Abstract

CASTILLO, Julián A; OLIVERA, Martha; PABON, Martha L  and  CARULLA, Juan E. Reduction of the biohydrogenation of linoleic and alpha-linolenic acid by addition of different proportions of eicosapentaenoic acid and docosahexaenoic acid. Rev.Colomb.Quim. [online]. 2012, vol.41, n.3, pp.395-408. ISSN 0120-2804.

The effect of adding docosahexaenoic (DHA) and eicosapentaenoic acid (EPA) on the in vitro biohydrogenation of linoleic (ALi) and alpha-linolenic acid (ALn) using ruminal fluid was evaluated. To 500 mg of kikuyo, 18 μL of a mixture of ALi:ALn (75:25) (Control) or a mixture of 14,9 μL ALi:ALn (75:25) and 3,1 μL of a mixture containing four ratios of EPA:DHA (100:0, 75:25, 25:75, 0:100) were added. In 50 mL tubes, kikuyo without fatty acids (FA) (negative control) or with their addition was incubated with ruminal fluid by triplicate during 0, 5 or 16 hours. Lipids in the incubated material were extracted, methylated and fatty acids were quantified by GC-FID. Relative concentrations (g/100 g FA) of incubated fatty acids and their main isomerization and ruminal biohydrogenation products were compared by a completely randomized model using PROC GLM of SAS. The relative concentration of ALi and ALn decreased with incubation time but was not different between EPA and DHA treatments at 16 hours. Addition of EPA and DHA, pure or in mixtures, decreased the relative concentration of C_18:0 and increased the relative concentration of C_18:1 trans-11 (TVA) (P<0,01 ) and C_18:2 trans-11, cis-15 (P<0,01), while changes in the relative concentration of C_18:2 cis-9, trans-11 (CLA) were not clear. Our results suggest that EPA and DHA inhibit the final steps of ruminal biohydrogenation of ALi and ALn.

Keywords : conjugated linoleic acid; trans-vaccenic acid; ruminal fluid; in vitro.

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