The effects of ozone and probiotics on the survival of black tiger shrimp (Penaeus monodon)

Total ozone production (TOP) from an ozonator, residual ozone concentration (ROC) in water, and the effects of ozone with or without probiotic supplemented feeds on bacterial growth, and shrimp (Penaeus monodon) survival were investigated. Minimal effective ROC to inhibit 3 log units of Vibrio harveyi D331 for 6 h and 2 log units of Bacillus S11 for 9 h was 0.38 g O₃/l of ROC from 5-min ozonation. Shrimp postlarvae exposed to 0.34–0.50 mg O₃/l ROC (8-h ozonation) caused loss of balance, immobility and destruction of gill lamellar epithelium. In vivo treatment of juvenile P. monodon reared on probiotic feed for 1 month revealed that 0.35 mg O₃/l ROC (30-min ozonation) effectively inhibited 3 log units of V. harveyi D331 for 24 h. At this ROC dosage, there was no effect either on shrimp or on intestinal probiotics (Bacillus S11). Shrimp survival from probiotic treatment, coupling with ozonation, increased significantly (P≤0.05) compared with controls.