Dietary administration of the probiotic, Bacillus subtilis E20, enhances the growth, innate immune responses, and disease resistance of the grouper, Epinephelus coioides

► Bacillus subtilis promoted feed efficiency and growth rate of Epinephelus coioides. ► B. subtilis-supplemented diets enhanced immune responses of E. coioides. ► B. subtilis-supplemented diets increased the resistance against pathogens. ► B. subtilis at 108 cfu g diet−1 for at least 28 days of feeding is an optimal regime.