Renal Function in the Spectacled Hare-Wallaby, Lagorchestes conspicillatus: Effects of Dehydration and Protein Deficiency

1983 ◽  
Vol 31 (2) ◽  
pp. 101 ◽  
Author(s):  
HR Bakker ◽  
SD Bradshaw
Keyword(s):  
Renal Function ◽  
Glomerular Filtration ◽  
Protein Intake ◽  
Protein Diet ◽  
Inulin Clearance ◽  
Field Observations ◽  
Clearance Ratio ◽  
Low Protein ◽  
Urine Production ◽  
Protein Diets

Renal function was studied in a marsupial, the spectacled hare-wallaby Lagorchestes conspicillatus, and the effects of acute dehydration and exposure to a low-protein diet assessed. The rate of glomerular filtration (GFR), measured as the inulin clearance, fell significantly with both treatments but tubular function was unaffected. This reduction in GFR accounted entirely for the antidiuresis observed with both dehydration and exposure to low-protein intake and accords with field observations of the hare- wallaby, where urine volumes are characteristically low and have low osmolalities. When data from animals on both high and low-protein diets were considered together, the clearance ratio for urea (C*urea/C*in) was found to be positively correlated with the rate of urine production, and it is evident that mechanisms which invoke antidiuresis in this species will automatically enhance the reabsorption of urea.

Renal Regulation of Urea Excretion in Sheep

1958 ◽  
Vol 194 (2) ◽  
pp. 221-228 ◽  
Author(s):  
Bodil Schmidt-Nielsen ◽  
Humio Osaki ◽  
H. V. Murdaugh ◽  
Roberta O'Dell
Keyword(s):  
Protein Intake ◽  
Urine Flow ◽  
Inulin Clearance ◽  
Urea Clearance ◽  
Clearance Ratio ◽  
Plasma Urea ◽  
Urea Excretion ◽  
Low Protein ◽  
Abrupt Changes ◽  
Sudden Decrease

In order to elucidate the renal mechanism for the regulation of urea excretion the urea clearance and the GFR were studied in sheep during normal and low protein intake in a range of urine flows from extreme osmotic diuresis to minimal flows. Differences in the effects of osmotic and water diureses and the effects of abrupt changes in rate of urine flow were also studied. In sheep on normal protein intake the urea/inulin clearance ratio was constant in the range of urine flows corresponding to inulin U/P ratios from 10 to 500. On low protein intake the urea/inulin clearance ratio decreased markedly with decreasing urine flow. At extremely high urine flows no difference was found between the urea/inulin clearance ratios on different diets. Regulation was found to be independent of GFR, plasma urea concentration and osmotic load and must therefore be on the tubular level. Observations during abrupt changes in urine flow showed that the urea clearance is not only abnormally high during increasing flows but also abnormally low during a sudden decrease in flow. The first phenomenon is known as ‘exaltation,’ and we have termed the latter phenomenon ‘abatement.’ The data on exaltation and abatement and on the effects of urine flow are consistent with a previously suggested hypothesis that the excretion of urea in the mammalian kidney is brought about through a regulated active transport of urea, accentuated by a countercurrent multiplier system represented by Henle's loops and vasa recta.

The effects of amino acid loading on glomerular filtration in dogs on different protein diets: a controlled study

1988 ◽  
Vol 66 (7) ◽  
pp. 993-996
Author(s):  
A. Fine
Keyword(s):  
Amino Acid ◽  
Glomerular Filtration ◽  
High Protein Diet ◽  
Protein Diet ◽  
Controlled Study ◽  
Acid Infusion ◽  
Amino Acid Infusion ◽  
Low Protein ◽  
Acid Loading ◽  
Protein Diets

Considerable variation in both the magnitude and pattern of response of glomerular filtration rate (GFR) to protein loading in omnivores has been reported in the literature. These experiments were designed to examine, under carefully controlled conditions, the effects of different acute protein loads given to a group of dogs placed on a normal protein (NP) intake for 4 weeks and to the same dogs when on a low protein (LP) intake for the same duration. GFR did not change when the dogs were changed from NP to LP diets, 3.0 + 0.2 (NP) vs. 3.2 + 0.3 (LP) mL∙min−1∙kg−1. Intravenous amino acid was infused at 15, 25, and 40 mL/h on different days. Regardless of whether on a low or high protein diet, the GFR did not change. Another set of experiments was performed in another Canadian centre 2000 miles away. In these studies with dogs on a similar normal protein diet, a striking rise in GFR occurred following amino-acid infusion at 25 mL/h, 3.1 + 0.3 vs. 4.8 + 0.6 mL∙min−1∙kg−1 (p < 0.001). These results demonstrate, at least in the dog, that contrary to previous reports, dietary protein changes do not affect the GFR. Furthermore, the GFR response to an acute intravenous protein load does not depend on the amount of protein given nor the previous protein diet but appears to be possibly dependent on other factors that may be environmental or congenital.

Food and protein intake, glucagon, and distribution of alpha-aminoisobutyrate in the rat

1980 ◽  
Vol 238 (4) ◽  
pp. E358-E363
Author(s):  
J. K. Tews ◽  
A. E. Harper
Keyword(s):  
Dietary Protein ◽  
Protein Intake ◽  
Control Diet ◽  
High Protein Diet ◽  
High Protein ◽  
Protein Diet ◽  
Tissue Water ◽  
Low Protein ◽  
Protein Diets ◽  
Different Tissues

Distribution of alpha-aminoisobutyric acid (AIB) in the rat was modified by food, dietary protein, and glucagon. In rats last fed 24 h before AIB injection, AIB clearance from plasma and uptake into liver were greater in rats fed a high-protein diet (60% casein) than in rats fed the control diet (18% casein); AIB clearance from plasma and uptake into muscle were lowered by a low-protein diet (6% casein). Feeding rats lowered clearance of AIB from plasma in low- and high-protein groups. Distribution ratios (AIB concentration in tissue water/AIB in plasma) were low in all tissues but liver during the first 7 h after feeding high protein when compared to the control values; ratios were low in muscle, heart, and kidney after feeding low protein. Maximum ratios occurred at different times for different tissues; the time was delayed by the high-protein diet in all tissues but liver. Glucagon increased all ratios in rats fed the control or low-protein diets, with the smallest changes occurring in liver and muscle from low-protein rats.

scholarly journals PSIV-6 Effect of a Phytogenic Water Additive on Growth Performance, Blood Metabolites and Gene Expression of Amino Acids Transporters in Nursery Pigs Fed with Low Protein Diets

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 281-282
Author(s):  
Cedrick N Shili ◽  
Mohammad Habibi ◽  
Julia Sutton ◽  
Jessie Barnes ◽  
Jacob Burchkonda ◽  
...  
Keyword(s):  
Gene Expression ◽  
Amino Acids ◽  
Growth Performance ◽  
Mrna Abundance ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Blood Calcium ◽  
Low Protein ◽  
Protein Diets ◽  
Standard Protein

Abstract Moderately low protein (MLP) diets can help decrease nutrient excretion from the swine production. However, MLP diets negatively impact growth performance. We hypothesized that supplementing MLP diets with phytogenics may reduce the negative effects of these diets on growth. The objective of this study was to investigate the effect of a phytogenic water additive (PWA; Herbanimal®) on growth performance, blood metabolite and gene expression of amino acids transporters in pigs fed with MLP diets. Forty-eight weaned barrows were allotted to six dietary treatments (n = 8) for 4 weeks: &gt;CON-NS: standard protein diet-no PWA; CON-LS: standard protein diet-low PWA dose (4 ml/L); CON-HS: standard protein diet-high PWA dose (8 ml/L); LP-NS: low protein diet-no PWA; LP-LS: low protein diet-low PWA dose (4 ml/L); LP-HS: low protein diet- high PWA dose (8 ml/L). Feed intake and body weight were recorded daily and weekly, respectively. At week 4, blood and tissue samples were collected and analyzed for metabolites using a chemistry analyzer and amino acid transporters using qPCR, respectively. The data were analyzed by univariate GLM (SPSS®) and the means were separated using paired Student’s t-test corrected by Benjamini-Hochberg. Pigs fed CON-HS improved the average daily gain and serum calcium and phosphorus concentrations compared to CON-NS. Pigs fed LP-LS had higher serum phosphorus and blood urea nitrogen compared to the pigs fed with LP-NS. The mRNA abundance of SLC7A11 in the jejunum was lower in CON-LS and CON-HS compared to CON-NS. Additionally, mRNA abundance of SLC6A19 in the jejunum of pigs fed with LP-LS was higher compared to LP-NS and lower in CON-HS relative to pigs fed with CON-LS. In conclusion, PWA improved the growth performance of pigs fed standard protein diets but not low protein diets. Further, the PWA improved the concentrations of blood calcium and phosphorous in pigs fed MLP diets. Funding: Agrivida and Animal Health and Production and Animal Products: Improved Nutritional Performance, Growth, and Lactation of Animals from the USDA-NIFA.

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

Effects of growth hormone and IGF-I on renal function in rats with normal and reduced renal mass

1990 ◽  
Vol 259 (5) ◽  
pp. F747-F751 ◽  
Author(s):  
S. B. Miller ◽  
V. A. Hansen ◽  
M. R. Hammerman
Keyword(s):  
Growth Hormone ◽  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Renal Mass ◽  
Filtration Rate ◽  
Inulin Clearance ◽  
Mass Reduction ◽  
Contralateral Kidney ◽  
Igf I

To characterize actions of growth hormone (GH) and insulin-like growth factor ( (IGF-I) on renal function in rats with normal and reduced renal mass, we administered recombinant bovine growth hormone (bGH) or human IGF-I (hIGF-I) to normal rats or to rats that had undergone unilateral nephrectomy and two-thirds infarction of the contralateral kidney, and measured inulin and p-aminohippurate clearances over 10-17 days. Administration of either bGH (100-200 micrograms/day) or hIGF-I (200 micrograms/day) to rats with normal renal mass increased inulin and p-aminohippurate clearances compared with those measured in animals that received vehicle. Filtration fractions were not affected by either bGH or hIGF-I. Inulin clearance was decreased to approximately 17% of normal 1 day after reduction of renal mass in rats. Over the next 3 days insulin clearance increased significantly in rats with reduced renal mass that were administered vehicle. No further enhancement occurred during the next 7 days. Neither bGH nor hIGF-I affected inulin clearance in rats with reduced renal mass. We conclude that both GH and IGF-I enhance glomerular filtration rate when administered to rats with normal renal mass, but not when administered in the same quantities to rats in which renal functional mass is reduced. Glomerular filtration rate increases within 4 days of renal mass reduction independent of exogenous GH or IGF-I.

scholarly journals Effects of Different Methionine Levels in Low Protein Diets on Production Performance, Reproductive System, Metabolism, and Gut Microbiota in Laying Hens

2021 ◽  
Vol 8 ◽  
Author(s):  
Miaolin Ma ◽  
Shunju Geng ◽  
Meiling Liu ◽  
Lihong Zhao ◽  
Jianyun Zhang ◽  
...  
Keyword(s):  
Reproductive System ◽  
Laying Hens ◽  
Production Performance ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Microbial Composition ◽  
Low Protein ◽  
System Metabolism ◽  
Protein Diets ◽  
Different Levels

This study investigated the effects of different levels of methionine (Met) in a low protein diet on the production performance, reproductive system, metabolism, and gut microbial composition of laying hens to reveal the underlying molecular mechanism of Met in a low protein diet on the host metabolism and gut microbial composition and function of hens. A total of 360 healthy 38-week-old Peking Pink laying hens with similar body conditions and egg production (EP) were randomly divided into four groups with nine replicates per treatment and 10 hens per replicate. The hens in each treatment group were fed low protein diets containing different levels of Met (0.25, 0.31, 0.38, and 0.47%, respectively) for 12 weeks. Feed and water were provided ad libitum throughout the trial period. The results showed that, compared with the 0.25% Met group, the final body weight (FBW), average daily gain (ADG), EP, egg weight (EW), and average daily feed intake (ADFI) in the other groups were significantly increased and feed egg ratio (FER) was decreased. Meanwhile, the EW and yield of abdominal fat (AFY) in the 0.47% Met group were higher than those in other groups. The triglyceride (TG), estradiol (E2), total protein (TP), albumin (ALB), and immunoglobulin A (IgA) in the 0.38 and 0.47% Met groups were higher than those in other groups. In addition, 16S rRNA gene sequencing revealed that there was no difference in the Sobs index, ACE index, and Shannon index among all groups. However, it is worth noting that feeding low protein diets with Met changed the gut microbial composition (e.g., the supplementation of Met increased the level of Lactobacillus and decreased the proportion of Faecalibacterium). Also, our results showed that the changes in gut microbial composition induced by the diets with different levels of Met were closely related to the changes of key parameters: ADFI, EW, FBW, TG, EM, EP, ADG, FER, and uric acid (UA). Our results highlight the role of adding an appropriate amount of Met to the low protein diet in laying hens, which could improve the gut microbial composition, production performance, reproductive system, and nutrient metabolism of laying hens. In conclusion, this study suggested that when the Met level was 0.38%, the production performance of the laying hens was pretty good.

scholarly journals Protein intake and outcome of critically ill patients: analysis of a large international database using piece-wise exponential additive mixed models

Critical Care ◽  
2022 ◽  
Vol 26 (1) ◽  
Author(s):  
Wolfgang H. Hartl ◽  
Philipp Kopper ◽  
Andreas Bender ◽  
Fabian Scheipl ◽  
Andrew G. Day ◽  
...  
Keyword(s):  
Hospital Discharge ◽  
Critically Ill ◽  
Acute Phase ◽  
Critically Ill Patients ◽  
Protein Intake ◽  
High Protein ◽  
Protein Diet ◽  
High Protein Intake ◽  
Low Protein ◽  
Standard Protein

Abstract Background Proteins are an essential part of medical nutrition therapy in critically ill patients. Guidelines almost universally recommend a high protein intake without robust evidence supporting its use. Methods Using a large international database, we modelled associations between the hazard rate of in-hospital death and live hospital discharge (competing risks) and three categories of protein intake (low: < 0.8 g/kg per day, standard: 0.8–1.2 g/kg per day, high: > 1.2 g/kg per day) during the first 11 days after ICU admission (acute phase). Time-varying cause-specific hazard ratios (HR) were calculated from piece-wise exponential additive mixed models. We used the estimated model to compare five different hypothetical protein diets (an exclusively low protein diet, a standard protein diet administered early (day 1 to 4) or late (day 5 to 11) after ICU admission, and an early or late high protein diet). Results Of 21,100 critically ill patients in the database, 16,489 fulfilled inclusion criteria for the analysis. By day 60, 11,360 (68.9%) patients had been discharged from hospital, 4,192 patients (25.4%) had died in hospital, and 937 patients (5.7%) were still hospitalized. Median daily low protein intake was 0.49 g/kg [IQR 0.27–0.66], standard intake 0.99 g/kg [IQR 0.89– 1.09], and high intake 1.41 g/kg [IQR 1.29–1.60]. In comparison with an exclusively low protein diet, a late standard protein diet was associated with a lower hazard of in-hospital death: minimum 0.75 (95% CI 0.64, 0.87), and a higher hazard of live hospital discharge: maximum HR 1.98 (95% CI 1.72, 2.28). Results on hospital discharge, however, were qualitatively changed by a sensitivity analysis. There was no evidence that an early standard or a high protein intake during the acute phase was associated with a further improvement of outcome. Conclusions Provision of a standard protein intake during the late acute phase may improve outcome compared to an exclusively low protein diet. In unselected critically ill patients, clinical outcome may not be improved by a high protein intake during the acute phase. Study registration ID number ISRCTN17829198

Sign in / Sign up

Export Citation Format

Share Document