Utilization of urea by sheep

1964 ◽  
Vol 63 (3) ◽  
pp. 289-296 ◽  
Author(s):  
H. M. Schwartz ◽  
C. A. Schoeman ◽  
M. S. Färber
Keyword(s):  
Rumen Fluid ◽  
Soluble Starch ◽  
Large Numbers ◽  
Food Particles ◽  
Freely Suspended ◽  
Micro Organisms ◽  
Strained Material

1.The breakdown of urea, soluble starch and glucose was followed in the rumen of fistulated sheep and in artificial rumens containing rumen ingesta or strained rumen fluid.2. Carbohydrate remained in the rumen two to three times as long when starch was dosed in vivo as when glucose was given.3. The relative rates of breakdown of urea and carbohydrate by strained rumen fluid in vitro differed markedly from those in vivo. This was due to the fact that straining removed large numbers of starch- and glucose-utilizing micro-organisms which were attached to the larger food particles, while the concentration of the urea-splitting organisms which were freely suspended in the strained liquor was apparently the same as that obtained in the strained material. Strained rumen fluid should therefore not be used for studies of the utilization of urea in vitro.

Repeatability of in vitro digestibility assays of forages when using fresh, frozen or freeze-dried cow faeces instead of sheep rumen liquor as sources of micro-organisms

1995 ◽  
Vol 1995 ◽  
pp. 110-110 ◽  
Author(s):  
S Akhter ◽  
E Owen ◽  
M K Theodorou ◽  
S L Tembo ◽  
E R Deaville
Keyword(s):  
Freeze Drying ◽  
Rumen Fluid ◽  
In Vitro Digestibility ◽  
Two Stage ◽  
Freeze Dried ◽  
Fresh Frozen ◽  
Sheep Rumen ◽  
Micro Organisms

Previous studies (El Shaer, Omed and Axford, 1987; Akhter, Owen, Fall, O'Donovan and Theodorou, 1994) with the two-stage in vitro procedure of Tilley and Terry (1963) have shown a high correlation between digestibilities of forages as determined using either sheep rumen liquor, sheep faeces or cow faeces as the microbial inoculum. In the first study of the of the present investigation one objective was to examine the repeatability of these digestibility measurements when made on different occasions. A second objective was to assess whether the correlations between faecal and rumen fluid based inocula could be improved if microorganisms were obtained from pairs rather than individual animals. The objective in the second study using forages of known in vivo digestibility, was to investigate the effect of freezing or freeze-drying of faeces on the repeatability of digestibilities of forages determined in vitro using micro-organisms from cow faeces.

The effect of chlorite delignification on digestibility of some grass forages and on intake and rumen microbial activity in sheep fed barley straw

1987 ◽  
Vol 108 (1) ◽  
pp. 129-136 ◽  
Author(s):  
C. W. Ford ◽  
R. Elliott ◽  
P. J. Maynard
Keyword(s):  
Secondary Growth ◽  
Microbial Colonization ◽  
Barley Straw ◽  
Similar Degree ◽  
Sodium Chlorite ◽  
Rumen Ph ◽  
Large Numbers ◽  
Micro Organisms

SummarySodium chlorite increased the degradability of fibre from a range of mature grass forages inoluding barley straw by 40–50 digestibility units when comparisons were made using ground (1 mm sieve) material incubated eitherin vitrowith cellulase or in nylon bags in the rumen. However, when fed to sheep, chlorite-treated barley straw was digested to a similar degree to untreated straw (49 and 57% respectively), but intake was significantly reduced (385 and 790 g/day respectively). The poorin vivoutilization of chlorite-treated straw coincided with high proportions of propionic to acetic acid in the rumen (0·85, cf. 0·28 with untreated feed) and absence of rumen fungi. Rumen pH and ammonia concentrations were not significantly different between diets. When incubated in nylon bags in the rumen of animals fed the corresponding diet, both untreated and treated straw (< 1 mm) were well colonized with micro-organisms, as measured by cystine accumulation which showed peaks on the fibres after 24 and 72 h. While large numbers of fungal sporangia were observed after 24 h incubation on digesta from untreated forage, no fungi could be detected on the chlorite-treated material. Cystine accumulation on the untreated straw after 72 h was not associated with a secondary growth of fungi.Although barley straw chaff, ground (< 1 mm) after treatment with chlorite, was highly degraded in nylon bags in the rumen and with cellulasein vitro, larger particles (1 cm) suspended in nylon bags in an animal fed chlorite-treated straw actually gained weight, probably due in part to the degree of microbial colonization.

Animal Models and Alternatives in the Quality Control of Vaccines: Are In Vitro Methods or In Vivo Methods the Scientific Equivalent of the Emperor's New Clothes?

1995 ◽  
Vol 23 (1) ◽  
pp. 61-73
Author(s):  
Coenraad Hendriksen ◽  
Johan van der Gun
Keyword(s):  
Quality Control ◽  
Test Methods ◽  
In Vitro Test ◽  
Large Numbers ◽  
Alternative Approach ◽  
Inactivated Vaccines ◽  
Vitro Test

In the quality control of vaccine batches, the potency testing of inactivated vaccines is one of the areas requiring very large numbers of animals, which usually suffer significant distress as a result of the experimental procedures employed. This article deals with the potency testing of diphtheria and tetanus toxoids, two vaccines which are used extensively throughout the world. The relevance of the potency test prescribed by the European Pharmacopoeia monographs is questioned. The validity of the potency test as a model for the human response, the ability of the test to be standardised, and the relevance of the test in relation to the quality of the product are discussed. It is concluded that the potency test has only limited predictive value for the antitoxin responses to be expected in recipients of these toxoids. An alternative approach for estimating the potency of toxoid batches is discussed, in which a distinction is made between estimation of the immunogenic potency of the first few batches obtained from a seed lot and monitoring the consistency of the quality of subsequent batches. The use of animals is limited to the first few batches. Monitoring the consistency of the quality of subsequent batches is based on in vitro test methods. Factors which hamper the introduction and acceptance of the alternative approach are considered. Finally, proposals are made for replacement, reduction and/or refinement (the Three Rs) in the use of animals in the routine potency testing of toxoids.

Activation of the peptidergic neurosecretory system in Diphyllobothrium dendriticum (Cestoda: Pseudophyllidea)

Parasitology ◽  
1981 ◽  
Vol 83 (2) ◽  
pp. 243-247 ◽  
Author(s):  
Margaretha K. S. Gustafsson ◽  
Marianne C. Wikgren
Keyword(s):  
Neurosecretory Cells ◽  
Final Host ◽  
Fish Host ◽  
Neurosecretory System ◽  
Weak Reaction ◽  
Diphyllobothrium Dendriticum ◽  
Large Numbers ◽  
Short Times

SUMMARYThe activation of the peptidergic neurosecretory system in Diphyllobothrium dendriticum was studied following cultivation of plerocercoids for short times in vitro and in vivo. In the plerocercoid the neurosecretory cells gave a very weak reaction with paraldehyde fuchsin (PAF). After cultivation for 1 h large numbers of neurosecretory cells filled with PAF-positive granules were evident. The significance of the activation of the neurosecretory system during the transfer of the worm from the cold-blooded fish host to the warm-blooded final host is discussed.

The prediction of digestibility by rumen fluid and enzymatic methods

1996 ◽  
Vol 1996 ◽  
pp. 211-211
Author(s):  
Peter Young ◽  
F. P. O'Mara ◽  
M. Rath ◽  
P. J. Caffrey
Keyword(s):  
Organic Matter ◽  
Rumen Fluid ◽  
Organic Matter Digestibility ◽  
Enzymatic Methods

Rumen fluid and cellulase based techniques are widely used to predict the digestibility of compound feeds and their ingredients. Recently gammanase enzymes have been added to some cellulase based techniques (Dowman, 1993; De Boever et al., 1994). Few comparisons of these techniques have involved by-product concentrate ingredients. The objective of this experiment was to compare the ability of three techniques, in vitro rumen fluid (RF), pepsin cellulase gammanase (PCG), and neutral detergent cellulase gammanase (NCDG), to predict the in vivo organic matter digestibility (OMD) of concentrate ingredients.

scholarly journals ELECTRON MICROSCOPY OF PLASMA-CELL TUMORS OF THE MOUSE

1961 ◽  
Vol 9 (2) ◽  
pp. 369-381 ◽  
Author(s):  
D. F. Parsons ◽  
M. A. Bender ◽  
E. B. Darden ◽  
Guthrie T. Pratt ◽  
D. L. Lindsley
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Complex Structure ◽  
Granular Body ◽  
Virus Particles ◽  
Culture Cells ◽  
Large Numbers ◽  
Tumor Agent

The X5563 tumor has been grown in tissue culture. Cells similar to those of the original tumor migrated from the explant and attached to the glass walls of the culture vessels. Electron microscopy showed that large numbers of particles, similar in morphology to virus particles, were associated with these cells after 7 days of culture. The two principal types of particles found in the tumor in vivo appear to be present in vitro. Many more of these particles, however, were larger and showed a more complex structure. Whereas the particles were mainly localized inside endoplasmic reticulum or the Golgi zone in the tumors in vivo, in the tissue culture the majority of the particles were associated with the plasma membrane and were found outside of the cells. The relation of the particles to the granular body is discussed as well as a possible relation to the mammary tumor agent.

scholarly journals Digestion of timothy silage and hay in reindeer

Rangifer ◽  
1998 ◽  
Vol 18 (1) ◽  
pp. 35
Author(s):  
R. Moen ◽  
M. A. Olsen ◽  
Ø. E. Haga ◽  
W. Sørmo ◽  
T. H. Aagnes Utsi ◽  
...  
Keyword(s):  
Food Intake ◽  
Rangifer Tarandus ◽  
Rumen Fluid ◽  
Total Concentration ◽  
Phleum Pratense ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Energy Deficiency

Leafy timothy (Phleum pratense) silage (S), silage mixed with molasses (SM) and hay (H) were fed to nine male reindeer (Rangifer tarandus tarandus) calves in winter to investigate rumen function and digestion. Three calves were given S with 18.5% dry matter (DM), three were given SM (21.9% DM) and three were given H (85.0% DM). The content of water soluble carbohydrates (in % of DM) was 8.2% in S, 16.0% in SM and 8.5% in H. Median (range) daily DM food intake per kg BM was 12.9 (9-2-14.4) g in calves fed S, 19.0 (19-0-21.9) g in calves fed SM and 21.0 (19.2&not;21.1) g in calves fed H. In vivo digestion of S and SM DM ranged from 78.5-83.1% compared to only 69-9-72.9% in calves fed H. In vitro DM digestion (IVDMD) of cellulose (median) incubated for 48 hours in rumen fluid was, however, significantly (F = 0.05) lower in calves fed S (24.4%) compared to calves fed SM (42.2%). Median IVDMD of cellulose (48 hours) in calves fed H was 36.4%. Total concentration of VFA (range) in the rumen fluid from reindeer fed H (99.7-113.6 mM) and was significantly (P&lt;0.05) higher compared to animals fed S (57.7-85.9 mM) or SM (51.4-72.0 mM). Likewise, the pH of the rumen fluid (range) was significantly (P&lt;0.05) lower in reindeer fed H (6.40-6.78) compared to animals fed S (6.97-7.30) or SM (6.79-7.27). Based on this study it is concluded that leafy timothy preserved as hay seems to be more suitable as emergency feed compared to silage. Supplementation of molasses to silage seems to stimulate food intake and ruminal cellulose digestion in reindeer. The lower intake of S compared to SM or H by reindeer may be explained by ruminal energy deficiency.

scholarly journals Hydrolysis of14C-labelled proteins by rumen micro-organisms and by proteolytic enzymes prepared from rumen bacteria

1983 ◽  
Vol 50 (2) ◽  
pp. 345-355 ◽  
Author(s):  
R. J. Wallace
Keyword(s):  
Proteolytic Enzymes ◽  
Rumen Fluid ◽  
Performic Acid ◽  
Cross Linking ◽  
Acid Oxidation ◽  
Rumen Bacteria ◽  
Rate Of Hydrolysis ◽  
Micro Organisms ◽  
Hydrolysis Of

1. Proteins were labelled with14C in a limited reductive methylation using [14C]formaldehyde and sodium borohydride.2. The rate of hydrolysis of purified proteins was little (< 10%) affected by methylation and the14C-labelled digestion products were not incorporated into microbial protein during a 5 h incubation with rumen fluid in vitro. It was therefore concluded that proteins labelled with14C in this way are valid substrates for study with rumen micro-organisms.3. The patterns of digestion of14C-labelled fish meal, linseed meal and groundnut-protein meal by rumen micro-organisms in vitro were similar to those found in vivo.4. The rates of hydrolysis of a number of14C-labelled proteins, including glycoprotein II and lectin from kidney beans (Phaseolus vulgaris), were determined with mixed rumen micro-organisms and with proteases extracted from rumen bacteria. Different soluble proteins were digested at quite different rates, with casein being most readily hydrolysed.5. Proteins modified by performic acid oxidation, by cross-linking using 1,6-di-iso-cyanatohexane or by diazotization were labelled with14C. Performic acid treatment generally increased the susceptibility of proteins to digestion, so that the rates of hydrolysis of performic acid-treated proteins were more comparable than those of the unmodified proteins. Cross-linking resulted in a decreased rate of hydrolysis except with the insoluble proteins, hide powder azure and elastin congo red. Diazotization had little effect on the rate of hydrolysis of lactoglobulin and albumin, but inhibited casein hydrolysis and stimulated the breakdown of γ-globulin.

Anaerobes in ejaculates of subfertile men

1995 ◽  
Vol 1 (5) ◽  
pp. 462-478 ◽  
Author(s):  
Waltraud Eggert-Kruse ◽  
Gerhard Rohr ◽  
Wolfram Ströck ◽  
Susanne Pohl ◽  
Beate Schwalbach ◽  
...  
Keyword(s):  
Tract Infection ◽  
Genital Tract ◽  
Anaerobic Bacteria ◽  
Cervical Mucus ◽  
Anaerobic Growth ◽  
Pathogenic Species ◽  
Genital Tract Infection ◽  
Micro Organisms

Abstract The clinical significance of micro-organisms in semen samples of asymptomatic subfertile patients is a matter of constant debate. Usually little attention is paid to anaerobic bacteria as they are sensitive to transportation and culturing, and differentiation is difficult, costly and time-consuming. In the present study, special screening was carried out for anaerobes in ejaculates in addition to the routine microbial cultures of genital secretions of both partners. In addition to standard semen analysis and evaluation of sperm ability to penetrate cervical mucus (CM) in vivo (postcoital testing) and in vitro using a standardized test system, semen samples from 126 randomly chosen males of couples with a median duration of infertility of 4 years were examined for colonization with anaerobic bacteria. All couples were without clinical signs or symptoms of genital tract infection. The special care taken for anaerobic growth in semen samples gave a high rate of positive cultures and showed that nearly all ejaculates (99%) were colonized with anaerobic micro-organisms, and potentially pathogenic species were found in 71% of men. This rate was more than four times higher than that obtained with routine cultures and standard transportation (16%). Anaerobic bacterial growth of ≥106 colony forming units (CFU)/ml was seen in 42% (total range 103-108 CFU/ml). In addition, aerobic growth was found in 96%(≥106 CFU/ml in 21%), potentially pathogenic species in 61% of semen specimens. There were no marked differences in the prevalence of anaerobic micro-organisms in patients with reduced or normal sperm count, motility or morphology. Nor was there any significant difference in anaerobic colonization between samples with impaired or good ability to penetrate CM of female partners (in vivo or in vitro), or the CM of fertile donors in the in-vitro sperm-cervical mucus penetration test (SCMPT) in this asymptomatic group of patients. There was no clear association between microbial colonization and subsequent fertility in vivo within an observation period of 6 months. The results of this study suggest that anaerobic bacteria are often not detected when routine methods for microbial evaluation are used. This should be considered during assisted reproduction and in patients with symptoms of genital tract infection and should lead to further studies in infertile patients where subclinical infection or inflammation is indicated by specific markers in semen samples.

scholarly journals Platelet Alterations Caused by Antiplatelet Antibodies in the Circulation

1977 ◽  
Author(s):  
T. Nagasawa ◽  
B.K. Kim ◽  
M.G. Baldini
Keyword(s):  
Platelet Count ◽  
Specific Activity ◽  
Rabbit Model ◽  
Antiplatelet Antibodies ◽  
Large Numbers ◽  
Severe Reduction ◽  
Series Of Experiments ◽  
Specific Activities

It is known that antiplatelet antibodies cause loss of platelet cytoplasmic and granular contents in vitro. It is, however, unknown whether similar platelet changes occur in vivo, in the circulation, leading to destruction and phagocytosis of platelets in the R.E. system. To study this possibility a rabbit model was devised. Severe and stable thrombocytopenia was first produced in rabbits by one intravenous injection of Adriamycin. Large numbers of allogenic platelets labeled in vitro with 51Cr and 14C-serotonin were then infused to raise the circulating platelet count to 180-250 × 103/mm3. A dilute heteroimmune antiplatelet serum prepared in the guinea pig was infused intravenously and platelet samples were collected four times during the subsequent 30 minutes to 24 hours. Platelet hexokinase and β-glucuronidase, 14C-serotonin and 51Cr were measured. Within the first 60 min the specific activity of 51Cr in platelets decreased by 21%, 14C-serotonin declined by 30%, hexokinase by 5% and β-glucuronidase by 29%. During the subsequent 24 hours only 51Cr and hexokinase registered a mild decrease but 51C-serotonin and β-glucuronidase remained essentially unchanged. In a second series of experiments the effect of platelet alloantibodies was studied in rabbits previously immunized with allogenic platelets. The decline in the specific activities of the enzymes and 14C-serotonin was similar to that observed in animals treated with heteroimmune sera but loss of 51Cr was more severe. These results demonstrate that the platelets remaining in the circulation after the disappearance of the immediate effect of hetero- or alloantibodies were qualitatively altered with a severe reduction of their granular and cytoplasmic contents.

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