INACTIVE VACCINE FOR HEMORRHAGE OF GRASS CARP:COMPARISON OF IMMUNOGENICITY AND IMMUNIZING DOSE BETWEEN TWO STRAINS

Vaccine FR-854 and FR-836-w have high immungenicity and theirPRP (percentage relative protection) are both more than 70%. However, it ispreliminarily demonstrated that strain FR-854 has much higher immunogenicitythan strain FR-836-w by means of measuring the PRP and ANT (antiserum neu-tralization titre) of vaccinated grass carp with them. It hes been obtained that PRPand ANT are 88.9±12.0(6)% and 160.5±58.9 (6) respectively for FR-854, while 71.3±14.2(6)% and 88.3±26.2 (6) for FR-836-w. Also, the effective immunizingdoses to 1⁺or 0⁺ grass carp, 3-5×10^(4.5)TCID₍₅₀₎/fish for FR-854 and 3-5×10^(7.5)TCID⁽⁵⁰⁾/fish for FR-836-w, are all determined. The results show that immunopro-phylaris to the hemorrhage of grass carp with this inactive vaccine is in prospect.