scholarly journals Urea nitrogen recycling via gut symbionts increases in hibernators over the winter fast

2021 ◽  
Author(s):  
Matthew D. Regan ◽  
Edna Chiang ◽  
Yunxi Liu ◽  
Marco Tonelli ◽  
Kristen M. Verdoorn ◽  
...  
Keyword(s):  
Gut Microbiome ◽  
Ground Squirrels ◽  
Late Winter ◽  
Nitrogen Recycling ◽  
Protein Balance ◽  
Urea Nitrogen ◽  
Body Protein ◽  
Dietary Nitrogen ◽  
Protein Pool ◽  
Gut Symbionts

AbstractHibernation is a mammalian strategy that uses metabolic plasticity to reduce energy demands and enable long-term fasting. Fasting mitigates winter food scarcity but eliminates dietary nitrogen, jeopardizing body protein balance. Here, we reveal gut microbiome-mediated urea nitrogen recycling in hibernating 13-lined ground squirrels (TLGS). Ureolytic gut microbes incorporate urea nitrogen into organic compounds that are absorbed by the host, with the nitrogen reincorporated into the TLGS protein pool. Urea nitrogen recycling is greatest after prolonged fasting in late winter, when urea transporter abundance in gut tissue and urease gene abundance in the microbiome are highest. These results reveal a functional role for the gut microbiome in hibernation and suggest mechanisms by which urea nitrogen recycling contributes to protein balance in other monogastric animals, including humans.One Sentence SummaryGround squirrels and their gut symbionts benefit from urea nitrogen recycling throughout hibernation.

scholarly journals Effect of increasing digestible undegraded protein supply to dairy cows in late gestation on the yield and composition of milk during the subsequent lactation

1996 ◽  
Vol 63 (2) ◽  
pp. 201-213 ◽  
Author(s):  
J. M. Moorby ◽  
R. J. Dewhurst ◽  
S. Marsden
Keyword(s):  
Dairy Cows ◽  
Milk Protein ◽  
Barley Straw ◽  
Protein Supplement ◽  
Dry Period ◽  
Body Protein ◽  
Grass Silage ◽  
Management Regime ◽  
Protein Pool ◽  
Ad Libitum

AbstractEffects of feeding a protein supplement to dairy cows during the dry period on performance during the following lactation were investigated in two experiments. Holstein-Friesian cows were paired towards the end of lactation, and, after drying off, one of each pair received a typical dry cow management regime of ad libitum grass silage (experiment 1), or a mix of grass silage and distillers' grains or pressed beet pulp (experiment 2). The other cows were offered restricted access to the same basal diet, together with ad libitum access to barley straw and 0·5 kg/day high protein maize gluten meal. During the following lactation, animals from both groups were treated without reference to dry period treatment, and were offered equal access to the same lactation diet. Data were analysed by analysis of variance of experiment means and by parallel curve analysis using sample means. In experiment 1, milk yields were similar (27·2 v. 27·9 (s.e.d. 2·12) kg/day for control and supplemented animals respectively) but milk protein yields, and hence concentrations, were significantly higher (P < 0·001) from supplemented animals (28·9 v. 31·8 (s.e.d. 0·58) g/kg). In experiment 2, milk yields were significantly higher (P < 0·001) from supplemented animals (mean 33·3 v. 35·4 (s.e.d. 1·66) kg/day; however, milk protein yields were also significantly increased (P < 0·001) and the change in milk protein concentration was small. No difference in dry-matter intake was recorded in a subset of animals during early lactation in experiment 2. It is hypothesized that the maternal labile body protein pool was maintained or replenished during the dry period by the provision of the protein supplement, and that this had a significant effect on subsequent lactation performance.

scholarly journals Biochemical indicators of condition, nutrition and nitrogen excretion in caribou

Rangifer ◽  
1996 ◽  
Vol 16 (4) ◽  
pp. 201 ◽  
Author(s):  
Ray Case
Keyword(s):  
Body Composition ◽  
Adult Female ◽  
Rangifer Tarandus ◽  
Nitrogen Excretion ◽  
Late Winter ◽  
Marrow Fat ◽  
Urea Nitrogen ◽  
Biochemical Indicators ◽  
Fat Reserves ◽  
Nitrogen Concentrations

Urinary urea nitrogen to creatinine ratios, urinary Nt-methylhistidine to creatinine ratios, serum urea nitrogen concentrations (SUN mg/dl), and serum Nt-methylhistidine concentrations were compared with physical measures of body composition in adult female barren-ground caribou (Rangifer tarandus groenlandicus) from the Bathurst and Southampton Island herds during late winter. Body weight and UUC were used to estimate urinary urea nitrogen (urea-N) excretion in free ranging caribou. Only mean UUC reflected differences in fat reserves between populations. None of the biochemical indicators were directly related to body composition. However, elevated UUC were only observed in caribou with depleted fat reserves as demonstrated by low kidney fat index (KFK40) and/or reduced femur marrow fat (FMF&lt;80). UUC greater than 0.25 were indicative of undernourished animals with depleted fat reserves. SUN and UN -MHC showed no clear relationship with fat reserves. The mean estimated daily urea-N excretion for adult female caribou in late winter was extremely low (0.11+0.01SE g urea-N/day, n=76, range=0.011-0.510). The results of my study suggest that UUC can be used to detect nutritionally stressed caribou with depleted fat reserves on lichen winter ranges.

scholarly journals Nitrogen recycling buffers against ammonia toxicity from skeletal muscle breakdown in hibernating arctic ground squirrels

2020 ◽  
Vol 2 (12) ◽  
pp. 1459-1471
Author(s):  
Sarah A. Rice ◽  
Gabriella A. M. Ten Have ◽  
Julie A. Reisz ◽  
Sarah Gehrke ◽  
Davide Stefanoni ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Ground Squirrels ◽  
Ammonia Toxicity ◽  
Nitrogen Recycling ◽  
Muscle Breakdown ◽  
Arctic Ground Squirrels

Combined ingestion of protein and free leucine with carbohydrate increases postexercise muscle protein synthesis in vivo in male subjects

2005 ◽  
Vol 288 (4) ◽  
pp. E645-E653 ◽  
Author(s):  
René Koopman ◽  
Anton J. M. Wagenmakers ◽  
Ralph J. F. Manders ◽  
Antoine H. G. Zorenc ◽  
Joan M. G. Senden ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Whole Body ◽  
Vastus Lateralis Muscle ◽  
Protein Balance ◽  
Body Protein ◽  
Breakdown Rates ◽  
Postexercise Recovery ◽  
Male Subjects

The present study was designed to determine postexercise muscle protein synthesis and whole body protein balance following the combined ingestion of carbohydrate with or without protein and/or free leucine. Eight male subjects were randomly assigned to three trials in which they consumed drinks containing either carbohydrate (CHO), carbohydrate and protein (CHO+PRO), or carbohydrate, protein, and free leucine (CHO+PRO+Leu) following 45 min of resistance exercise. A primed, continuous infusion of l-[ ring-13C6]phenylalanine was applied, with blood samples and muscle biopsies collected to assess fractional synthetic rate (FSR) in the vastus lateralis muscle as well as whole body protein turnover during 6 h of postexercise recovery. Plasma insulin response was higher in the CHO+PRO+Leu compared with the CHO and CHO+PRO trials (+240 ± 19% and +77 ± 11%, respectively, P < 0.05). Whole body protein breakdown rates were lower, and whole body protein synthesis rates were higher, in the CHO+PRO and CHO+PRO+Leu trials compared with the CHO trial ( P < 0.05). Addition of leucine in the CHO+PRO+Leu trial resulted in a lower protein oxidation rate compared with the CHO+PRO trial. Protein balance was negative during recovery in the CHO trial but positive in the CHO+PRO and CHO+PRO+Leu trials. In the CHO+PRO+Leu trial, whole body net protein balance was significantly greater compared with values observed in the CHO+PRO and CHO trials ( P < 0.05). Mixed muscle FSR, measured over a 6-h period of postexercise recovery, was significantly greater in the CHO+PRO+Leu trial compared with the CHO trial (0.095 ± 0.006 vs. 0.061 ± 0.008%/h, respectively, P < 0.05), with intermediate values observed in the CHO+PRO trial (0.0820 ± 0.0104%/h). We conclude that coingestion of protein and leucine stimulates muscle protein synthesis and optimizes whole body protein balance compared with the intake of carbohydrate only.

scholarly journals Usefulness of Urinary Creatinine/Urea Nitrogen Ratio as Indicator of Body Protein Catabolism in Dogs Fed Low Protein Diets

2019 ◽  
Vol 6 ◽  
Author(s):  
Shushi Yamamoto ◽  
Yoshiyuki Ohta ◽  
Etsuko Hasegawa ◽  
Shiori Hashida ◽  
Yasuyuki Kaneko ◽  
...  
Keyword(s):  
Protein Catabolism ◽  
Urea Nitrogen ◽  
Body Protein ◽  
Urinary Creatinine ◽  
Low Protein ◽  
Nitrogen Ratio ◽  
Protein Diets

The effect of dietary asynchrony on rumen nitrogen recycling in sheep

1995 ◽  
Vol 1995 ◽  
pp. 70-70 ◽  
Author(s):  
P. Holder ◽  
P.J. Buttery ◽  
P.C. Garnsworthy
Keyword(s):  
Nitrogen Deficiency ◽  
Nitrogen Sources ◽  
Ammonia Concentration ◽  
Rumen Bacteria ◽  
Dietary Energy ◽  
Nitrogen Recycling ◽  
Dietary Nitrogen ◽  
Dietary Nutrients ◽  
Rumen Nitrogen ◽  
Energy Components

Recent work (Sinclair et al. 1993) has suggested that synchronising the rate of rumen breakdown and availability of dietary energy and nitrogenous components can increase capture of rumen degradable nitrogen and improve efficiency of microbial protein synthesis. For rumen bacteria to function efficiently they require a supply of both energy and nitrogen sources together i.e a synchronous diet. Nitrogen recycling between the blood and the rumen is a major contributor to the nitrogen economy of the animal and supplies substantial quantities of nitrogen to the rumen bacteria (Kennedy & Milligan 1980). The amount of nitrogen recycled to the rumen is diet dependant. This dependency may not solely be due to the levels of dietary nutrients but also to their rate of breakdown and availability to the rumen bacteria. The predominant mechanism controlling nitrogen recycling between the blood and the rumen appears to be rumen ammonia concentration It has been suggested that the recycling of nitrogen between the blood urea pool and the rumen ammonia pool may be able to compensate for periods of dietary nitrogen deficiency in the rumen due to the asynchrony of availability of the nitrogen and energy components to the rumen bacteria.

Human protein metabolism: its measurement and regulation

2002 ◽  
Vol 283 (6) ◽  
pp. E1105-E1112 ◽  
Author(s):  
Zhenqi Liu ◽  
Eugene J. Barrett
Keyword(s):  
Protein Synthesis ◽  
Whole Body ◽  
Body Protein ◽  
Architectural Support ◽  
Protein Mass ◽  
Protein Pool ◽  
Tracer Kinetic ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

The body's protein mass not only provides architectural support for cells but also serves vital roles in maintaining their function and survival. The whole body protein pool, as well as that of individual tissues, is determined by the balance between the processes of protein synthesis and degradation. These in turn are regulated by interactions among hormonal, nutritional, neural, inflammatory, and other influences. Prolonged changes in either the synthetic or degradative processes (or both) that cause protein wasting increase morbidity and mortality. The application of tracer kinetic methods, combined with measurements of the activity of components of the cellular signaling pathways involved in protein synthesis and degradation, affords new insights into the regulation of both protein synthesis and breakdown in vivo. These insights, including those from studies of insulin, insulin-like growth factor I, growth hormone, and amino acid-mediated regulation of muscle and whole body protein turnover, provide opportunities to develop and test therapeutic approaches with promise to minimize or prevent these adverse health consequences.

Ketone body metabolism in a ground squirrel during hibernation and fasting

1985 ◽  
Vol 249 (4) ◽  
pp. R462-R470 ◽  
Author(s):  
B. L. Krilowicz
Keyword(s):  
Energy Source ◽  
Glucose Uptake ◽  
Ground Squirrel ◽  
Ketone Body ◽  
Glucose Utilization ◽  
Ground Squirrels ◽  
Body Protein ◽  
Muscle Tissues ◽  
Spermophilus Beldingi

Hibernating Belding's ground squirrels (Spermophilus beldingi) are ketotic relative to fed nonhibernators. Muscles from torpid individuals, when incubated in media containing physiological concentrations of glucose and ketone, show reduced uptake of glucose in the presence of ketone. The magnitude of the reduction is dependent on ketone concentration and reaches 60% in heart and 100% in pectoralis at 1.4 mM ketone. Fasted squirrels are also ketotic. However, ketone does not reduce glucose uptake in muscles from fed or fasted animals. Glucose utilization by muscles decreases during a long-term fast, but the reduction is independent of ketone. Thus both a long-term fast and hibernation lead to changes in muscle tissues that decrease their reliance on glucose as an energy source. Ketosis leads to glucose sparing during hibernation, whereas muscle glucose utilization is decreased independently of ketone during a fast. The glucose sparing achieved in both hibernation and fasting leads to conservation of body protein, the major source of gluconeogenic precursors in fasting mammals.

scholarly journals Effect of Dietary Extruded Linseed and Walnut Meal Mixture (8:1) on Performance and Plasma Protein Profile in Weaned Piglets

2018 ◽  
Vol 75 (2) ◽  
pp. 121 ◽  
Author(s):  
Anca GHEORGHE ◽  
Mihaela HĂBEANU ◽  
Nicoleta Aurelia LEFTER ◽  
Daniela Mihaela GRIGORE
Keyword(s):  
Uric Acid ◽  
Plasma Protein ◽  
Soybean Meal ◽  
Total Protein ◽  
Total Bilirubin ◽  
Protein Profile ◽  
Weaned Piglets ◽  
Urea Nitrogen ◽  
Blood Samples ◽  
Dietary Nitrogen

The effects of dietary extruded linseed (ELS):walnut meal (WM) mixture (8:1) on performance and plasma protein profile in weaned piglets was evaluated for 21 d. Topigs piglets (n=40; BW=8.02±0.82 kg), age 30±3 days, were allotted into 2 groups and fed 2 diets: control [C, based on corn-triticale-soybean meal (SBM)] and experimental (ELS:WM, where the ELS:WM mixture (8:1) partially replace SBM). Blood samples were collected at 7d and 21d after weaning. The plasma protein profile (total protein, total bilirubin, albumin, creatinine, uric acid, urea nitrogen-BUN) were determined by a chemistry analyser. Dietary ELS:WM mixture improve the BW (P=0.047) and ADG (P=0.036) of piglets at 21d after weaning vs C, whereas ADFI and F:G ratio were increase (P>0.05). The plasma protein profile of piglets fed dietary mixture was not affected at 7d and 21d after weaning, except plasma BUN concentration that was decrease (P=0.027) at 21d after weaning. Lower BUN concentration indicated higher availability of dietary nitrogen reflected in a higher deposition of protein. We concluded that dietary ELS:WM mixture improve piglets performance and positively afect plasma protein profile, especially BUN in weaning period.

scholarly journals Preoperative Insulin Resistance and the Impact of Feeding on Postoperative Protein Balance: A Stable Isotope Study

2011 ◽  
Vol 96 (11) ◽  
pp. E1789-E1797 ◽  
Author(s):  
Francesco Donatelli ◽  
Davide Corbella ◽  
Marta Di Nicola ◽  
Franco Carli ◽  
Luca Lorini ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Protein Metabolism ◽  
Metabolic Response ◽  
Major Surgery ◽  
Anabolic Effect ◽  
Protein Balance ◽  
Body Protein ◽  
Before And After ◽  
The Impact ◽  
Effect Of Feeding

Abstract Context: Major surgery induces a catabolic state resulting in a net loss of body protein. Objectives: Our objective was to compare protein metabolism before and after surgery in nondiabetic patients with and without preoperative insulin resistance (IR). It was hypothesized that the anabolic response to feeding would be significantly impaired in those patients with preoperative insulin resistance. Design: A hyperinsulinemic-euglycemic clamp has been used to identify two groups of patients: IR and insulin sensitive (IS). A tracer kinetics technique has been used to evaluate the metabolic response to food intake in both groups. Setting: Patients undergoing cardiopulmonary bypass participated. Patients or Other Participants: Ten IS patients and 10 IR patients were enrolled in the study. Intervention: After an overnight fasting, a 3-h infusion of a solution composed of 20% glucose and of amino acids at a rate of 0.67 and 0.44 kcal/kg · h, respectively, was started in each group. Phenylalanine kinetics were studied at the end of fasting and feeding. Main Outcome Measure: Effect of feeding on protein balance before and after surgery was evaluated. Protein balance has been measured as the net difference of protein breakdown minus protein synthesis. Results: Protein balance increase after postoperative feeding was blunted only in the IR group. In contrast, in the IS group, the postoperative anabolic effect of feeding was the same as before surgery. Conclusions: These findings propose a link between insulin resistance and protein metabolism. When non-IR patients are fed, a significant anabolic effect in the postoperative period is demonstrated. In contrast, IR patients are less able to use feeding for synthetic purposes.

Sign in / Sign up

Export Citation Format

Share Document