Objective  To study the effects of feeding the diets at different protein levels on the structure and number of cecal microflora in goslings.

Method  Seventy-two one-day-old geese were randomly divided into three groups, including group A, B and C fed with diets containing 16%, 20% and 24% crude protein, respectively. On the 14th day, the cecum contents of six geese in each group were used for bacterial culture, isolation and counting. The cecal contents of other three geese in each group were taken, and primer sequences were designed according to the conservation of bacterial 16S rDNA. The V4 region genes of bacterial 16S rDNA were sequenced based on the IlluminaHiSeq sequencing platform, and microbial species diversity was analyzed based on the sequences.

Result  A total of 1 066 175 high-quality bacterial 16S rDNA sequences were obtained from group A, B and C. The total number of operational taxonomic unit(OTU) shared by three groups was 1 013, the contribution rate of principle component 1 (PC1) to total microbes was 46.64%, and the contribution rate of principle component 2 (PC2) was 16.46%. The dominant flora at the phylum level were Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria, Verrucomicrobia and etc. The dominant flora at the family level were Bacteroidaceae, Enterobacteriaceae, Lachnospiraceae, Ruminococcacea, and Rikenellaceae. The dominant flora at the genus level were Akkermansia, Bacteroides, Corynebacterium and Lactococcus. Comparing with group A, the number of Bifidobacteria in group C was significantly lower (P<0.05), and the number ofEscherichia coli and Salmonella in group C were significantly higher (P<0.05).

Conclusion  Feeding high-protein diet can change the diversity and abundance of cecal microflora in goslings, reduces the number of bifidobacteria and lactobacilli, and increases the number of E. coli and Salmonella.