Call number: LD2668 .T4 1979 B76 / Master of Science

Call number: LD2668 .T4 1955 H36 / Master of Science

Call number: LD2668 .T4 1965 A13 / Master of Science

A series of studies was conducted using SEM in conjunction with chemical analysis, in situ and in vitro digestion techniques, to characterize the anatomical components from barley, corn, sorghum and wheat grains which constitute "fiber" and investigate their susceptibility to rumen microbial digestion. Fractured grains were used to identify anatomical features and cell types prior to and after extraction or digestion. Certain anatomical features, including pericarp tissue, aleurone cells, endosperm cell walls, corneous and floury endosperm tissue and lemma and palea from barley, were easily identifiable in fractured and ground grains, and in neutral detergent extracted or digested residues. In situ and in vitro incubation conditions were varied to assess the effect of concentrate and/or reduction of pH on the disappearance of identifiable grain fractions. In situ incubations were conducted using steers adapted to 0-, 30- and 90% concentrate diets. In vitro inoculum buffered at pH 7 or 6 was provided by a steer fed 0- or 90% concentrate. Tissues resistant to rumen microbial digestion during extended (144-h) in situ incubations and shorter term (12- to 48-h) in vitro incubations were primarily those identified in NDF, and included pericarp, lemma and palea, and small amounts of corneous endosperm. Remaining tissues identified included barley lemma, palea and pericarp; corn pericarp, tip cap and small amounts of corneous endosperm; sorghum pericarp and corneous endosperm with matrix and protein bodies; and wheat pericarp. In vitro disappearance of isolated NDF after 48-h ranged from 43% for barley to 89% for corn. Labile structures included embryonic tissue and portions of endosperm cell walls, protein matrix and residual starch. Resistant tissues included pericarp, aleurone cell walls, tip cap and portions of the corneous endosperm. Relative rankings of NDF digestibility under all conditions studied were similar (corn > sorghum > wheat > barley) whether determined using isolated NDF or calculated from TIVDMD residues. Neither concentrate level fed to the host animal nor pH of the in vitro incubation flask affected rankings among grains, although increasing concentrate level and/or reducing pH appeared to reduce in vitro NDF disappearance. Evaluation of electron micrographs of fractured grains suggested that similar anatomical structures in the various grains differed in their resistance to microbial digestion. For example, pericarp from barley and wheat appeared to be more resistant than that from corn or sorghum. Endosperm of barley was less resistant than that of sorghum.

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No description available.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Ruminants possess a unique digestive system. Using the high metabolic potential of the symbiotic microflora of the rumen, ruminants are capable of digesting plant material and obtaining nutrients and energy from this process. Because of the ruminal fermentation, the most bioactives are not stable in the harsh ruminal environment. Therefore there is a need to improve the bioavailability of a bioactive by protecting it from the ruminal digestion. The formulation of protected bioactive can be delivered in the rumen in a controlled manner and over a long period of time. In this project the degree of rumen protection was estimated using model substrates (sugar pellets and granules). These materials were coated with the pH-sensitive polymer Eudragit E. The model bioactive (phloridizin) was coated using the coating methodology adopted from exploratory studies with model substrates. The bioavailability of protected (coated) phloridizin was assessed by administering directly into the abomasum of fistulated cows. Formulation of protected phloridizin was used to demonstrate the feasibility of bioactive controlled delivery based on ART ( Active Rumen Technology ). This technology uses an elevated gas pressure created by a hydrogen-producing cell to drive a plunger which extrudes bioactive formulation from an intraruminal controlled-release device. Four groups of devices filled with formulation containing different amounts of protected phloridizin were tested. The bioactive was released in a controlled manner over several days. The formulation release profiles were reproducible suggesting that in principle the technology can be further developed to use in a commercial sense or for research purposes. The limitations of the technology, including formulation issues and gas diffusion through barrel walls, were identified.

Dry matter, crude protein and starch degradation characteristics of one corn (Pioneer 39P78) and four barley grain varieties (CDC Bold, CDC Dolly, Harrington and Valier) were evaluated in two in situ nylon bag trials. Trial 1 compared ground and rolled treatments of Harrington barley and Pioneer 39P78 corn, whereas Trial 2 evaluated ground and rolled treatments of the four barley varieties. Rumen degradability characteristics were compared with analytical results from thermal- and synchrotron-source FTIRM. Infrared absorbance spectra were collected from corn and four barley varieties using thermal-source FTIRM on the mid-IR beamline at the Canadian Light Source, Ltd. (Saskatoon, SK). Synchrotron-source FTIRM spectral data was collected for corn, Harrington barley and Valier barley on the U2B mid-IR beamline at NSLS-BNL (Upton, NY). CHO:Amide I peak area ratios were compared to the in situ rumen degradation results to determine if FTIRM spectral data could be related to the rate and extent of rumen degradation, and if thermal- and synchrotron-source FTIRM yielded different results. A grain x processing method interaction (P<0.01) was observed in both in situ trials where grinding produced a greater increase in the rate and extent of rumen degradation for Harrington barley than it did for corn (Trial 1) along with a greater increase in the rate and extent of rumen degradation for CDC Bold and CDC Dolly than for Harrington and Valier (Trial 2). Among barley varieties, increasing rate and extent of rumen degradation (CDC Bold>CDC Dolly>Harrington>Valier) corresponded to increasing starch:protein ratio as estimated by chemical analysis. This relationship was reversed for corn and Harrington barley where corn had a higher starch:protein ratio yet slower rumen degradation kinetics. For both thermal- and synchrotron-source FTIRM, CHO:amide I peak area ratios were greater (P<0.05) for corn than for Harrington barley. Comparison of CHO:amide I peak area ratios of barley varieties measured with thermal-source FTIR showed that varieties with higher (P<0.05) CHO:Amide I peak area ratios generally had higher rate and extent of rumen degradation. This indicates that starch:protein ratio estimated with FTIRM may be an indicator of rumen degradability characteristics when comparing varieties of the same grain, but not for different species of grains.

ABSTRACT Two experiments were conducted to determine the effects of various forage to concentrate ratios on the rumen microbial ecosystem and rumen fermentation parameters using culture-independent methods. In the first experiment, cattle were fed either a high concentrate (HC) or a high concentrate without forage (HCNF) diet. Comparison of rumen fermentation parameters between these two diets showed that duration of time spent below pH 5.2 and rumen osmolality were higher for HCNF. Calculations using Simpson’s index showed a greater diversity of dominant species for HCNF than in HC based on 16S rRNA PCR-DGGE. Real-time real-time PCR showed populations of Fibrobacter succinogenes (P=0.01) were lower in HCNF than HC diets. Ruminococcus spp., F. succinogenes and Selenomonas ruminantium were present at higher (P≤0.05) concentrations in solid than in liquid digesta in both diets. The second experiment compared cattle as they adapted from a strictly forage to a concentrate diet, after which they were subject to an acidotic challenge and a recovery period (Forage, Mixed Forage, High Grain, Acidosis and Recovery). A total of 153,621 high-quality bacterial sequences were obtained from biopsied rumen epithelium, and 407,373 sequences from the solid and liquid phases of rumen contents. Only 14 epithelial genera representing >1.0% of the epimural population differed (P ≤ 0.05) among dietary treatments. However, clustering showed a closer relation in bacterial profiles for the Forage and Mixed Forage diets as compared to the High Grain, Acidosis and Recovery diets. Several epithelial identified genera including Atopobium, Desulfocurvus, Fervidicola, Lactobacillus and Olsenella increased as a result of acidosis. However, any changes in bacterial populations during the acidosis challenge were not sustained during the recovery period. This indicates a high level of stability within the rumen epimural community. An epithelial core microbiome was determined which explained 21% of the enumerable rumen population across all treatment samples. Cluster analysis of the solid and liquid phase rumen bacterial showed that these populations differed (P ≤ 0.10) between forage and grain-based diets. Rumen core microbiome analysis found 32 OTU’s representing 10 distinct bacterial taxa in whole rumen contents for all dietary treatments. Heifers that developed clinical acidosis vs the subclinical acidosis showed increases in the genera Acetitomaculum, Lactobacillus, Prevotella, and Streptococcus. Variation in microbial taxa as an effect of both treatment and animal was evident in the solid and liquid fractions of the rumen digesta. However, impacts of a dietary treatment were transient and despite an acidotic challenge, rumen microbiota were able to recover within a week of perturbation. The bacterial populations in the rumen are highly diverse as indicated by DGGE analysis and showed clear distinction between not only dietary treatments, individual animals, but also between epithelial, liquid and solid associated populations on the same diet. Molecular techniques provide an increased understanding of the impact of dietary change on the nature of rumen bacterial populations and conclusions derived using these techniques may not match those previously derived using traditional laboratory culturing techniques.