Longitudinal assessment revealed the shifts in rumen and colon mucosal-attached microbiota of dairy calves during weaning transition

The objectives of this study were to investigate the shifts in rumen and colon mucosa-associated microbiota dairy calves fed a high milk replacer feeding rate before after weaning determine whether such are associated with tissue physiological measures. Longitudinal biopsy was performed collect mucosal tissues 4 ruminally cannulated Holstein bull (weaned at 6 wk age) end 5 (before weaning), 7 (weaning adaptation) 12 (after used assess their changes using amplicon sequencing. Both bacterial communities shifted during process, as evidenced by clear separation among 3 different periods increased ? diversity (Shannon Chao1 indices) transition. Among dominant phyla identified (relative abundance >1.0%), relative Proteobacteria Bacteroidetes decreased mucosa, whereas Firmicutes both mucosa In Campylobacter (0.6–22.1%) gradually became prevalent transition, Succinivibrio (6.2–10.3%) Prevotella 1 (4.7–10.5%) regardless Bacteroides (12.8–25.4%) although its weaning. meantime, uncultured Lachnospiraceae from 2.2% 25.7% period. addition, genera Pyramidobacter (in mucosa) Lachnoclostridium positively correlated papilla surface area thickness, respectively. Moreover, Ruminococcaceae UCG-005 Sharpea molar proportion propionate butyrate, Overall, our findings revealed that altered response some taxa these may have positive effects on development