Daily Urinary Nitrogen Excretion Research Articles

The effect of feeding a mix of condensed and hydrolyzable tannins to heifers on rumen fermentation patterns, blood urea nitrogen, and amino acid profile

The objective of this pilot study was to begin to evaluate the effect of feeding a mix of condensed and hydrolyzable tannins to heifers on rumen fermentation patterns, blood urea nitrogen (BUN), and amino acid profile. Four growing Holstein-Friesian × Jersey heifers with a mean live weight of 319.5 ± 8.38 kg and a mean body condition score of 4 ± 0.17 out of 10 were used in a cross-over design. Heifers were either orally administered the mixed tannin treatment at 0.15% of daily DMI or a control dose of water whilst consuming perennial ryegrass baleage and soybean meal for 12 days in a cross-over trial. Administration of mixed tannins reduced non-glucogenic volatile fatty acid (VFA) production by 2%, the acetate to propionate (A:P) ratio by 13%, and the relative abundances of specific methanogenic archaea – i.e., Methanobrevibacter and Methanosarcina. The tannin treatment also reduced BUN concentration by 12% in comparison with the control dose of water, which indicates associated reductions in daily urinary nitrogen excretion and therefore environmental impact. The effects of ingestion of mixed tannins on rumen function in this study would be expected to result in a reduction of both methane and urinary nitrogen excretion and thereby reducing the environmental impact of heifers consuming conventional feeds.

Prognostic value of serum albumin and urea nitrogen excretion in COVID-19 ICU patients: a single-center, prospective, cohort study

Introduction. Catabolic syndrome is typical for most critical illness situations. A long progressive course of hypercatabolism is considered by a number of authors as a prognostic criterion for negative clinical outcome of the disease. Objective. Evaluation of the prognostic value of some indicators of the severity of catabolic syndrome in ICU patients with COVID-19. Materials and methods. A prospective cohort study was conducted in 55 patients of the intensive care unit in the period from May 2020 to March 2021. The severity of hypercatabolism was determined by the dynamics of serum albumin and daily urinary nitrogen excretion within 14 days from admission to the ICU. Comparative analysis of nonparametric quantitative data was carried out using the Mann–Whitney test. To determine the predictive value of the diagnostic test, we plotted using the curves of operating characteristics (ROC, Receiver Operating Characteristics) with the subsequent determination of the sensitivity and specificity at the separation point. Results. ROC analysis revealed moderate sensitivity (75.9 %) and low specificity (58.1 %) of the daily urinary nitrogen excretion during the first 14 days of treatment in the ICU in patients with severe SARSCoV-2. It was also shown that the dynamics of serum albumin has a low predictive value for negative clinical outcome. It should be noted that in the group of survived patients a significant increase in daily urinary nitrogen excretion was observed on days 4–7 (p = 0.022) and 8–14 (p = 0.01) of intensive therapy. Conclusion. Nitrogen urinary excretion is a more accurate prognostic marker of poor clinical outcome than serum albumin in ICU patients with severe COVID-19. The main feature of the catabolic syndrome in patients with positive clinical outcome is a progressive increase in the rate of urinary nitrogen excretion from 4 to 14 days after admission to ICU.

Variability in daily urinary nitrogen excretion of gestating gilts does not affect estimates of nitrogen retention

Daily urinary nitrogen excretion (UN, g d−1) was quantified in gestating gilts during 5 d nitrogen (N) balance periods. Abbreviated collection days (<22 h) can be used in N balance calculations when extrapolated to reflect a complete 24 h collection. Variation in daily UN did not affect overall N retention calculations.

Nutritional Influence on the Plasma and Urine‐Free Alkaline Ribonuclease Levels in Severe Trauma Victims

The significance of free alkaline ribonuclease (RNase) activity as a criterion of protein metabolism and nutrition in traumatized man is evaluated in this report. Plasma and urinary levels of RNase were measured in severely injured, hypermetabolic patients and in normal controls. Significant increases in the plasma and urinary RNase levels were seen in these polytrauma victims and they were positively correlated. Plasma RNase levels were also significantly related to blood urea nitrogen and daily urinary nitrogen excretion. Urinary clearance of RNase was increased by 220% in trauma victims, although the creatinine clearance was not affected by trauma. In a subgroup of eight patients who were fed intravenously (1.4 times basal energy expenditure calories and 250-300 mg of N per kilogram per day) for 6 days, the daily excretions of urinary RNase, nitrogen, 3-methylhistidine, creatinine, and catecholamines were measured. There was a significant negative correlation between daily urine RNase and nitrogen balance. A general increase in all the metabolic parameters on the first day of feeding was seen, suggesting a nutritional stress superimposed on the trauma-induced metabolic stress. Excretion of RNase, 3-methylhistidine, and creatinine peaked on the first day of feeding and then decreased. The normal levels could not be reached even after 6 days of adequate nutrition. The results suggest that RNase levels could be used as a biomarker of protein metabolism.

Estimation of urinary nitrogen losses from urea excretion in patients with intestinal diseases requiring parenteral nutrition, and in those with hepatic decompensation

A comparison of daily urinary nitrogen excretion measured directly, with values derived from urea excretion, was carried out on 110 occasions in patients with either gastrointestinal disease requiring total parenteral nutrition or with alcoholic liver disease. The values were found to correlate well in both patient groups ( r = 0.88 and 0.9 respectively). Values of urinary nitrogen loss calculated from urea excretion may safely be used when performing nitrogen balance studies in such cases.

Urea Utilization by Lactating Cows

Efficiency of urea nitrogen utilization was determined in 6-day total collection digestibility and nitrogen retention trials conducted at three stages of lactation with four cows per diet in two trials. The cows had been fed their respective diets for an average of 1 yr (Trial 1) or 2 yr (Trial 2) prior to the study. Diets contained three percents urea of dietary nitrogen: 0 (control), 28 to 30 (low urea), and 40 to 45 (high urea). Corn silage was the only roughage offered. In Trial 1, the average daily absorbed nitrogen was greater for cows fed the high urea diet (203g) than for cows offered the low urea (172g) or the control (145g) diets; this was attributed to greater nitrogen intake. Average daily urinary nitrogen excretion of cows increased as quantity of urea in the diet increased: control, 76g; low urea, 113g; and high urea, 152g. Higher urinary excretion of nitrogen by cows fed urea diets was associated with lower productive nitrogen in midlactation (38g) and dry period (19g) but not in early lactation (107g). Apparent and true digestibility of protein was greater for the high urea diet (66.3%, 84.85%) than for the control (58.9%, 81.6%) or low urea (61.4%, 82.1%) diets. In Trial 2, absorbed nitrogen and productive nitrogen were not significantly affected by source of dietary nitrogen, but average daily urinary nitrogen excretion was greater for cows fed the high urea diet (121g) than for cows fed the control diet (97g). Differences among diets were not significant for apparent or true digestibility of protein. Dry matter, organic matter, and nitrogen-free extract digestibility of the control diet was greater than for other diets. Urea was effective as a partial substitute for dietary nitrogen protein in lactating cows fed urea daily for 2 to 3 yr. However, urea nitrogen was utilized less efficiently than nitrogen from soybean meal.

Starvation in man.

ALTHOUGH it has been known for over a century that fat is the principal storage form of energy, only in the past two decades have the physiologic mechanisms for its deposition and mobilization been partially clarified. Benedict,1 in his classic study on Mr. L., a normal man who over 50 years ago fasted experimentally for 30 days, noted that fat provided more than 75 per cent of the calories utilized after the first few days of food deprivation. He also observed a progressive decrease in daily urinary nitrogen excretion that suggested an increasing conservation of body protein. In this review . . .

Minimum Dietary Essential Amino Acid-to-total Nitrogen Ratio for Whole Egg Protein Fed to Young Men

Daily urinary nitrogen excretion was measured for 11 young men fed constant nitrogen intakes, equivalent to 0.36 to 0.54 g protein/kg body wt, which approximated their minimum daily requirement. Whole egg furnished 78.6 to 90% of the nitrogen of the basal diet, and oatmeal and tomato juice the remainder. When the ntirogen of the basal diet was replaced isonitrogenously by a mixture of glycine and diammonium citrate, with each compound supplying equal amounts of nitrogen, a 30% replacement did not significantly alter urinary nitrogen excretion. In 4 subjects, a 40% replacement had no significant effect on urinary nitrogen excretion after initial adaptation. A 50% replacement caused no apparent decrease in dietary nitrogen utilization in one subject. A 30% replacement gave an essential amino acid-to-total nitrogen ratio (E/TN) of 2.16 corresponding to 25% of the total nitrogen furnished by essential amino acids. A 40% replacement gave an E/TN ratio of 1.85 and 21% of the nitrogen from essential amino acids.