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Number of nitrate‐ and nitrite‐reducing Selenomonas ruminantium in the rumen, and possible factors affecting its growth
Author(s) -
YOSHII Takahiro,
ASANUMA Narito,
HINO Tsuneo
Publication year - 2003
Publication title -
animal science journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.606
H-Index - 38
eISSN - 1740-0929
pISSN - 1344-3941
DOI - 10.1046/j.1344-3941.2003.00142.x
Subject(s) - nitrite , rumen , nitrate , food science , bacteria , microbiology and biotechnology , chemistry , biology , fermentation , ecology , genetics
The cell number of Selenomonas ruminantium ( S. ruminantium ) that reduces nitrate and nitrite in the rumen was usually 8–10% of the total number of S. ruminantium (an order of 10 6 /mL). The percentage was not affected by the roughage/concentrate ratio or nitrate content of the diet in 2 weeks. However, feeding a high‐nitrate diet for 12 weeks increased the percentage. The percentage of lactate‐using S. ruminantium , such as the ssp. lactilytica , was less than 1% of the total number of S. ruminantium. No S. ruminantium was found that used formate as an electron donor for nitrate and nitrite reduction. Lactate and H 2 appeared to be important for nitrate and nitrite reduction by S. ruminantium . Nitrate reduction by S. ruminantium was enhanced by the coexistence of amylolytic bacteria in a medium containing starch, and as a result, nitrite accumulation increased. Coexistence of cellulolytic bacteria facilitated the growth of S. ruminantium in a medium containing cellulose, and consequently increased nitrite reduction. In order to suppress nitrite accumulation in the rumen, it may be important to enhance fiber digestion.