The Role of the Colon in Urea Metabolism in Man

1976 ◽  
Vol 50 (1) ◽  
pp. 51-59 ◽  
Author(s):  
J. A. Gibson ◽  
N. J. Park ◽  
G. E. Sladen ◽  
A. M. Dawson
Keyword(s):  
Dietary Protein ◽  
Colonic Mucosa ◽  
Normal Subjects ◽  
Urea Concentration ◽  
Low Protein ◽  
Urea Content ◽  
Colonic Lumen ◽  
Urea Metabolism ◽  
Protein Diets

1. The urea content of ileostomy effluent has been measured by the urease method as an indirect estimate of the urea concentration in the lumen of the normal ileum. 2. The plasma disappearance of intravenously administered [14C]urea was used to study intestinal urea breakdown. Normal subjects on high and low protein diets and patients with either excised (i.e. with ileostomies) or excluded colons were studied. 3. The 24 h intestinal urea breakdown was considerably greater than the quantity of urea estimated to be entering the colon from the ileum and across the colonic mucosa. 4. Intestinal urea breakdown increased with increase in dietary protein and decreased with, but was not abolished by, exclusion or excision of the colon. 5. Our results suggest that the colonic lumen is not the only site of intestinal ureolysis and that significant quantities of urea must be broken down either at a juxtamucosal site or in the ileum.

scholarly journals Severe protein deficiency induces hepatic expression and systemic level of FGF21 but inhibits its hypothalamic expression in growing rats

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joanna Moro ◽  
Catherine Chaumontet ◽  
Patrick C. Even ◽  
Anne Blais ◽  
Julien Piedcoq ◽  
...  
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Energy Expenditure ◽  
Energy Intake ◽  
Dietary Protein ◽  
Protein Deficiency ◽  
Protein Diet ◽  
Growing Rats ◽  
Low Protein ◽  
Protein Diets

AbstractTo study, in young growing rats, the consequences of different levels of dietary protein deficiency on food intake, body weight, body composition, and energy balance and to assess the role of FGF21 in the adaptation to a low protein diet. Thirty-six weanling rats were fed diets containing 3%, 5%, 8%, 12%, 15% and 20% protein for three weeks. Body weight, food intake, energy expenditure and metabolic parameters were followed throughout this period. The very low-protein diets (3% and 5%) induced a large decrease in body weight gain and an increase in energy intake relative to body mass. No gain in fat mass was observed because energy expenditure increased in proportion to energy intake. As expected, Fgf21 expression in the liver and plasma FGF21 increased with low-protein diets, but Fgf21 expression in the hypothalamus decreased. Under low protein diets (3% and 5%), the increase in liver Fgf21 and the decrease of Fgf21 in the hypothalamus induced an increase in energy expenditure and the decrease in the satiety signal responsible for hyperphagia. Our results highlight that when dietary protein decreases below 8%, the liver detects the low protein diet and responds by activating synthesis and secretion of FGF21 in order to activate an endocrine signal that induces metabolic adaptation. The hypothalamus, in comparison, responds to protein deficiency when dietary protein decreases below 5%.

EFFECTS OF GRADED DIETARY PROTEIN LEVELS ON UREA RECYCLING IN THE PIG

1982 ◽  
Vol 62 (4) ◽  
pp. 1193-1197 ◽  
Author(s):  
P. A. THACKER ◽  
J. P. BOWLAND ◽  
L. P. MILLIGAN ◽  
E. WELTZIEN
Keyword(s):  
Dietary Protein ◽  
Protein Diet ◽  
Nitrogen Excretion ◽  
Entry Rate ◽  
Protein Nitrogen ◽  
Protein Levels ◽  
Low Protein ◽  
Key Words Pig ◽  
Urea Recycling ◽  
Protein Diets

The kinetics of urea recycling were determined in six female crossbred pigs utilizing a radioisotope dilution technique. The experimental animals were fed three times daily 500 g of a corn-soybean meal diet formulated to contain 8.4, 15.8 or 24.7% crude protein. Nitrogen digestibility, urinary nitrogen excretion, total nitrogen excretion and retained nitrogen were highest on the 24.7% protein diet and decreased with decreasing dietary protein. Urea pool size, entry rate and excretion rate were also highest on the 24.7% protein diet and decreased with decreasing protein intake. Expressed as a percentage of the total entry rate, a significantly higher percentage of urea was recycled in pigs fed the low protein diets compared with those fed a higher protein diet. Key words: Pig, urea, recycling, kinetics, protein

scholarly journals Effects of Dietary Protein Levels on Bamei Pig Intestinal Colony Compositional Traits

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Dong Wang ◽  
Guoshun Chen ◽  
Lili Song ◽  
Mingjie Chai ◽  
Yongfeng Wang ◽  
...  
Keyword(s):  
Dietary Protein ◽  
Protein Level ◽  
Crude Protein ◽  
Microbial Flora ◽  
Protein Levels ◽  
Low Protein ◽  
Dietary Crude Protein ◽  
Protein Diets ◽  
Crude Protein Level ◽  
Microbial Diversities

Diets containing different crude protein levels (16%, 14%, and 12%) were created to feed Bamei pigs in order to study the effect of these compositions on intestinal colonies. Therefore, 27 healthy Bamei pigs of similar weight ( 20.99   kg ± 0.16   kg ) were selected and randomly divided into three groups for microbial diversity analysis. The results of this study show that microbial diversities and abundances in Bamei pig jejunum and caecum samples after feeding with different dietary protein levels were significantly different. Dietary crude protein level exerted no significant effect on the Shannon index for cecum microbes in these pigs, while Simpson, ACE, and Chao1 indices for group I were all significantly higher than those of either the control group or group II ( P < 0.05 ). Indeed, data show that microbial diversities and abundances in the 14% protein level group were higher than those in either the 16% or 12% groups. Dominant bacteria present in jejunum and cecum samples given low-protein diets were members of the phyla Firmicutes and Bacteroidetes. Data show that as dietary crude protein level decreases, representatives of the microbial flora genus Lactobacillus in jejunum and cecum samples gradually increases. Values for the KEGG functional prediction of microbial flora at different dietary protein levels also show that genes of jejunum and cecum microorganisms were mainly enriched in the “metabolism” pathway and indicate that low protein diets increase intestinal metabolic activity. Therefore, we recommend that Bamei pig dietary protein levels are reduced 2% from their existing level of 16% crude protein. We also suggest that essential synthetic amino acids (AA) are added to optimize this ideal protein model as this will increase intestinal flora diversity in these pigs and enhance health. These changes will have a positive effect in promoting the healthy growth of Bamei pigs.

scholarly journals Effect of Overeating Dietary Protein at Different Levels on Circulating Lipids and Liver Lipid: The PROOF Study

Nutrients ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3801
Author(s):  
George A. Bray ◽  
Leanne M. Redman ◽  
Jennifer Rood ◽  
Lilian de Jonge ◽  
Steven R. Smith
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Dietary Fat ◽  
Dietary Protein ◽  
Hdl Cholesterol ◽  
Fat Free Mass ◽  
Protein Diet ◽  
Liver Fat ◽  
Low Protein ◽  
Protein Diets

Background: During overeating, a low protein diet slowed the rate of weight gain and increased the energy cost of the added weight, suggesting that low protein diets reduced energy efficiency. The Protein Overfeeding (PROOF) study explored the metabolic changes to low and high protein diets, and this sub-study examined the changes in body composition and blood lipids when eating high and low protein diets during overeating. Methods: Twenty-three healthy volunteers (M = 14; F = 9) participated in an 8-week, parallel arm study where they were overfed by ~40% with diets containing 5% (LPD = low protein diet), 15% (NPD = normal protein diet), or 25% (HPD = high protein diet) protein. Dual energy X-ray absorptiometry (DXA) and computer tomography (CT) were used to quantify whole body and abdominal fat and intrahepatic lipid, respectively. Metabolites were measured by standard methods. Results: Protein intake and fat intake were inversely related since carbohydrate intake was fixed. Although overeating the LPD diet was associated with a significant increase in high density lipoprotein (HDL)-cholesterol (p < 0.001) and free fatty acids (p = 0.034), and a significant decrease in fat free mass (p < 0.0001) and liver density (p = 0.038), statistical models showed that dietary protein was the main contributor to changes in fat free mass (p = 0.0040), whereas dietary fat was the major predictor of changes in HDL-cholesterol (p = 0.014), free fatty acids (p = 0.0016), and liver fat (p = 0.0007). Conclusions: During 8 weeks of overeating, the level of dietary protein intake was positively related to the change in fat free mass, but not to the change in HDL-cholesterol, free fatty acids, and liver fat which were, in contrast, related to the intake of dietary fat.

scholarly journals Possible role of available phosphorus in potentiating the use of low-protein diets for broiler chicken production

2020 ◽  
Vol 99 (12) ◽  
pp. 6954-6963
Author(s):  
A.J. Cowieson ◽  
R. Perez-Maldonado ◽  
A. Kumar ◽  
M. Toghyani
Keyword(s):  
Broiler Chicken ◽  
Available Phosphorus ◽  
Low Protein ◽  
Protein Diets

Free-feeding patterns of rats: effects of pyrogen and dietary protein content

1975 ◽  
Vol 228 (4) ◽  
pp. 1284-1287 ◽  
Author(s):  
PM Leung ◽  
BA Horwitz
Keyword(s):  
Food Intake ◽  
Body Temperature ◽  
Heat Production ◽  
Dietary Protein ◽  
Low Protein ◽  
Bacterial Pyrogen ◽  
Free Feeding ◽  
High Protein Diets ◽  
Protein Diets ◽  
Voluntary Food Intake

Infusion of bacterial pyrogen (Priomen) was accompanied by an increase in body temperature, an increase in heat production, and a decrease in the voluntary food intake ofrats fed high-as well as low-protein diets. The magnitude of this pyrogen-induced depression of food intake was comparable for both diets. However, in rats fed high-protein diets, this decrease was additive to that normally seen following administration of such diets. These data indicate that the control of food intake cannot be explained in terms of a behavioral the more regulatory response.

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.

scholarly journals THE ROLE OF HOMOCYSTINE IN PROTECTING PROTEIN-DEPLETED DOGS EXPOSED TO FATAL DOSES OF CHLOROFORM

1955 ◽  
Vol 101 (2) ◽  
pp. 197-204
Author(s):  
George P. Vennart ◽  
Frank W. McKee
Keyword(s):  
Liver Damage ◽  
Methyl Groups ◽  
Histological Changes ◽  
Long Period ◽  
Lethal Action ◽  
Low Protein ◽  
Depletion Period ◽  
Protein Diets ◽  
Cellular Destruction

In dogs maintained on low protein diets and subjected to phlebotomy over a long period of time, the inhalation of chloroform, for 30 minutes, produced uniform fatality within 48 hours. The histological changes of massive hepato-cellular destruction were observed at autopsy. Homocystine, in the amount of 2.0 gm., given orally 2 hours after or 2 hours prior to the administration of chloroform, protected dogs against the lethal action of the toxin. Inconstant changes in fibrinogen and icteric indices were observed in the protected animals, indicating some mild liver damage, but this was not correlated with the length of the previous depletion period, the phase of the experiment, or any other factor. No evidence was obtained that methyl groups are necessary for the protection of the liver by homocystine.

Sign in / Sign up

Export Citation Format

Share Document