Location: Food and Feed Safety Research
Title: Enrichment of 3-nitro-1-propionic acid-metabolizing bacteria in avian feces Authors
|Lan, Wen-Shiaw - TX A&M UNIVERSITY|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 9, 2007
Publication Date: June 21, 2007
Citation: Anderson, R.C., Lan, W., Hume, M.E., Krueger, N.A., Callaway, T.R., Nisbet, D.J. 2007. Enrichment of 3-nitro-1-propionic acid-metabolizing bacteria in avian feces [abstract]. In: Proceedings of 5th International Symposium on Anaerobic Microbiology, June 21-24, 2007, Domzale, Slovenija. p. 2-3. Technical Abstract: Denitrobacterium detoxificans is a Gram-positive anaerobe that conserves energy for growth exclusively via anaerobic respiration, oxidizing H2, formate or lactate for the reduction of nitrate, trimethylamine oxide, dimethyl sulfoxide or nitroalkanes such as 3-nitro-1-propionic acid (NPA). At present, D. detoxificans has been isolated only from the bovine rumen but evidence suugests its presence in human oral flora. The objective of this experiment was to assess if D. detoxificans may reside within the avian gut. Freshly collected feces obtained from at least 2 broiler hatches were enriched separately in anaerobic enrichment medium containing salts, vitamins, clarified ruminal fluid (8% vol/vol), 8% phytone peptone (wt/vol), 12 mM sodium formate, cysteine-HCl and sodium carbonate under H2:C02 (1:1). The electron acceptor was NPA (9 mM) and its rate of disappeareance (dNPA/dt) during enrichment was determined colorimetrically. Numbers of NPA-metabolizing bacteria were determined via most probable number (MPN) estimation. During enrichment (3 consecutive 24 h transfers at 39 deg C), dNPA/dt increased from 0.04 to 0.06 µmol ml**-1 h**-1 and MPN of NPA-metabolizing bacteria increased from <3 x 10**2 to 9 x 10**3 cells ml**-1. Enrichment of populations in a more restricted medium, modified to contain 0.1% peptone and 3% clarified ruminal fluid resulted in a 30% increase in dNPA/dt and an increase in MPN of NPA-metabolizing bacteria to 1 x 10**8 cells ml**-1 (approximately 10% that of the total bacterial population). These results suggest that D. Detoxificans-like bacteria reside within the avian gut and that their isolation may require enrichment in restricted media.