Ocena skutecznosci szczepionki przeciwko CyHV-3 u narybku karpia [Cyprinus carpio L.] - badania doswiadczalne

The study focuses on how to improve the potency and efficacy of a vaccine against CyHV-3 in carp fingerlings. The study material comprised the KoVax vaccine (Israel) applied through immersion (1 ml of vaccine diluted in 10 l of water) and 1 kg of carp fingerlings with individual weights of about 10 g. The immersion time was 40 minutes at different temperatures (16°C, 18°C, 20°C, 22°C). After 21 days, 50 fish from each temperature variant were infected experimentally through injections of CyHV-3 isolated from Polish carp at the same temperatures, and 50 fish were infected likewise from each group and held at a temperature of 22°C. The control group comprised fish that had only been vaccinated. The fish were held in tanks with a volume of 500 l (100 fish per tank) and were fed daily with commercial pellets. Mortality was tabulated and monitored, and the presence of the pathogen was confirmed through isolation from the gills and pronephros. The results of the study indicated that the temperature at vaccination is very important for achieving protection from CyHV-3. The highest mortality was observed in fish vaccinated at 16°C and then infected with live virus at 22°C (80%) in comparison to the group of fish vaccinated at 18°C (68%) or 20°C (40%). The fish vaccinated and infected at similar temperatures presented different levels of protection against CyHV-3. Mortality was the lowest at 22°C (20%), in comparison to that at 16°C (32%), 18°C (40%), or 20°C (38%).