Production of autovaccines depends on the specific formulation required by the customer because the different bacterias have a variety of growth processes and times.
Generally, the process usually takes around 5- 6 weeks to be completed.
Factors such as the wide diversity of aquatic systems, the variability of response between different species or between animals of the same species in different productive stages or the intrinsic immunogenicity of each species with which autovaccines are manufactured determine the final result.
Thus, the parameter DOI (Duration of Immunity) inherent in each vaccination formulation or process may vary significantly and it is practically impossible to predict the evolution of the immune response. However, there are certain general factors that can help with the design of the vaccine protocols:
Theadministration route Immersion vaccines generate a response mainly at mucosal level, less durable and therefore less effective than intraperitoneal injection. At present, both the formulations applied by immersion or orally are considered effective as a reinforcement or booster vaccine.
The formulation of the vaccines The specific humoral immune response is delayedafter injection of an oleaginous vaccine with respect to the administration of aqueous formulations and hydrogels, but once this response is generated it is more intense and can last for up to 8 months. However, emulsion formulations generate a more severe initial massive inflammatory response than aqueous bacterins.
In continental aquaculture, the primary response after vaccination of naive fish by injection appears from the fourth or fifth week post-vaccination, depending on the water temperature. This response has a limited duration of approximately 3 months, after which it is advisable to administer a booster vaccine. The secondary response is faster, more intense and can be maintained for 6-8 months post vaccination.
The choice of adjuvant depends on the pressure that exists at each facility and the characteristics of the production system.
Oleaginous adjuvants can contribute to the control of endemic pathogens in high-risk situations and are usually the most suitable option in facilities with frequent relapses associated with pathogens that do not respond to antibiotic therapy. In addition, if the production cycle is long, the application of formulations in emulsion form can contribute to maintaining a good health status during most of it.
However, the administration of emulsions carries a greater risk for both the vaccinator and the animal, with the latter having side effects in the form of granulomas, adhesions, organ congestion and micro-pigmentation.
Salmonids are especially susceptible to oleaginous formulations, and their use in breeding animals of these continental species is not recommended.
In facilities with lower pressure, with short-term productions or with more sensitive species, the use of an aqueous adjuvant is recommended.
Recent studies show that the efficacy of different valencies decreases as the valencies of a vaccine are multiplied.
Therefore, it is important to have expert advice to determine the appropriate formulation based on the needs of the facility, previous outbreaks and possible antigenic competition between the valencies of a vaccine.
After the stress associated with handling and the pro-inflammatory response generated by vaccination, it is advisable to respect a period of 350 degrees/day before moving the animals.
This is also the approximate period in which a vaccination will generate a significant level of immune response, and therefore specific protection.
The wait between vaccinations would be in the same range.
When defining the ideal size for vaccination, we need to understand the production system of the facility to determine the optimum time. The ideal time for vaccination is defined taking into account the time when the fish are immune-competent and the period of risk of outbreaks.
Vaccination takes place once the fish has a fully developed immune system and before the period in which outbreaks usually appear in facilities. Factors such as temperature, water resources or the production cycle affect the decision about when to vaccinate.