A BIVALENT INACTIVATED VACCINE OF VIRAL NERVOUS NECROSIS VIRUS AND GROUPER IRIDOVIRUS APPLIED TO GROUPER BROODFISH (EPINEPHELUS COIOIDES) REDUCES THE RISK OF VERTICAL TRANSMISSION

Forty-one broodfish of orange-spotted groupers (Epinephelus coioides) were selected to evaluate the effectiveness of a viral nervous necrosis virus (VNNV) and grouper iridovirus (GIV) inactivated bivalent vaccine in grouper broodfish. Real-time quantitative PCR analysis showed that a detection rate of 10.5% (2/19) was found in egg specimens of VNNV and GIV, which carried approximately 1780 copies of GIV viral DNA in the egg specimens from broodfish before vaccination. This confirmed the vertical transmission route of GIV in broodfish. A significant increase of the anti-VNNV serum antibody titer was more than 50% in the high titer level (1:1810 to 1:5120) and 45% in the moderate titer level (1:452 to 1:1280), which were higher than those of the anti-GIV display, with 50% (10/20) in a titer of 1:57 to 1:320 and 40% (8/20) in a titer of 1:452 to 1:1280 one month after the vaccination. This result showed that the VNNV is a highly antigenic virus and can effectively induce neutralizing antibodies better than G...