A candidate probiotic strain of Enterococcus faecium from the intestine of the crucian carp Carassius auratus

AMB Express

Yongjun Guo¹  Aijun Lv¹  Feng Zhang¹  Xiucai Hu¹  Qing Mao¹  Xueliang Sun¹  Jingfeng Sun¹ 

[1] Tianjin Key Lab of Aqua-ecology and Aquaculture, Fisheries College, Tianjin Agricultural University;

关键词: Carassius auratus;    Enterococcus faecium;    16S rDNA;    Bacteriostatic experiment;    Growth characteristics;   

DOI  :  10.1186/s13568-020-00973-0

来源: DOAJ

【 摘 要 】

Abstract In the present study, a Gram-positive bacterium was isolated from the intestine of healthy crucian carp Carassius auratus and named strain R8. It was initially identified as Enterococcus faecium according to its morphological, physiological and biochemical characteristics. Further identification by using 16S rRNA gene sequence analysis confirmed the R8 strain (Genbank accession no. MF928076) as E. faecium. Challenge and hemolysis experiments showed that the E. faecium R8 strain had no toxicity to the crucian carp. Bacteriostatic experiment showed that this isolate obviously inhibited the growth of Aeromonas veronii and Staphylococcus haemolyticus. The proliferation of E. faecium R8 strain occurred after exposure to various growth conditions such as at pH values from 2.0 to 4.0 for 8 h, bile concentrations from 0.2 to 1.2% and high temperature of 80 °C. This bacterial strain grew best under the condition of 37 °C, pH 7.0 and salinity 30 ppt, and its growth curve exhibited four distinct phases. These results showed that the E. faecium R8 strain had potential probiotic characteristics and could be used as a candidate strain for aquatic probiotics.

【 授权许可】

Unknown