Abstract #W328
Section: Ruminant Nutrition
Session: Ruminant Nutrition: Dairy III
Format: Poster
Day/Time: Wednesday 7:30 AM–9:30 AM
Location: Gatlin Ballroom
Session: Ruminant Nutrition: Dairy III
Format: Poster
Day/Time: Wednesday 7:30 AM–9:30 AM
Location: Gatlin Ballroom
# W328
Investigating the impact of dietary changes on rumen microbial community during the transition period in Holstein dairy cows using high-throughput sequencing.
Ousama Al Zahal*1, Suzanne L. Ishaq2, Benoit St-Pierre3, Andre-Denis G. Wright4, Brian W. McBride1, 1University of Guelph, Guelph, Ontario, Canada, 2University of Vermont, Burlington, VT, 3South Dakota State University, Brookings, SD, 4The University of Arizona, Tucson, AZ.
Key Words: dairy cow, transition period, 16S rRNA
Investigating the impact of dietary changes on rumen microbial community during the transition period in Holstein dairy cows using high-throughput sequencing.
Ousama Al Zahal*1, Suzanne L. Ishaq2, Benoit St-Pierre3, Andre-Denis G. Wright4, Brian W. McBride1, 1University of Guelph, Guelph, Ontario, Canada, 2University of Vermont, Burlington, VT, 3South Dakota State University, Brookings, SD, 4The University of Arizona, Tucson, AZ.
The transition period is a critical time in the life of a dairy cow and is associated with a dietary shift from a high-forage-based diet (HF) to a high-grain based (HG) diet. This study investigated the impact of such a dietary shift on the structure of the rumen bacterial population. Fourteen Holstein dairy cows were used in this experiment. Rumen digesta samples were obtained using an oral stomach tube 3 weeks before calving (HF) and 9 weeks postcalving (HG). Twenty-eight samples were collected, and bacterial 16S rRNA genes were sequenced using Roche 454 pyrosequencing with titanium chemistry. Processing of sequences, performing α and β diversities, and classifying sequences were conducted using MOTHUR. A total of 198,276 non-chimeric sequences were generated. Those sequences were assigned to 16,833 operational taxonomic units based on a 95% genetic similarity for each sample. Shannon and Inverse Simpson indices were calculated for each sample, and revealed an overall reduction (P < 0.05) in the diversity of the rumen bacterial population when cows were shifted from the HF to the HG (from 5.4 ± 0.2 to 4.3 ± 0.2 and from 153 ± 26 to 47 ± 26, respectively). UniFrac was used to test whether HF samples were different from HG samples. The normalized-weighted P test was <0.001, indicating a significant difference between the 2 bacterial communities; and the calculated UniFrac metric value was 0.968, indicating that most of the branch length belonged to one community or the other. Sequences from HF were allocated mainly into the following phyla: Bacteroidetes (38 ± 4%), an unclassified group (33 ± 2%), Firmicutes (23 ± 3%), and Proteobacteria (5 ± 4%), whereas samples from HG were allocated mainly into the Proteobacteria (36 ± 4%), Bacteroidetes (34 ± 4%), Firmicutes (15 ± 3%), and an unclassified group (14 ± 2%). ANOVA with time as the fixed effect showed that Proteobacteria and the unclassified group were significantly different (P < 0.001) between HF and HG, and Firmicutes had a tendency (P = 0.07) to be different.
Key Words: dairy cow, transition period, 16S rRNA
