ANTIBODY RESPONSE AND PROTECTIVE CAPACITY BY             VIBRIO- VACCINE  DELIVERED THROUGH LIVE FEED IN TIGER GROUPER LARVAE

Vibriosis by Vibrio alginolyticus is one of the major cause of mortality in cultured grouper especially at their early stage of life. The mortality due to this disease can reach up to 100% and caused extensive losses to the hatchery. Administration of vaccine against vibriosis at the larval stage was considered as one of the best solutions to developed strong and specific immunity in grouper as well as to increase the survival rate. However, delivery of vaccine by injection or immersion route are nearly impossible due to the nature of the grouper larvae that are very sensitive to handling. Hence, oral delivery by bioencapsulating the formalin-killed V. Alginolyticus (later termed as Vib0cine) into rotifer and artemia was selected as the best route to vaccinate the grouper larvae. The present study was conducted to determine the antibody immune response and protective capacity provided by oral administration of bioencapsulated Vib0cine in grouper larvae at 15-DAH, 30-DAH and last booster at 60-DAH. Then, fish were challenged by immersion with virulent live V.alginolyticus four weeks after last booster. Results demonstrated that the antibody level was significantly increased (p<0.05) fifteen days after first administration and went higher after adminstration of booster doses.  Significantly (P< 0.05) higher survival rate also observed in vaccinated grouper that indicated the oral vaccination with bioencapsulated Vib0cine at early stage provided adequate protection against vibriosis in grouper.