345
were maintained for 12 weeks [RPS = 81 %]. Furthermore, some success resulted
from oral application for 5 days [RPS = 56 %] when incorporated in alginate microspheres [dosed at 10
9 CFU/fi sh/day], with challenge 5 weeks later, but less so for
immersion vaccination at 10
8 CFU/ml for 15 h [RPS = 21 %] (Cheng et al. 2010b ).
Hu et al. ( 2011 ) continued the work by developing a recombinant product that
expressed V. harveyi DegQ as a soluble antigen that elicited signifi cant protection
against both Edw. tarda and V. harveyi in laboratory-based experiments with turbot
when administered by i.p. (RPS = 89.2 %) orally (RPS = 60.1 %) or immersion
(RPS = 42.1 %) or a combination of oral plus immersion (RPS = 66.1 % after 1 month
in a mock fi eld trial; RPS = 75 % after 2 months).
Interest in live attenuated vaccines continued with the study of Xiao et al. ( 2011 )
who used a deletion mutant of the aroC gene, which is involved in the biosynthesis
of chorismic acid. This was applied intramuscularly in 5 μl amounts [4 × 10
7 CFU/
fi sh] to zebra fi sh with RPS of 68.3–81 % resulting after challenge 5-weeks later.
A temperature-sensitive mutant was generated by replacement of the alr gene promoter, and upon use as a primary and booster vaccine in olive fl ounder gave 100 %
protection after challenge (Choi et al. 2012 ).
An auxotrophic mutant ( Δalr Δasd E. tarda ) was administered orally (10
9 CFU/
fi sh) to olive fl ounder which were completely protected against challenge (Choi
et al. 2011 ).
A pressure (600 kgf/cm
2 for 5 s using a French press) inactivated whole cell
preparation adjusted with 0.85 % (w/v) saline to contain 10
9 cells/ml administered
as 0.1 ml amount by i.p. led to an RPS of >85 % in Japanese eels, 6-months after
vaccination (Hossain and Kawai 2009 ).
Consideration has been given to the comparative effi cacy of adjuvants in injectable vaccines based on a weakly protective antigen, Et49, with research evaluating
the effects of aluminium hydroxide, aluminium phosphate and FIA in Japanese
fl ounder. Results demonstrated that the adjuvants increased the RPS by 19 %, 35 %
and 47 %, respectively (Jiao et al. 2010b ).
Pseudomonas P1SW and Vibrio V3SW were recovered from seawater and
administered live separately or together by immersion and orally (the bacteria were
embedded in sodium alginate microspheres) to turbot ( Scophthalmus maximus ) at
doses equivalent to 2 × 10
8 CFU with evidence that both organisms became distributed in the internal organs, and some protection became apparent after challenge.
Better protection was reported with both bacteria administered together (Wang et al.
2013 ). Vaccines or probiotics?
Immunostimulants/Dietary Supplements Yano et al. ( 1989 ) published data that
showed ß-1,3 glucans, when applied by i.p. injection at 2–10 mg/kg of fi sh, enhanced
resistance to infection by Edw. tarda. This effect was measured by heightened
phagocytic activity. Durve and Lovell ( 1982 ) and Misra et al. ( 2007 ) pointed to a
role for vitamin C in immunostimulation and protection against challenge with Edw.
tarda.
Incorporated into a purifi ed basal medium (Table 6.2 ), vitamin C (dosed at
150 mg/kg of food) dramatically increased the resistance of catfi sh to Edw. tarda
Edwardsiella tarda
were maintained for 12 weeks [RPS = 81 %]. Furthermore, some success resulted
from oral application for 5 days [RPS = 56 %] when incorporated in alginate microspheres [dosed at 10
9 CFU/fi sh/day], with challenge 5 weeks later, but less so for
immersion vaccination at 10
8 CFU/ml for 15 h [RPS = 21 %] (Cheng et al. 2010b ).
Hu et al. ( 2011 ) continued the work by developing a recombinant product that
expressed V. harveyi DegQ as a soluble antigen that elicited signifi cant protection
against both Edw. tarda and V. harveyi in laboratory-based experiments with turbot
when administered by i.p. (RPS = 89.2 %) orally (RPS = 60.1 %) or immersion
(RPS = 42.1 %) or a combination of oral plus immersion (RPS = 66.1 % after 1 month
in a mock fi eld trial; RPS = 75 % after 2 months).
Interest in live attenuated vaccines continued with the study of Xiao et al. ( 2011 )
who used a deletion mutant of the aroC gene, which is involved in the biosynthesis
of chorismic acid. This was applied intramuscularly in 5 μl amounts [4 × 10
7 CFU/
fi sh] to zebra fi sh with RPS of 68.3–81 % resulting after challenge 5-weeks later.
A temperature-sensitive mutant was generated by replacement of the alr gene promoter, and upon use as a primary and booster vaccine in olive fl ounder gave 100 %
protection after challenge (Choi et al. 2012 ).
An auxotrophic mutant ( Δalr Δasd E. tarda ) was administered orally (10
9 CFU/
fi sh) to olive fl ounder which were completely protected against challenge (Choi
et al. 2011 ).
A pressure (600 kgf/cm
2 for 5 s using a French press) inactivated whole cell
preparation adjusted with 0.85 % (w/v) saline to contain 10
9 cells/ml administered
as 0.1 ml amount by i.p. led to an RPS of >85 % in Japanese eels, 6-months after
vaccination (Hossain and Kawai 2009 ).
Consideration has been given to the comparative effi cacy of adjuvants in injectable vaccines based on a weakly protective antigen, Et49, with research evaluating
the effects of aluminium hydroxide, aluminium phosphate and FIA in Japanese
fl ounder. Results demonstrated that the adjuvants increased the RPS by 19 %, 35 %
and 47 %, respectively (Jiao et al. 2010b ).
Pseudomonas P1SW and Vibrio V3SW were recovered from seawater and
administered live separately or together by immersion and orally (the bacteria were
embedded in sodium alginate microspheres) to turbot ( Scophthalmus maximus ) at
doses equivalent to 2 × 10
8 CFU with evidence that both organisms became distributed in the internal organs, and some protection became apparent after challenge.
Better protection was reported with both bacteria administered together (Wang et al.
2013 ). Vaccines or probiotics?
Immunostimulants/Dietary Supplements Yano et al. ( 1989 ) published data that
showed ß-1,3 glucans, when applied by i.p. injection at 2–10 mg/kg of fi sh, enhanced
resistance to infection by Edw. tarda. This effect was measured by heightened
phagocytic activity. Durve and Lovell ( 1982 ) and Misra et al. ( 2007 ) pointed to a
role for vitamin C in immunostimulation and protection against challenge with Edw.
tarda.
Incorporated into a purifi ed basal medium (Table 6.2 ), vitamin C (dosed at
150 mg/kg of food) dramatically increased the resistance of catfi sh to Edw. tarda
Edwardsiella tarda