Submitted to: Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: February 20, 2009
Publication Date: May 21, 2009
Citation: Kerr, B.J., Ziemer, C.J. 2009. Isolation and Identification of Fiber-utilizing Bacteria From Pigs [abstract]. In: Proceedings of the American Society Microbiology 109th General Meeting, May 17-21, 2009, Philadelphia, PA 2009 CDROM. Technical Abstract: Pigs can obtain up to 30% of their maintenance energy from short chain fatty acids. The major source of short chain fatty acids is bacterial fiber fermentation in the large intestine; however, fiber-utilizing bacterial communities in pigs are not well defined. In order to gain better insight into fiber utilization in the pig intestine, we isolated cellulose, xylan, and pectin utilizing bacteria. Twelve chemostats were inoculated with a swine fecal slurry from individual pigs (n=6, 2 chemostats/pig) which were adapted to diets containing 8.6% cellulose and 10.3% hemicellulose. Chemostats had a working volume of 700 ml with a carbohydrate-free nutrient buffer medium flow rate of 0.35 ml/min. All chemostats were anaerobic with a temperature of 38ºC and pH of 6.7. Carbohydrates were fed twice daily (3 g/feeding) as either cellulose or xylan (2 g) + pectin (1 g). Samples were taken 4, 6, or 8 weeks post-inoculation and diluted prior to plating on anaerobic agar. Replicate plating was used to transfer colonies to selective agars each containing a single carbohydrate (cellulose, carboxymethyl cellulose, oat spelt xylan, beechwood xylan, or pectin). A total of 1190 isolates were recovered and partial 16S rRNA gene sequencing was used to group isolates. Nearly full length sequences of 16S rRNA genes were obtained for 633 isolates. Isolate sequences were most closely related (97%) to Clostridium species (26.7%) or uncultured clones (26.2%). Bacteroides and Eubacterium species were represented at 12% and 6%, respectively. Those groups that made up between 6% and 3% included Lactobacillus, Staphylococcus, Bacillus, and the Enterobacteriaceae. Those isolates with sequences matching cloned sequences represent newly cultured organisms. Clostridium species are the primary fiber-utilizing bacteria in pigs.