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PubMed1987

Induced non-enzymatic browning of soybean meal. I. Effects of factors controlling non-enzymatic browning on in vitro ammonia release.

Non-enzymatic browning was tested as a means of suppressing degradation of soybean meal (SBM) by ruminal microbes in five trials with in vitro ammonia release as the response criterion. Treatments imposed on SBM included reducing sugar source (xylose, glucose, fructose and lactose), reducing sugar level (1, 3 and 5 mol/mol SBM-lysine), pH (6.5, 8.5 and 10.0), dry matter (DM) content (65, 70, 75, 80, 85 and 90%) and varying lengths of heating time (0 to 90 min) at 150 C. Samples heated under conditions that promoted non-enzymatic browning gave greater (P less than .01) ammonia release suppression that when SBM was heated without these treatments. Xylose was the most reactive sugar, but extended heating of SBM containing glucose, fructose or lactose resulted in ammonia release similar to xylose. Increasing sugar level from 1 to 5 mol/mol SBM-lysine caused linear decreases (P less than .01) in ammonia release for xylose, glucose and fructose, but not lactose. Ammonia release was higher (P less than .01) at pH 6.5 than pH 8.5 and 10.0, and higher (P less than .01) at pH 9.5 than pH 10.0. Rate of non-enzymatic browning decreased when samples containing greater than 80% DM were heated. These results are interpreted to show that controlled non-enzymatic browning may be effective for reducing ruminal degradation of SBM.

Amines↗
PubMed2003

Effect of dietary carbohydrate composition and availability on utilization of ruminal ammonia nitrogen for milk protein synthesis in dairy cows.

A trial with four ruminally and duodenally cannulated, late-lactation dairy cows was conducted to investigate the effect of dietary carbohydrate (CHO) composition and availability on ruminal ammonia N utilization and transfer into milk protein. Two diets were fed at 8-h intervals in a crossover design. The diets differed in CHO composition: the ruminally fermentable non-structural carbohydrates (RFSS) diet (barley and molasses) contained a larger proportion of ruminally available CHO in the nonstructural carbohydrate fractions and the ruminally fermentable fiber (RFNDF) diet (corn, beet pulp, and brewer's grains) contained a larger proportion of CHO in ruminally available fiber. Nitrogen-15 was used to label ruminal ammonia N and consequently microbial and milk N. Fermentation acids, enzyme activities, and microbial protein production in the rumen were not affected by diet. Ruminal ammonia concentration was lowered by RFNDF. Ruminal and total tract digestibility of nutrients did not differ between diets except that apparent ruminal degradability of crude protein was lower for RFNDF compared with RFSS. Partitioning of N losses between urine and feces was also not affected by diet. Milk yield and fat and protein content were not affected by treatment. Average concentration of milk urea N was lower for RFNDF than for RFSS. Proportion of milk protein N originating from ruminal microbial N (based on the areas under the 15N-enrichment curves) was higher for RFNDF than for RFSS. Cumulative recovery of 15N in milk protein was 13% higher for RFNDF than for RFSS indicating enhanced transfer of 15N-ammonia into milk protein with the former diet. The results suggested that, compared to diets containing higher levels of ruminally fermentable starch, diets providing higher concentration of ruminally fermentable fiber may enhance transfer of ruminal ammonia and microbial N into milk protein.

Ammonia↗
PubMed2004

Effect of sodium laurate on ruminal fermentation and utilization of ruminal ammonia nitrogen for milk protein synthesis in dairy cows.

A crossover design trial with 4 ruminally and duodenally cannulated lactating dairy cows was conducted to study the effect of sodium laurate on ruminal fermentation, nutrient digestibility, and milk yield and composition. The daily dose of sodium laurate (0, control or 240 g/cow, LA) was divided in 2 equal portions and introduced directly into the rumen through the cannula before feedings. Ruminal samples (29 in 114 h) were analyzed for fermentation variables and protozoal counts. Sodium laurate had no effect on ruminal pH and total and individual volatile fatty acids concentrations. Ruminal ammonia concentration, ammonia N pool size, and the irreversible loss of ammonia N were unaffected by treatment. Compared to control, protozoal counts were reduced by 91% by LA. Carboxymethylcellulase and xylanase activities of ruminal fluid were decreased (by 40 and 36%, respectively), and amylase activity was not affected by LA compared with control. Flow of microbial N to the duodenum was reduced by LA. Dry matter intake and apparent total tract digestibility of dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber were not different between the 2 treatments. Milk yield, fat-corrected milk yield, milk fat and protein concentrations and yields, and milk urea N content were not affected by treatment. Sodium laurate did not affect transfer of ruminal ammonia-15N into bacterial or milk protein. In conclusion, LA at approximately 0.3% of the rumen weight reduced ruminal protozoal population and had a negative effect on fibrolytic activities of ruminal fluid and microbial protein flow to the intestine. Treatment had no other significant effects on ruminal fermentation, total tract digestibility, or transfer of ruminal ammonia-15N into milk protein.

Ammonia↗
PubMed2004

The effect of steam flaked or dry ground corn and supplemental phytic acid on nitrogen partitioning in lactating cows and ammonia emission from manure.

The effect of starch source and supplemental phytic acid (PA) on N partitioning and excretion and ammonia volatilization from dairy manure was evaluated with 8 midlactation cows. Cows were randomly assigned to treatments in replicated 4 x 4 Latin squares with four 18-d periods. Diets were 61% forage, 25% starch, 17.2% crude protein, and 31% neutral detergent fiber and included dry ground corn (DG) or steam flaked corn (SF) with no supplemental P (L; 0.34% P) or supplemental purified PA (0.45% P) to provide additional P from a non-mineral source. Total collection of milk, urine, and feces was conducted on d 16 to 18 of each period. Cows fed SF had lower dry matter (DM) intakes than those fed DG, which, in addition to increased starch digestibility and ruminal fermentation, contributed to higher DM digestibility. Cows fed SF had reduced feces and urine excretion compared with cows fed DG. Also, N intake for cows fed SF was lower, and N digestibility was higher, compared with cows fed DG; therefore, N excretion in both feces and urine was reduced in these cows. Despite the differences in DM intake, lactation performance was not affected by starch sources. Therefore, the efficiency of N utilization increased with SF. Addition of PA did not affect N intake or utilization. Feces and urine were subsampled from each cow, and wet feces and urine were mixed in sealed chambers in the proportions excreted. Ammonia volatilization was measured for 36 h using acid traps sampled on a planned time course. Nitrogen at time zero (A0), rate of ammonia emission (k), and residual N (R) were calculated using the exponential decay model At = A0 e(-kt) + R. Rate of ammonia loss from mixed feces and urine was lower from cows fed SF than from those fed DG. Altering dietary starch source to improve nutrient digestibility and to reduce N excretion by lactating cows may provide opportunity to reduce ammonia losses from manure.

Ammonia↗
PubMed1976

Effect of sampling location, time, and method of concentration of ammonia nitrogen in rumen fluid.

In experiment 1, rumen fluid samples were obtained from dorsal, midpoint, and ventral regions of the rumen of rumenfistulated dairy cows at hourly intervals for 24 h. Dorsal, midpoint, and ventral rumen fluid samples contained 16.1, 14.2, and 12.1 mg/100 ml of ammonia nitrogen. Time after feeding resulted in differences in the concentration of ammonia in rumen fluid with the greatest concentration 30 to 90 min postfeeding. The concentration of ammonia nitrogen was greater for cows fed a high-concentrate diet (14.7% crude protein, 86% concentrate) than for cows receiving a normal diet (15.1% crude protein, 42% concentrate), 15.2 versus 13.1 mg/100 ml. In a second experiment, rumen fluid samples were obtained immediately before feeding and at 1 and 6 h postfeeding by stomach tube and from dorsal, midpoint, ventral, and mixed rumen contents via a rumen cannula. Concentrations of ammonia nitrogen (mg/100 ml) in the respective rumen fluid samples were 14.3, 23.0, 18.3, 17.2, and 19.6. Location of sampling, method of sampling, time of sampling, type of diet, and rumen fluid volume are factors that affect the concentration of ammonia nitrogen in rumen fluid.

Ammonia↗
PubMed1983

Ruminal infusion of ammonium chloride in lactating cows to determine effect of pH on ammonia trapping.

Milking rations containing 16 (control), 13.2, and 10.4% protein were fed to four midlactation, rumen-fistulated Holstein cows. Ammonium chloride was infused ruminally for 5 consecutive days after morning feeding when cows were fed milking rations containing 13.2 and 10.4% protein. Amount infused was equivalent to the ammonia in 1 or 2% dietary urea. Rumen and blood samples were taken prior to and following morning feedings. Intake of milking ration was the same across treatments. Initial rumen pH was higher for ammonium chloride treatments. It then declined, as did the control, to the same, lowest pH at 1.5 to 3 h postfeeding. Rumen ammonia increased rapidly for cows receiving both ammonium chloride treatments to .5 h postfeeding and then declined rapidly. Blood urea nitrogen was highest for cows fed the control ration, peaked .5 h postfeeding for cows infused with the low ammonium chloride, then dropped and peaked again 6 h postfeeding. Blood ammonia was highest among treatments for control cows and differed by sampling time only for control cows with a peak .5 h postfeeding. Because lower rumen pH traps ammonia preventing rapid absorption into blood, interpretation of high rumen ammonia must consider effect of rumen pH.

Ammonia↗
PubMed1984

Effect of ruminal ammonia-nitrogen concentration on protein degradation in situ.

Two experiments were conducted to determine the effect of ruminal ammonia-nitrogen concentration on rate of ruminal protein degradation. In Experiment 1, four Holstein steers were fed a basal diet of corn grain and corn silage at hourly intervals. Continuous intraruminal infusions of solutions containing sodium bicarbonate and either sodium chloride or ammonium chloride resulted in ruminal ammonia-nitrogen concentrations that averaged 4.8 and 17.3 mg/dl. Ruminal fluid pH, fluid volume, and turnover rate of fluid and molar percentage of acetate, propionate, and butyrate were similar across treatments, reflecting steady state conditions. Rates of nitrogen and dry matter disappearance from polyester bags containing soybean protein supplements with 10.2 or 50.1% soluble nitrogen were not affected by increase of ruminal ammonia-nitrogen concentrations from 4.8 to 17.3 mg/dl. In Experiment 2, Holstein steers were fed twice daily a basal diet of urea-supplemented corn grain and corn silage. Polyester bags containing soybean protein supplements were placed in the rumen at -4, 0, or 4 h with reference to feeding and incubated from 1 to 12 h. Peak ruminal ammonia-nitrogen concentrations occurred during different periods of incubation for each treatment. Ruminal ammonia-nitrogen concentrations ranged from 3 mg/dl at 6 h postfeeding to 46 mg/dl at 1 h postfeeding. Nitrogen and dry matter disappearance rates during 0 to 1 and 1 to 12 h of incubation did not differ among treatments.

Ammonia↗
PubMed1986

Effects of broiler litter volatiles and ammonia on fungal spore germination.

The effects of broiler litter volatiles on spore germination of 12 fungal species were determined. The volatiles inhibited spore germination of all species except Scopulariopsis brevicaulis. The inhibitory effect was fungistatic. The inhibitory volatile substances in litter were higher in built-up litter than in freshly used litter and were soluble in an acid solution. Ammonia was identified by infrared analysis as a fungal inhibitory substance in litter. The effect of various concentrations of ammonia produced from ammonium chloride (NH4Cl) was studied, and it was determined that concentrations of ammonia below 150 micrograms/g dry weight of litter were fungistatic for most species. At higher concentrations, ammonia was fungitoxic, with the exception of S. brevicaulis whose spore germination was not inhibited at this high concentration. Fungitoxic levels of ammonia were not found in the litter samples, but broiler house conditions necessary to produce fungitoxic levels are discussed.

Ammonia↗
PubMed1977

[Experimental studies on clinical application of 13N-ammonia; a metabolic model and functional image based on animal experiment].

Ammonia has been known to be an inducing agent of hepatic coma associated with liver cirrhosis. In order to establish a non-invasive method of investigating the portal circulation and the metabolism of ammonia at liver the following studies were performed, by using cyclotron produced 13N-labeled ammonia and delayed line-camera interphased with on-line computer system. 1) Animal experiment. Dynamic scintigraphy of thoraco-abdominal region of a rabbit after intrasigmoidal as well as intravenous administration of 13N-ammonia were performed. 2) Theoretical consideration on the functional image of liver: According to the results of the animal experiments, a model of ammonia metabolism having the minimal complexity necessary to represent data in the case of intrasigmoidal administration was proposed. Starting from the solution to the differential equation describing the model, relevant parameters characterizing the dynamic curve of liver were duded.

Ammonia↗
PubMed1998

Swimming-exercise increases the capacity of perfused rat liver to produce urea from ammonia and L-glutamine.

We designed this study to determine whether the capacity of the liver to uptake ammonia and produce urea was affected by exercise (swimming at 24 degrees C with a 2.5% extra body-weight load). For this purpose, livers from sedentary rats at rest were perfused with a buffer containing increasing concentration of NH4Cl. The maximal hepatic capacity to produce urea was found at an NH4Cl concentration of 0.25 mM. Based on this finding all experiments with livers obtained from rats subject to swimming exercise were also carried out with a NH4Cl concentration of 0.25 mM. Thus, employing this concentration of ammonia, livers from sedentary and endurance trained rats, (for a period of 11 days ), that had either been resting or had been subjected to swimming exercise for 5 min or until exhaustion, were perfused in situ and ammonia uptake and urea production were measured. Clearly, both parameters were increased by exercise. However, these changes were not affected by swimming training. In addition, we demonstrate that the effect of an acute exercise on hepatic metabolism is not restricted to ammonia metabolism since livers from sedentary rats which had been subjected to swimming exercise for 5 min or until exhaustion showed higher urea production from L-glutamine. Our results also suggest that part of the changes in ureogenesis induced by exercise is mediated by cortisol (increased ammonia uptake) and part of the changes is mediated by glucagon (urea production).

Ammonia↗
PubMed1999

Effects of L-arginine on picrotoxin-induced increase in brain ammonia concentrations and convulsions in rats.

The effect of L-arginine (840 mg/kg) pre- (30 min before challenge) and post-treatment (5 min after challenge) period was tested on picrotoxin-induced increase in ammonia concentrations in brain regions (cerebral cortex, brain stem and cerebellum) and the accompanying convulsive responses in adult male rats. The combined effect of L-arginine and diazepam was also tested against picrotoxin-induced convulsions. Picrotoxin-induced increase in ammonia was reverted partially by L-arginine pretreatment. However, L-arginine pretreatment did not show anticonvulsant effect independently or concurrently with diazepam. On the other hand, L-arginine post-treatment reverted ammonia to control level in all brain regions. A partial but significant inhibition of convulsion responses was found in these animals. The combined effect of diazepam and L-arginine post-treatment was much greater than that produced by these agents independently. These findings suggest that ammonia has a partial but significant participation in the convulsant action of picrotoxin. L-arginine has a potential to revert brain ammonia to control level in picrotoxin-treated animals and thereby it has produced a partial protection. The data further indicate that the duration of action of L-arginine is considerably short and has an additive anticonvulsant action with diazepam.

Ammonia↗
PubMedDate not supplied

Helicobacter pylori infection does not correlate with plasma ammonia concentration and hepatic encephalopathy in patients with cirrhosis.

BACKGROUND/AIMS: In patients with cirrhosis, infection of the stomach with Helicobacter pylori may increase ammonia production and, consequently, the incidence of hepatic encephalopathy. To test this hypothesis a retrospective analysis was performed in patients with a transjugular intrahepatic portosystemic shunt. These patients are regarded to be ideal candidates for such a study since they have a high bioavailability of gut-derived ammonia and many of them develop spontaneous hepatic encephalopathy. METHODOLOGY: In 132 patients (Child-Pugh class A: 24%, B: 49%, C: 27%) with stable transjugular intrahepatic portosystemic shunt function for more than 3 months (mean follow-up: 15.5 +/- 10.8 months) the diagnosis of H. pylori infection was established by a specific and sensitive immunoblot assay for IgG- and IgA-antibodies. During follow-up, hepatic encephalopathy was assessed by clinical examination and a structured questionnaire. Venous plasma ammonia concentration was measured at the time of antibody determination (end of study period). RESULTS: Eighty-four patients (64%) had negative and 48 patients (36%) had positive immunoblots for H. pylori. The groups were comparable with respect to age, gender, etiology of cirrhosis, Child-Pugh class, follow-up after transjugular intrahepatic portosystemic shunt, and shunt function. The ammonia concentrations of the patients without (group 1) and with antibodies against H. pylori (group 2) were 73 +/- 27 and 69 +/- 28 mumol/L (mean +/- SD), respectively. Hepatic encephalopathy occurred in 23 of 84 patients (27%) of group 1 and in 11 of 48 patients (23%) of group 2. CONCLUSIONS: A positive immunoblot for H. pylori antibodies neither correlates with plasma ammonia concentration nor with the incidence of hepatic encephalopathy in patients with cirrhosis of the liver and portosystemic shunt.

Adult↗
PubMed2001

[Kinetics of anaerobic ammonia oxidation].

The kinetic characteristics of anaerobic ammonia oxidation was studied. The cell yield was 1.573 mgVS (mmolNH4+)-1 and the cell decay coefficient was 0.052 mgVS(gVS.d)-1. The maximal rate of anaerobic ammonia oxidation and nitrite conversion rate by the mixed culture were 1.320-2.761 mmol(gVS.d)-1 and 14.497 mmol(gVS.d)-1, respectively. Km for ammonia and for nitrite were 1.801-4.215 and 0.468 mmol.L-1. Ki for ammonia was 38.018-98.465 mmol.L-1, the optimal ammonia concentration was 16.656 mmol.L-1. Ki for nitrite was 5.401-11.995 mmol.L-1. The optimal pH was around 7.5 and the theoretical value was 7.605. The optimal temperature was about 30 degrees C. The activation energy for Vmaxa, Kma, Kia and Kin was 37.316, 30.239, 33.695 and 30.473 kJ.mol-1.

Ammonia↗
PubMed2002

[Diffusion coefficients of ammonia, nitrate and nitrite in cell-free and cell-containing PVA gel membranes].

The cell-free PVA gel membrane and cell-containing PVA gel membrane were prepared by iterative freezing and thawing, and the diffusion coefficients of ammonia, nitrate and nitrite in PVA gel membranes were determined. The effect of the conditions of preparing PVA gel membranes and cell concentration on the diffusion coefficients of ammonia in PVA gel membranes were investigated. The results shown the diffusion coefficients of ammonia in PVA gel membranes decreased while the iteration times of freezing-thawing or PVA concentration or cell concentration increased. The diffusion coefficients of ammonia, nitrate and nitrite in cell-free PVA gel membranes (PVA concentration was 15%) were 0.69 x 10(-9) m2/s, 0.52 x 10(-9) m2/s, and 0.56 x 10(-9) m2/s, respectively. The diffusion coefficients of ammonia, nitrate and nitrite in cell-containing PVA gel membranes (the cell concentration was 60 g/L) were 0.55 x 10(-9) m2/s, 0.46 x 10(-9) m2/s, and 0.45 x 10(-9) m2/s, respectively.

Ammonia↗
PubMed1976

Reduction of gastric ammonia by ampicillin in normal and azotemic subjects.

Ampicillin was tested with regards to its capacity to reduce gastric ammonia production in basal and betazole-stimulated gastric secretion. A 7-day course of oral ampicillin (4 g per day) reduced basal gastric ammonia concentration from 5.5 +/- 1.4 to 1.8 +/- 0.3 mM and postbetazole ammonia from 4.7 +/- 0.9 to 1.3 +/- 0.3 mM (P less than 0.01) in 7 control subjects. Similar results were obtained after oral neomycin (4 g per day) or intramuscular ampicillin (4 g per day), each given to a separate group of 7 control subjects. In 5 azotemic patients, oral ampicillin treatment resulted in a reduction of ammonia concentration from 16.3 +/- 4.7 to 3.1 +/- 0.7 mM in basal secretion and from 18.3 +/- 8.1 to 2.3 +/- 0.6 mM in betazole-stimulated gastric juice (P less than 0.01). Antibiotic therapy did not alter volume of gastric secretion. Gastric acidity appeared lower in azotemic patients and increased significantly after treatment, indicating that the higher ammonia content could account for at least part of the hypoacidity. Because ampicillin is active orally as well as parenterally and can be readily used in renal failure, it may be of value for the treatment of hepatic encephalopathy, especially in the azotemic patient in whom neomycin is toxic.

Ammonia↗
PubMed2002

[Oxygen consumption and ammonia-N excretion rates of Chlamys farreri].

The oxygen consumption and ammonia-N excretion rates of Chlamys farreri were studied from April to June, 1999. The results showed that the oxygen consumption and ammonia-N excretion rates of Chlamys farreri were positively correlated with water temperature, and negatively correlated with its body weight under appropriate temperature conditions. Under the test temperature (8-28 degrees C), the oxygen consumption rate ranged from 0.48 to 9.09 mg.g-1.h-1, and the ammonia-N excretion rate ranged from 0.05 to 1.01 mg.g-1.h-1. With the raising water temperature, the oxygen consumption rate reached peak value at 23 degrees C, and began to decrease at 28 degrees C. The ammonia-N excretion rate continuously increased from 8 to 28 degrees C. The routine metabolism of Chlamys farreri under treatment was obvious higher than the standard metabolism, and the oxygen consumption and ammonia-N excretion rates increased by 35.8% and 75.9%, respectively.

Ammonia↗
PubMedDate not supplied

[Blood ammonia and transaminases in full term infants suffering from perinatal asphyxia].

AIMS: To find hepatic markers of perinatal asphyxia. PATIENTS AND METHODS: Variations in blood ammonia during the first week of life and in transaminase in serum during the first 48 hours were analysed in four groups of newly born infants (NBI): Group I or control, in which 65 NBI were included, with suspected unconfirmed infection and no other pathologies; Group II, made up of 15 NBI with loss of foetal well being (LFW) with no posterior neurological clinical features; Group III, consisting of 27 NBI with LFW criteria and mild hypoxic ischemic encephalopathy (HIE); and Group IV, with 25 NBI with LFW criteria and mild HIE according to Amiel s criteria. RESULTS: The average blood ammonia values in full term infants remain steady during the first week of life (87.66 21.69 mg/dL), as occurs in infants with LFW but without HIE (89.08 24.69 mg/dL) and in those with mild HIE (89.08 20.75 mg/dL). In moderate HIE, the blood ammonia level rises until the third day (108.55 7.04 mg/dL) and then drops back to the initial values (p= 0.0045). When grouped by days, these values show significant differences (p= 0.04), with higher values in Group IV. The NBI with HIE presented higher levels of transaminases, especially of AST (GOT) (p= 0.000001), and this increase is proportional to its gravity. No relation was found between values of blood ammonia and transaminases. CONCLUSIONS: Both blood ammonia and transaminases can be considered to be perinatal asphyxia markers.

Alanine Transaminase↗
PubMed1992

Tubular metabolism of aprotinin 99mTc and urinary ammonia: effects of proteinuria.

Increased renal ammoniagenesis is pathogenic in animals. Thus, tubular degradation of filtered proteins to ammonia might link proteinuria to disease progression. The tubular uptake, metabolism and fractional degradation of aprotinin 99mTc (Trasylol), were measured in 26 glomerulonephritic patients with normal renal function, 10 with proteinuria > 5 g/24 h. In addition, urinary ammonia pH, and titratable acidity were measured. Patients with heavy proteinuria had a higher tubular metabolism, a lower uptake and a higher fractional degradation of aprotinin. Urinary ammonia and titratable acidity were also increased. Fractional degradation and urinary ammonia were strongly correlated as were urinary ammonia and proteinuria.

Acids↗