Efficacy of bivalent vaccine against black body syndrome (BBS) of barramundi Lates calcalifer B.

Abstract

ABSTRACT Black body syndrome causes mass mortality in barramundi (Lates calcarifer) in Asia mariculture. This study aimed to evaluate the efficacy of bivalent vaccine derived from local isolate for black body syndrome (BBS) prevention on the Barramundi. The bacteria used in the bivalent vaccine were Pseudomonas stutzeri and Vibrio harveyi in a ratio of 50:50. Barramundi, 5‒6 cm in length, was intraperitoneally injected with bivalent vaccine and phosphate buffer saline (PBS). After a 21-day vaccination, fish was injected with pathogenic bacteria P. stutzeri, V. harveyi, the combination of P. stutzeri and V. harveyi with a dose of bacteria 107 CFU/fish. We observed relative percent survival (RPS), mortality, blood profile, antibody level, lysozyme activity, and histopathology of vaccinated fish. The result showed that vaccinated fish had higher antibody levels and lysozyme activity than control treatment (P>0.05). Vaccinated fish had RPS of 80.00%, 64.29%, 57.69%, after challenged test with P. stutzeri, V. harveyi, and combination of P. stutzeri and V. harveyi, respectively. Hemoglobin and hematocrit were not significantly different (P>0.05). However, the erythrocytes, leucocytes, and phagocytic activity were higher compared to there were higher erythrocytes, leucocytes, and phagocytic activity compared to control (P0.05). Titer antibodi dan aktifitas lisosim ikan yang divaksin lebih tinggi dari kontrol (P<0.05). Vaksin bivalen P. stutzeri dan V. harveyi dapat melindungi benih ikan kakap putih dari infeksi BBS. Kata kunci : Lates calcalifer, vaksin bivalen, Pseudomonas stutzeri, Vibrio harveyi