Evaluation of the effectiveness of probiotic preparations in controlling toxic gases and Vibrio spp. in the culture water of pacific white shrimp Penaeus vannamei in Binh Khanh commune

Abstract

Aquaculture water polluted by organic matter and toxic gases (NH₃, H₂S, NO₂^-, etc.) negatively affects shrimp growth, thereby reducing farming productivity. Probiotics are one of the measures used to prevent and improve water quality throughout the shrimp farming process. This study applied a probiotic preparations containing Bacillus spp. and Corynebacterium variabile strains isolated from shrimp pond sludge. The preparation was applied at a concentration of 10³ CFU/ml of culture water and tested under two conditions: a 1 m³ composite tank and a 2,000 m² earthen pond with plastic lining on the banks. During the culture period, the levels of NH₃, H₂S, and NO₂^- remained below permissible limits, thus not affecting shrimp health. After 84 days of culture in the composite tanks with a stocking density of 250 shrimp per tank, the survival rate reached 86%, the average shrimp weight was 22.22 g/individual, which was higher than the control tank without probiotics. In the lined earthen pond, PL15 shrimp were stocked at a density of 250,000 shrimp/2,000 m². Shrimp cultured in ponds treated with the preparation achieved a survival rate of 80.8%, an average weight of 32.64 g/individual, and an FCR of 1.25. In addition, the density of Vibrio spp. in both the composite tanks and lined earthen ponds remained below 10³ CFU/ml.