Probiotic Bacterium and Microalga Interaction on Rearing Kumamoto Oyster Crassostrea sikamea Spat

This study assessed in vitro interaction between Bacillus bacteria and microalgae and their posterior in vivo effect on rearing Kumamoto oyster Crassostrea sikamea . The probiotic strains Bacillus licheniformis (MAt32), B. subtilis (MAt43) and B. subtilis (GAtB1) were individually inoculated in triplicate into 250 mL flasks containing 1 × 10 4 colony forming units (CFU) mL −1 of bacteria and 4.5 × 10 4 cell mL −1 of microalgae ( Isochrysis galbana or Chaetoceros calcitrans ) to evaluate their growth during a 7-day culture. Single cultures of microalgae or bacilli served as control. Additionally, C. sikamea spat was treated for 28 days with four single/combined bacillus treatments in triplicate at a concentration of 1 × 10 6 CFU mL −1 as follows: (a) control, without treatments; (b) combination of two antibiotics (10 mg L −1 ); (c) B. licheniformis ; (d) B. subtilis ; (e) B. subtilis subtilis and (f) mixed bacilli. The results showed a significantly ( P 0.05) compared with the control group. C. sikamea spat treated with Bacillus showed significantly ( P