Antagonism Pseudomonas diminuta on The Growth of Vibrio harveyi with Mix Culture Method

One of the obstacles often encountered in white shrimp farming is the presence of bacterial diseases caused by Vibrio group bacteria. One of the efforts to control Vibriosis is by using antagonistic bacteria as biocontrol agents, one of which is using Pseudomonas diminuta. In this study Pseudomonas diminuta and Vibrio harveyi were co-cultured with the aim of determining the optimal density and effective incubation time of P. diminuta which could provide the highest inhibition of V. harveyi growth. This study used a completely randomized design with six treatments P0 (P. diminuta 10⁵ CFU/ml), P1 (V. harveyi 10⁶ CFU/ml), P2 (P. diminuta 10⁵ CFU/ml+V. harveyi 10⁶ CFU/ml), P3 (P. diminuta 10⁶ CFU/ml+V. harveyi 10⁶ CFU/ml), P4 (P. diminuta 10⁷ CFU/ml+V. harveyi 10⁶ CFU/ml), P5 (P. diminuta 10⁸ CFU/ml+V. harveyi 10⁶ CFU/ml). The results of this study showed that P2, P3, P4 and P5 had decreased growth of V. harveyi when compared to control P1 (V.harveyi 10⁶  CFU/ml). The decrease in the growth of V. harveyi occurred at the 8^th to 48^th  hour. V. harveyi in P3 (2.72 í— 10⁸ CFU/ml), P2 (2.80 í— 10⁸ CFU/ml), P4 (2.96 í— 10⁸ CFU/ml) and P5 (2.90 í— 10⁸ CFU/ml) at the 48^th hour of incubation was lower than P1 (3, 15í—10⁸ CFU/ml). Based on the results of the Duncan test showed that P2, P3, P4 and P5 were significantly different (p <0.05) from P1. From this study it was concluded that administration of P. diminuta at a density of 10⁶ CFU/ml was able to reduce the growth of V. harveyi. The greatest decrease in the growth of V. harveyi occurred at the 48^th hour.