Characteristics Of Fecal Microbial Community And The Isolation And Identification Of Its Dominant Bacteria In Dagu Chickens With Different Laying Levels

ObjectiveIn order to explore the differences of intestinal microflora in Dagu chickens with different laying levels,the fecal microflora of hens with high,medium and low laying levels were sequenced and analyzed by high-throughput sequencing of V3~V4 region of 16 S r DNA gene;According to the analysis results,we screened and isolated the high-yield fecal specific microbial strains of Dagu chicken.Methods1、The F5 generation of Dagu hens from the same family but with different laying levels were selected from the scientific research experimental site of Jinzhou Medical University.There were 3 hens in the high level group,the middle level group and the low level group.Fresh feces were collected for high-throughput sequencing of V3~V4 regions of 16 S r DNA and quality detection of sequencing data;Qiime2,picrust2,SPSS and R language were used to analyze the composition,diversity,annotation of species taxonomy,species difference and marker species,metabolic pathway,and the correlation between egg production and fecal microflora of Dagu chicken.2、According to the results of sequencing and analysis,facultative screening medium was used to isolate and culture feces from high level breeder hens;Then,Gram staining,3% catalase,gelatin biochemistry and bromocresol green indicator medium were used for preliminary identification;The qualified strains were sent to the biological company for strain sequencing,and then NCBI blast homology was compared.Results1、The relative abundance of Firmicutes and Bacteroidetes was the highest,accounting for more than 93.1% of the community;The results of beta diversity PCo A analysis showed that the microbial communities were significantly different among the groups with different laying levels,and Lactobacillus was the microbial characteristics of faeces of high-yield Dagu chickens.The function of faecal microbial community of Dagu chicken involves seven first level metabolic pathways,among which 15 metabolic pathways have significant(P<0.05)or extremely significant(P<0.01)differences between high-yield egg level group and middle and low-level groups.The main function of faecal microbial community of high-yield egg level group is biosynthesis and glycolysis.2、The 5-month cumulative egg production of all Dagu chicken samples was significantly positively correlated with the abundance of Firmicutes(P<0.05),and extremely significantly positively correlated with the abundance of Bacillus,Lactobacillales,Lactobacillaceae,Lactobacillus(P<0.01).1、117 strains were isolated from feces of high-yield egg level group of Dagu chicken;55 strains were identified as Lactobacillus;After sequencing and comparison,a strain with 99.85% homology with Lactobacillus reuteri strain 08-3C01 was obtained and named Lactobacillus reuteri SYH001.Conclusions1、Differences in egg production between Dagu chicken hens and fecal microorganisms.The microbial characteristics of the Dagu chickens with high egg production performance are highly abundant Lactobacillus,and the microbial composition of Dagu chickens with low egg production performance is complicated.The function of the microbial flora in the digestive tract of the Dagu chicken with high egg production performance is mainly biosynthesis and glycolysis.2、A fecal specific strain with 99.85% homology with Lactobacillus reuteri strain 08-3C01 was obtained.