PCA plot generated using the Ade4 R phylogenetic package [24].

Principal Component Analysis combined with duality diagram functions (dudi) [32] was used to perform Between-Class Analysis (bca) with respect to sample assignment to treatment groups. Monte Carlo test based on 999 permutations demonstrates that groups are significantly (Monte Carlo P-value = 0.003) different. The graph shows sample and group relationship with respect to microbiota structure. The OTU table used for the analysis was 100 times rarefied (normalised) and OTUs with abundance lower than 0.001 were removed.本研究结合对偶图函数（duality diagram functions, dudi）[32]，采用主成分分析（Principal Component Analysis）针对样本在处理组中的分配情况开展类间分析（Between-Class Analysis, bca）。基于999次置换的蒙特卡洛检验（Monte Carlo test）证实，各组间存在显著差异（蒙特卡洛P值=0.003）。该图表展示了样本与分组在微生物群落结构层面的关联关系。本分析所用的操作分类单元（Operational Taxonomic Unit, OTU）表经100倍稀疏化（标准化）处理，且丰度低于0.001的OTU已被移除。