THE APPLICATION OF NITRIFYING BACTERIA ON DIFFERENT SUBSTRATE AND ITS EFFECT TO Vibrio harveyi FOR WHITE SHRIMP POSTLARVAE CULTURE (Litopenaeus vannamei Boone.)

• Main Author: Ria Antarini, Rd
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/34803
• Institution: Institut Teknologi Bandung

White Shrimp (Litopenaeus vannamei) is one of the commodities of fish industry in Indonesia with a high economic value. Even though white shrimp industry has increased its productivity, there are several problems related with its culture water quality and pathogenic bacteria, especially Vibrio harveyi. This research was aimed to find an optimum activity of nitrifying bacteria on different substrates, which were granular CaCO3 and powder CaCO3, and its capability to inhibit V. harveyi in white shrimp (L. vannamei) post larvae culture. This research was conducted through two consecutive steps which were (1) The optimization of nitrifying bacteria ratio, and (2) the application of nitrifying bacteria on different substrate in white shrimp (L. vannamei) post larvae culture. Two different types of nitrifying bacteria was isolated from different location. The Ammonia Oxidation Bacteria (AOB) was isolated from Batam water area and Nitrite Oxidation Bacteria (NOB) was isolated from Situbondo water area. These isolates were then used as inoculums for optimization of nitrifying bacteria ratio. Approximately 10 % (v/v) of nitrifying bacteria inoculums with 106 CFU/mL of concentration were inoculated to adaptation medium with the ratio of AOB:NOB = 1:1, 2:1, and 1:2. Ammonium was added into the culture increasingly during optimization experiment. Based on the results, the highest ammonia oxidation rate was obtained from AOB:NOB ratio = 2:1 (7,005 mg/l/day), followed by AOB:NOB ratio = 1:1 (5,630 mg/l/day) and AOB:NOB ratio = 1:2 (5,048 mg/l/day). The highest nitrite oxidation rate was obtained from AOB:NOB ratio = 1:2 (3,035 mg/l/day), followed by AOB:NOB ratio = 1:1 (0,7757 mg/l/day) and AOB:NOB ratio = 2:1 (0,7586 mg/l/day). Based on the results, the AOB:NOB ratio = 2:1 was the most effective ratio for nitrification process and will be used for the next step. The second step was aimed to find the best substrate that can support an optimum activity of nitrifying bacteria and its capability to inhibit Vibrio harveyi. Approximately 0.1% (v/v) of Vibrio harveyi inoculums with 106 CFU/mL of concentration were inoculated into white shrimp culture. There were 4 different treatment, besides control and control V. harveyi, which were white shrimp postlarvae culture with powder CaCO3 substrate as nitrifying bacteria substrate (treatment 1); white shrimp post larvae culture with V. harveyi inoculums and powder CaCO3 substrate as nitrifying bacteria substrate (treatment 2); white shrimp post larvae culture granular CaCO3 substrate as nitrifying bacteria substrate (treatment 3); and white shrimp post larvae culture with V. harveyi inoculums and granular CaCO3 substrate as nitrifying bacteria substrate (treatment 4). Based on the results, the highest survival rate was obtained in treatment 3 sebesar 82%, followed by control (75,6%); treatment 4 (60,20%); treatment 1 (59,4%); treatment 2 (54,6%); and control V. harveyi (37,8%). The highest total bacteria number was obtained in treatment 2 (9.85 x 105 CFU/ml), followed by treatment 1 (8,9 x 105 CFU/ml); control V. harveyi (7.97 x 105 CFU/ml); treatment 4 (6.37 x 105 CFU/ml); treatment 3 (5.73 x 105 CFU/ml); and control (5.14 x 105 CFU/ml). The lowest V. harveyi number was obtained in treatment 3 (0.054 x 106 CFU/ml), followed by treatment 1 (0.083 x 106 CFU/ml); treatment 4 (0.367 x 106 CFU/ml); treatment 2 (S+V) (0.467 x 106 CFU/ml); control (15.3 x 106 CFU/ml); and control V. harveyi (232 x 106 ). The lowest ammonia concentration was obtained in treatment 3 (0,064 mg/l), followed by treatment 4 (0,076 mg/l), treatment 1 (0,103 mg/l), treatment 2 (0,165 mg/l), control V. harveyi (0,0423 mg/l), dan control (0,423 mg/l). The lowest nitrite concentration was obtained in treatment 3 (0,001-0,012 mg/l); treatment 4 (0,003-0,047 mg/l); control (0,043-0,077 mg/l); dan control V. harveyi (0,034-0,083 mg/l). At the end of culture period, the highest nitrate concentration was obtained in treatment 4 (5.152 mg/l), followed by treatment 3 (4.150 mg/l), treatment 1 (2.172 mg/l), treatment 2 (2.088 mg/l), control (1.125 mg/l), and control V. harveyi (1.112 mg/l). The water physical condition of all treatment were ranged in optimum range of white shrimp and nitrifying bacteria with salinity, DO, pH, and temperature ranged from 28-29 ppt; 5,1-6,8 mg/l; 7,63-8,1; dan 24,9-26,2oC, respectively. Based on the results, it can be concluded that the application of nitrifying bacteria with AOB:NOB = 2:1 on granular CaCO3 can improve water quality of white shrimp culture and inhibit V. harveyi growth rate.