Dynamics of Intestinal Mucosa Microbiota in Juvenile Sika Deer During Early Growth

The establishment of gut microbiota in young ruminants has a profound impact on their productive performance in adulthood. The microbial communities of ruminants differ significantly across the different regions of the digestive tract, as well as between the mucosa and lumen. In this study, we analyzed the characteristics of the microbiota of the small intestine (jejunum and ileum) and large intestine (cecum and colon) of sika deer on day 1 (birth), day 42 (transition period) and day 70 (rumination period) using 16S rRNA gene sequencing. The results showed that the microbial diversity of the mucosa in the jejunum, ileum, cecum and colon of sika deer was higher on day 70 than on day 1, and the diversity of the cecal mucosa was significantly higher than that in the small intestine. Principal coordinates analysis (PCoA) showed that the microbial community structures of the small and large intestinal mucosa were significantly different, and the microbial community structure of sika deer on day 1 was significantly different from that on days 42 and 70. The relative abundances of Methylobacterium-Methylorubrum, Pelagibacterium, Acinetobacter and Staphylococcus were higher in the small intestinal mucosa, while Alistipes, Prevotellaceae UCG-004, Eubacterium coprostanoligenes group and Lachnospiraceae unclassified were higher in the large intestinal mucosa. We also observed increased levels of specific microbiota in the small intestinal (Turicibacter and Cellulosilyticum) and large intestinal mucosa (Treponema, Romboutsia, Oscillospirales UCG-005 and Peptostreptococcaceae unclassified) with animal growth. A comparison of the predicted function showed that the microbiota of the small intestinal mucosa was enriched for replication and repair, while carbohydrate metabolism was enriched in the microbiota of the large intestinal mucosa. In addition, the relative abundances of amino acid and energy metabolism were significantly higher on days 42 and 70 than on day 1. Our results revealed that the microbial community composition and the dynamics of the intestinal mucosa from birth to rumination in juvenile sika deer, which may provide insights into similar processes in other juvenile ruminants.