Effects of using GaroVak immersion vaccine in rearing the juvenile Asian sea bass (Lates calcarifer) and experimentally infected with Streptococcus iniae

Abstract

Introduction: The aim of this study was to investigate the effects of GaroVak
immersion vaccine against lactococcosis and streptococcosis disease in different
weights on growth and feeding performance and some immunological responses and
survival rate of Asian Sea bass (Lates calcarifer).
Materials & Methods: Fish with an average weight of 5, 10 and 14 g in 300-liter
polyethylene circular tanks in 6 treatments and 2 repetitions including vaccinated groups
in low, medium and high-weights and control groups of each the weight without
vaccination (SC, MC, LC) were examined. Feeding was done twice a day ad libitum for
8 weeks.
Results: The obtained results showed that GaroVak immersion vaccine has no
significant effect on growth and feeding performance the vaccinated fish and the control
fish (P>0.05). Regarding immunological responses, the amount of total protein and
albumin was significantly higher in the low weight-treatment compared to the lowweight
control group, and no significant difference was observed in the medium-weight
and the high-weight between the vaccinated treatments and the control group (P>0.05).
Also, vaccination did not show a significant effect on antibody titer and lysozyme
activity in any of the treatments (P>0.05). In addition, the survival rate at the end of the
experiment did not show a significant difference between the vaccinated treatments and
the control group (P>0.05). However, the result of the bacterial challenge showed that
mortality rate in the low-weight vaccinated group was lower than the medium-weight
control group (P<0.05).
Conclusion: According to the general results of this study, administration of GaroVak
immersion vaccine against streptococcosis disease has been able to improve the survival
rate after bacterial challenge in low-weight of Asian seabass.