title: In vitro study of the response of rumen microorganisms to different doses of abierixin, a new antibiotic ionophore, according to the nature of nitrogen supplies.
abstract: An in vitro study on a "batch" type fermentation system was carried out in order to evaluate the effect of different doses of a new ionophore antibiotic, abierixin, on the rumen fermentation parameters. The reaction of microorganisms to the antibiotic were determined according to the nature of the nitrogen introduced into the fermenter: ammonium sulfate alone or complemented with protein nitrogen (peanut meal or a mixed pelleted feed). This molecule had a protective effect with respect to dietary protein degradation in the rumen, at the lowest dose tested (13.5 ppm). The dose (8 ppm) used with the pelleted feed led to a decrease in the protein degradability but the significant threshold was not reached. Abierixin failed to modify bacterial ammonia uptake with the nitrogen sources used in our experiment. In addition, it had no effect on rumen fermentations. It neither led to any alteration in the total VFA and gas productions during 6 hours of fermentation, nor on their molar composition, whatever the dose of antibiotic used and the nitrogen source considered.
authors.affiliation: I.N.R.A., Centre de Recherches de Clermont-Theix, Station de Recherches sur la Nutrition des Herbivores, Ceyrat, France.
authors.forename: M C
authors.initials: MC
authors.lastname: Hillaire
authors.forename: L
authors.initials: L
authors.lastname: Gomez
authors.forename: J P
authors.initials: JP
authors.lastname: Jouany
mesh_terms: D000821:Animal Feed; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D010367:Arachis; D001419:Bacteria / Q000187:drug effects* / Q000378:metabolism; D004044:Dietary Proteins / Q000378:metabolism; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D007476:Ionophores / Q000494:pharmacology*; D009584:Nitrogen / Q000378:metabolism*; D011714:Pyrans / Q000494:pharmacology; D012417:Rumen / Q000382:microbiology*; D012756:Sheep
chemical_list: D000900:Anti-Bacterial Agents; D004044:Dietary Proteins; D007476:Ionophores; D011714:Pyrans; C047796:abierixin; D009584:Nitrogen