title: Supplemental protein influences on carbohydrate degradation and bacterial 16S ribosomal ribonucleic acid.
abstract: This research examined the mechanism by which soybean protein stimulates growth of mixed ruminal anaerobes and degrades structural polysaccharides in vitro. Soybean meal, isolated soy protein, or branched-chain VFA was added to orchardgrass hay substrate in Experiment 1. Cell-wall degradation increased 14.5% over that of the control by protein addition. Protein addition resulted in 1.3- to 1.5-fold increases in bacterial growth. Hybridization with a 16S probe specific for Fibrobacter succinogenes indicated that protein addition did not influence the proportion of this species. For in vitro Experiment 2, optimal protein for cell-wall degradation was 2 g/L in cultures containing tall fescue hay. To determine whether protein stimulated microbial colonization of plant cell wall (Experiment 3), orchardgrass hay was placed in 14-L fermentors; treatments were control, NH3 N (2 g of N/L), or isolated soy protein (2 g of N/L). Addition of protein and NH3 N increased the extent of cell-wall disappearance 9.7% above control. Protein and ammonia improved cell-wall digestion, but protein had the greatest stimulatory effect on prokaryote growth with no preferential effect of F. succinogenes.
authors.affiliation: Department of Animal Sciences, University of Missouri, Columbia 65211.
authors.forename: T
authors.initials: T
authors.lastname: May
authors.forename: M S
authors.initials: MS
authors.lastname: Kerley
authors.forename: J E
authors.initials: JE
authors.lastname: Williams
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000818:Animals; D001421:Bacteria, Anaerobic / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D050260:Carbohydrate Metabolism; D002417:Cattle / Q000382:microbiology*; D002473:Cell Wall / Q000378:metabolism; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000494:pharmacology; D005232:Fatty Acids, Volatile / Q000494:pharmacology; D005260:Female; D005285:Fermentation; D006089:Gram-Negative Anaerobic Bacteria / Q000235:genetics; D009584:Nitrogen / Q000378:metabolism / Q000494:pharmacology; D009693:Nucleic Acid Hybridization; D014674:Plant Proteins, Dietary / Q000008:administration & dosage / Q000494:pharmacology; D015347:RNA Probes; D012336:RNA, Ribosomal, 16S / Q000378:metabolism*; D012417:Rumen / Q000382:microbiology*; D030262:Soybean Proteins
chemical_list: D004044:Dietary Proteins; D005232:Fatty Acids, Volatile; D014674:Plant Proteins, Dietary; D015347:RNA Probes; D012336:RNA, Ribosomal, 16S; D030262:Soybean Proteins; D000641:Ammonia; D009584:Nitrogen