Vaccination has been established as an effective method for
prevention of infectious diseases in farmed fish. Currently, most
commercial vaccines were inactivated vaccines administered by
injection or immersion [1]. However, another route of vaccination
is currently emphasised; the oral vaccination since it is more
practical for farmers to utilise. Nevertheless, there is still limitation
in understanding the mechanisms that are involved in the uptake
of antigens [1e3]. Furthermore, oral vaccination has to focus on
protecting the antigens from digestion within the stomach and
anterior part of the gut [1]. Thus, protection provided after oral
vaccination is short compared to injection or immersion [4].
Another study on oral vaccination concluded that adjuvanted vaccine
incorporated in pellets resulted in high antibody levels for up
to 5 weeks [