title: Effects of a twin strain of saccharomyces cerevisiae live cells on mixed ruminal microorganism fermentation in vitro.
abstract: This experiment was designed to investigate the effects of different concentrations (0, 0.33, 0.66, 0.99, and 1.32 g/L) of a twin-strain of Saccharomyces cerevisiae live cells on in vitro mixed ruminal microorganism fermentation of corn starch, soluble potato starch, and sudangrass hay (60.5%, DM basis) plus concentrate mixture (39.5%, DM basis). Ruminal fluid was collected from two dairy cows, mixed with phosphate buffer (1:2), and incubated (30 mL) anaerobically at 38 degrees C for 6 and 24 h with or without yeast supplement, using 200 mg (DM basis) of each substrate. Medium pH, ammonia-N, and numbers of protozoa were unaffected (P = 0.38) by yeast cells in all substrates. Molar proportion of acetate was unchanged (P = 0.56) with cornstarch and soluble potato starch, but increased quadratically (P = 0.02) with hay plus concentrate by treatment. Addition of yeast cells caused a linear increase of total VFA (P = 0.008) in all substrates. Excluding the soluble potato starch, supplementation of S. cerevisiae resulted in a quadratic increase of propionate (P = 0.01), with a quadratic decrease (P = 0.04) of acetate:propionate. When soluble potato starch was used as a substrate, a linear increase (P = 0.006) of the molar proportion of propionate and a quadratic decrease (P = 0.007) in acetate:propionate was observed by treatment. Molar proportion of butyrate was unchanged (P = 0.35) with cornstarch and soluble potato starch, whereas it decreased linearly (P = 0.007) with hay plus concentrate by yeast cell supplementation. When cornstarch and soluble potato starch were used as a substrate, minor VFA were decreased (P = 0.05) by treatment. Accumulation of lactate was linearly decreased by treatment (P = 0.007) in all substrates. During incubation with hay plus concentrate, IVDMD was linearly increased (P = 0.006), whereas production of methane (linear; P = 0.02) and accumulation of hydrogen was decreased (quadratic; P = 0.005) by treatment after 24 h. These results showed that a twin strain of S. cerevisiae live cells stimulated in vitro mixed ruminal microorganism fermentation with decreased lactate, and a small decrease of methane and hydrogen with hay plus concentrate.
authors.affiliation: Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan.
authors.forename: Z A
authors.initials: ZA
authors.lastname: Lila
authors.forename: N
authors.initials: N
authors.lastname: Mohammed
authors.forename: T
authors.initials: T
authors.lastname: Yasui
authors.forename: Y
authors.initials: Y
authors.lastname: Kurokawa
authors.forename: S
authors.initials: S
authors.lastname: Kanda
authors.forename: H
authors.initials: H
authors.lastname: Itabashi
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001421:Bacteria, Anaerobic / Q000378:metabolism*; D002417:Cattle; D015169:Colony Count, Microbial; D056890:Eukaryota / Q000254:growth & development; D005232:Fatty Acids, Volatile / Q000032:analysis / Q000096:biosynthesis*; D005260:Female; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D019936:Probiotics; D012417:Rumen / Q000737:chemistry / Q000378:metabolism / Q000382:microbiology* / Q000469:parasitology; D012441:Saccharomyces cerevisiae / Q000378:metabolism / Q000502:physiology*; D013213:Starch / Q000378:metabolism
chemical_list: D005232:Fatty Acids, Volatile; D000641:Ammonia; D013213:Starch