In vitro studies on the effect of pH and of glucose on ammonia accumulation in the rumen of sheep

1959 ◽  
Vol 10 (1) ◽  
pp. 71 ◽  
Author(s):  
PJ Ries ◽  
RL Reid
Keyword(s):  
Casein Hydrolysate ◽  
Ammonia Production ◽  
Protein Nitrogen ◽  
Effect Of Ph ◽  
Nitrogen Levels ◽  
Ammonia Accumulation ◽  
Optimum Ph ◽  
Alkaline Side ◽  
Sheep Rumen

The effect of pH and of glucose on ammonia accumulation in rumen liquor, obtained from sheep rumen contents, was studied during 4-hr in vitro incubations. Control of pH over the range 4.5-7.3 was effected with sodium phosphate-citric acid buffer. Casein hydrolysate was added as a substrate for ammonia production. There was an optimum pH for ammonia accumulation which varied between 6.0 and 6 . 7 on different diets, and which appeared to be correlated with the range of pH normally encountered in the rumen on each diet. Ammonia accumulation fell rapidly on the acid side of the optimum pH and usually less rapidly on the alkaline side. This effect of pH is most probably due to an effect on ammonia production, i.e. an effect on deamination of amino acids. Glucose reduced ammonia accumulation to an extent greater than could be accounted for by the fall in pH due to the fermentation of glucose; protein nitrogen levels in the reaction mixture were significantly increased. It was concluded that the effect of glucose was due largely to a stimulation of ammonia utilization for synthesis of microbial protein and not to an inhibition of ammonia production.

Influence of kanamycin on the rumen bacteria and ammonia production in supplemented sheep rumen liquor in vitro

1979 ◽  
Vol 4 (3) ◽  
pp. 247-253
Author(s):  
J. Gonzalez ◽  
V. Salmeron ◽  
J. Acosta ◽  
J. Silva
Keyword(s):  
Rumen Bacteria ◽  
Ammonia Production ◽  
Sheep Rumen

scholarly journals In vitro effect of pH on resistance of ruminal bacteria to intracellular potassium depletion, and effect of pH and ionophores on ammonia and microbial protein production

2005 ◽  
Vol 57 (6) ◽  
pp. 778-783 ◽  
Author(s):  
W.M. Leopoldino ◽  
R.P. Lana ◽  
A.C. Borges ◽  
H.C. Mantovani ◽  
R.M.A. Teixeira ◽  
...  
Keyword(s):  
Protein Production ◽  
Culture Media ◽  
Low Ph ◽  
Potassium Depletion ◽  
Ammonia Production ◽  
Microbial Protein ◽  
Ruminal Bacteria ◽  
Effect Of Ph ◽  
Vitro Effect

Ruminal fluid from steers fed on pasture was incubated with artificial media at pH 5.5 and 7.0 in two experiments. In the first, the effect of monensin level on resistance of ruminal bacteria to potassium depletion was evaluated; in the second, effects of the ionophores monensin and lasalocid on ammonia and protein production were quantified. In experiment 1, culture media affected potassium level. The monensin concentration needed to cause half maximal potassium depletion was 2.77µM at pH 5.5 but was 0.056µM at pH 7.0, showing that bacteria incubated at pH 5.5 were more tolerant to monensin than those incubated at pH 7.0. Both ionophores as well as increased acidity caused decreased ammonia production. Both ionophores inhibited ammonia production by 56%, independently of pH. In cultures incubated at pH 5.5 compared to pH 7.0, ammonia production was decreased by 50.5%, independently of the ionophores. Therefore, effects of ionophores and acidity were additive, and the maximum inhibition occurred in the presence of an ionophore at low pH (75.2%). Microbial protein production was lowest when lasalocid was present in a low pH culture medium, causing inhibition of microbial growth.

scholarly journals Acetylation of peptides inhibits their degradation by rumen micro-organisms

1992 ◽  
Vol 68 (2) ◽  
pp. 365-372 ◽  
Author(s):  
R. J. Wallace
Keyword(s):  
Rumen Fluid ◽  
Inhibitory Effect ◽  
Peptidase Activity ◽  
Ammonia Production ◽  
Terminal Amino ◽  
Sheep Rumen ◽  
A Minor ◽  
Micro Organisms ◽  
Proteins And Peptides

Proteins and peptides were acetylated using acetic anhydride in order to block their N-terminal amino groups and thereby to prevent their hydrolysis by rumen microbial aminopeptidases. The effects of acetylation on peptide breakdown and ammonia production were determined by incubating unmodified and acetylated substrates with sheep rumen micro-organisms in vitro. Ammonia production from casein and lactalbumin was affected little by acetylation, but acetylation of the corresponding enzymic hydrolysates caused ammonia production to be more than halved after 3.6 h incubation. Estimation of peptides remaining in rumen fluid showed that the decreased ammonia production was a consequence of peptides being hydrolysed more slowly. Acetylated Ala-Ala, Ala-Ala-Ala (Ala3), Leu-Gly-Gly, Phe-Gly-Gly and Val-Gly-Ser-Glu survived incubation with rumen fluid in vitro for 6 h, whereas almost none of the corresponding unmodified peptides was present at 6 h. The protection afforded to larger pure peptides was less reliable: for example, 72% of acetylated bradykinin was hydrolysed after 1 h.N-Acetyl Ala3had only a minor inhibitory effect on the breakdown of Ala3and Ala4, suggesting that although acetyl peptides were broken down more slowly than unmodified peptides they did not inhibit peptidase activity.

Trans-sialidase Associated with Atherosclerosis: Defining the Identity of a Key Enzyme Involved in the Pathology

2019 ◽  
Vol 20 (9) ◽  
pp. 938-941
Author(s):  
Victor Y. Glanz ◽  
Veronika A. Myasoedova ◽  
Andrey V. Grechko ◽  
Alexander N. Orekhov
Keyword(s):  
Acid Metabolism ◽  
Research Subject ◽  
Disease Pathogenesis ◽  
Sialidase Activity ◽  
Ph Values ◽  
Ldl Particles ◽  
Optimum Ph ◽  
Key Enzyme ◽  
St6gal I

Atherosclerosis is associated with the increased trans-sialidase activity, which can be detected in the blood plasma of atherosclerosis patients. The likely involvement in the disease pathogenesis made this activity an interesting research subject and the enzyme that may perform such activity was isolated and characterized in terms of substrate specificity and enzymatic properties. It was found that the enzyme has distinct optimum pH values, and its activity was enhanced by the presence of Ca2+ ions. Most importantly, the enzyme was able to cause atherogenic modification of lowdensity lipoprotein (LDL) particles in vitro. However, the identity of the discovered enzyme remained to be defined. Currently, sialyltransferases, mainly ST6Gal I, are regarded as major contributors to sialic acid metabolism in human blood. In this mini-review, we discuss the possibility that atherosclerosis- associated trans-sialidase does, in fact, belong to the sialyltransferases family.

scholarly journals A Novel In Vitro Model for Determining the Optimum pH and Dose Volume of New Liquid Alginate for Infant Reflux Suppression

Drugs in R&D ◽  
2021 ◽  
Author(s):  
Jeanine Fisher ◽  
Fiona McLaughlin ◽  
Neil Fawkes ◽  
Hannah Tipple ◽  
Cathal Coyle ◽  
...  
Keyword(s):  
In Vitro Model ◽  
Dose Volume ◽  
Optimum Ph ◽  
Vitro Model

scholarly journals Effect of pH on Fermentation Characteristics and Protein Degradation by Rumen Microorganisms In Vitro

1982 ◽  
Vol 65 (8) ◽  
pp. 1457-1464 ◽  
Author(s):  
J.D. Erfle ◽  
R.J. Boila ◽  
R.M. Teather ◽  
S. Mahadevan ◽  
F.D. Sauer
Keyword(s):  
Protein Degradation ◽  
Rumen Microorganisms ◽  
Effect Of Ph

The digestibility and the nitrogen, phosphorus and ash contents of the leaves of some Australian trees and shrubs

1973 ◽  
Vol 13 (62) ◽  
pp. 245 ◽  
Author(s):  
MN McLeod
Keyword(s):  
Significant Variation ◽  
Dry Matter ◽  
Mature Trees ◽  
Lower Range ◽  
Nitrogen Levels ◽  
Dry Matter Digestibility ◽  
Individual Trees ◽  
Trees And Shrubs ◽  
Nitrogen Phosphorus

The dry matter digestibility measured in vitro and the levels of nitrogen, phosphorus and ash were determined on the leaves from mature trees of twenty-one species growing in two arboreta in southeastern Queensland and known to be grazed by animals. Most of the leaf samples had digestibilities in the lower range (68 per cent samples < 50 per cent D.M.D.) and low ash levels (65 per cent samples < 7 per cent ash). Nitrogen levels were satisfactory (86 per cent samples in range 1.5-3.0 per cent N) but the level of phosphorus tended to be low (84 per cent samples < 0.20 per cent P). Statistically significant variation between individual trees and seasons was found with some species.

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