Abstract

Probiotics are beneficial microbial population, which enhance the growth and immunity of fish under stressful environmental conditions by modulating the gut colonization of the probiotic bacterial strains. The present investigation was designed to isolate fish gut bacterial samples. Isolated strains were screened and four strains were assessed with probiotic activity towards the growth of fish in the particular habitat. The experiments were conducted by admixing the strain with water and fortified with the commercial feed for the growth of Labeo rohita. The result clearly revealed that only two strains showed better activity. These isolated probiotic microorganism’s genomic DNA was analysed using Universal 16S primers and electrophoresed to confirm the taxonomic identity. The 16S rRNA sequence of the isolates was amplified using primers using PCR. Blast analysis of 16S rRNA sequence was carried out with the sequences available in the NCBI database. The 16S rRNA sequences of the isolates were aligned with reference sequences obtained from the GenBank databases. Identical 16S rRNA sequence was recognized by Phylogenetic trees and manual comparisons. These sequences were found to be associated with enzyme amylase and peptidases. Amylase enzyme, protease and lipase enzymes are markedly increase the activity of the probiotics by improving the water quality parameters, food absorption and growth of L. rohita. The identified strain was examined for its effect on fish growth and considered for improving L. rohita fish growth.

Keywords

16S rRNA sequence, Blast, GenBank databases, Labeo rohita, PCR primers.

Received on 02/07/2016, Accepted on 28/08/2016, Published on 20/10/2016