| During sheep breeding,the disease resistance of lambs is weak,and they are vulnerable to diarrhea caused by external environmental factors.The prevalence of diarrhea in lambs is very high,which severely affects the growth and development of lambs.In order to explore the changes in the structure of the intestinal flora of diarrheal lambs,this experiment used 16 S r RNA gene sequencing technology to analyze the composition and structure of the fecal flora of diarrheal lambs and healthy lambs.And the similarity of the fecal flora of diarrheal lambs in different farms was analyzed,so as to screen out the pathogenic bacteria causing diarrhea of lambs,and provide a basis for the treatment of diarrhea of clinical breeding lambs.Eight one-month-old diarrheal and eight healthy Hu lambs were selected from the large-scale Hu sheep farms in Chengde City,Hebei Province to compare the difference of fecal flora between diarrheal and healthy lamb.The fecal samples of ten one-month-old diarrheal lambs were collected in two large-scale farms to analyze the diversity of fecal flora of diarrheal lambs in different farms.The samples were sequenced for microbial diversity,and the results were as follows:(1)According to the difference test of Alpha diversity index between groups showed that the Ace index and Chao index of the healthy lambs were higher than those of the diarrheal lambs(P<0.05).The Shannon index of the healthy lambs was higher than those of the diarrheal lambs(P<0.01),and the Simpson index was lower than those of the diarrheal group(P<0.01).These results indicated that the number and diversity of fecal microflora in the healthy group were higher than those of the diarrheal group.(2)PCo A analysis of Beta diversity showed that there was a significant difference in composition of microbial species between healthy and diarrheal lambs(P=0.001).(3)The relative abundance of Proteobacteria(P<0.01)and Fusobacterium(P<0.001)in diarrheal lambs was significantly higher than in healthy lambs.The relative abundance of Verrucomicrobiota(P<0.001)and Cyanobacteria(P<0.01)in diarrheal lambs was significantly lower than in healthy lambs.(4)The abundance of Escherichia-Shigella(P<0.01),Streptococcus(P<0.05),Clostridium＿sensu＿stricto＿1(P<0.001),Fusobacterium(P<0.001),Butyricicoccus(P<0.001)and Ruminococcus＿gnavus＿group(P<0.001)was significantly higher in diarrheal lambs than that of healthy lambs.The abundance of norank＿f＿＿Eubacterium＿coprostanoligenes＿group(P<0.01),Ruminococcus＿torques＿group(P<0.01),norank＿f＿Muribaculaceae(P<0.05),Barnesiella(P<0.05),norank＿f＿UCG-010(P<0.05)and Ruminococcus＿gauvreauii＿group(P<0.05)was significantly lower in diarrheal lambs than that in healthy lambs.(5)There were no significant differences in Ace index,Coverage index,Simpson index and Shannon index of Alpha diversity in the diarrheal lambs of two farms(P>0.05),indicating that there were no significant differences in species richness,species coverage and species diversity of diarrheal lamb feces microorganisms of two farms.PCo A analysis of Beta diversity showed no significant difference in microbial species composition between the fecal samples of diarrheal lambs from the two farms(P>0.05).There were no significant differences in the phylum and genus level between diarrheal lambs of two farms.In summary,the abundance of Proteobacteria and Fusobacterium in diarrheal lambs increased,Escher-Shigella and Fusobacterium were the main pathogenic bacteria of diarrheal lambs,while Clostridium＿sensu＿stricto＿1,Butyricicoccus,Ruminococcus＿gnavus＿group may play a protective role in the process of diarrhea.The fecal flora of diarrheal lamb feces in different farms in the same area are similar,and effective treatment measures can be referred to in neighboring sheep farms.However,at the same time,it should also be noted that the different feeding management conditions of different farms may cause differences in pathogenic microorganisms,and treatment measures should also be adjusted appropriately according to the actual situation when necessary. |
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