Browsing by Subject "Hops"
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Item Effects of bismuth subsalicylate and beta extract of hops (Humulus lupulus) on in vitro fermentation with ruminal microbes(2013-08) Fessenden, Samuel WilliamSymbiosis between microbes and ruminants gives the animal a unique ability to digest fiber and transform it into meat, milk, power and other useful products. Manipulation of rumen ecology with selective antimicrobial compounds can have beneficial effects by altering microbial output, allowing the animal to achieve greater levels of production per unit of input. Two experiments were conducted to determine effects of antimicrobial compounds on in vitro fermentation with ruminal microbes in continuous culture. Inclusion of bismuth subsalicylate decreased (P < 0.05) organic matter digestion, volatile fatty acid production and had negative influences on nitrogen and fatty acid metabolism. Results indicate that bismuth subsalicylate at 0.5% of diet dry matter was detrimental to overall fermentation with rumen microbes, and lower dosage levels should be investigated. In experiment 2, beta extract from the hop plant (Humulus lupulus) was administered to continuous culture fermenters at 0, 600, 1200 or 1800 mg of beta acids / kg of dry matter. Inclusion of beta extract did not affect (P > 0.05) ingredient digestion, volatile fatty acid production or nitrogen metabolism. Beta extract tended (P = 0.09) to increase culture pH, however effects were modest and lower than biologically relevant values. Further research investigating the adaptation of microbial populations to hop beta extract was recommended.Item Effects of iso-alpha-acids on rumen fermentation and comparison of microbial populations between rumens and continuous culture fermenters(2015-08) Salfer, IsaacTwo experiments were conducted using dual-flow continuous culture fermenters to study rumen fermentation in vitro. The first experiment examined the effects of iso-alpha-acids from Humulus lupulus (Hops) extract on rumen fermentation. Iso-alpha-acid extract (IE) was provided to continuous culture fermenters to supply 0 (CON), 600 (LOW), 1200 (MED) or 1800 mg of IE/kg of diet DM/day. There was no effect (P > 0.05) of IE inclusion on DM, OM, NDF or ADF digestion (%). Volatile fatty acid (VFA) metabolism was not affected by IE treatment (P > 0.05), with total VFA concentrations of 105.5, 93.4, 87.9 and 103.6 mM for the CON, LOW, MED and HIGH treatments, respectively. Nitrogen metabolism was also not affected (P > 0.05) by IE level, with the CON, LOW MED, and HIGH treatments resulting in nitrogen concentrations of 7.4, 5.3, 7.6 and 6.8 mg N/dL of rumen fluid, respectively. No effects (P > 0.05) of treatment on fermenter pH were observed. It was concluded that administration of IE had no impact on fermentation by ruminal microbes maintained in continuous culture fermenters. Experiment 2 used 16S amplicon sequencing to compare microbial populations between the rumen of dairy cattle and continuous culture fermenters and to determine the temporal changes in microbial community during fermenter operation. Redundancy analysis (RDA) was performed to determine correlations between fermentation measurements based on microbial community. Correlations were also conducted to determine associations between prominent microbial families and fermentation measures from the In vitro system. Differences in microbial community were assessed using UniFrac metrics, Analysis of molecular variance (AMOVA) and analysis of similarity (ANOSIM) based on Bray-Curtis dissimilarity matrices. Differences in taxonomic composition of different sample types were analyzed at kingdom, phylum, class, order and family taxonomic levels. Functional inferences were made by matching taxonomic data to KEGG Orthology terms using PICRUSt software, and analyzed based on sample type. Community profile did not differ (P > 0.10) between cows in either rumen or inoculum samples, but was different (P < 0.05) in fermenter samples. Microbial community within fermenters appeared to stabilize on day 7 of the experimental period according to AMOVA and ANOSIM analyses. Bacteroidetes and Firmicutes made up the two most abundant phyla in rumen, inoculum and fermenters and neither group was different (P > 0.10) based on sample type. Proteobacteria, Tenericutes, Spirochaetes and Verrucomicrobia were different (P < 0.05) between sample types. Rumen, inoculum and fermenters did not differ (P > 0.10) in relative abundance of Prevotellaceae, which was the most abundant family in all three samples. Abundant families that were different (P < 0.05) by sample type included Succinivibrionaceae, Lachnospiraceae and Paraprevotellaceae. PICRUSt predictions showed that amino acid metabolism, membrane transport, energy metabolism and cellular processes and signaling were different (P < 0.05) between sample types. Metabolism of carbohydrates, cofactors and vitamins, and lipids were not affected (P > 0.10) by sample type according to PICRUSt inferences.