Aplikasi probiotik Bacillus untuk pencegahan infeksi Aeromonas hydrophilla pada ikan lele Application of Bacillus probiotic to prevent Aeromonas hydrophilla infection in Clarias sp.

The aim of this study was to test the effectiveness of a probiotic Bacillus for the prevention of motile aeromonad septicemia (MAS) disease caused by Aeromonas hydrophila in African catfish ( Clarias gariepinus). The study consisted of the inhibition testing of A. hydrophila by Bacillus (in vitro) and the application of probiotic in African catfish ( in vivo). The in vivo test, consisted of five treatments such as the addition of probiotic Bacillus P4I1 Rif R , Bacillus P4I2 Rif R , Bacillus P4I1 Rif R + Bacillus P4I2 Rif R (Kom), positive control (K+; only added with A. hydrophila) and negative control (K-; without probiotic nor A. hydrophila addition). African catfish (13.35±2.80 g) was maintained in 15 aquariums (40 L in volume) with 30 fishes each for 30 days. Probiotic bacteria was applied in water once a day, whereas pathogenic bacteria A. hydrophila Rif R (10 3 cfu/mL) were added once in earlier treatment (except for the negative control). The result showed that the optimal concentration of Bacillus to inhibit A. hydrophila on in vitro test was 10 4 cfu/mL. In vivo test showed that the addition of probiotic in media of cultivation could reduce the number of A. hydrophila, improve immune response, and also increase the survival of African catfish compared to positive control. Application of probiotic P4I1 Rif R showed the highest survival (92.23%) of all treatments.