COMPARISON OF LABORATORY AND FIELD RESULTS FOR Streptococcus agalactiae Ib INTRAPERITONEAL VACCINATION IN NILE TILAPIA Oreochromis niloticus

The aquaculture of Nile tilapia ( Oreochromis niloticus ) is a growing  industry and that is greatly affected by disease outbreaks. Intraperitoneal (IP) vaccination remains the most cost-effective approach  to protect for  fishes  from above 20 grams onwards.  Additionally, the oral vaccinatione could increase survivability until fish are of IP vaccine size and could be used after as a booster post IP vaccination during know times of increased pathogen pressure.

In our  this study we have utilised the Tilavac Volta commercialised vaccine against  Streptococcus agalactiae Ib as our primary target antigen. The vaccine contains a specialised adjuvant designed for warm water fish species. We investigated the efficacity of the vaccine io n Nile tilapia with  using an IP injection followed by a subsequent challenge of the targeted pathogen with S. agalactiaeea Ib in the laboratory. A second study with a second,  two-year investigation, was conducted io n the field for two years atinwithin a   a  commercial Nile tilapia farm suffering from S. agalactiae Ib outbreaks . The results indicated a relative percentage survival (RPS) of 89.8 % and 66.8 % in the laboratory and field results respectively. The study indicated a significant advantage ofimprovement of survival with theafter use of the vaccine against  S. agalactiae Ib within both in both thethe laboratory and production cyclefarm settings of Nile tilapia within the field .

An intraperitoneal vaccine dose of 0.1 ml was administered in experimental and commercial animals . All  fish were allowed 600-degree days post  vaccination in order to develop protection before the laboratory challenge and field data gathering.  

In the laboratory, the effect of the Tilavac Volta  vaccine  was evaluated  using an in vivo challenge. In this study we illustrate the efficacy A total of four vaccine batches. were tested for efficacy with Aa significant difference in survivability (P<0.01**, nn=20)105)  with all batches achieving an RPS above  average of 891.83 % compared to an un-vaccinate control treatment was obtained (Table 1).

The  field results were extracted from afrom 422 cages located at the production site with t total number of 254 vaccinated cages (n=189) against 201  control cages (n=233).  within the production site. A significant difference in survirivability (P<0.01***, n=455)  was observed with an RPS of 66.8% compared to the un-vaccinated cages (Table 2) .  

The study demonstrated the application of this commercial vaccine against  S. agalactiae Ib with t he RPS  results  indicating  its effectiveness against  laboratory controlled ,  and in the field, pathogen pressure.The application of Tilavac Volta against S. agalactiae Ib proves its effectiveness against the pathogen with under laboratory and commercial conditions.

The study demonstrated the application of this commercial vaccine against S. agalactiae Ib with the RPS results indicating its effectiveness against laboratory controlled, and in the field, pathogen pressure.