Mengrong Su, Kaisi Hu, Yingcheng Gao, Liuyan Fang, Bingfeng Zheng, Ruxu Qi, Hongxin Li, Wei Zhang, Wenjie Zhang, Jian Ma
Alpha diversity analysis revealed that microplastics exposure slightly reduced the ruminal Shannon index (p = 0.087), but significantly increased the Chao1 and PD indexes in the ileum, as well as the Shannon and PD indexes in the colon (p < 0.05). At the phylum level, the CON group exhibited a significantly higher Tenericutes abundance than MP group (p < 0.05) in the ileum. Compared with CON group, the relative abundance of Proteobacteria was increased by 51.54 and 138.3% in the jejunum and ileum of MP group, respectively (0.05 < p < 0.10). Conversely, the relative abundance of Proteobacteria in the cecum (p < 0.05) and colon (p = 0.056) of MP group was lower than that in CON group, while the Firmicutes and Elusimicrobia relative abundances in the colon were significantly higher in MP group than CON group (p < 0.05). At the genus level, after microplastics exposure, the relative abundance of unclassified Muribaculaceae showed a decreasing trend in the rumen (0.05 < p < 0.10). In the jejunum of MP group, the pathogenic genus Ralstonia abundance exhibited a slight increase (0.05 < p < 0.10), whereas the Mycoplasma and [Eubacterium] coprostanoligenes group abundances in the ileum were significantly decreased (p < 0.05). The relative abundance of Rikenellaceae RC9 gut group was decreased in the cecum (p < 0.05) after microplastics exposure.
INTRODUCTION: This study aimed to investigate the effects of polystyrene microplastics (PS MPs) on microbial communities in the rumen, jejunum, ileum, cecum and colon of fattening Hu sheep lambs.
METHODS: The 16S ribosomal RNA gene amplicon sequencing was employed to analyze the gastrointestinal microbial diversity and composition between the control (CON) and microplastic-exposed (MP, 100 μm PS MPs, 150 mg/d per lamb for 40 d) groups, each with 10 lambs.
RESULTS: Alpha diversity analysis revealed that microplastics exposure slightly reduced the ruminal Shannon index (p = 0.087), but significantly increased the Chao1 and PD indexes in the ileum, as well as the Shannon and PD indexes in the colon (p < 0.05). At the phylum level, the CON group exhibited a significantly higher Tenericutes abundance than MP group (p < 0.05) in the ileum. Compared with CON group, the relative abundance of Proteobacteria was increased by 51.54 and 138.3% in the jejunum and ileum of MP group, respectively (0.05 < p < 0.10). Conversely, the relative abundance of Proteobacteria in the cecum (p < 0.05) and colon (p = 0.056) of MP group was lower than that in CON group, while the Firmicutes and Elusimicrobia relative abundances in the colon were significantly higher in MP group than CON group (p < 0.05). At the genus level, after microplastics exposure, the relative abundance of unclassified Muribaculaceae showed a decreasing trend in the rumen (0.05 < p < 0.10). In the jejunum of MP group, the pathogenic genus Ralstonia abundance exhibited a slight increase (0.05 < p < 0.10), whereas the Mycoplasma and [Eubacterium] coprostanoligenes group abundances in the ileum were significantly decreased (p < 0.05). The relative abundance of Rikenellaceae RC9 gut group was decreased in the cecum (p < 0.05) after microplastics exposure.
DISCUSSION: Overall, PS MPs induced segment-specific dysbiosis of the gastrointestinal microbiota across multiple intestinal segments in lambs, and the ileum and colon were the most sensitive to microplastics exposure, with their microbial diversity, dominant phyla and genera, and interspecies interactions all being disrupted.