The Efficacy of Inactivated Photobacterium damselae subsp. piscicida Combined with Levan/Alum as Vaccine against Photobacteriosis in Cobia, Rachycentron canadum

Abstract

Photobacterium damselae subsp. piscicida (Phdp) is a major pathogen of cultured cobia (Rachycentron canadum), a primary target species for offshore cage culture in Taiwan. Serum antibody titers as well as efficiency and duration of protection against Phdp were evaluated following intraperitoneal administration of a candidate vaccine prepared with formalin-inactivated whole cells in combination with levan/alum adjuvants. The results showed vaccinates delayed the disease onset and had significantly (P < 0.05) less mortality than control nonvaccinates during Days 21-105 postvaccination with highest relative percentage of survival (RPS) and antibody titer up to 81.4% and 1:614, respectively. There was a highly significant positive linear correlation between the RPS and antibody titer (R 2 = 0.841). Long-lasting and significant protection against Phdp can be achieved with inactivated Phdp plus levan/alum, a potential cobia vaccine against photobacteriosis. Levan/alum complex may represent a promising adjuvant formula for the development of a Phdp vaccine.

Immune Responses and Protective Efficacy of a Formalin-Killed Francisella Noatunensis Subsp. Orientalis Vaccine Evaluated through Intraperitoneal and Immersion Challenge Methods in Oreochromis Niloticus

“…Owing to the high virulence of this strain, it was selected as the candidate strain for combination with the oil-based adjuvant Montanide TM ISA 763 AVG for the development of the first vaccine in Taiwan. Several studies have documented that the injectable inactivated formalin-killed vaccines can induce protective antibodies against various bacterial diseases in fish [ 12 , 14 , 19 , 22 , 25 , 26 ]. The first vaccine for francisellosis was documented by Soto et al, (2011) [ 13 ], which was a live attenuated vaccine administered by the immersion method.…”