title: As yet uncultured bacteria phylogenetically classified as Prevotella, Lachnospiraceae incertae sedis and unclassified Bacteroidales, Clostridiales and Ruminococcaceae may play a predominant role in ruminal biohydrogenation.
abstract: Microbial biohydrogenation of dietary poly-unsaturated fatty acids (PUFA) to saturated fatty acids (SFA) in the rumen results in the high ratio of SFA/PUFA in ruminant products, such as meat and milk. In vitro, Butyrivibrio proteoclasticus-related bacteria extensively biohydrogenate PUFA to SFA, yet their contribution in the rumen has not been confirmed. The aim of this study was to evaluate the role of Butyrivibrio proteoclasticus group bacteria in ruminal biohydrogenation and to assess the possible role of other bacteria. Fish oil at 0%, 1.5% and 3% dry matter intake was fed to eight Holstein × Friesian steers, in order to elicit changes in the extent of PUFA biohydrogenation. Fatty acid and B. proteoclasticus group 16S rRNA concentrations in rumen digesta were determined. Correlation between digesta 18:0 concentration and B. proteoclasticus group 16S rRNA concentration was low. Terminal restriction fragment length polymorphism and denaturing gradient gel electrophoresis (DGGE) coupled with multivariate statistics revealed that many terminal restriction fragments (T-RFs) and DGGE bands were linked to cis-9, trans-11 conjugated linoleic acid (CLA), 18:1 trans-11 and 18:0 ruminal concentrations. MiCA T-RF predictive identification software showed that these linked T-RFs were likely to originate from as yet uncultured bacteria classified as Prevotella, Lachnospiraceae incertae sedis, and unclassified Bacteroidales, Clostridiales and Ruminococcaceae. Sequencing of linked DGGE bands also revealed that as yet uncultured bacteria classified as Prevotella, Anaerovoax (member of the Lachnospiraceae incertae sedis family), and unclassified Clostridiales and Ruminococcaceae may play a role in biohydrogenation.
authors.affiliation: Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Gogerddan, Aberystwyth SY23 3EB, UK.
authors.forename: Sharon A
authors.initials: SA
authors.lastname: Huws
authors.forename: Eun J
authors.initials: EJ
authors.lastname: Kim
authors.forename: Michael R F
authors.initials: MR
authors.lastname: Lee
authors.forename: Mark B
authors.initials: MB
authors.lastname: Scott
authors.forename: John K S
authors.initials: JK
authors.lastname: Tweed
authors.forename: Eric
authors.initials: E
authors.lastname: Pinloche
authors.forename: R John
authors.initials: RJ
authors.lastname: Wallace
authors.forename: Nigel D
authors.initials: ND
authors.lastname: Scollan
mesh_terms: D000818:Animals; D041963:Bacteroidetes / Q000145:classification / Q000235:genetics*; D001483:Base Sequence; D045856:Butyrivibrio / Q000145:classification / Q000235:genetics*; D058645:Denaturing Gradient Gel Electrophoresis; D005227:Fatty Acids / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005395:Fish Oils / Q000378:metabolism; D006865:Hydrogenation; D044243:Linoleic Acids, Conjugated / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D018720:Prevotella / Q000145:classification / Q000235:genetics*; D012417:Rumen / Q000382:microbiology
chemical_list: D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D005395:Fish Oils; D044243:Linoleic Acids, Conjugated