Diversity of bacterial community and screening of protease producing bacteria in red swamp crayfish (Procambarus clarkii) intestine

Abstract:

[Background] The digestion and utilization of feed by cultured animals are often closely related to intestinal microbiota. [Objective] The composition of intestinal bacterial community of red swamp crayfish (Procambarus clarkii) was studied, and protease producing bacteria was screened from the intestinal tract of red swamp crayfish. [Methods] The bacterial community diversity in crayfish intestinal tract was analyzed by sequencing the bacterial 16S rRNA gene V3?V4 region on Illumina MiSeq PE300 platform, and the protease producing bacteria were screened by casein plate method and identified by molecular biology methods. [Results] The most prevalent bacterial phyla were Proteobacteria, Tenericutes, Firmicutes and Bacteroidetes in crayfish intestinal tract, accounting for 98.53% in total. There were 7 prevalent genera of Citrobacter, Candidatus_ Bacilloplasma, Hafnia, Enterococcus, Bacteroides, unclassified_f_Clostridiaceae and Shewanella, accounting for 91.67% in total. The protease producing bacteria screened by casein plate method belonged to Hafnia, Citrobacter, Klebsiella and Bacillus. [Conclusion] The core groups of bacteria in red swamp crayfish intestinal tract played an important role in protein digestion and utilization.