The succession of fecal bacterial community and its correlation with the changes of serum immune indicators in lambs from birth to 4 months

Early bacterial colonization and succession within the gastrointestinal tract have been suggested to be crucial in the development of host immunity. In this study, we have investigated the changes in live weight and concentrations of selected serum parameters in relation to their fecal bacterial communities as determined by high throughput sequencing of the 16S rRNA gene over the same period in lambs. The results showed that lambs’ growth performance, the serum parameters, fecal bacterial community and fecal bacterial functions were all affected (P<0.05) by age of the lambs. Similarity within age groups of fecal microbiota was lower in the preweaning period and increased sharply (P<0.05) after weaning at 60 days. The similarity between the samples collected from birth to 90 days of age and those collected at 120 days of age, increased (P<0.05) sharply after 30 days of age. Some age-associated changes in microbial genera were correlated with the changes in concentrations of immune indicators, including negative (P