宏基因组学揭示二氟沙星对牦牛瘤胃微生态及CAZy谱影响

Metagenomics reveals effects of difloxacin on rumen microecology and CAZy in yak

反刍动物瘤胃微生物结构和功能关系到生态系统正常的物质循环、能量流动。为了探讨抗生素对瘤胃微生态的影响,揭示抗生素对反刍动物瘤胃微生物影响的规律,以牦牛为研究对象,进行二氟沙星(DIF)处理,采集瘤胃液,提取DNA,采用宏基因组学方法分析DIF对瘤胃微生物组成及碳水化合物酶类(CAZy)的影响。结果显示,拟杆菌门(Bacteroidetes)、变形菌门(Proteobacteria)等相对丰度下降,而厚壁菌门(Firmicutes)、广古菌门(Euryarchaeota)等增加。普雷沃菌属(Prevotella)、拟杆菌属(Bacteroides)等相对丰度下降,而金黄杆菌属(Chryseobacterium)、链球菌属(Streptococcus)等增加;CAZy酶类中,CBM17、CBM25等丰度上调(P<0.01或P<0.05);GH53、CE8、CE13、CBM21、CBM26及对接蛋白(dockerin)等下调(P<0.01或P<0.05)。结论:DIF影响瘤胃微生物结构,并不同程度改变各优势门、属的相对丰度,抑制部分有益菌的作用;改变CAZy酶中部分家族基因丰度,影响瘤胃微生物对淀粉及果胶的降解作用,降低瘤胃微生物降解植物纤维素的效率。

The structure and function of rumen microbes in ruminants are important for the normal material cycle and energy flow in the ecosystems.To explore the effects of antibiotics on rumen micro-ecology,yaks were used in the present research,and were randomly divided into the treatment group and the control group.The treatment group was given difloxacin(DIF).The rumen fluid samples of the treated yaks were collected and DNA was extracted and sequenced.The sequencing data was analyzed by the metagenomic method to identify the effects of antibiotics on rumen microbial composition and carbohydrate enzymes(CAZy).The results showed that the relative abundance of Bacteroidetes and Proteobacteria decreased,while Firmicutes and Euryarchaeota increased.The relative abundance of Prevotella and Bacteroides decreased,while Chryseobacterium and Streptococcus increased.Among the CAZys,the abundance of CBM17 and CBM25 was up-regulated(P<0.01 and P<0.05 respectively).The abundance of GH14,GH53,CE8,CE13,CBM21,CBM26 and dockerin were all down-regulated(P<0.01 or P<0.05).In conclusion:DIF affected the rumen microbial structure,changed the relative abundance of the dominant phylum and genus,and inhibited the function of some beneficial bacteria.It also changed the abundance of some gene families in CAZy,which hindered the degradation of starch and pectin by rumen microbes and reduced the efficiency of microbial degradation of plant cellulose.