Effect of Bacillus spp. on the composition of gut microbiota in early life stages of Indian white shrimp, Penaeus indicus

To study the effects of the probiotics on the gut microbial community of Penaeus indicus larvae, a combination of three probiotics-Bacillus subtilis, B. lichiniformis, and B. pumilus (5 x 10(10) cfu/gram)-were added to the rearing environment of shrimp larvae (5,000/500 L). Altered microbial communities due to the application of probiotics were studied using 16S rRNA-based Illumina sequencing. The results suggest that the probiotics-treated group showed higher richness; the control group was even as measured by alpha diversity indices. The abundance of Proteobacteria was higher in the probiotic-treated group (94.85%) compared to the control (58.29%). At the genus level, the probiotics group was dominated by Vibrio (44.17%), Rhodobacteraceae_unclassified (25.22%), Catenococcus (12.89%), Pseudoalteromonas (4.76%), and Kordia (1.53%); Tenacibaculum (24.29%), Catenococcus (19.38%), Vibrio (7%), Gammaproteobacteria_unclassified (6.6%), Fluviicola (5.91%), and Chlamydiales_unclassified (4.61%) dominated in the control group. Results indicate that probiotic application influenced the taxonomic profile of gut microbes. This information helps us to understand the effect of probiotic application especially in penaeid shrimp hatcheries.