Establishment of ruminal bacterial community in dairy calves from birth to weaning is sequential

Abstract

Aim: Establishment of ruminal bacterial community in dairy calves. Methods and Results: Rumen bacterial community was analysed on 6 calves bred according to commercial practices from day one to weaning at day 83 of age, using 454 16S rRNA-based pyrosequencing. Samples taken at day 1 did not produce amplicons. Analysis of data revealed a three-stage implantation process with a progressive but important shift of composition. At day 2, the bacterial community was mainly composed of Proteobacteria (70%) and Bacteroidetes (14%), and Pasteurellaceae was the dominant family (58%). The bacterial community abruptly changed between days 2 and 3, and until day 12, dominant genera were Bacteroides (21%), Prevotella (11%), Fusobacterium (5%) and Streptococcus (4%). From 15 to 83 days, when solid food intake rapidly increased, Prevotella became dominant (42%) and many genera strongly decreased or were no longer detected. A limited number of bacteria genera correlated with feed intake, rumen volatile fatty acids and enzymatic activities. Conclusion: The ruminal bacterial community is established before intake of solid food, but solid food arrival in turn shapes this community. Significance and Impact of the Study: This study provides insight into the establishment of calves' rumen bacterial community and suggests a strong effect of diet.

Ruminal Bacterial Community Composition in Dairy Cows Is Dynamic over the Course of Two Lactations and Correlates with Feed Efficiency

“…Previous large-scale sequencing work with calves has shown that the bacterial community converges on an "adult" profile as the calves age, and in particular, as they are fed increasing percentages of dietary roughage (4). The idea of a stable adult ruminal community with only minor, smallscale fluctuations was further supported by a study using wholecommunity fingerprinting of adult cows over the course of 21 days (41).…”

“…Investigations into time-dependent changes in the ruminal community have, to date, focused on the first year of life, as during that time the anatomical structure of the preruminant stomach changes rapidly as the calf's diet shifts from protein-and fat-rich milk to cellulose-and starch-rich feed (22). As calves mature, there are major and significant changes in the digestive bacterial population, even at the phylum level, and a general convergence toward an "adult" profile numerically dominated by bacteria in the phyla Firmicutes, Bacteroidetes, and Proteobacteria (4,6,23). The difficulty of defining when an animal is physiologically mature (with respect to lactation) as opposed to sexually mature, the granularity of sampling (6,23), assumptions regarding community similarity when animals are sacrificed (6), and if animals were sampled concurrently instead of sequentially (23) leave unresolved many questions regarding ruminal community dynamics.…”

“…These symbionts are capable of fermenting host-indigestible feed into nutrient sources usable by the host, such as volatile fatty acids (1,2). Ruminants are born without a functional rumen and are thought to acquire their digestive microbes from the environment as the rumen develops (3)(4)(5)(6). Although the means by which ruminants acquire this ruminal microbial community remains unclear, the membership and stability of the ruminal community can have a direct and measurable impact on host function and health (7).…”

Taxonomic Identification of Ruminal Epithelial Bacterial Diversity during Rumen Development in Goats

“…Meanwhile, most of the alpha diversity indices (except ACE and the Simpson index) increased with age, suggesting that the microbiota in older age groups is more diverse than that in earlier age groups. This is similar to the process of microbial colonization of the rumen contents (11,26).…”

A glimpse of the future in animal nutrition science. 2. Current and future solutions

“…Recently, Rey et al (2014) andDe Barbieri et al (2015) have shown that there is a pattern of establishment and that this can be influenced by the species that are initiated into the microbiome soon after birth from maternal or other sources. This is a fascinating field of study opening up the possibility of long-term manipulation of the rumen microbiome.…”