52
of 1.0 × 10
8 CFU/fi sh via injection, immersion or orally with challenge after 15-days,
the RPS values obtained were 96.88, 67.22, and 71.81 %, respectively. Challenge
after 30-days led to a reduction in protection with corresponding RPS values of
93.61, 60.56, and 53.16 %, respectively. Vaccination with less vaccine (1 × 10
6 and
1 × 10
7 CFU/fi sh) led to inferior protection. The antibody levels peaked at 14–21 days
after vaccination, but decreased signifi cantly after 28 days. The bacteria were recovered from the brain, liver, kidney, and spleen of fi sh after oral vaccination, and persisted in the spleen for up to 15 days (Li et al. 2015 ).
Two surface proteins, i.e. phosphoglycerate kinase and ornithine carbamoyltransferase were over-expressed in Esch. coli , purifi ed and used as subunit vaccines
and as components in whole cell vaccines in tilapia. The results revealed the the
compound vaccine with purifi ed protein – particularly phosphoglycerate kinase -
led gave superior survival after challenge (Wang et al. 2014b ). In a further development, surface immunogenic protein of Str. agalactiae was expressed in Esch. coli,
and the purifi ed recombinant protein was administered to Nile tilapia before challenge in which the RPS was 90.62 % (Wang et al. 2014b ). Two genes encoding cell
surface proteins, i.e. fi brinogen-binding protein A and α-enolase were expressed in
Esch. coli, and the purifi ed recombinant proteins examined as potential subunit vaccines to protect Nile tilapia leading to RPS values of 40.63 +/− 17.21 % and 62.50
+/− 18.75 %, respectively. In comparison, an inactivated whole cell vaccine led to
an RPS of 93.75 +/− 5.41 % (Yi et al. 2014 ). An inactivated recombinant vaccine
expressing the cell wall surface anchor family protein was administered orally with
an equivalent dose of 10
6 CFU/ml to tilapia leading to an RPS of 70 % after challenge (Nur-Nazifah et al. 2014 ).
A recombinant plasmid pVAX1-sip, which contained a 1.02 kb DNA fragment
encoding for a portion of the surface immunogenic protein (Sip) was inserted into
an attenuated Salmonella enteritidis serovar Typhimurium and as a DNA vaccine
used orally at 10
8 CFU/fi sh to vaccinate tilapia. The Salmonella localized in the
digestive tract, liver and spleen for up to 4-weeks without harmful effects, and protected against lethal challenge (Huang et al. 2014a )
Immunostimulants/Dietary Supplements
Rosemary Leaves Feeding dried rosemary leaves to tilapia led to reduced mortalities following challenge (Zilberg et al. 2010 ).
Saccharomyces cerevisiae Saccharomyces cerevisiae cell wall with or without
intraperitoneal vaccination [0.5 ml of a vaccine containing 10
8 CFU/ml] on day 60
and challenge 15 days later. All the fi sh receiving the dietary supplement survived,
whereas 28.5 % of those that were not fed with yeast cell wall died compared to
38.09 % mortality among the controls. The mode of action refl ected stimulation of
innate and cellular immunity, specifi cally related to lymphocyte, macrophage and
thrombocyte activity (Salvador et al. 2012 ).
2 Gram-Positive Bacteria (Anaerobes and ‘Lactic Acid’ Bacteria)
of 1.0 × 10
8 CFU/fi sh via injection, immersion or orally with challenge after 15-days,
the RPS values obtained were 96.88, 67.22, and 71.81 %, respectively. Challenge
after 30-days led to a reduction in protection with corresponding RPS values of
93.61, 60.56, and 53.16 %, respectively. Vaccination with less vaccine (1 × 10
6 and
1 × 10
7 CFU/fi sh) led to inferior protection. The antibody levels peaked at 14–21 days
after vaccination, but decreased signifi cantly after 28 days. The bacteria were recovered from the brain, liver, kidney, and spleen of fi sh after oral vaccination, and persisted in the spleen for up to 15 days (Li et al. 2015 ).
Two surface proteins, i.e. phosphoglycerate kinase and ornithine carbamoyltransferase were over-expressed in Esch. coli , purifi ed and used as subunit vaccines
and as components in whole cell vaccines in tilapia. The results revealed the the
compound vaccine with purifi ed protein – particularly phosphoglycerate kinase -
led gave superior survival after challenge (Wang et al. 2014b ). In a further development, surface immunogenic protein of Str. agalactiae was expressed in Esch. coli,
and the purifi ed recombinant protein was administered to Nile tilapia before challenge in which the RPS was 90.62 % (Wang et al. 2014b ). Two genes encoding cell
surface proteins, i.e. fi brinogen-binding protein A and α-enolase were expressed in
Esch. coli, and the purifi ed recombinant proteins examined as potential subunit vaccines to protect Nile tilapia leading to RPS values of 40.63 +/− 17.21 % and 62.50
+/− 18.75 %, respectively. In comparison, an inactivated whole cell vaccine led to
an RPS of 93.75 +/− 5.41 % (Yi et al. 2014 ). An inactivated recombinant vaccine
expressing the cell wall surface anchor family protein was administered orally with
an equivalent dose of 10
6 CFU/ml to tilapia leading to an RPS of 70 % after challenge (Nur-Nazifah et al. 2014 ).
A recombinant plasmid pVAX1-sip, which contained a 1.02 kb DNA fragment
encoding for a portion of the surface immunogenic protein (Sip) was inserted into
an attenuated Salmonella enteritidis serovar Typhimurium and as a DNA vaccine
used orally at 10
8 CFU/fi sh to vaccinate tilapia. The Salmonella localized in the
digestive tract, liver and spleen for up to 4-weeks without harmful effects, and protected against lethal challenge (Huang et al. 2014a )
Immunostimulants/Dietary Supplements
Rosemary Leaves Feeding dried rosemary leaves to tilapia led to reduced mortalities following challenge (Zilberg et al. 2010 ).
Saccharomyces cerevisiae Saccharomyces cerevisiae cell wall with or without
intraperitoneal vaccination [0.5 ml of a vaccine containing 10
8 CFU/ml] on day 60
and challenge 15 days later. All the fi sh receiving the dietary supplement survived,
whereas 28.5 % of those that were not fed with yeast cell wall died compared to
38.09 % mortality among the controls. The mode of action refl ected stimulation of
innate and cellular immunity, specifi cally related to lymphocyte, macrophage and
thrombocyte activity (Salvador et al. 2012 ).
2 Gram-Positive Bacteria (Anaerobes and ‘Lactic Acid’ Bacteria)