Rice straw biochar as a novel niche for improved alterations to the cecal microbial community in rats

Biochar as additive has been shown positive effect in animal production, which may be linked to the role of gastrointestinal microbial modulation. This study aimed to assess the effects of biochar on the gut microbial communities in terms of their structure and diversity. Illumina high-throughput technology was utilized to evaluate the cecal microbial community in Wistar rats received oral rice straw biochar (RSB) at 1120 mg/kg of body weight for 5 weeks. RSB improved the gut mucosal structure and epithelial integrity. More importantly, principal coordinate analysis of UniFrac distances based on a 97% operational taxonomic unit composition and abundance indicated that the bacterial community was ameliorated after RSB addition (P < 0.05). Firmicutes and Bacteroidetes were found to be the prevalent phyla accounting for approximately 90% of the sequences and their ratio of relative abundance was increased by RSB addition (P < 0.05). Improved bacterial proportion of unclassified Lachnospiraceae (P < 0.001), Oscillibacter (P = 0.02), and Clostridium IV (P = 0.02) and XIVa (P = 0.02) as well as decreased abundances of Prevotella (P < 0.001) and Bacteroides (P = 0.03) were also detected at genus level following RSB treatment. These results revealed that RSB altered and improved the cecal microbial community, which may contribute to the affected growth and gut status in rats.