Ammonia Output Research Articles

Resistant starch lowers fecal concentrations of ammonia and phenols in humans

We investigated the effect of resistant starch (RS) on markers of colonic protein metabolism. Eleven subjects participated in a randomized crossover study in which they consumed either high-RS (39 +/- 3 g/d, -chi +/- SEM) or low-RS (5 +/- 0.4 g/d) diets for 3 wk. All other macronutrients were kept constant. During the high-RS diet daily excretion of fecal nitrogen increased from 1.84 +/- 0.15 to 2.86 +/- 0.42 g/d (P < 0.01) and excretion of fecal phenols fell from 9.2 +/- 1.4 to 5.3 +/- 0.8 mg/d (P < 0.01). Fecal concentrations of ammonia decreased from 397 +/- 33 to 278 +/- 49 microgram/g (P < 0.01) and phenols decreased from 69 +/- 8 to 39 +/- 10 microgram/g (P < 0.001). Daily output of urinary ammonia, urea, phenols, and total nitrogen did not change significantly, but pH decreased from 6.4 +/- 0.1 to 6.2 +/- 0.1 (P < 0.05) during the high-RS period. These results suggest that RS significantly attenuates the accumulation of potentially harmful byproducts of protein fermentation in the human colon.

The effect of oligosaccharides and lactitol on the ileal digestibilities of amino acids, monosaccharides and bacterial populations and metabolites in the small intestine of weanling pigs

An experiment was carried out to examine the effects of supplementing diets for weanling pigs with oligosaccharides and LAC on nutrient digestion and bacterial populations and metabolites in the small intestine. Twelve barrows, weaned at 28 d, were fitted with a simple T-cannula at the distal ileum. The BW of the pigs at weaning and at the conclusion of the experiment were 9.1 and 13.8 kg, respectively. The pigs were fed four diets based on barley, wheat and soybean meal according to a two-period change-over design. The diets were formulated to contain 18% CP. Transgalactosylated oligosaccharides (0.2%), GUO (0.2%) and LAC (1%, 4-O-β-D-galactopyranosyl-D-sorbitol) were included at the expense of corn starch. Supplementation with oligosaccharides or LAC had little effect on the apparent ileal digestibilities of AA and monosaccharides. Supplementation of diets with oligosaccharides or LAC did not affect (P &gt; 0.05) the monosaccharide concentrations in ileal digesta except for galactose which was higher (P &lt; 0.05) in digesta from pigs fed the diet supplemented with LAC. The daily ileal output of monosaccharides, pH, ammonia and VFA concentrations, bacterial populations in ileal digesta and incidence of diarrhea were not affected (P &gt; 0.05). Therefore, the supplementation of diets for weanling pigs (9.1–13.8 kg) with oligosaccharides or LAC at these levels does not affect nutrient digestibilities and bacterial populations in the small intestine. Key words: Pigs, oligosaccharides, lactitol, digestibility, bacteria

Effect of air exposure on ammonia excretion and ammonia content of branchial water of the crab Cancer pagurus

AbstractC. pagurus (mean weight 280 g) was exposed to air for 18 h at 16–18°C in presence of a small volume of filtered seawater (FSW = 45 ml) and then reimmersed. Ammonia excretion rate was measured and the amount of ammonia that accumulated in branchial water and haemolymph during emersion was evaluated. During the whole emersion period, ammonia that was released into both FSW (42 μmoles·crab−1) and branchial water (&lt; 11 μmoles·crab−1) amounted to 6% of the pre‐emersion release, at the very most.In the first 5 min immediately following reimmersion, a large burst of ammonia output (203 μmoles·crab−1) was observed. Neither ammonia stored in branchial water and haemolymph nor breakdown of urate accumulated in haemolymph can account for it. As this burst was not the result of an increase in metabolism only, its potential sources are discussed. Following this burst, ammonia excretion rate returned to its pre‐emersion value within the next 1 h. Then, ammonia excretion rate again increased; this second increase was relatively moderate and lasted for 2–3 h. Recovery was fully achieved within 8 h. The ammonia excess that was excreted during recovery was mainly released at the onset of re‐immersion. © 1994 Wiley‐Liss, Inc.

Combined effects ofAspergillus oryzaefermentation extract and monensin on fermentation in the rumen simulation technique (Rusitec)

SUMMARYMonensin, an ionophore, andAspergillus oryzaefermentation extract (AO), a fungal feed additive, are growth promoters which modify rumen fermentation. The effects of combining these additives were determined in the rumen simulation technique (Rusitec). Sixteen vessels received 20 g/day of a diet of hay, barley, molasses, fishmeal and a mineral/vitamin mixture (500, 299·5, 100, 91 and 9·5 g/kg DM respectively). AO, monensin (M) and AO + monensin (AO/M) were each added to four vessels at 500, 10 and (500 + 10) mg/day respectively. Both M and AO/M increased propionate (14·5 and 138v.91 mmol/day in controls;P&lt; 0·001) and reduced butyrate production (6·6, 5·2 and 9·1 mmol/day respectively;P&lt; 0·01), whereas AO had no effect. AO increased bacterial numbers by 70% (P&lt; 0·055), while M had no effect, and in the presence of M, AO also had no effect. Proteolytic activity in samples from the vessels decreased (P&lt; 0·05) in all treatments (1·06, 0·71, 0·60 and 0·47 mg14C-casein/mg protein/h for control, AO, M and AO/M respectively). In contrast, deamination of amino acids increased (P&lt; 0·001) with AO and AO/M but decreased slightly with M alone (482, 646, 434 and 644 nmol NH3/mg protein/h). Ammonia output was unchanged (47·4, 57·2, 42·7 and 44·8 mg/day). Thus each additive was dominant over the other for different activities, with monensin generally suppressing the effects of AO rather than vice-versa.

The peculiarities of nitrogen excretion in sturgeons ( Acipenser ruthenus) (Pisces, Acipenseridae)—I. the influence of ration size

1. 1. The nonfaecal nitrogenous excretion rate in starved sterlet fingerlings and fingerlings fed on different rations was investigated. The weight of the fish and temperature of the water was 43 g and 17.5°C, respectively. 2. 2. In the nonfaecal excrements of starved sterlets the ammonia: urea ratio was substantially lower than in teleosts. This ratio was found to be 1.4:1. 3. 3. In fed sterlets the urea excretion rate was higher than in starved ones but independent of ration size. 4. 4. During the day the urea excretion rate in sterlets was constant. 5. 5. The ammonia excretion rate accelerated 2 hr after feeding and reached its peak duration 6–11 hr after depending on the ration size. 6. 6. Total ammonia output in the sterlet increased following the increase of ration size up to 8.4% of body wt. Further increases in ration size did not cause the corresponding elevation of ammonia excretion rate.

The effect of a biocide treatment and a silicone treatment on the weathering of limestone

Abstract The effects of a biocide treatment, pentachlorophenol, and a silicone water repellant on the dissolution processes of limestone were investigated. Limestone microcatchment units were exposed on the pavillion roof of Trinity College, Dublin for a period of 68 days. The effect of the treatment on the chemical composition of runoff from the units was investigated. The pentachlorophenol treatment appeared to cause a decrease in the output of bicarbonate and an increase in the output of nitrite, nitrate and ammonia from the limestone when compared with untreated control stones. These effects are thought to be due to the elimination of biological growth from the stone. The silicone treatment appeared to have decreased the bicarbonate and particulate output relative to the untreated stones. This effect is thought to be due to the decreased residence time of water in the stone.

Influence of yeast culture on the in vitro fermentation (Rusitec) of diets containing variable portions of concentrates

Incubation trials were carried out with the rumen simulation technique Rusitec to study the effects of a yeast culture (YC) from Saccharomyces cerevisiae on the fermentation of three different diets. The diets, having a forage: concentrate ratio (dry matter (DM) basis) of 70:30 (low-concentrate diet), 50:50 (medium-concentrate diet) and 30:70 (high-concentrate diet), were each incubated either with or without yeast culture (15 mg YC g −1 DM). Overall, the addition of YC had only a small influence on the fermentation parameters with the low-concentrate diet. Molar proportions of volatile fatty acids (VFA), however, were significantly affected ( P < 0.05). When the medium-concentrate diet was supplemented with YC, methane production ( P < 0.06), protozoal concentration ( P < 0.03) and acetate concentration ( P < 0.01) were reduced, while butyrate and valerate concentrations were increased ( P < 0.01). However, the degradability of DM and neutral detergent fibre (NDF), output of ammonia and microbial nitrogen synthesis were not affected ( P > 0.10) by the addition of YC. Adding YC to the high-concentrate diet increased DM and NDF degradabilities ( P < 0.01), VFA production ( P < 0.05), methane production ( P < 0.07) and the concentration of protozoa ( P < 0.02). On the other hand, the output of ammonia was reduced ( P < 0.10). These results indicate that YC influenced the rumen population and had a diet-dependent effect on the fermentation pattern.

Alanine, glutamate, and ammonia exchanges in acutely ischemic swine myocardium.

Coronary artery disease causes an increase in glutamate uptake and alanine output by the heart. We assessed the effects of acute myocardial ischemia on alanine and glutamate exchange and ammonia production in 10 anesthetized open-chest domestic swine (46.9 +/- 0.7 kg). Coronary blood flow was controlled through an extracorporal perfusion circuit. After a nonischemic control period (aerobic) the blood flow in the left anterior descending coronary artery was reduced by 60%. Arterial and anterior interventricular venous samples where drawn before and during 35 min of ischemia. Subendocardial blood flow, measured using radiolabeled microspheres, decreased from 1.27 +/- 0.16 to 0.25 +/- 0.09 (ml/g)/min, and left-ventricular wall-thickening fell to 47% of aerobic values. Ischemia resulted in a significant increase in the rate of glucose uptake (p less than 0.05) and a switch to net lactate production (p less than 0.01). Ischemia did not affect the rates of alanine output (-0.9 +/- 1.0 vs. -0.3 +/- 0.3 mumol/min) or glutamate uptake (-0.4 +/- 1.1 vs. 0.3 +/- 0.6 mumol/min), but did increase the venous-arterial difference for ammonia (-4.1 +/- 4.1 to 52.7 +/- 5.5 microM, p less than 0.0001) and the ammonia output (-0.33 +/- 0.24 to 1.34 +/- 0.14 mumol/min, p less than 0.0001). In conclusion, acute ischemia did not stimulate greater alanine output or glutamate uptake. However, acute ischemia did cause an increase in anaerobic glycolysis rate and ammonia output, which reflects a profound disruption in myocardial energy metabolism.

The ecophysiology of under-ice fauna

During exposure to low salinity, the under-ice amphipods Gammarus wilkitzkii and Onisimus glacialis appeared as euryhaline osmoregulators, displaying regulation of haemolymph concentrations of sodium and chloride. Free amino acids took part in the regulation. During freezing and brine formation, the amphipods were freeze-sensitive and did not tolerate being frozen into solid ice. However, they could stay in the vicinity of the ice, conforming osmotically to the ambient brine and thus lowering the melting point of the amphipods' body fluids. This prevented internal ice formation in the absence of antifreeze agents (THF) in the haemolymph. When G. wilkitzkii, O. glacialis and Apherusa glacialis were exposed to dilute seawater, elevated rates of oxygen consumption and ammonia excretion were observed. The O:N atomic ratio was kept nearly constant during hyposmotic stress, indicating protein/lipids as metabolic substrate. Rates of oxygen consumption and ammonia excretion increased with increasing osmotic differences between the haemolymph and the medium, indicating higher energy requirements for osmotic and ionic regulation at low salinities. A minor decrease in haemolymph sodium concentrations coincided with the increased ammonia output during hyposmotic stress, indicating a possible counter ion regulation of NH+4 and Na+. An increased rate of oxygen consumption, ammonia excretion and 0:N ratio versus temperature was observed for all species.

Interaction of gut and liver in nitrogen metabolism during exercise

The role of the gut and liver in nitrogen metabolism was studied during rest, 150 minutes of moderate-intensity treadmill exercise, and 90 minutes of recovery in 18 hour-fasted dogs (n = 6). Dogs underwent surgery 16 days before an experiment for implantation of catheters in a carotid artery and in the portal and hepatic veins, and Doppler flow cuffs on the hepatic artery and portal vein. Arterial glutamine, alanine, and α-amino nitrogen (AAN) levels decreased gradually with exercise ( P < .05), while arterial glutamate, NH 3, and urea were unchanged. Net gut glutamine uptake was 1.3 ± 0.5 μmol/kg · min at rest, and increased transiently to 2.5 ± 0.3 μmol/kg · min at 60 minutes of exercise ( P < .05) as gut extraction increased. Net hepatic glutamine uptake was 0.6 ± 0.4 μmol/kg · min at rest, and increased to 3.4 ± 0.6 and 2.6 ± 0.5 μmol/kg · min after 60 and 150 minutes of exercise ( P < .05) as hepatic extraction increased. Net gut glutamate and NH 3 output both increased transiently with exercise ( P < .05). These increases were matched by parallel increments in the net hepatic uptakes of these compounds. Alanine output by the gut and uptake by the liver were unchanged with exercise. Net gut AAN output was −2.1 ± 1.8 μmol/kg · min at rest (uptake occurred), and increased transiently to 11.2 ± 3.5 μmol/kg · min after 30 minutes of exercise ( P < .05). Net hepatic AAN uptake was 6.9 ± 1.9 μmol/kg · min at rest, and increased to 21.7 ± 4.0 and 18.5 ± 2.7 μmol/kg · min after 30 and 150 minutes of exercise ( P < .02). Net hepatic urea output increased from 3.8 ± 0.8 μmol/kg · min at rest to 6.8 ± 1.0 and 5.6 ± 1.0 μmol/kg · min after 30 and 150 minutes of exercise ( P < .05). In summary, during exercise, (1) glutamine uptake by the gut and liver is increased as fractional extraction rises; (2) gut amino acid and ammonia output occur in synchrony with, but exceed gut glutamine uptake; (3) hepatic glutamate and NH 3 uptake increase in parallel with the increased gut output of these substrates and appear to be closely regulated by their hepatic delivery rates; and (4) hepatic urea output is increased with the increase in hepatic uptake of nitrogenous precursors, but is quantitatively insufficient to explain the entire fate of these nitrogenous compounds within the liver. These studies demonstrate that gut and liver interactions play an important role in nitrogen metabolism during exercise.

The relative importance of the gills to ammonia and urea excretion in five seawater and one freshwater teleost species

The classic Homer Smith divided box experiment (Smith, 1929) was repeated upon five marine and one freshwater teleost species. Of the nitrogenous output (as ammonia and urea), 50–70% occurred in the head region for marine teleosts, while the freshwater tilapia studied excreted 90% from the head. Together with the data of Smith, these data indicate that nitrogen excretion by the gills is of lesser importance in marine teleosts than in freshwater species.In the dab, Limanda limanda, the head, anus and urinary opening were all in the anterior chamber of the divided box, but 47% of nitrogen excretion still occurred in the posterior chamber, presumably across the skin. In the blenny, Blennius pholis, exposed to air, the head region accounted for 46% of urea elimination, and 26% of ammonia output.

Inhibition of intracellular protein degradation by ethanol in perfused rat liver.

Ethanol (50 mM) inhibited proteolysis in the perfused rat liver during stringent amino acid deprivation and also in the presence of normal and 10 times normal concentrations of plasma amino acids. The concentration-response curve of ethanol reached a plateau after 5 mM in both the presence and the absence of normal plasma amino acids, suggesting inhibition by oxidation products of ethanol. Intracellular glutamine, tyrosine and proline increased in concentration with ethanol, but the increases were too small to explain the observed inhibition of proteolysis. The uptake of 125I-asialofetuin was slightly decreased and the output of ammonia increased in the presence of ethanol. These, together with a significant suppression of basal proteolysis in the presence of amino acids, suggest that lysosomal function was directly affected. Electron-microscopic examination of lysosomal components showed that the aggregate volume of autophagosomes (initial vacuoles) were significantly smaller in livers perfused with ethanol than in controls. However, the equivalent volume of autolysosomes (degradative vacuoles) was the same in both groups. According to these results, ethanol inhibits protein degradation in the liver by two discrete mechanisms: one decreasing the formation of autophagic vacuoles and the other involving lysosomotropic inhibition, possibly via ammonia.

NITROGEN EXCRETION IN MARINE AND FRESH‐WATER CRUSTACEA

Summary1. The major characteristic of aquatic Crustacea is ammonotelism as shown by the relative importance of various nitrogenous end‐products of their nitrogen metabolism.2. In contrast to urico‐ and ureo‐genesis pathways, ammoniogenesis pathways have received recent attention; some specific enzymes such as glutamate dehydrogenase, AMP‐deaminase and glutaminase are now admitted to play a possible key role in ammoniogenesis of various crustacean species.3. Processes involved in ammonia output through the gill epithelium (diffusion and/or ionic exchanges) are discussed though few data related to Crustacea are as yet available compared to those obtained in ammonotelic fishes.4. The effects of some environmental factors as well as the physiological state of animals on nitrogen excretion of Crustacea are envisaged. The effects of temperature, salinity and NH4 concentration in the external medium are discussed first, followed by the changes in nitrogen excretion associated with the moult cycle, the nutritional state of animals and possible neuroendocrine control. It is demonstrated that the response of the excretion rate to these factors presents various patterns according to the species, its osmoregulatory abilities and its body reserves. Changes can also occur in the requisite metabolic pathways, thus increasing the difficulty of generalization.5. In spite of the great diversity encountered within Crustacea an attempt to bring out general trends of their nitrogen excretion is proposed.6. The present review is focused on metabolic and physiological aspects of crustacean nitrogen excretion but the significance of nitrogen release in nutrient regeneration in marine and fresh‐water ecosystems is foreseen.

Ammonia and urea excretion in the amphibious teleost Blennius Pholis exposed to fluctuating salinity and pH

1. 1. Excretion of ammonia and urea by the intertidal teleost Blennius (Lipophrys) pholis (L.) was investigated whilst fish were subjected to changes in salinity and pH. 2. 2. Ammonia output was not significantly altered by exposure either to low salinity or to low pH. 3. 3. Excretion of urea increased in fresh water, accounting for 52.2% of total nitrogenous excretion (measured as ammonia and urea), compared with 22.5% in normal sea-water.

Nitrogen balance in marine fish larvae: influence of developmental stage and prey density

The utilization and fate of nitrogen in larvae of plaice (Pleuronectes platessa), blenny (Blennius pavo) and herring (Clupea harengus), from the stage of first-feeding to metamorphosis, was examined under laboratory conditions. Rates of ammonia excretion, primary amine defaecation, and growth in terms of protein-nitrogen were monitored throughout larval life. Data were used to calculate daily ration, the coefficient of nitrogen utilization (absorption efficiency), and gross and net growth efficiencies. The developmental pattern of nitrogen balance was similar for plaice and blenny larvae. These species showed increasing growth efficiency (k1: 55 to 80%) with decreasing weight-specific waste nitrogen losses with age. Absorption efficiencies. were high (83 to 98%) in plaice and blenny larvae, and tended to increase with development in the former species. Ration relative to body weight decreased with growth in both species. Herring larval development, although at a slower rate than blenny and plaice, appeared normal up to 33 d, after which high mortality occurred. Absorption efficiency in this species tended to decline (83 to 43%) with age, until metabolic costs exceeded the absorbed ration and growth ceased. Artemia sp. nauplii proved a suitable food source for the rearing of plaice and blenny larvae, but this diet may have long-term toxicity or deficiency effects on herring. Availability and density of food affected nitrogen balance in the larvae of all three species. Feeding stimulated the output of wastes in excretion and defaecation by a factor of up to ten times the 12-h non-feeding basal rates. Waste nitrogen output reached a peak some 2 to 3 h after commencement of feeding and returned slowly to the baseline in 5 to 10 h after cessation of feeding. There was an asymptotic increase in ration, ammonia output and growth of larvae as prey density increased. Ration saturated at a higher prey density (>4 prey ml-1) than either growth or excretion rate (1 prey ml-1). Thus the efficiency with which food is absorbed and utilized for growth must eventually decline in response to high prey density. The idea that larval fish are adapted to maximize ingestion and growth rate, rather than optimize growth efficiency and thus to respond to prey occurring in either low density or in occasional patches, is supported by these results.

Effects of monensin and sodium propionate on net nutrient absorption in steers fed high-grain diets (1986)

Adding either monensin or sodium propionate alone or in combination to the diet of steers fed high-grain diets resulted in increased net absorption of glucose. Monensin reduced ammonia output and gut uptake of urea. We propose that increased propionate availability reduces the utilization of glucose by gut tissues. allowing more glucose to reach the portal system. These changes may contribute to the increased feed efficiency seen when monensin is fed.

Ammonia output by eggs and larvae of the lumpsucker,Cyclopterus lumpus, the cod,Gadus morhuaand the plaice,Pleuronectes platessa

Cod and plaice eggs show a gradually increasing rate of ammonia excretion during development and in neither species was there a great change in individual output at hatching. The rates of ammonia excretion recorded for cod and plaice larvae were similar to those recorded for planktonic Crustacea of comparable size by Conover &amp; Corner (1968).Lumpsucker eggs and larvae have a basically low rate of ammonia excretion (consistent with their slow rate of development and low oxygen consumption), but much ammonia was released from the eggs in the first day or two after spawning. This ammonia was of non-metabolic origin, but was not accumulated from the ovarian fluid prior to spawning. Lumpfish eggs become very sticky when they are first exposed to sea water, but this stickiness is lost within 24 h. Stickiness stems from a viscous elastic slime; it is suggested that the non-metabolic output of ammonia is caused by changes in the composition of the slime as the eggs are bound together in a lattice.

Leucine metabolism in skeletal muscle of the tumour-bearing rat

Leucine oxidation was increased and its incorporation into protein decreased in incubated hemidiaphragms from rats bearing a Walker 256 carcinoma. Homogenates of diaphragms from these rats exhibited a moderate increase in branchedchain oxo-acid dehydrogenase activity but no change in leucine aminotransferase. Hemidiaphragms of tumour-bearing rats incubated with 0.1 mM leucine showed a decreased release of alanine, no alteration in glutamine release, and an increased output of ammonia. When glucose was added to the medium, leucine oxidation was still increased in hemidiaphragms of tumour-bearing rats, alanine release increased but only to control levels, ammonia release decreased and glutamine release remained at control levels. It was concluded that the increased leucine oxidation accompanying increased net protein breakdown in the tumour-bearing animal is not providing an increase in the output of gluconeogenic precursors.

Ammonia Quotient in Sockeye Salmon (Oncorhynchus nerka)

Ammonia quotients (A.Q., ratio of ammonia excreted to oxygen consumed) were computed from data on daily-fed and starved sockeye salmon (Oncorhynchus nerka). In 22-d starved salmon, where a diel pulse in oxygen consumption, but not in ammonia excretion, persisted, the A.Q. was 0.125 at the prepulse stage (0.11 in fed fish); the lowest A.Q. was 0.06 (0.05 in fed fish) at peak oxygen consumption. The highest A.Q. of 0.24 was obtained in fed fish at the peak of ammonia output. Based on a theoretical estimate of an aerobic maximum A.Q. of 0.33, it is estimated that protein oxidation changes from 18 to 38% in starved sockeye and 15 to 73% in fed fish. The latter value is possibly an overestimate because of the involvement of nonoxidative protein breakdown, but this anaerobic involvement in routine metabolism of sockeye may be negligible. Key words: ammonia excretion, ammonia quotient, Oncorhynchus nerka, daily metabolic pattern, protein catabolism, starvation effect, energy utilization, nitrogen-excretion ratio, Rhinomugil corsula

The purine nucleotide cycle. Studies of ammonia production by skeletal muscle in situ and in perfused preparations.

Ammonia production by hind limbs of rat was studied in perfused preparations during rest, exercise, and hypoxia, and while the perfusate contained epinephrine or cyanide. Ammonia production by hind limbs was also studied in situ during rest and exercise. Strong correlations were observed between ammonia, IMP, and lactate formation. Adenylosuccinate was not present in detectable amounts in resting muscle (less than 1 nmol/g dry weight) but it appeared and rose sharply in exercising muscle, and then declined during recovery. The maximum found was about 18 nmol/g dry weight. When IMP accumulation exceeded 2.8 mumol/g dry weight, the formation of adenylosuccinate diminished, presumably because of an inhibition of adenylosuccinate synthetase by excess substrate. Exercise resulted in a greatly increased output of ammonia and a decreased output of alanine and glutamine. The tissue contents of aspartate and glutamate were decreased, while that of alanine was increased. The content of malate increased 3-fold during exercise. Epinephrine, hypoxia, and cyanide each caused an increased output of ammonia at the expense of the amino acid content of the tissue. These results provide evidence for the operation of the purine nucleotide cycle in skeletal muscle under various conditions that are associated with an increased rate of glycolysis.