Identification of C18 Intermediates Formed During Stearidonic Acid Biohydrogenation by Rumen Microorganisms In Vitro

• Type: Article in International Scientific Journal
• Date: 2012

Authors

A.R.J. Cabrita (Author) FCUP; A. J. M. Fonseca (Author) ICBAS; S. P. Alves (Author) Other; R. J. B. Bessa (Author) Other; M. R. G. Maia (Author) Other

Journal

Title: Lipids

Vol. 47

Pages: 171-183

ISSN: 0024-4201

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 8 Citations

Scopus - 8 Citations

Scientific classification

CORDIS: Natural sciences > Agrarian Sciences > Zootechnics

FOS: Agrarian Sciences > Animal and Dairy science

Other information

Authenticus ID: P-002-DKR

DOI: 10.1007/s11745-011-3621-6

Abstract (EN): In vitro batch incubations were used to study the rumen biohydrogenation of unsaturated fatty acids. An earlier study using increasing supplementation levels of stearidonic acid (18:4n-3), revealed that the rumen microbial population extensively biohydrogenates 18:4n-3 after 72 h of in vitro incubation, though several intermediates formed were not completely characterized. Therefore, in the present study, samples were reanalyzed in order to identify the 18:2, 18:3 and 18:4 biohydrogenation intermediates of 18:4n-3. Gas-liquid chromatography coupled to mass spectrometry was used to characterize these intermediates. The acetonitrile chemical ionization mass spectrometry of the fatty acid methyl esters derivatives enabled the discrimination of fatty acids as non-conjugated or conjugated biohydrogenation intermediates. In addition, the acetonitrile covalent adduct chemical ionization tandem mass spectrometry yielded prominent ions indicative of the double bond position of the major 18:3 isomers, i.e. Delta 5,11,15 18:3. Furthermore, the 4,4-dimethyloxazoline derivatives prepared from the fatty acid methyl esters enabled the structure of novel 18:2, 18:3 and 18:4 biohydrogenation intermediates to be elucidated. The intermediates accumulated in the fermentation media after 72 h of incubation of 18:4n-3 suggest that similar to the biohydrogenation pathways of linoleic (18:2n-6) and alpha-linolenic (18:3n-3) acids, the pathway of the 18:4n-3 also proceeds with the formation of conjugated fatty acids followed by hydrogenation, although no conjugated dienes were found. The formation of the novel biohydrogenation intermediates of 18:4n-3 seems to follow an uncommon isomerization pattern with distinct double bond migrations.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13