Measurement of Undegradable Grass Hay Ribonucleic Acid by <i>In sacco</i> and <i>In vivo</i> Methods and Their Effect on the Estimation of Microbial Production in the Rumen of Sheep

• ZHAO Guoqi

  Faculty of Agriculture, Iwate University

• SASAKI Hiraku

  Faculty of Agriculture, Iwate University

• KUROSAWA Masayoshi

  Faculty of Agriculture, Iwate University

• SAKAI Masato

  Faculty of Agriculture, Iwate University

• NAKASHIMA Yoshiya

  Faculty of Agriculture, Iwate University

Bibliographic Information

Other Title

• ヒツジの反芻胃内における<i>in sacco</i>および<i>in vivo</i>法による非分解性乾草RNA量の測定とその微生物合成量の推定値に及ぼす影響

Abstract

Four sheep, fitted with ruminal and duodenal cannulas and given only orchardgrass hay, were used for in sacco and in vivo estimation of the ruminal degradation of the hay ribonucleic acid (RNA) and for measurement of duodenal digesta flow. Other four rumen cannulated sheep given orchardgrass hay were used to isolate bacterial and protozoal samples from strained rumen content and to determine the concentration of RNA (purines), diaminopimelic acid (DAPA) and phosphatidylcholine (PC) as markers of rumen microbes. Samples of hay and duodenal digesta were also analyzed for these markers. The degradation characteristics in sacco of hay RNA, dry matter (DM) and crude protein (CP) were measured by incubating hay sample in polyester bags in the rumen. The results were fitted to the exponential equation p=a'+b'{1-e^-c(t-Lt)}, where p is disappearance for each constituent from the bag after t (h), a' the solubility (washing loss), b' the insoluble but potentially fermentable material, c the constant of degradation rate of b' and Lt the lag time of degradation. Particle outflow rate (k1) from the rumen was estimated using chromium mordated hay. Effective degradability (ED) of each constituent of hay was given by the equation ED=a'+bc/(c+k1)e^-(c+k1)Lt. Average ED of RNA was 79.4% which was remarkably higher compared to them of DM (49.3) and CP (60.4%). The average flow of DM to the duodenum of sheep was 10.4gDM/kgBW/d. Concentrations of RNA in hay, bacteria, protozoa and duodenal digesta were 5.2, 123.5, 77.5 and 29.8mg/gDM, respectively. DAPA was found only in bacteria (2.0mg/gDM) and duodenal samples (0.4mg/gDM). PC was obtained in protozoa (19.2mg/gDM) and in duodenal digesta (1.9mg/gDM). On the basis of these data, average total RNA (310), DAPA (4) and PC (20mg/kgBW/d) duodenal flow was calculated. The average amounts of bacteria reaching duodenum calculated by DAPA as a marker, and of protozoa calculated by PC, were 1, 829 and 1, 022mg/kgBW/d, respectively. Using these amounts and concentrations of RNA in bacterial and protozoal samples, it was estimated bacterial and protozoal RNA flux to duodenum: 226 and 79mg/kgBW/d, respectively. The sum of bacterial and protozoal RNA was subtracted from the total duodenal RNA flow. The result was assumed as an amount of ruminally escaped RNA with hay origin: 5mg/kgBW/d. Undegraded feed RNA was devided by the intake of RNA with hay (104mg/kgBW/d), expressed as percent (5.0) and subtracted from 100 in order to get rumen degradability in vivo of grass hay RNA: 95.7%. Consequently, the proportions of bacteria amount, estimated from the undegraded hay RNA in sacco and in vivo, to that calculated from the total RNA duodenal flow, were 6.8 and 1.3%, respectively.

Journal

• Nihon Chikusan Gakkaiho

  Nihon Chikusan Gakkaiho 69 (2), 146-153, 1998

  Japanese Society of Animal Science

Keywords

• <i>in sacco</i>
• <i>in vivo</i>
• Microbial synthesis
• Ruminal degradation
• Hay RNA

Details

• CRID: 1390001205195615616
• NII Article ID: 10021726886
• NII Book ID: AN00195188
• DOI: 10.2508/chikusan.69.146
• ISSN: 18808255
• ISSN: 1346907X
• Text Lang: ja
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed