title: Augmentation of vaccenate production and suppression of vaccenate biohydrogenation in cultures of mixed ruminal microbes.
abstract: To increase ruminal outflow of trans-vaccenic acid (t-VA), a new strain of Butyrivibrio fibrisolvens (MDT-10) was isolated that has a great ability to hydrogenate linoleic acid (LA) to t-VA. When strain MDT-10 was added to the batch cultures of mixed ruminal microbes (1% of the total number of viable ruminal bacteria), LA conversion to t-VA increased greatly; after 3 h, t-VA levels were > 4-fold higher than the control. By 10 h, all of the t-VA was hydrogenated to stearic acid. However, when a new strain of Bifidobacterium adolescentis (HF-11), which has a high capacity for incorporation of t-VA, was added in conjunction with MDT-10 (1% of the total number of ruminal bacteria), t-VA levels after 10 h were 6 times higher than with MDT-10 alone. These results suggest that t-VA produced by MDT-10 was incorporated into HF-11 cells, resulting in protection of t-VA from t-VA-hydrogenating microbes. Similar results were obtained in a continuous culture of mixed ruminal microbes in which addition of HF-11 simultaneously with MDT-10 increased the amount of t-VA in the effluent 2.5-fold. Both MDT-10 and HF-11 appeared to grow readily in the presence of mixed ruminal microbes. Sixty-two percent of t-VA incorporated by HF-11 was present in the free form, whereas 19, 15, and 3%, respectively, were incorporated into monoacylglycerol, glycerophospholipid, and diacylglycerol fractions. Because these lipids can be digested in the small intestine, it is likely that most t-VA in HF-11 cells is absorbed. Thus, introduction of MDT-10 and HF-11 simultaneously to the rumen might increase the amount of t-VA absorbed and might consequently increase the conversion of t-VA to conjugated linoleic acid in tissue.
authors.affiliation: Department of Life Science, Meiji University, Kawasaki 214-8571, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Fukuda
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.forename: M
authors.initials: M
authors.lastname: Murai
authors.forename: N
authors.initials: N
authors.lastname: Asanuma
authors.forename: T
authors.initials: T
authors.lastname: Hino
mesh_terms: D000818:Animals; D001644:Bifidobacterium / Q000378:metabolism; D045856:Butyrivibrio / Q000302:isolation & purification / Q000378:metabolism; D002264:Carboxylic Acids / Q000032:analysis; D004926:Escherichia coli / Q000378:metabolism; D005227:Fatty Acids / Q000032:analysis; D005243:Feces / Q000382:microbiology; D006041:Goats; D006801:Humans; D006865:Hydrogenation; D007778:Lactobacillus / Q000378:metabolism; D019787:Linoleic Acid / Q000378:metabolism; D009829:Oleic Acids / Q000096:biosynthesis* / Q000378:metabolism*; D012417:Rumen / Q000382:microbiology*; D013229:Stearic Acids / Q000378:metabolism
chemical_list: D002264:Carboxylic Acids; D005227:Fatty Acids; D009829:Oleic Acids; D013229:Stearic Acids; C031183:stearic acid; D019787:Linoleic Acid; C050413:11-octadecenoic acid