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Effects of nitrate addition to a diet on fermentation and microbial populations in the rumen of goats, with special reference to S elenomonas ruminantium having the ability to reduce nitrate and nitrite
Author(s) -
Asanuma Narito,
Yokoyama Shota,
Hino Tsuneo
Publication year - 2015
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 - 10.1111/asj.12307
Subject(s) - rumen , fermentation , food science , biology , nitrate , microbiology and biotechnology , zoology , chemistry , ecology
This study investigated the effects of dietary nitrate addition on ruminal fermentation characteristics and microbial populations in goats. The involvement of S elenomonas ruminantium in nitrate and nitrite reduction in the rumen was also examined. As the result of nitrate feeding, the total concentration of ruminal volatile fatty acids decreased, whereas the acetate : propionate ratio and the concentrations of ammonia and lactate increased. Populations of methanogens, protozoa and fungi, as estimated by real‐time PCR , were greatly decreased as a result of nitrate inclusion in the diet. There was modest or little impact of nitrate on the populations of prevailing species or genus of bacteria in the rumen, whereas S treptococcus bovis and S . ruminantium significantly increased. Both the activities of nitrate reductase ( NaR ) and nitrite reductase ( NiR ) per total mass of ruminal bacteria were increased by nitrate feeding. Quantification of the genes encoding NaR and NiR by real‐time PCR with primers specific for S . ruminantium showed that these genes were increased by feeding nitrate, suggesting that the growth of nitrate‐ and nitrite‐reducing S . ruminantium is stimulated by nitrate addition. Thus, S . ruminantium is likely to play a major role in nitrate and nitrite reduction in the rumen.