The Effect of Adding Bacillus NP5 to Feed on Growth, Survival Rate, and Protection Against Aeromonas hydrophila of Catfish (Clarias sp.)

Abstract

Probiotics are useful organisms in preventing the spread of disease in aquaculture. Therefore this study aims to evaluate the effect of administering Bacillus NP5 on the growth, survival rate, and histology of catfish with Aeromonas hydrophila infection. To achieve this, catfish (7.75 ± 0.02 g) were reared for 45 days with a density of 20 per tank. Furthermore, the study consisted of 4 treatments and 3 replications, namely K+: 0% Bacillus NP5+0.1 mL A. hydrophila injection, K-: 0% Bacillus NP5 + without A. hydrophila injection, A: 0.3% Bacillus NP5, and B: 0.8% Bacillus NP5. The results showed that the addition of probiotics significantly increased the growth and survival rate of catfish (P <0.05) compared to K+. The higher value of specific growth rate was found in treatments A and B (0.22 ± 0.03 and 0.23 ± 0.03% day-1, respectively) and the lowest in K+ (0.14 ± 0.03% day-1). Also, the tissue damage in K+ was higher than in the probiotic treatment. Besides, hyperplasia, congestion, and secondary lamella fusion in the gill tissue were found in the K+, while other treatments were found only in hyperplasia. Melanomacrophages occurred in catfish kidney tissue for all treatments, however, hydropic degeneration was found in the control treatment. The addition of Bacillus NP5 in feed resulted in higher growth, survival, and tissue damage compared to K+. Also, the addition of 0.8% Bacillus NP5 resulted in less catfish tissue damage.