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

Ten strains of anaerobic, gram negative, monotrichous, butyric acid-producing curved rods have been isolated from ingesta of the bovine rumen. These 10 strains of butyrivibrio represented 1/5 of all isolates at 1 x 10⁻⁸ dilutions. Morphological and physiological characteristics of the 10 strains and a strain isolated by gill and king (1958) have also been studied. No two of the isolates were identical in all reactions. Most of the organisms produced a large amount of butyric and some lactic, formic, propionic and succinic acids with the utilization of acetic acid in a rumen fluid glucose medium. The fermentation carried on by these organisms was sensitive to most tested environmental changes. Studies with buffered rumen fluid-glucose media demonstrated a shift of the fermentation products with pH. Addition of fatty acids to this medium indicated that these organisms were active in the conversion of acetate and possibly propionate to butyrate. Two strains apparently had the ability to produce propionate at the expense of lactate. The results of the fermentation tests in 98 per cent rumen fluid medium showed that the tested strains used acetic (plus formic) or lactic (plus succinic) to produce butyric or propionic acid, and produced higher concentrations of fatty acids under a carbon dioxide atmosphere than under nitrogen. When rumen fluid and acetic acid were absent all strains had the ability to produce either formic or acetic acid. / 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.

Objectives were to determine dry matter, fiber and nitrogen fractions, and in vitro and in situ degradability of forages and by-product feeds, and to compare in vitro methods of estimating rumen degradability with the in situ bag technique. Feeds analyzed with number of samples in parentheses included alfalfa as baled hay (23), alfalfa ensiled in conventional (43), and. oxygen limiting silos (39), ammonia· treated (25), and untreated corn silage from conventional (17) and bunker silos (17), rye (25), sorghum (7), wheat (6), barley (5), and orchardgrass (4) silages, orchardgrass (19) and fescue hay (3), and dried distillers grains dark colored (2) and light (1), wet brewers grains (1), and whole cottonseeds (3). Samples were analyzed for dry matter, crude protein, buffer-soluble protein, protease insoluble nitrogen, neutral and acid detergent fiber and insoluble nitrogen, and in situ degradability of nitrogen, dry matter, and fiber. Protease insoluble nitrogen, buffer-insoluble protein, and neutral detergent insoluble nitrogen were lowest for alfalfa from conventional upright silos. Oxygen limiting silo samples had greater dry matter, insoluble protein, and bound nitrogen compared to conventional upright silo samples. Oxygen limiting silos had 35.9% of samples with bound nitrogen greater than 15% of total nitrogen compared to 14% of conventional upright silo samples. Baled hay and oxygen limiting silo samples had similar protease insoluble nitrogen, however, ensiled samples had greater bound nitrogen. In situ nitrogen degradability was greatest for ensiled forages compared to hays. Ensiled forages had the greatest A fraction (rapidly solubilized), alfalfa hay the greatest B fraction (slowly degraded), and orchardgrass hay the greatest C fraction (not degraded). Degradation of dry matter and fiber followed similar patterns for each forage and by-product. Significant results were found by comparing in vitro and in situ techniques for estimating degradability. Due to differences between hay and silage, use of one technique can not be recommended at this time to predict degradability. For silage, the best measure related to in situ degradability was buffer-soluble protein; for hay, the best measure was neutral detergent insoluble nitrogen. / Ph. D. / incomplete_metadata

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