Effects of saponins, quercetin, eugenol, and cinnamaldehyde on fatty acid biohydrogenation of forage polyunsaturated fatty acids in dual-flow continuous culture fermenters.
Four different plant secondary metabolites were screened for their effect on rumen biohydrogenation of forage long-chain fatty acids, using dual-flow continuous culture fermenters. Treatments were as follows: control (no additive), positive control (12 mg/L of monensin), and plant extracts (500 and 1,000 mg/L of triterpene saponin; 250 and 500 mg/L of quercetin; 250 mg/L of eugenol; 500 mg/L of cinnamaldehyde). Monensin increased propionate, decreased acetate and butyrate proportions, and inhibited the complete biohydrogenation of fatty acids resulting in the accumulation of intermediates of the biohydrogenation process (C18:2 trans-11, cis-15 rather than C18:1 trans-11). Cinnamaldehyde decreased total VFA concentration and proportions of odd and branched-chain fatty acids in total fat effluent. Apparent biohydrogenation of C18:2n-6 and C18:3n-3 was also less, and a shift from the major known biohydrogenation pathway to a secondary pathway of C18:2n-6 was observed, as evidenced by an accumulation of C18:1 trans-10 and trans-10, cis-12 CLA. Quercetin (500 mg/L) increased total VFA concentration, but no shifts in the pathways or extent of biohydrogenation were observed. Eugenol resulted in the accumulation of C18:1 trans-15 and C18:1 cis-15, end products of an alternative biohydrogenation pathway of C18:3n-3. Triterpene saponins did not affect the fermentation pattern, the biohydrogenation pathways, or the extent of biohydrogenation. At the doses tested in this study, we could only show a direct relation between changes in the rumen fatty acid metabolism and the presence of cinnamaldehyde but not for eugenol, quercetin, or triterpene saponins.
Laboratory for Animal Production and Animal Product Quality, Department of Animal Production, Ghent University, Proefhoevestraat 10, 9090 Melle, Belgium.
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Cardozo
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Calsamiglia
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Fievez
D000171:Acrolein / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002417:Cattle / Q000378:metabolism*; D005054:Eugenol / Q000494:pharmacology; D005227:Fatty Acids / Q000032:analysis; D005231:Fatty Acids, Unsaturated / Q000032:analysis / Q000378:metabolism*; D005232:Fatty Acids, Volatile / Q000032:analysis; D005260:Female; D005285:Fermentation / Q000187:drug effects*; D006865:Hydrogenation / Q000187:drug effects; D066298:In Vitro Techniques; D008129:Lolium / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology*; D011794:Quercetin / Q000494:pharmacology; D012503:Saponins / Q000494:pharmacology
D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D005232:Fatty Acids, Volatile; D010936:Plant Extracts; D012503:Saponins; D005054:Eugenol; D000171:Acrolein; D011794:Quercetin; C012843:cinnamaldehyde