Studies on Biocoating Oral Immunization of Oreochromis niliticus Fingerlings with Aeromonas hydrophila Bacterin

Oral vaccination is a very easy vaccine administration method with no stress to the immunized fish but it should be in formulation protect antigen containing from inactivation or digestion during passage through foregut and hindgut. In the present study artemia nauplii was used as bio-encapsulation for Aeromonas hydrophila bacterin to immunize tilapia fingerling via oral route comparing with immersion and intra-peritoneum routes. The relative percent of survival in tilapia groups vaccinated by oral, immersion and intra-peritoneum routes was 92.68%, 81.4%and87.5%respectively. The humoral immune response of immunized fish was investigated by micro titre agglutination  test showed end point 400, 400 and 800 for oral, immersion and intra-peritoneum routes. And investigated by hemagglutination inhibition test that showed end point 128, 128 and 256 respectively. Also, immune response was measured by ELISA that showed similarly optic density between oral and immersion immunization routes. In conclusion, the current trial for fish vaccination showed that the coated oral vaccine can be effectively used in diseases prevention programs.