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ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Research » Publications at this Location » Publication #107885
Title: THE ISOLATION, CHARACTERIZATION AND ENUMERATION OF HYPER-AMMONIA PRODUCING RUMINAL BACTERIA

Author
item Russell, James
item RYCHLIK, JENNIFER - CORNELL UNIVERSITY

Submitted to: Asian-Australasian Journal of Animal Sciences
Publication Type: Review Article
Publication Acceptance Date: 6/30/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Ruminal amino acid deamination is a wasteful process that often produces more ammonia than bacteria can utilize. Some carbohydrate-fermenting ruminal bacteria can deaminate amino acids, but these species have specific activities of ammonia production that are lower than mixed ruminal bacteria. In the 1980's and 1990's, bacteria that could not utilize carbohydrates were isolated from the rumen, and these bacteria could deaminate amino acids at a very rapid rate and grow rapidly on peptide and amino acids. Based on 16S RNA sequences, the American isolates were identified as Peptostreptococcus anaerobius, Clostridium sticklandii, and Clostridium aminophilum. Australian workers recently isolated a bacterium phylogenetically similar to P. anaerobius, but other isolates were more closely related to Peptostreptococcus asaccharolyticus, Eubacterium nodatum and Fusobacterium necrophorum. Mixed ruminal bacteria from cattle fed grain produced ammonia half as fast as bacteria from cattle fed hay, and a mathematical model predicted that grain-fed cattle would have fewer hyper-ammonia producing bacteria than hay-fed cattle. When mixed bacteria from cattle fed hay were incubated at acidic pH, the ammonia production decreased, and some hyper-ammonia producing bacteria are sensitive to acidic pH. Most hyper-ammonia producing bacteria are monensin sensitive, and monensin decreased the ruminal ammonia concentration of cattle fed hay. However, C. aminophilum grows with relatively high concentrations of monensin in vitro, and 16S rRNA probes indicated that monensin (350 mg/day) did not eliminate this bacterium from the rumen. Hyper-ammonia-producing bacteria are nutritionally detrimental, and additional avenues are needed decrease their numbers in the rumen.