Shrihari Ashok Pingle¹, Abhay John Khandagle^2,

The present study aimed to explore and compare the gut microbiome of Labeo rohita (rohu) from wild and aquaculture setting through 16S rDNA sequencing. The amplification of the library of 16S rDNA V3-V4 hypervariable regions of the gut microbiome was carried out followed by sequencing using Illumina MiSeq. The analysis of sequencing data was carried out through the Quantitative Insights into Microbial Ecology (QIIME2) pipeline. Proteobacteria, Firmicutes, Cyanobacteria and Actinobacteria represented the bacterial phyla with large abundance. The abundance of Bacillus spp. and Clostridium spp. was high in cultured forms. Vagococcus spp. and Carnobacterium spp. were found to be abundant in wild forms. Cyanobium spp., and Pseudomonas spp. were abundant in both wild and cultured forms. In the present study, the gut of cultured forms of rohu shows a diverse microbiome than that of wild forms. The harbouring gut microbes may offer several benefits to the host fish such as carbohydrate digestion, antimicrobial activity, xenobiotic degradation and faster growth rate. The functional profiles from the 16s rRNA gene amplicon confirm that the cultured rohu hosts the bacteria that have a role in metabolism and compromised disease resistance. Absence of Bacillus spp. in wild form, and low abundance of Lactococcus spp. indicates the need of finding alternatives for probiotics. The information from the present study and its understanding can be used for exploring the role of the gut microbiome with regard to the growth, immunity and other physiological functions of the fish.

rohu, fish gut, metagenomics, major carps, aquaculture, gut microbiome