-EXPOSED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 149-160 ◽  
Author(s):  
John R. Beaton ◽  
T. Orme ◽  
A. Turner ◽  
J. Laufer
Keyword(s):  
Dietary Protein ◽  
Protein Level ◽  
Corn Oil ◽  
Amino Nitrogen ◽  
Metabolic Effects ◽  
Albino Rats ◽  
Blood Levels ◽  
Dietary Protein Level ◽  
Isocaloric Diets ◽  
Environmental Temperatures

Male albino rats were fed isocaloric diets (5%, 20%, and 40% protein and 10% corn oil by weight) in restricted amounts (6 g/rat per day) at environmental temperatures of 22 °C and 2 °C. Measurements were made of urinary excretion of nitrogen, potassium, sodium, phosphorus, and creatinine, of blood levels of glucose, urea, amino nitrogen, packed cell volume, and serum total proteins and of body contents of protein, moisture, and total crude fatty acids. Metabolic effects of food restriction were readily apparent at 22 °C and the diet appeared to play a role in modifying some of these effects in approximate proportion to the dietary protein level. With superimposition of cold exposure, metabolic differences among groups were decreased in degree with some suggestive evidence of a beneficial effect of increased dietary protein level and of a deleterious effect of decreased dietary protein (high carbohydrate) under these conditions.

METABOLIC EFFECTS OF THREE DIETARY PROTEIN LEVELS FED ISOCALORICALLY TO COLD-EXPOSED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 161-170 ◽  
Author(s):  
John R. Beaton ◽  
T. Orme ◽  
J. Laufer ◽  
A. Turner
Keyword(s):  
Dietary Protein ◽  
Protein Level ◽  
Corn Oil ◽  
Amino Nitrogen ◽  
Metabolic Effects ◽  
Albino Rats ◽  
Blood Levels ◽  
Beneficial Effects ◽  
Dietary Protein Level ◽  
Environmental Temperatures

Male albino rats were fed isocalorically on diets containing 5%, 20%, and 40% protein (casein) and 10% corn oil by weight at environmental temperatures of 22 °C and 2 °C. Since the 5% protein fed group consumed less than normal amounts of food, consequently the food intake of all groups was moderately restricted. Measurements were made of urinary excretion of nitrogen, potassium, sodium, phosphorus, and creatinine, of blood levels of glucose, urea, amino nitrogen, packed cell volume, and serum total proteins and of total body content of protein, water, and crude fatty acids. Metabolic effects of dietary protein level were readily apparent at both environmental temperatures. Unlike earlier studies with ad libitum and severely restricted feeding, superimposition of cold exposure did not eliminate metabolic differences among groups. As observed in previous studies, reduction of dietary protein level from 20% to 5% had a deleterious effect in cold-exposed rats. In the present study no beneficial effects due to increasing dietary protein level from 20% to 40% were observed.

METABOLIC EFFECTS OF THREE DIETARY PROTEIN LEVELS FED ISOCALORICALLY TO COLD-EXPOSED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 161-170 ◽  
Author(s):  
John R. Beaton ◽  
T. Orme ◽  
J. Laufer ◽  
A. Turner
Keyword(s):  
Dietary Protein ◽  
Protein Level ◽  
Corn Oil ◽  
Amino Nitrogen ◽  
Metabolic Effects ◽  
Albino Rats ◽  
Blood Levels ◽  
Beneficial Effects ◽  
Dietary Protein Level ◽  
Environmental Temperatures

Male albino rats were fed isocalorically on diets containing 5%, 20%, and 40% protein (casein) and 10% corn oil by weight at environmental temperatures of 22 °C and 2 °C. Since the 5% protein fed group consumed less than normal amounts of food, consequently the food intake of all groups was moderately restricted. Measurements were made of urinary excretion of nitrogen, potassium, sodium, phosphorus, and creatinine, of blood levels of glucose, urea, amino nitrogen, packed cell volume, and serum total proteins and of total body content of protein, water, and crude fatty acids. Metabolic effects of dietary protein level were readily apparent at both environmental temperatures. Unlike earlier studies with ad libitum and severely restricted feeding, superimposition of cold exposure did not eliminate metabolic differences among groups. As observed in previous studies, reduction of dietary protein level from 20% to 5% had a deleterious effect in cold-exposed rats. In the present study no beneficial effects due to increasing dietary protein level from 20% to 40% were observed.

METABOLIC EFFECTS OF DIETARY PROTEIN LEVEL IN COLD-EXPOSED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 139-147 ◽  
Author(s):  
John R. Beaton ◽  
T. Orme ◽  
A. Turner ◽  
J. Laufer
Keyword(s):  
Cold Exposure ◽  
Dietary Protein ◽  
Protein Level ◽  
Corn Oil ◽  
Urine Volume ◽  
Amino Nitrogen ◽  
Metabolic Effects ◽  
Albino Rats ◽  
Blood Levels ◽  
Dietary Protein Level

Male albino rats were fed ad libitum isocaloric diets containing 5%, 20%, and 40% protein and 10% corn oil by weight. Measurements were made of nitrogen retention, urine volume, water intake, body composition, and blood levels of glucose, amino nitrogen, and urea at environmental temperatures of 22 ± 2 °C (7 days) followed by 2 ± 1 °C (8 days). Significant metabolic differences were evident among the three dietary groups at 22 °C but these differences were, in general, reduced under conditions of cold exposure. It is of interest that the rats on the 40% protein diet did not exhibit the typical increases in food consumption and urine volume when exposed to cold and, further, that these animals appeared able to maintain body weight and synthesize body fat during cold exposure. It seems that dietary protein level may play an important role during exposure to cold.

METABOLIC EFFECTS OF DIETARY PROTEIN LEVEL WITH CALORIC RESTRICTION IN COLD-EXPOSED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 149-160 ◽  
Author(s):  
John R. Beaton ◽  
T. Orme ◽  
A. Turner ◽  
J. Laufer
Keyword(s):  
Dietary Protein ◽  
Protein Level ◽  
Corn Oil ◽  
Amino Nitrogen ◽  
Metabolic Effects ◽  
Albino Rats ◽  
Blood Levels ◽  
Dietary Protein Level ◽  
Isocaloric Diets ◽  
Environmental Temperatures

Male albino rats were fed isocaloric diets (5%, 20%, and 40% protein and 10% corn oil by weight) in restricted amounts (6 g/rat per day) at environmental temperatures of 22 °C and 2 °C. Measurements were made of urinary excretion of nitrogen, potassium, sodium, phosphorus, and creatinine, of blood levels of glucose, urea, amino nitrogen, packed cell volume, and serum total proteins and of body contents of protein, moisture, and total crude fatty acids. Metabolic effects of food restriction were readily apparent at 22 °C and the diet appeared to play a role in modifying some of these effects in approximate proportion to the dietary protein level. With superimposition of cold exposure, metabolic differences among groups were decreased in degree with some suggestive evidence of a beneficial effect of increased dietary protein level and of a deleterious effect of decreased dietary protein (high carbohydrate) under these conditions.

METABOLIC EFFECTS OF DIETARY PROTEIN LEVEL IN COLD-EXPOSED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 139-147 ◽  
Author(s):  
John R. Beaton ◽  
T. Orme ◽  
A. Turner ◽  
J. Laufer
Keyword(s):  
Cold Exposure ◽  
Dietary Protein ◽  
Protein Level ◽  
Corn Oil ◽  
Urine Volume ◽  
Amino Nitrogen ◽  
Metabolic Effects ◽  
Albino Rats ◽  
Blood Levels ◽  
Dietary Protein Level

Male albino rats were fed ad libitum isocaloric diets containing 5%, 20%, and 40% protein and 10% corn oil by weight. Measurements were made of nitrogen retention, urine volume, water intake, body composition, and blood levels of glucose, amino nitrogen, and urea at environmental temperatures of 22 ± 2 °C (7 days) followed by 2 ± 1 °C (8 days). Significant metabolic differences were evident among the three dietary groups at 22 °C but these differences were, in general, reduced under conditions of cold exposure. It is of interest that the rats on the 40% protein diet did not exhibit the typical increases in food consumption and urine volume when exposed to cold and, further, that these animals appeared able to maintain body weight and synthesize body fat during cold exposure. It seems that dietary protein level may play an important role during exposure to cold.

scholarly journals Performance of the African giant rat (Cricetomys gambianus Waterhouse) on commercial rations and varying dietary protein levels

1978 ◽  
Vol 12 (2) ◽  
pp. 109-112 ◽  
Author(s):  
S. S. Ajayi ◽  
O. O. Tewe
Keyword(s):  
Growth Performance ◽  
Dietary Protein ◽  
Protein Level ◽  
Efficiency Ratio ◽  
Experimental Diet ◽  
Protein Levels ◽  
Dietary Protein Level ◽  
Food Efficiency Ratio ◽  
Cricetomys Gambianus ◽  
African Giant Rat

The growth performance of 24 weanling giant rats was studied in 2 experiments of 30 weeks duration with commercial livestock rations and graded levels of protein. Daily average liveweight gain was 5·1-7·3 g, food consumption 26·9-36·3 g on 6 diets. Food intake, growth rate and food efficiency ratio were very similar using the different commercial diets. Growth performance improved as the dietary protein level was raised from 10 to 13%, but a further increase to 16% did not result in greater growth. The commercial pig ration and the experimental diet containing 13% dietary protein level were found to give satisfactory growth, and are recommended for studies with these animals.

Effect of dietary protein level on some key enzymes of the tryptophan-NAD pathway

1977 ◽  
Vol 38 (1) ◽  
pp. 39-45 ◽  
Author(s):  
U. Satyanarayana ◽  
B. S. Narasinga Rao
Keyword(s):  
Nicotinic Acid ◽  
G Protein ◽  
Dietary Protein ◽  
Protein Level ◽  
Urinary Metabolites ◽  
List Type ◽  
Key Enzymes ◽  
Protein Levels ◽  
Dietary Protein Level ◽  
Quinolinate Phosphoribosyltransferase

1.Six groups of rats were given diets containing protein at three levels (SO, 100 and 200 g/kg), with and without nicotinic acid. After 4 weeks on these diets some key enzymes of the tryptophan and nicotinic acid-NAD pathway, liver nicotinamide nucleotide concentration, and urinary metabolites of tryptophan and nicotinic acid were studied.2.Liver nicotinamide nucleotide levels were lower in rats given the diet with 50 g protein/kg as compared to those in rats given diets with 100 and 200 g protein/kg. The addition of nicotinic acid to the diet resulted in a significant increase in the levels of nicotinamide nucleotides only in rats given 50 g protein/kg diet but not in those given either 100 or 200 g protein/kg diet.3.Liver tryptophan oxygenase (EC 1.13.1.12) activity increased with increasing dietary protein level. Nicotinic acid in the diet had no effect on its activity.4.Quinolinate phosphoribosyltransferase (EC 2.4.2.a) activity in liver was inversely related to dietary protein level, and nicotinic acid in the diet had no effect on its activity.5.Liver nicotinate phosphoribosyltransferase (EC 2.4.2.11) activity and kidney picolinate carboxylase (EC 4.1.1.45) activity were not altered either by dietary protein level or nicotinic acid in the diet.6.The addition of nicotinic acid to the diet resulted in increased excretion of W-methylnicotinamide at all dietary protein levels.7.The inverse relationship between protein level in the diet and liver quinolinate phosphoribosyltransferase activity, the rate-limiting enzyme of the tryptophan-NAD pathway suggests that the efficiency of conversion of tryptophan to NAD is related to protein level in the diet, the efficiency decreasing with an increase in the level of dietary protein.

Carbohydrate utilization and its protein-sparing effect in diets for grouper (Epinephelus malabaricus)

2001 ◽  
Vol 73 (2) ◽  
pp. 299-304 ◽  
Author(s):  
S. Y. Shiau ◽  
Y. H. Lin
Keyword(s):  
Weight Gain ◽  
Dietary Protein ◽  
Protein Level ◽  
Starch Content ◽  
Carbohydrate Utilization ◽  
Protein Levels ◽  
Dietary Protein Level ◽  
Protein Sparing ◽  
Epinephelus Malabaricus ◽  
Glucose Group

AbstractTo investigate the utilization of different carbohydrate sources and the possible protein-sparing effects of carbohydrates for grouper (Epinephelus malabaricus), six isoeneregtic purified diets were prepared. Three dietary protein levels (500, 460, 420 g/kg) were achieved by substitution with three levels (143, 195, 246 g/kg) and two sources (glucose and starch) of dietary carbohydrate. Each of the six diets was given to triplicate groups of grouper in a recirculating rearing system for 8 weeks. In the glucose group, weight gain of fish decreased with increasing dietary glucose and decreasing protein content. In the starch group, weight gain of fish given the 500 g/kg protein diet was higher (P < 0 ·05) than fish given the 460 and 420 g/kg protein diets. At each of the dietary protein levels weight gain of the glucose-group fish and the starch-group fish were similar (P > 0·05). At the 500 g/kg dietary protein level body lipid content of the starch-group fish was higher than that of glucose-group fish. At 500 and 460 g/kg dietary protein levels, fish given starch diets had higher hepatic hexokinase activity than fish given the glucose diets. These results suggest that, at the levels studies, the utilization of starch and glucose by grouper is similar. Decreasing the dietary protein level from 460 g/kg to 420 g/kg by increasing the starch content in the diet from 195 g/kg to 246 g/kg did not reduce (P > 0·05) weight gain and food efficiency, suggesting that starch could spare some protein when the dietary protein level is low.

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