Astragalus affects fecal microbial composition of young hens as determined by 16S rRNA sequencing

The gut microbiota play important roles in the degradation of chemical compounds of herbal medicines (HMs). However, little information regarding the interplay between HMs and the gut microbiota is available. Thus, the aim of this study was to investigate the composition of the fecal microbiota of young (age, 11 weeks) hens fed a conventional diet containing a crude Astragalus (0.5%) additive for 21 days (group A) vs. controls (group B) that were fed only conventional feed. The fecal contents of 14-week-old hens were collected for DNA extraction, and then the V3 and V4 hyper-variable regions of the 16S rRNA gene were amplified and analyzed using high-throughput sequencing technology. A distinctive difference in microbial diversity was observed between the two groups. The microbial composition of hens fed a diet supplemented with Astragalus was greater than that of the control group. At the genus level, Lactobacillus was more abundant in group A than group B (p < 0.05). Importantly, this study is the first to report the observation of a novel Romboutsia sp. in the feces of hens. However, Romboutsia was less abundant in group A than group B (17.94 vs. 33.98%, respectively, p < 0.05). The microbial community differed significantly between the two groups at the genus level, suggesting that Astragalus modulates the composition of the fecal microbiota. Based on these differences, these findings provide fresh insights into the application of Astragalus in the poultry industry, as well as a better understanding of the interplay between HMs and the gut microbiota.