Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich. mehr Informationen...
Rumen microbial responses to supplemental nitrate. I. Yeast growth and protozoal chemotaxis in vitro as affected by nitrate and nitrite concentrations
Ist Teil von
Journal of dairy science, 2019-03, Vol.102 (3), p.2207-2216
Ort / Verlag
United States: Elsevier Inc
Erscheinungsjahr
2019
Quelle
EZB Electronic Journals Library
Beschreibungen/Notizen
Nitrates have been fed to ruminants, including dairy cows, as an electron sink to mitigate CH4 emissions. In the NO3− reduction process, NO2− can accumulate, which could directly inhibit methanogens and some bacteria. However, little information is available on eukaryotic microbes in the rumen. Protozoa were hypothesized to enhance nitrate reductase but also have more circling swimming behavior, and the yeast Saccharomyces cerevisiae was hypothesized to lessen NO2− accumulation. In the first experiment, a culture of S. cerevisiae strain 1026 was evaluated under 3 growth phases: aerobic, anoxic, or transition to anoxic culture. Each phase was evaluated with a control or 1 of 3 isonitrogenous doses, including NO3−, NO2−, or NH4+ replacing peptone in the medium. Gas head phase, NO3−, or NH4+ did not influence culture growth, but increasing NO2− concentration increasingly inhibited yeast growth. In experiment 2, rumen fluid was harvested and incubated for 3 h in 2 concentrations of NO3−, NO2−, or sodium nitroprusside before assessing chemotaxis of protozoa toward glucose or peptides. Increasing NO2− concentration decreased chemotaxis by isotrichids toward glucose or peptides and decreased chemotaxis by entodiniomorphids but only toward peptides. Live yeast culture was inhibited dose-responsively by NO2− and does not seem to be a viable mechanism to prevent NO2− accumulation in the rumen, whereas a role for protozoal nitrate reductase and NO2− influencing signal transduction requires further research.