旋毛虫感染和色氨酸补充对长爪沙鼠肠道菌群的影响

Effects of Trichinella spiralis infection and tryptophan supplementation on intestinal flora in Mongolian gerbil

目的 动态观察长爪沙鼠(Meriones unguiculatus,Mongolian gerbil)感染旋毛虫(Trichinella spriralis)和补充色氨酸后体内肠道菌群的变化,计数长爪沙鼠体内成虫与肌幼虫荷虫量,初步探究补充色氨酸对旋毛虫病的影响。方法 建立长爪沙鼠旋毛虫感染模型,分别于感染后0 d(对照组)、7 d(TS7组)、14 d(TS14组)、28 d(TS28组)无菌采集长爪沙鼠新鲜粪便进行16S rDNA高通量测序,分析各组长爪沙鼠肠道菌群的动态变化。将感染旋毛虫第7 d的长爪沙鼠处死,用无菌剪刀截取其小肠,纵向剖开,置于生理盐水中孵育并收集成虫计数;在感染旋毛虫肌幼虫的第28 d处死,称取1 g肌肉,消化后在显微镜下计数肌幼虫数量,计算成虫和幼虫减虫率。结果 沙鼠肠道菌群在门水平中,拟杆菌门与厚壁菌门占总组成90%以上。与对照组相比,感染组肠道期拟杆菌门占比下降7.98%;色氨酸组拟杆菌门占比呈先升高后下降的趋势,在囊包期降低至45.60%。感染组沙鼠厚壁菌门占比逐渐降低至33.30%;色氨酸组厚壁菌门在感染初期开始下降,于幼虫移行期降至28.07%,随后开始恢复。在属水平,各感染阶段Muribaculaceae菌属、拟杆菌属和乳酸杆菌属的变化较为明显。LEfSe分析显示,厌氧棒状菌属、杜氏杆菌属、双歧杆菌属、乳酸杆菌属、副拟杆菌属、候选单胞生糖菌属是对照组、感染组和色氨酸组以及各个感染阶段之间具有显著差异的菌属。补充色氨酸后,感染旋毛虫长爪沙鼠体内成虫数量和肌幼虫数量与未补充组比较均显著减少,成虫减虫率为22.08%(P<0.05),肌幼虫减虫率为33.83%(P<0.01)。结论 旋毛虫感染和补充色氨酸可改变沙鼠肠道菌群组成,但在不同感染阶段有所差异。此外,补充色氨酸能显著减少长爪沙鼠体内虫体的数量。

Objective To dynamically observe the changes of intestinal flora in Mongolian gerbil(Meriones unguicu-latus)infected with T.spriralis and supplemented with tryptophan,The number of adult worms and muscle larvae in Mongolian gerbil was counted,and the effect of tryptophan supplementation on trichinosis was preliminarily explored.Methods The model of Mongolian gerbils infected with T.spiralis was established,and the fresh feces of Mongolian ger-bils were collected aseptically at 0d(control group),7d(TS7group),14d(TS14group)and 28d(TS28group)after infection for 16SrDNA high-throughput sequencing,and the dynamic changes of intestinal flora of each group of Mongoli-an gerbils were analyzed.Mongolian gerbils infected with T.spiralis was killed on the 7d,and its small intestine was cut with aseptic scissors,and then it was incubated in physiological saline and the adult worms were collected and counted.Mongolian gerbils were killed on the 28dafter they were infected with the muscle larvae of T.spiralis,and 1g of muscle was weighed.After digestion,the number of muscle larvae was counted under the microscope,and the worm reduction rate of adults and larvae was calculated.Results Bacteroidetes and Firmicutes accounted for more than 90%of intestinal flora of gerbils in the phylum level.Compared with the control group,the proportion of Bacteroidetes in the intestinal phase of the infection group decreased by 7.98%;The proportion of Bacteroidetes in the tryptophan group increased first and then decreased to 45.60%in the encystation stage.The proportion of Firmicutes in infected gerbils gradually de-creased to 33.30%;Firmicutes in the tryptophan group began to decline at the early stage of infection,decreased to 28.07%at the larval migration stage,and then began to recover.At the genus level,the changes of Muribaculaceae,Bac-teroides and Lactobacillus were more obvious in each infection stage.LEfSe analysis showed that Anaerostipes,Dubosiela,Lactobacillus,Parabacteroides,and Candidatus_Saccharimonas were the genera with significant differences between the control,infection,and tryptophan groups as well as between the infection stages.After tryptophan supplementation,the number of adult worms and muscle larvae in Mongolian gerbils infected with T.spiralis were significantly reduced compared with those in the non supplemented group,and the reduction rate of adult worms was 22.08%(P<0.05),and the reduction rate of muscle larvae was 33.83%(P<0.01).Conclusion T.spiralis infection and tryptophan supple-mentation can change the composition of intestinal flora in gerbils,but there are differences in different infection stages.In addition,tryptophan supplementation could significantly reduce the number of worms in Mongolian gerbils.