The hematological response of cantang hybrid grouper (Epinephelus fuscoguttatus x epinephelus lanceolatus) injected with extracellular product, intracellular component and whole cell vaccine of vibrio alginolyticus

Vibriosis is a bacterium disease that is often found in grouper cultivation from the eggs, larvae, seeds, and broodstocks. One of the alternatives to overcome fish infection is vaccine administration. A material can be used as a vaccine if it has an immunogenic substance. Several vaccines are used in fish culture such as whole cell vaccine (WCV), extracellular products (ECP), intracellular components (ICC). The aim of this study was to determine the effectiveness of WCV, ECP, and ICC of Vibrio alginolyticus and to compare the various vaccines which had the best influence on the hematological response of the hybrid grouper (Epinephelus fuscoguttatus × Epinephelus lanceolatus). This study was conducted by design of Complete Randomized Design (CRD) with four treatments, i.e. treatment A (i.p injection with 0.1 mL phosphate buffer saline per fish as a control), B (i.p injection with 0.1 mL whole cell vaccine per fish), C (i.p injection with 0.1 mL extracellular products per fish) and D (i.p injection with 0.1 mL intracellular components per fish), each treatment repeated three times. A second vaccination (booster) was carried out a week after the first vaccination. Blood collection was carried out four times during the study on day 7, 14, 21 and 28 after the first vaccination. The results showed that WCV, ECP, ICC of V. alginolyticus produced total leukocytes/WBC (33.83±0.96 x 10³ µL^-1, 35.17±2.19 x 10³ µL^-1 and 27.33±1.37 x 10³ µL^-1 respectively) lower compared to the control fish (41.60±6.25 x 10³ µL^-1) on the 28^th day. Group D also showed total erythrocytes/RBC (1.46±0.27 x 10⁶ µL^-1), hematocrit (20.13±0.40%), thrombocytes/PLT (248.33±12.34 x 10³ µL^-1) and blood glucose levels (39.00±9.85 mg dL^-1) better than treatments B, C, and A two weeks after the challenge test. Treatment D provides 80% of the highest survival rate two weeks post-challenge.