Synergistic effects of Bacillus pumilus and exogenous protease on Nile tilapia (Oreochromis niloticus) growth, gut microbes, immune response and gene expression fed plant protein diet

The synergistic effects of probiotic (Bacillus pumilus) and/or exogenous enzyme (protease) on growth, immunity, serum parameters, gene expression and gut bacteria of Nile tilapia (3.62 ± 0.06 g) were investigated. Plant protein-based diets were formulated as the control diet, probiotic (pro, 1.85 × 105 B. pumilus CFU kg−1), protease enzyme (enzy, 0.5 g protease kg −1), and their mixture of 1.85 × 105 B. pumilus CFU kg−1 + 0.5 g protease kg −1 (pro-enzy), respectively. After 84 days, the results revealed that fish fed pro-enzy diet resulted in better (P