A procedure was developed for the quantitative separation of major fermentation products of uniformly labeled glucose-C¹⁴ produced by bovine rumen microorganisms in vitro. After 45 min, the fermentation mixture was fractionated into (a) one control subsample, and duplicate fractions of (b) solid matter “precipitate“, (c) ether extract, (d) “amino acid“, (e) “sugar“, (f) CO₂, and (g) CH₄. Similar fractionation of an unfermented control sample was made. A portion of the fermentation ether extract was subjected to column chromatography to resolve (a) C₁, (b) C₂, (c) C₃, (d) C₄, and (e) C₅ fatty acids, (f) succinic, and (g) lactic acids. Each fraction was analyzed in triplicate for C¹⁴ by a direct plating technique. Corrections for geometry, self absorption, and efficiency were made by direct plating additional triplicate fraction subsamples, each containing a uniformly labeled glucose-C¹⁴ internal standard. The data were expressed as per cent recovery of added C1u. The results indicated that glucose was rapidly fermented with most of the C¹⁴ found in the ether extractable fraction as acetic acid. Significant levels of C¹⁴ were found in the “precipitate“ fractions. The data were compatible with evidence that CH₄ was derived from CO₂. The results of 6 trials indicated that there was no significant difference in the distribution of products resulting from the in vitro fermentation of uniformly labeled glucose-C¹⁴ between animals, between days within animals, or between times within days. / Ph. D.

Two media were adapted to the culture of proteolytic bacteria from the bovine rumen. Modifications were made in the double indicator dairy medium of Donovan and Vincent (SRBP) and in the medium of Hungate for rumen bacteria (SRP). Modifications included use of plant protein suspensions, casein, and skim milk as the nitrogen sources of which skim milk was the most suitable, producing a uniformly opaque medium. Proteolytic colonies were characterized by clear zones in the medium. A third medium containing the artificial sheep-saliva salts mixture of McDougall was developed but was found unsatisfactory for the study of proteolytic organisms. Dilutions of rumen contents to 1 x 10⁻⁸/ml were made in anaerobic dilution fluids. Cultures were grown in roll tubes or bottles containing CO₂ atmosphere. All of the media used in this study repeatedly produced an average count of 40 colonies per tube with 10⁻⁸ dilutions of comminuted whole rumen ingesta as inocula. The average ratio of proteolytic to total colonies was found to be 1 to 5. Each of the media was compared for its ability to support the proteolytic isolates from the other. Minor differences in the specificity of the media were found to exist. Colonial and morphological studies of the proteolytic isolates were made. / Master of Science

Call number: LD2668 .T4 1984 A43 / Master of Science

Includes bibliographical references (leaves [259]-290) Investigates nitrogen assimilation and metabolism in rumen bacteria with the object of understanding the basic process and their controls.

Includes bibliographical references (leaves 122-138). / xvii, 138 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates the use of microbial inoculants to prevent the onset of acidosis in acutely grain fed animals; and, the most effective combination of virginiamycin and lactic acid utilising bacteria (selenomonas ruminantium subsp. lactilytica and Megasphaera elsdenii) in controlling lactic acid accumulations in vitro. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Science, 1995

Includes bibliographical references (leaves [259]-290) / xxviii, 290 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates nitrogen assimilation and metabolism in rumen bacteria with the object of understanding the basic process and their controls. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Sciences, 1991

Bibliography: leaves 122-138. Investigates the use of microbial inoculants to prevent the onset of acidosis in acutely grain fed animals; and, the most effective combination of virginiamycin and lactic acid utilising bacteria (selenomonas ruminantium subsp. lactilytica and Megasphaera elsdenii) in controlling lactic acid accumulations in vitro.

The yeast expression system Pichia pastoris was investigated as an encapsulation technology capable of serving as a rumen escape vehicle. Cellularly encapsulated protein is protected from the ruminal environment so long as the cell membrane, which surrounds and isolates the intracellular protein is physically intact. Intracellular expression of Green Fluorescent Protein (GFP) allows for the monitoring of cellular integrity as necessary for the protection of encapsulated protein from ruminal proteases. Upon cellular lysis GFP is exposed to extracellular proteases which result in both the proteolytic degradation of the protein-based GFP chromophore and its associated fluorescence. Visualization of rumen fluid under epifluorescent microscopy revealed a high level of background autofluorescence owing to the fluorescent plant particles, microbes, and fluorescent compounds therein. Visualization of GFP in rumen fluid can be optimized through GFP variant selection, filter set design, and light source selection based on bulb emission spectra. Incubation of intracellular GFP expressing P. pastoris in batch culture ruminal in vitro simulations demonstrated that 93%, 97%, and 25% of the P. pastoris inoculum maintained cellular integrity in clarified rumen fluid, bacterial fraction of rumen fluid, and whole rumen fluid, respectively, when incubated over 36 to 48 h. Continuous fermentation in vitro rumen simulations (Rusitec) demonstrated a P. pastoris escape rate of 19% when added daily to fully adapted Rusitec vessels having a dilution rate of 0.75d-1. Abomasal in vitro simulations demonstrated that 84% of the P. pastoris inoculum was lysed within 12 h, as necessary for the release of encapsulated protein. P.pastoris may be an effective post-fuminal delivery vehicle, provided that similar results are obtained in vivo. / xiv, 120 leaves : ill. ; 28 cm.

Dried rumen microblota were isolated from fistulated steers. Proximate analyses were conducted and the amino acid composition and B-vitamin content were determined. Protein quality tests were carried out using the Bender-Miller method. The data obtained from the investigation indicated that the protein quality of dried rumen microbiota is comparable with that of dried defatted egg, dried milk, fish meal and meat meal, but it is better than that of a soy protein and wheat gluten. No amino acid deficiency appeared in the feeding trials even though the amino acid composition showed that the dried rumen microbiota might be deficient in sulfur-containing amino acids. / Master of Science

Forage may undergo extensive proteolysis during fermentation. The objectives of this study were to determine if treatment of forage with heat can reduce proteolysis during subsequent fermentation. In Experiment 1, direct-cut barley and alfalfa were either microwaved or steamed then ensiled in laboratory silos as were untreated and wilted forage. Silages of microwaved or steamed forage showed marked increase in NDIN and recovery of hot water insoluble N; however, alfalfa silages also had high pH and butyric acid. In Experiment 2, steaming was compared to formic acid and anhydrous ammonia treatments for their ability to prevent proteolysis in alfalfa silages. Steamed and ensiled alfalfa also was evaluated with addition of microbial inoculant or formic acid. Silage of steamed alfalfa had greater NDIN and recovery of precipitable N than controls, formic acid, or ammonia treated silage. There was no difference in precipitable N between formic acid and ammonia treatments. Silage of steam treatment had lower pH than wilted or direct-cut controls, and additives to steamed forage favored a more homolactic fermentation. Additives to steamed forage also increased aerobic stability of the silage. Steamed silage had less aerobic stability than direct-cut silage. Rumen degradability of silage CP and OM from both experiments were evaluated. In Experiment 1, CP degradability of microwaved or steamed silages was 8 to 26% less than unheated silages, but all had similar undegraded CP after incubation for 72 h. In Experiment 2, wilting, steam, formic acid and ammonia treatments had similar, but decreased CP degradability when compared to direct-cut silage. Longer duration heat in Experiment 1 resulted in greater silage protein preservation, and greater decrease in rumen degradability of CP than Experiment 2. / Master of Science