ARS | Publication request: Efficacy of Streptococcus Agalactiae (Group B) Vaccine in Tilapia (Oreochromis Niloticus) by Intraperitoneal and Bath Immersion Administration

Submitted to: Vaccine
Publication Acceptance Date: March 1, 2004
Publication Date: August 23, 2004
Citation: Evans, J.J., Klesius, P.H., Shoemaker, C.A. 2004. Efficacy Of Streptococcus Agalactiae (Group B) Vaccine In Tilapia (Oreochromis Niloticus) By Intraperitoneal And Bath Immersion Administration. Vaccine. Vol 22 (27-28). P. 3769-3773.

Interpretive Summary: We evaluated the effectiveness of Streptococcus agalactiae vaccine in tilapia (Oreochromis niloticus), for prevention of streptococcal disease. Intraperitoneal (IP) and bath immersion (BI) vaccine trials were conducted at two temperatures, 32'C and 26'C, and mean fish weights, 5 and 30 g. Control tilapia were injected with tryptic soy broth. Thirty gram tilapia vaccinated and challenged by IP injection with S. agalactiae at 30 days post immunization had a relative percent survival (RPS) of 80. Smaller tilapia vaccinated and challenged under similar conditions had an RPS of 25. An RPS of 0 was noted in 30 g fish IP vaccinated with S. iniae and IP challenged with S. agalactiae. Five and 30 g tilapia bath immunized and IP challenged with S. agalactiae had RPS values of 34. Intraperitoneal administration of the vaccine provided efficacious protection only in the 30 g tilapia regardless of whether the fish were immunized and challenged at 26 or 32'C. Bath immunization of both five and 30 g tilapia resulted in RPS values that were two times lower than those achieved with IP vaccination. The results of this study indicated that protection against S agalactiae infection is only provided through vaccination with an S. agalactiae vaccine and not by an S. iniae vaccine. The results of the present study indicate that the S. agalactiae vaccine preparation yields excellent efficacy against S agalactiae infection by IP injection in 30 g tilapia. Bath immersion of this vaccine preparation in either 5 or 30 g fish provided a degree of protection that may be satisfactory in nursery and production systems where the fingerling and juvenile size fish can to be vaccinated against S. agalactiae

Technical Abstract: We evaluated the effectiveness of Streptococcus agalactiae vaccine prepared from formalin-killed cells and concentrated extracellular products (greater than 2 kDa) of a single isolate of S. agalactiae (ARS KU MU 11) in tilapia (Oreochromis niloticus) for prevention of streptococcal disease. Intraperitoneal (IP) and bath immersion (BI) vaccine trials were conducted at two temperatures, 32'C and 26'C, and mean fish weights, 5 and 30 g. Control tilapia were injected with tryptic soy broth. Thirty gram tilapia vaccinated and challenged by IP injection with 1.5 ' 104 colony-forming units (CFU)/fish of S. agalactiae at 30 days post-immunization had a relative percent survival (RPS) of 80. Smaller tilapia vaccinated and challenged under similar conditions had an RPS of 25. An RPS of 0 was noted in 30 g fish IP vaccinated with S. iniae and IP challenged with S. agalactiae. Five and 30 g tilapia bath immunized with S. agalactiae and IP challenged with 3.6 ' 105 and 1.7 ' 106 CFU/fish of S. agalactiae had RPS values of 34. Intraperitoneal administration of the vaccine provided efficacious protection only in the 30 g tilapia regardless of whether the fish were immunized and challenged at 26 or 32'C. Bath immunization of both 5 and 30 g tilapia resulted in RPS values that were two times lower than those achieved with IP vaccination. The results of this study indicate that protection against S agalactiae infection is only provided through vaccination with a S. agalactiae vaccine and not by an S. iniae vaccine.