IMMUNE RESPONS OF JUVENILES TIGER GROUPER Epinephelus fuscoguttatus TO POLIVALENT VACCINE ADMINISTERED THROUGH IMMERSION

Tiger grouper is one of export commodities in fisheries of Indonesia. This species have been widely cultured in coastal region of Indonesia with a relatively high market value. However, infectious disease is becoming severe with expanding culture, and abuse of effective antibiotics has caused adverse problems. Vaccination was thus considered to be an essential and effective way to control fish diseases. The present study was conducted to evaluate the effectiveness of polivalent vaccine to improve immunity of juvenile tiger grouper against disease in floating net cages. The vaccine was delivered via immersion.

Tiger grouper (Epinephelus fuscoguttatus) juveniles with Total Length ± 7 cm were vaccinated by bathing of fish in vaccines solution for 1 hour. The fish then were reared in concrete tanks equipped with filter and aeration systems in Pathology Laboratory of Institute for Mariculture Research and Development, Gondol, Bali. When they reached 9-10 cm TL, the fish then were stocked in floating net cages located at Pegametan Bay, North Bali. Titer antibody values and survival were recorded for 2 months trial.

Results showed that titer antibody values of vaccinated fish increased significantly during rearing period. The highest titer antibody value showed by the fish vaccinated with polivalent bacterial vaccine and grouper sleepy disease iridovirus (GSDIV) vaccine followed by fish vaccinated with combination of polivalent bacterial vaccine with GSDIV vaccine. In the control fish, titer antibody value was lowest (Table 1). The highest survival rate showed by fish vaccinated with combination of polivalent bacterial vaccine with GSDIV vaccine followed by fish vaccinated with GSDIV vaccine, fish vaccinated with GSDIV vaccine, and fish vaccinated with polivalent bacterial vaccine. The Relative Percentage Survival (RPS) of fish received vaccines ranged from 19 % - 50 % (Table 2). It is suggested that vaccines are effective to increase immunity of tiger grouper fish.