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Technical note: stearidonic acid metabolism by mixed ruminal microorganisms in vitro
M R G Maia1, C A S Correia, S P Alves
1REQUIMTE, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas, 4485-661 Vairão, Vila do Conde, Portugal. mrgmaia@mail.icav.up.pt
Journal of Animal Science
|October 25, 2011
Summary
Dietary stearidonic acid (SDA) is extensively metabolized in the rumen, with significant biohydrogenation into various fatty acids. SDA supplementation alters fatty acid profiles, but high levels may inhibit its own biohydrogenation pathway.
Area of Science:
- Rumen microbiology
- Nutritional biochemistry
- Animal science
Background:
- Dietary stearidonic acid (SDA; 18:4n-3) is a potential precursor for increasing n-3 unsaturated fatty acids in ruminant products.
- Limited information exists regarding SDA metabolism and biohydrogenation within the rumen environment.
Purpose of the Study:
- To investigate the in vitro metabolism of SDA in bovine ruminal digesta.
- To identify the biohydrogenation products of SDA and their relationship to SDA concentration.
Main Methods:
- In vitro batch incubations using bovine ruminal digesta.
- Supplementation of varying SDA concentrations (0-1.50 mg) to a corn silage-based total mixed ration.
- Analysis of fatty acid profiles in freeze-dried cultures after 72 hours of incubation.
Main Results:
- SDA supplementation significantly altered fatty acid profiles, decreasing branched-chain and odd-chain fatty acids.
- Apparent biohydrogenation of SDA was extensive but not influenced by SDA concentration up to 1.00 mg.
- High SDA inclusion rates led to decreased stearic acid and vaccenic acid, with increased unidentified C18:3 and C18:4 isomers, suggesting pathway inhibition.
Conclusions:
- Stearidonic acid undergoes extensive metabolism and biohydrogenation in the rumen.
- Rumen biohydrogenation of SDA produces significant amounts of vaccenic acid and stearic acid.
- Inhibition of the biohydrogenation pathway may occur at higher SDA supplementation levels.
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