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Wambui C.C.,Tottori University | Wambui C.C.,The University of Shimane | Ando S.,National Livestock Breeding Center | Abdulrazak S.A.,Kenya National Council for Science and Technology | And 2 more authors.
Grassland Science | Year: 2012

An in vitro ruminal gas production study was conducted to assess the effect of yeast supplementation on rumen fermentation of tanniniferous tropical browse mixtures prepared by mixing Berchemia discolor with Acacia brevispica, Acacia elatior, Acacia mellifera, Balanites aegyptiaca, Grewia bicolor or Zizyphus mucronata in a 1:1 dry weight ratio. The six browse mixtures were incubated with buffered rumen fluid alone or supplemented with dried Japanese Sake yeast (JSY) or polyethylene glycol (PEG). Ruminal gas production characteristics were evaluated using the Gompertz equation. The JSY addition increased gas production volume (P<0.05) and numerically increased the maximum gas production rate constant. Time to reach the maximum gas production rate was shortened by PEG addition as compared to the JSY and control treatments. It is possible that JSY promoted the rumen microbial activity in addition to forming complexes with tannins thereby upgrading the in vitro ruminal digestion of tropical browse mixtures. © 2012 The Authors. Grassland Science © 2012 Japanese Society of Grassland Science. Source


Wambui C.C.,Tottori University | Wambui C.C.,The University of Shimane | Awano T.,The University of Shimane | Ando S.,Japan National Agricultural Research Center | And 3 more authors.
Journal of Food, Agriculture and Environment | Year: 2010

Two experiments were conducted with the aim of i) evaluating the nutritive potential of seven Kenyan browse species {Acacia brevispica (Harms), Acacia elatior (Brenan), Acacia mellifera (Vahl) Benth, Balanites aegyptiaca (L.) Del, Berchemia discolor (Hemsley), Grewia bicolor (A. Juss) and Zizyphus mucronata (Willd)} through their chemical composition and in vitro gas production profiles and ii) assessing the effect of two yeast supplements (Japanese sake yeast (JSY) and bioethanol residue yeast (BRY)) on in vitro rumen dry matter degradability (IVRDMD). In the IVRDMD test, four treatments consisting of a control (no supplement), JSY, BRY and a positive control of soybean peptide (SP) were supplemented in the in vitro rumen incubation fluid and incubated with the browse foliage for 24 hours. The crude protein content ranged from 163 to 270 g kg -1 dry matter (DM) and neutral detergent fiber from 364 to 527 g kg -1 DM. Gas production (mL), organic matter digestibility (%) and metabolisable energy concentration (MJ/kg DM) differed significantly (p < 0.05) among the browse species, and were significantly influenced by the total phenolic contents (p < 0.05). The IVRDMD was significantly influenced by both the supplements (p < 0.0021) and browse foliages (p < 0.0001). The JSY had significantly higher IVRDMD than the other supplements (p < 0.05) and BRY and SP had numerically higher values than the control (p > 0.05). Berchemia discolor had significantly higher IVRDMD in response to all the supplements, while G. bicolor had the least response, respectively (p < 0.05). Difference of yeast strains (JSY vs. BRY) may have influenced the IVRDMD, while differences among browse foliages may have been as a result of varying levels of concentrations and chemical structure of tannins. The study shows that yeast has potential to attenuate the antinutritive effects of tannins in browse foliages on the rumen fermentation by providing microbial yeast protein and promoting growth and activity of fiber digesting microbes. Source

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