ISOLATION AND CHARACTERIZATION OF PROBIOTIC BACTERIA FROM BIOFLOC FOR ENHANCING FISH GROWTH

Abstract

Biofloc technology (BFT) enhances water quality, fish growth, and immunity through diverse heterotrophic bacterial communities while reducing feed costs. This study isolated 22 probiotic strains, predominantly Bacillus species, from microbial bioflocs in Peshawar, Karak, and Bannu, Pakistan. Among these, Bacillus subtilis (PBSI-5), Bacillus safensis subsp. safensis (KBS3-8), and Bacillus safensis subsp. safensis (BBS4-5) were identified as the most promising due to their enzyme activities (amylase, cellulase, and protease). These strains significantly improved weight gain and specific growth rates in Mori (Cirrhinus mrigala). Bacillus safensis subsp. safensis showed the highest weight gain (31.02±1.24g) and % weight gain (82.98±3.32%). The study emphasizes the potential of these probiotics to enhance fish growth in biofloc systems and suggests further research on their immunological benefits and use as feed supplements. These findings offer promising applications for enhancing fish health, productivity, and sustainable aquaculture practices through optimized probiotic formulations.