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Motile Aeromonad Septicemia (MAS) is caused by Aeromonas hydrophila and often attacks juvenile catfish. Probiotics could be an alternative to prevent MAS disease. This study aims to determine the dose of probiotics to improve the survival, growth performance, and immune response of juvenile catfish Pangasianodon hypophthalmus to the A. hydrophila infection. This probiotic was contained in Artemia sp. and artificial feed enriched with Bacillus sp. NP5 at concentrations of 106 CFU.mL-1, 107 CFU.mL-1, 108 CFU.mL-1, and the control. Larvae with an average weight of 1.52 ± 0.06 mg and an average length of 0.46 ± 0.007 cm were reared for 28 days in aquariums filled with 10 L of water and a stocking density of 15 individuals.L-1. After the rearing period, the fish was challenged by the immersion of A. hydrophila with a concentration of 107 CFU.mL-1. This study has revealed that probiotics could increase the fish’s survival, length growth, daily growth rate, and feed conversion ratio. The total bacterial count in larvae and probiotics in juvenile fish is higher than those in the control. After the fish had been challenged with the probiotics at a concentration of 108 CFU.mL-1, they had a better survival rate and immune responses (including leukocyte differential, phagocytosis activity, and respiratory burst activity) than the positive control. Probiotic Bacillus sp. NP5 is effectively administered through bioencapsulated Artemia sp. and commercial feed. |
