内蒙古某奶牛场两种致犊牛腹泻原虫的鉴定及遗传进化分析  

Identification and Phylogenetic Analysis of Two Intestinal Protozoa from a Dairy Farm in Inner Mongolia

作　　者：刘鼎 梁高星 房凯敏 任尊 牛雨薇 吴敏楠 宋军科[1] LIU Ding;LIANG Gao-xing;FANG Kai-min;REN Zun;NIU Yu-wei;WU Min-nan;SONG Jun-ke(College of Veterinary Medicine,Northwest A&F University,Yangling,Shaanxi 712100,China)

机构地区：[1]西北农林科技大学动物医学院,陕西杨凌712100

出　　处：《动物医学进展》2023年第12期1-5,共5页Progress In Veterinary Medicine

基　　金：陕西省重点研发计划项目(2020NY-006)。

摘　　要：为明确内蒙古某规模化奶牛养殖场腹泻犊牛寄生虫性病原的感染情况及其分子学特性,采集该养殖场18头发生腹泻犊牛的新鲜粪便样品。通过形态学方法并结合分子生物学方法对样品中隐孢子虫(Cryptosporidium)和蓝氏贾第虫(Giardia lamblia)进行分离鉴定和感染情况统计分析。形态学检查结果表明,18份粪便样品中隐孢子虫感染率为5.56%(1/18),蓝氏贾第虫感染率为72.22%(13/18)。进一步对18份粪便样品提取DNA,并基于SSU rRNA和BG基因位点分别对隐孢子虫和蓝氏贾第虫进行PCR扩增、序列比对和遗传进化分析。电泳检测结果显示,显微镜检测阳性粪便样品均在830 bp和511 bp处出现目的扩增条带。同时,序列比对及遗传进化分析也表明,所分离到的隐孢子虫与来自于不同国家和地区的牛隐孢子虫(C.bovis)在SSU rRNA基因位点上具有100%序列同源性,因此被归于同一个进化分支,而所分离的蓝氏贾第虫在BG基因位点上与集聚体E参考分离株的序列同源性高达99.78%以上,提示其属于集聚体E。通过形态学和分子学方法明确了牛隐孢子虫和蓝氏贾第虫是该奶牛场主要致犊牛腹泻的寄生虫性病原,此结果可为该地区犊牛腹泻的防治提供理论依据。To investigate the infection and molecular characteristics of important intestinal protozoa causing calf diarrhea of a dairy farm in Inner Mongolia,in this study,18 fresh feces samples of calves with diarrhea were collected to isolate and identify Giardia lamblia and Cryptosporidium sp.in the samples based on morphological and molecular biological methods.The results of microscopic observation on morphology showed that the infection rates of Giardia lamblia and Cryptosporidium sp.were 72.22%(13/18)and 5.56%(1/18),respectively.Furtherly,total DNA preparation was extracted from 18 fecal samples and used for PCR amplification,sequence comparison and phylogenetic analysis on the BG and SSU rRNA gene sequences of Giardia lamblia and Cryptosporidium sp.Electrophoresis results showed that the purpose stripes were detected at 830 bp and 511 bp in microscopically positive fecal samples.Meanwhile,sequence comparison and phylogenetic analysis also suggested that all isolations of Giardia lamblia here belonged to assemblage E due to possession of 99.78%sequence similarity in BG gene locus with assemblage E refe-rence isolates retrieved from GenBank.And the only Cryptosporidium sp.isolate in the study,shared 100%sequence similarity on SSU rRNA gene locus with Cryptosporidium bovis from different countries and areas,was grouped into the same evolutionary branch.In this study,C.bovis and Giardia lamblia were identified as intestinal parasitic protozoa causing calf diarrhea.The results can provide theoretical basis for the prevention and treatment of calf diarrhea in this area.

关 键 词：犊牛 腹泻 蓝氏贾第虫 牛隐孢子虫 鉴定 

分 类 号：S852.72[农业科学—基础兽医学] S858.23[农业科学—兽医学]