Differential Responses of Digesta- and Mucosa-Associated Jejunal Microbiota of Hu Sheep to Pelleted and Non-Pelleted High-Grain Diets

In the present study, we utilized 16S rRNA sequencing to uncover the impacts of non-pelleted (HG) or high-grain pelleted (HP) diets on the microbial structure and potential functions of digesta- and mucosa-associated microbiota in the jejunum of Hu sheep. Here, we randomly assigned 15 healthy male Hu sheep into three groups and fed the control diets (CON), HG, and HP diets, respectively. The experiment period was 60 days. The HP diets had the same nutritional ingredients as the HG diets but in pelleted form. At the finish of the experiment, the jejunal digesta and mucosa were gathered for microbial sequencing. The results of PCoA and PERMANOVA showed that different dietary treatments had significant impact (<i>p</i> < 0.05) on digesta- and mucosa-associated microbiota in the jejunum of Hu sheep. For specific differences, HG diets significantly increased (<i>p</i> < 0.05) the abundance of some acid-producing bacteria in both jejunal digesta (<i>Bifidobacterium</i>, OTU151, and OTU16) and mucosa (<i>Rikenellaceae RC9 gut group</i>, and <i>Bifidobacterium</i>) of Hu sheep compared with the CON diets. Besides the similar effects of the HG diets (increased the acid-producing bacteria such as <i>Olsenella</i>, <i>Pseudoramibacter</i>, and <i>Shuttleworthia</i>), our results also showed that the HP diets significantly decreased (<i>p</i> < 0.05) the abundance of some pro-inflammatory bacteria in the jejunal digesta (<i>Mogibacterium</i>, and <i>Marvinbryantia</i>) and mucosa (<i>Chitinophaga</i>, and <i>Candidatus Saccharimonas</i>) of Hu sheep compared with the HG diets. Collectively, these findings contributed to enriching the knowledge about the effects of HG diets on the structure and function of intestinal microbiota in ruminants.