Source Of Nonspecific Nitrogen Research Articles

Effect of dietary glutamine supplementation associated with threonine levels in the intestinal mucosa of broilers challenged with Eimeria sp. from 22 to 42 days of age

The aim of this study was to evaluate the effects of glutamine and threonine supplementation on the ileal mucosa of broilers aged 21-42 days. Six-hundred and forty-one-day old chicks of the Cobb Slow lineage were utilized in this study. From 1 to 21 days of age, the chicks received a commercial diet; and after 22 days, the broilers were distributed in a completely randomized design in a 2 ? 4 factorial scheme (challenge and diet), with 4 replications and 20 chicks per experimental unit. At 22 days of age, the challenged broilers received a commercial vaccine against coccidiosis. A commercial diet was utilized as control and three other diets were formulated with reduced crude protein (-3%), and were corrected with the addition of glutamine (Gln) and glutamic acid (Glu) as non-specific nitrogen sources, and finally supplemented with L-Threonine (Thr) at 0.70, 0.80, and 0.85% digestible threonine, respectively. At 28 days of age, diets with Gln/Glu + Thr resulted in greater ileal villi lengths. Challenge with Eimeria sp. reduced the number of goblet cells and increased the duodenal and jejunal crypt depths. At 42 days of age, an interaction was observed between diet and challenge in relation to ileal villi length; better results were observed in the challenged broilers that received 0.85% Gln/Glu + Thr. The mucosal morphology in the ileal villi extremities was preserved in the challenged broilers that received higher Thr levels in their diets. The results suggested that the inclusion of glutamine and threonine affected the morphometry and mucosa of the ileum, thereby improving the mucosal quality.

Source and amount of dietary nonspecific nitrogen in relation to whole-body leucine, phenylalanine, and tyrosine kinetics in young men

We studied the effects of amount and source of nonspecific nitrogen (NSN) on the oxidation of leucine and hydroxylation of phenylalanine. In phase 1, seven adult males received for 6 d diets providing indispensable amino acid intakes to meet the 1985 FAO/WHO/UNU (FAO) requirements or our proposed requirement values (MIT). During one diet period with each diet, the NSN of the basal diets (total nitrogen intake: 107 mg N.kg-1.d-1) was increased to a total of 160 mg N.kg-1.d-1. On the morning of day 7, an 8-h constant intravenous tracer-infusion protocol (3-h fast; 5-h fed state) was conducted with L-[1-13C]leucine, L-[ring-2H5]phenylalanine, and L-[3,3,2H2]-tyrosine as tracers. In phase 2, six subjects were given three diets for 6 d, supplying 107 mg N.kg-1.d-1; NSN was a mixture of dispensable amino acids in which glutamine accounted for 0%, 12.5%, and 100% of total NSN. Leucine oxidation and phenylalanine hydroxylation rates and whole-body leucine and phenylalanine balances were unaffected by addition of supplemental NSN to the diets in phase 1 or by amino acid source of NSN in phase 2. Leucine and phenylalanine balances were lower (P < 0.05) for FAO compared with MIT diets.

Effects of a Nonspecific Nitrogen Deficiency on Growth Rate and Leg Problems in Chicks

Five experiments were conducted using crystalline amino acid and semipurified diets containing adequate levels of all indispensable amino acids, vitamins, and minerals to study the effects of dispensable amino acids on growth and the incidence of leg abnormalities of male chicks. Purified diets containing 5% L-glutamic acid as the sole source of nonspecific nitrogen resulted in poor growth and feed efficiency, high mortality, and a high incidence of leg abnormalities with many severe cases of this condition. Increasing the dietary level of L-glutamic acid to 10% of the purified diet or supplementing the 5% L-glutamic acid diet with 2.40% glycine or 1.68% L-serine improved weight gain but did not eliminate the leg conditions . Higher L-serine (3.36%) resulted in a growth depression, indicating that this level was toxic to the birds. It was necessary to increase the dietary L-glutamic acid to 12.5% to reduce the incidence of leg problems to a minimum. Plasma dispensable amino acid levels (aspartic acid, glutamic acid, and alanine) paralleled the levels of L-glutamic acid in the diets fed to the chicks. Plasma serine and glycine levels were increased by adding either serine or glycine, but the magnitude of the increase of either amino acid was greatest with the addition of that amino acid to the diet. Plasma proline concentrations increased when chick diets were supplemented with high levels of glycine (2.4%), serine (3.36%), or glutamic acid (9.7%) in relation to those supplemented with only 5% L-glutamic acid. Feeding an intact protein (isolated soybean protein) diet did not alleviate leg disorders, although it did improve weight gain.

Nitrogen retention and plasma amino acids of men who consumed isonitrogenous diets containing egg albumen or mixtures of amino acids

Experimental diets that furnished approximately 6.0 g of nitrogen per day were consumed by young men. Nitrogen retention was not altered significantly when egg albumen was replaced by its constituent essential and nonessential amino acids or by the essential amino acids (including cystine, tyrosine and histidine) plus a source of nonspecific nitrogen. Concentrations of essential amino acids in fasting or postprandial plasma were not influenced significantly by source of amino acids or by replacement of nonessential amino acids by nonspecific nitrogen; but concentrations of certain nonessential amino acids were altered by treatment. Responses to an elemental diet or to a similar diet in which egg albumen replaced the amino acid mixture did not differ significantly.

Amino acid requirements and non-specific nitrogen.

These investigations report on the E/T ratios and the importance of the amino acid histidine. Proteins with high proportions of essential amino acids can be diluted to very low E/T ratios with non-specific nitrogen sources without losing their biological value. Histidine has to be regarded as an essential amino acid because the histidine level in plasma and in the muscles decreased by more than 50% when a histidine-free diet is administered.

Quantitative Evaluation of Nonspecific Nitrogen Sources for the Growing Chick

Several nitrogenous compounds were incrementally added to a purified crystalline amino acid diet adequate in essential amino acids but deficient in total nitrogen to quantitatively evaluate these compounds as sources of nonspecific nitrogen for the growing chick. Experimental diets were fed to 400 male crossbred chicks from day 8 to day 21 posthatching. The slopes from regression analyses using either weight gain or protein retention as the dependent variable and nitrogen consumption from the different nitrogenous compounds as independent variables were compared (slope-ratio technique). Setting l-glutamic acid at 100% efficacy, efficacies for the other compounds were as follows for weight gain and protein retention, respectively: diammonium citrate, 86.6 and 74.3; diammonium phosphate, 26.2 and 17.9; urea, 24.9 and 12.5; glycine, 96.0 and 149.5; l-leucine, 62.1 and 71.0; l-isoleucine, 68.4 and 82.9; l-valine, 73.0 and 80.9; l-proline, 98.8 and 110.2; l-arginine, 36.4 and 56.5; and l-lysine, 50.0 and 67.9%. These efficacy values are corrected for changes in feed consumption. All amino acids had higher efficacy values for protein retention reflecting the fact that they tended to depress voluntary feed consumption of chicks. The amino acids which can be synthesized by chicks had higher efficacy values than those which cannot be synthesized.

Availability of amino acids. Fructose--glycine as a source of nonspecific nitrogen for rats.

Availability of amino acids. Fructose--glycine as a source of nonspecific nitrogen for rats.

Utilization of Biuret as a Source of Nonspecific Nitrogen in a Crystalline Amino Acid Chick Diet

Three experiments were conducted to study the effect of adding biuret to crystalline amino acid diets as a source of nonspecific nitrogen. Growth and feed consumption were measured for chicks for the experimental period, 8 to 14 days of age. The addition of 2.33% biuret to a basal diet deficient in nonspecific nitrogen depressed growth, whereas addition of isonitrogenous amounts of urea or glutamic acid resulted in increased growth. Proportionate decreases in growth and feed consumption resulted from increased levels of biuret in a diet containing adequate amino acid nitrogen. Addition of 1.165 and 2.33% biuret to a diet containing 70% of the required amount of amino acid nitrogen resulted in increased feed consumption; however, successive decreases in growth and feed intake were observed with increases of biuret from 1.165 to 4.66% in the diet containing 100% of the required amount of amino acid nitrogen. When feed intake was equalized, 4.66% biuret had no effect on growth. These studies demonstrated that biuret did not serve as a source of nonspecific nitrogen and that the effect of biuret on growth was due to its effect on feed consumption.

D-Amino acids as source of non-specific nitrogen for growth of rats.

SummaryRats fed a diet containing physiological amounts of essential L-amino acids but lacking non-essential amino acids grew at a slow rate. Growth rate was increased by increasing concentration of all essential amino acids. Feeding a mixture of DL-amino acids in comparable amounts resulted in growth retardation of animals. Growth inhibition produced by the racemic mixture was traced to an isoleucine deficiency resulting from inclusion of DL-isoleucine, which was actually a mixture of all 4 isomers, thus effectively diluting the active isomer. Substitution of L-isoleucine or a mixture of L- and D allo-isoleucine for the racemic compound in the DL mixture entirely overcame inhibition and produced growth comparable to that obtained with L-amino acids. The experiments provide evidence that D-amino acids can be effectively used as source of nitrogen for biosynthesis of non-essential amino acids.

The Net Utilization of Non-Specific Nitrogen Sources for the Synthesis of Non-Essential Amino Acids: I. Growth and Nitrogen Utilization

The Net Utilization of Non-Specific Nitrogen Sources for the Synthesis of Non-Essential Amino Acids: I. Growth and Nitrogen Utilization

UTILIZATION OF NON-SPECIFIC NITROGEN SOURCES BY THE ADULT PROTEIN-DEPLETED RAT

UTILIZATION OF NON-SPECIFIC NITROGEN SOURCES BY THE ADULT PROTEIN-DEPLETED RAT