title: Post-prandial compositional changes of fluid- and particle-associated ruminal microorganisms.
abstract: Two ruminally cannulated cows were fed a diet containing 65% alfalfa haylage and 35% concentrate every 12 h. During two collection periods, whole ruminal contents were sampled before feeding, when feed not eaten was removed (1 h after initiation of feeding) and 1, 2, 3, 4, 6, 8, 10 and 12 h after removal. At each sampling, fluid-associated microorganisms were obtained by straining whole ruminal contents through eight layers of cheesecloth. A portion of the particle-associated population was obtained by chilling squeezed particles before seven successive extractions with saline solution. Microbial ash concentrations ranged from 9.9 to 16.6% of dry matter, with differences due to population (P less than .01) and to time after feeding for both fluid- (P less than .05) and particle-associated (P less than .01) microorganisms. Within 1 h after initiation of feeding, N decreased (P less than .05) from a pre-feeding concentration of 9.5% of organic matter to 7.7% for fluid-associated microorganisms, and from 9.2 to 6.7% for particle-associated microorganisms. Both populations did not return to pre-feeding concentrations until 6 h after feed removal. Nucleic acid concentrations decreased (P less than .05) in both populations after feeding, and did not return to pre-feeding concentrations until 6 h for fluid-associated and 4 h for particle-associated microorganisms. Nucleic acid-to-N ratios were higher (P less than .01) in the fluid- than particle-associated organisms.(ABSTRACT TRUNCATED AT 250 WORDS)
authors: Louisiana State University Agricultural Center, Baton Rouge 70803.
authors: W M
authors: WM
authors: Craig
authors: D R
authors: DR
authors: Brown
authors: G A
authors: GA
authors: Broderick
authors: D B
authors: DB
authors: Ricker
mesh_terms: D000818:Animals; D002417:Cattle / Q000382:microbiology*; D005260:Female; D005766:Gastrointestinal Contents / Q000032:analysis*; D008055:Lipids / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis*; D009696:Nucleic Acids / Q000032:analysis*; D011134:Polysaccharides / Q000032:analysis*; D012417:Rumen / Q000382:microbiology*
chemical_list: D008055:Lipids; D009696:Nucleic Acids; D011134:Polysaccharides; D009584:Nitrogen