Feed-based vaccination regime against streptococcosis in red tilapia, Oreochromis niloticus x Oreochromis mossambicus

Abstract

BackgroundStreptococcosis is an important disease of tilapia throughout the world. In Malaysia, streptococcosis outbreak was commonly reported during the 3-month period of high water temperature between April and July. This study describes the duration of protection following single and double booster dose regimes against streptococcosis in tilapia using a feed-based vaccine containing formalin-killed Streptococcus agalactiae. A total of 510 tilapias of 120 ± 10 g were selected and divided into 3 groups. Fish of Group 1 were vaccinated at weeks 0 and 2 (single booster group) while fish of Group 2 were vaccinated at weeks 0, 2 and 6 (double booster group) with a feed-based vaccine against streptococcosis. Fish of Group 3 was not vaccinated. Serum samples were collected weekly to determine the antibody level while samples of eye, brain and kidney were collected for bacterial isolation. At week 10, all fish were challenged with live S. agalactiae and the survival rate was determined.ResultsBoth vaccinated groups showed significant (p < 0.05) increase in the antibody levels following the first booster dose, which lasted until week 6. Group 2 showed consistent high level of antibody following the second booster dose at week 6 and remained high until week 12. Challenge trial at week 10 resulted in 45 %, 70 % and 0 % rate of survival for Groups 1, 2 and 3, respectively.ConclusionDouble booster regime is most suitable to be applied for feed-based vaccination against streptococcosis prior to the start of the hot season.

Secondary immune response of rainbow trout following repeated immersion vaccination

“…Only few descriptions of classical secondary immune responses in fish are available, but repeated injection vaccination of carp using sheep red blood cells (1‐month interval) was found to induce a secondary immune response with highly increased production of antibody producing cells (Rijkers et al., ). Other studies have indicated that repeated immunizations of tilapia with oral vaccines may lead to increased immune responses, which on the other hand are additive and not exponential (Huang et al., ; Ismail et al., ; Nur‐Nazifah, Sabri, & Siti‐Zahrah, ). With regard to rainbow trout immunized by repeated immersion vaccination, a procedure which increases and prolongs protection (Chettri et al., , ), knowledge on mechanisms behind the protection is limited.…”

Immunization Strategies against Piscirickettsia salmonis Infections: Review of Vaccination Approaches and Modalities and Their Associated Immune Response Profiles

“…Underpinning these observations is a recent study on prime-boost vaccination against infectious salmon anemia virus where the same response pattern was observed (34). Further, the effect of repeated oral boost has recently been shown for feed-based vaccination of red tilapia ( Oreochromis niloticus x Oreochromis mossambicus ) against streptococcosis (59). In the referred studies, no attempts were made to measure IgT on mucosal surfaces, but in the study by Chen et al (60) transcript levels of IgT in the gut mucosa was measured and increased mRNA expression levels were found.…”

Differential PCR detection of Streptococcus agalactiae and Streptococcus iniae in tilapia (Oreochromis niloticus) by a single primer pair

“…S. agalactiae and S. iniae were recently discovered as the two most frequently detected pathogenic bacteria that trigger streptococcosis with similar clinical signs in the infected tilapia. Considering that the control strategies and zoonotic risk are different between the two species, effective methods to detect and distinguish between S. agalactiae and S. iniae are important for proper treatment of streptococcosis in aquaculture‐derived samples (Anshary, Kurniawan, Sriwulan, Ramli, & Baxa, ; Evans, Klesius, & Shoemaker, ; Ismail et al, ; Rodkhum, Kayansamruaj, & Pirarat, ).…”

“…For example, the single PCR and ELISA assays have been applied to rapidly detect S. iniae, and the LAMP assay was applied for S. agalactiae identification (Ke, Huo, & Lu, 2014;Shelby, Shoemaker, Evans, & Klesius, 2001;Zhou, Fan, Zhu, Xie, & Li, 2011). Considering that S. agalactiae and S. iniae usually present in the same geographic area (Featherstone, 2014), duplex or multiplex PCR was developed to simultaneously and unambiguously detect S. agalactiae or S. iniae in tilapia (Itsaro, Suanyuk, & Tantikitti, 2012;Rodkhum et al, 2012).…”