Molecular analysis of autochthonous microbiota along the digestive tract of juvenile grouper Epinephelus coioides following probiotic Bacillus pumilus administration.
AIMS
To evaluate the diversity of dominant autochthonous microbiota along the digestive tract of juvenile Epinephelus coioides following the dietary administration of probiotic Bacillus pumilus for 60 days.


METHODS AND RESULTS
Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) with subsequently sequencing analysis was used to assess the gut microbiota. Generally similar DGGE patterns were observed in the foregut, midgut and hindgut of E. coioides, while the similarity dendrogram clearly revealed three different clusters depending on the three compartments of the GI tract. Dietary administration of B. pumilus stimulated its colonization in each compartment of the digestive tract. Samples collected from the probiotic group and the control group showed similar DGGE patterns, and no significant difference in the total number of bands and the Shannon index were detected between the probiotic group and the control group, suggested that B. pumilus exert no significant effect on the gut microbiota. However, various potentially beneficial bacteria, such as uncultured Bacillus sp. clone QJNY94-like, Nitratireductor sp. YCSC5-like, Methylobacterium hispanicum-like and Microbacterium sp. YACS1-like bacteria were stimulated by probiotic B. pumilus, while the potential harmful Staphylococcus saprophyticus-like bacterium was depressed.


CONCLUSIONS
Autochthonous gut microbiota of E. coioides was modulated to some degree, not significant, by probiotic B. pumilus, various potentially beneficial bacteria were selectively stimulated, while one potential harmful species was depressed.


SIGNIFICANCE AND IMPACT OF THE STUDY
This work represents the first report that dietary administration of probiotic B. pumilus modulated the gut microbiota of E. coioides. These findings broaden our understanding of probiotic effects at the gut level, which is helpful in understanding the mechanisms that underpin host benefits.
['Sun|Y-Z|YZ|', 'Yang|H-L|HL|', 'Ma|R-L|RL|', 'Song|K|K|', 'Lin|W-Y|WY|']
D000818:Animals D001407:Bacillus D001419:Bacteria D001492:Bass D058645:Denaturing Gradient Gel Electrophoresis D041981:Gastrointestinal Tract D064307:Microbiota D008969:Molecular Sequence Data D016133:Polymerase Chain Reaction D019936:Probiotics
probiotic Bacillus pumilus gut microbiota DGGE Epinephelus coloides