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

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ABSTRACT

Background: Streptococcosis 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.

Results: Both 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.

Conclusion: Double booster regime is most suitable to be applied for feed-based vaccination against streptococcosis prior to the start of the hot season.

No MeSH data available.


Serum antibody (IgM) response following oral vaccination with a feed-based vaccine. Double booster at weeks 2 and 6 prolonged the high antibody levels for up to 12 weeks compared to the single booster at week 2 that lasted 6 weeks
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Fig1: Serum antibody (IgM) response following oral vaccination with a feed-based vaccine. Double booster at weeks 2 and 6 prolonged the high antibody levels for up to 12 weeks compared to the single booster at week 2 that lasted 6 weeks

Mentions: The serum IgM antibody levels of all groups prior to vaccination showed insignificant (p > 0.05) differences. Following vaccination, both vaccinated groups showed significantly (p < 0.05) higher IgM levels compared to the control group. Following the first booster dose at week 2, the increasing pattern continued for both vaccinated groups and reached peak at week 3. The level, however, started to decrease insignificantly (p > 0.05) in the following week but significantly (p < 0.05) thereafter to reach the non-protective cut-off value (p > 0.05) at weeks 5 and 6 (Fig. 1). In the first 6 weeks post-vaccination, both vaccinated groups showed insignificantly (p > 0.05) high IgM value. However, following second booster in week 6, the antibody level significantly (p < 0.05) increased again to reach peak at week 8 before declining thereafter until week 12 (Fig. 1). The vaccinated group that received a single booster showed gradual decline in IgM levels to reach the same level (p > 0.05) as the cut-off value by week 7 and below the cut-off value thereafter until the end of the experimental period. At time of challenge in week 10, the IgM level of the double booster group was significantly (p < 0.05) higher while the single booster and control groups were significantly (p < 0.05) lower than the protective cut-off value (Fig. 1).Fig. 1


Feed-based vaccination regime against streptococcosis in red tilapia, Oreochromis niloticus x Oreochromis mossambicus
Serum antibody (IgM) response following oral vaccination with a feed-based vaccine. Double booster at weeks 2 and 6 prolonged the high antibody levels for up to 12 weeks compared to the single booster at week 2 that lasted 6 weeks
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5016990&req=5

Fig1: Serum antibody (IgM) response following oral vaccination with a feed-based vaccine. Double booster at weeks 2 and 6 prolonged the high antibody levels for up to 12 weeks compared to the single booster at week 2 that lasted 6 weeks
Mentions: The serum IgM antibody levels of all groups prior to vaccination showed insignificant (p > 0.05) differences. Following vaccination, both vaccinated groups showed significantly (p < 0.05) higher IgM levels compared to the control group. Following the first booster dose at week 2, the increasing pattern continued for both vaccinated groups and reached peak at week 3. The level, however, started to decrease insignificantly (p > 0.05) in the following week but significantly (p < 0.05) thereafter to reach the non-protective cut-off value (p > 0.05) at weeks 5 and 6 (Fig. 1). In the first 6 weeks post-vaccination, both vaccinated groups showed insignificantly (p > 0.05) high IgM value. However, following second booster in week 6, the antibody level significantly (p < 0.05) increased again to reach peak at week 8 before declining thereafter until week 12 (Fig. 1). The vaccinated group that received a single booster showed gradual decline in IgM levels to reach the same level (p > 0.05) as the cut-off value by week 7 and below the cut-off value thereafter until the end of the experimental period. At time of challenge in week 10, the IgM level of the double booster group was significantly (p < 0.05) higher while the single booster and control groups were significantly (p < 0.05) lower than the protective cut-off value (Fig. 1).Fig. 1

View Article: PubMed Central - PubMed

ABSTRACT

Background: Streptococcosis 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&thinsp;&plusmn;&thinsp;10&nbsp;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.

Results: Both vaccinated groups showed significant (p&thinsp;&lt;&thinsp;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&nbsp;%, 70&nbsp;% and 0&nbsp;% rate of survival for Groups 1, 2 and 3, respectively.

Conclusion: Double booster regime is most suitable to be applied for feed-based vaccination against streptococcosis prior to the start of the hot season.

No MeSH data available.