|Stebulis, Sarah - UNIV OF WISCONSIN-MADISON|
|Rosa, Guiherme - UNIV OF WISCONSIN-MADISON|
|Grummer, Ric - UNIV OF WISCONSIN-MADISON|
Submitted to: Journal Dairy Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: April 14, 2008
Publication Date: July 7, 2008
Citation: Stebulis, S., Stevenson, D.M., Rosa, G., Grummer, R.R. 2008. Use of ARISA to monitor shifts in rumen microbial populations caused by changes in diet [abstract]. Journal of Dairy Science E-Supplement 1. 91:89. Technical Abstract: The objective was to determine whether automated ribosomal intergenic spacer analysis (ARISA) is sensitive enough to detect shifts in rumen microbial populations caused by dietary changes. Six ruminally cannulated, non-lactating, non-pregnant Holstein cows were sampled for rumen contents in a randomized cross-over design. Treatments were either high-forage (HF) or low-forage (LF) diets offered for ad libitum intake. High forage was composed of 43.7% neutral detergent fiber (NDF) and 31.2% non-fiber carbohydrate (NFC), while LF contained 25.5% NDF and 44.6% NFC. The trial consisted of three periods, an adaptation period (30 d), period 1 and period 2 (14 d each). Cows were switched between periods with no adaptation. Treatment sequences, including the initial adaptation period, were HF-LF-HF and LF-HF-LF. Rumen samples were collected 4 h after feeding on d 14 of each experimental period. Bacterial DNA was extracted from each sample, and the ribosomal intergenic spacer region was PCR-amplified and used for ARISA. The effects of diet, fraction (liquid vs. solid), period, and cow on changes in rumen microbe population were analyzed using principal components methodology and Chi-squared tests. Rumen pH, analyzed with a mixed model, was significantly greater for HF than for LF (6.7 vs. 6.1 +/- 0.08; P < 0.001). There were 253 total phylotypes (unique PCR amplicon lengths) detected using ARISA. Of these phylotypes, 25 were unique to an individual cow. There were 12 phylotypes only found in liquid and 3 only in solid fractions, and 16 only in LF and 2 only in HF. Treatment had a significant effect (P < 0.05) on 19 phylotypes. Thirty-two phylotypes were affected (P < 0.05) by fraction, and 19 were significantly different between cows (P < 0.05). Period affected only 6 phylotypes (P < 0.05). These results suggest that ARISA is sensitive enough to pick up differences in rumen microbial populations due to diet composition changes, and other factors such as rumen fraction and cow.