不同粒径微塑料对剑尾鱼肠道结构及肠道微生物的影响

Effects of Microplastics with Different Particle Sizes on Intestinal Structure and Intestinal Microbe of Swordtail Fish

针对微塑料所带来的严重环境危害问题,为探究其对水生生物肠道的毒性作用,选用5月龄雄性剑尾鱼作为试验动物,共分为3组:M0组(对照组)、M1组(1μm、1×10^(7)microspheres·L^(-1))和M2组(5μm、1×10^(7)microspheres·L^(-1))。每组设置3个重复,每个重复10尾鱼,暴露于聚苯乙烯微塑料水环境中72 h。通过组织病理学和16S rRNA测序,探究不同粒径微塑料对剑尾鱼肠道损伤和肠道菌群的影响。研究结果显示:与对照组对比,1μm粒径组和5μm粒径组绒毛长度显著降低且杯状细胞数量显著减少(P<0.05),菌群多样性指数均降低。其中,1μm粒径组与5μm粒径组相比,5μm粒径组隐窝深度显著高于1μm粒径组(P<0.05),5μm粒径组变型菌门和疣微菌门的比例显著高于1μm粒径组(P<0.05)。不同粒径微塑料均可引起剑尾鱼肠道损伤,并改变肠道微生物群落结构,其中5μm粒径组中微塑料对剑尾鱼肠道损伤程度及肠道微生物群落结构与丰度变化均高于1μm粒径组。

In view of the serious environmental harm caused by microplastics,in order to explore its toxic effect on intestinal tract of aquatic organisms,5-month-old male swordtail fish were selected as experimental animals and divided into three groups:M0 group(control group),M1 group(1μm,1×10^(7)microspheres·L^(-1))and M2 group(5μm,1×10^(7)microspheres·L^(-1)).Three replicates were set in each group,and 10 fish in each group were exposed to polystyrene microplastic water environment for 72 h.The effects of microplastics with different particle sizes on intestinal damage and intestinal flora of swordtail fish were studied by histopathology and 16s rRNA sequencing.The results showed that compared with the control group,the villus length and the number of goblet cells are decreased significantly in 1μm particle size group and 5μm particle size group(P<0.05),and the bacterial diversity index decreased.Compared with the 5μm group,the crypt depth in the 5μm group is significantly higher than that in the 1μm group(P<0.05),and the proportion of Proteobacteria and Verrucomicrobia in the 5μm group is significantly higher than that in the 1μm group(P<0.05).The different particle sizes of microplastics cause intestinal damage and change the intestinal microbial community structure of swordtail fish.Among them,the degree of intestinal damage and the changes of intestinal microbial community structure and abundance in the 5μm particle size group are higher than those in the 1μm particle size group.