Among the uncultured Cabozantinib nmr Prevotella, 60 clones (43.2%) had 92–96% similarity to previously reported sequences (Table 4). The Chao1 and Shannon indices predicted more diversity in the hay library (Table 4), and libshuff comparison showed significant (P=0.001) differences in the composition of the two libraries (data not shown). Of the 17 clones that showed ≥97% sequence similarity with known Prevotella species, 16 clones were retrieved from concentrate-fed

sheep (Table 4) and 11 clones were related to P. ruminicola, while five were related to P. bryantii. Only a single clone from the hay diet was related to P. ruminicola at 97% sequence similarity. No sequences having ≥97% similarity with P. brevis and P. albensis were found. The results of phylogenetic analysis of 16S rRNA gene sequences from the two libraries are shown in this website Fig. 2. Although the bootstrap values were <50%, we divided the phylogenetic tree into seven sections to show the distribution of the clones. Sixty-six out of 79 clones from the concentrate library were found in sections 1 and 3; meanwhile, sections 4–7 contained 42 clones from the hay library. Hay clones were distributed in all sections of the tree. Application of molecular biological tools in the analysis of several environmental microbial communities revealed that only a small fraction of the microbiota is represented by cultured species (Janssen, 2006) and the rumen microbial community is no exception. A previous

study indicated that Nutlin-3 purchase only 11% of OTU detected in the rumen contain cultured representatives (Edwards et al., 2004). We focused on the population dynamics, ecology and diversity of Prevotella in order to estimate the contribution of this genus to digestion of feed in the rumen. Real-time PCR quantification revealed that the proportion of two representative Prevotella species (P. ruminicola and P. bryantii) was one-quarter of that of the genus (4.4% vs. 19.7% for concentrate-fed sheep). This result indicates

that Prevotella is abundant in the rumen and the majority of members of this genus are yet to be cultured. It was reported that the abundance of the other two ruminal Prevotella spp. (P. brevis and P. albensis) was negligible (Stevenson & Weimer, 2007). Similar to the other reports on rumen bacterial clone library analysis (Whitford et al., 1998; Tajima et al., 1999; Koike et al., 2003), we did not find the sequences of these two species in our clone libraries. Therefore, P. brevis and P. albensis seemed to be minor in the rumen, and they were not quantified. The high proportion of Prevotella observed in the present study agrees with the report of Wood et al. (1998), who estimated the combined Prevotella/Bacteroides ribotypes in the rumen in the range of 12–62%. The numerical dominance of Prevotella spp. reported in different experiments (Van Gylswyk, 1990; Wood et al. 1998; Stevenson & Weimer, 2007) suggests their importance in the ruminal digestion of feed.