EFFECT OF BIOFILM COATING OF INACTIVATED Pseudomonas Putida VACCINE ON THE ANTIBODY TITERS AND SURVIVAL OF RED TILAPIA (Oreochromis niloticus x Oreochromis mossambicus)
Abdelhadi Y.M.1*; Natrah Fatin M.I.2
and Ina-Salwany M.Y.2
1The Central Laboratory for Aquaculture Research (CLAR), Agricultural Research Center (ARC), Egypt.
2Department of Aquaculture, Faculty of Agriculture, University of Putra Malaysia (UPM) 43400, Serdang, Selangor, Malaysia.
*Corresponding author: Tel.: +201211279416, Fax: +20553400498, E-mail: [email protected]
Inactivated whole cell vaccines against Pseudomonas putida, previously isolated from Nile tilapia (Oreochromis niloticus) cultures in ponds, were developed and tested in this study. Red tilapia fingerlings (mean weight 12.08±0.79 g and mean length 7.41±0.50 cm) were tested in a vaccination trial for 3 months using 30 fishes in 120 liters glass tanks and triplicates for each treatment. The vaccines were mixed with feed and fed to the fish in the rate of 1010 cfu-1g of feed for 10 days at the beginning of the experiment (initial dose) then after 1&2 months respectively (as 2 booster doses). This study aimed to test the Biofilm coated vaccine (BFV) compared to free cell vaccine (FCV) and it includes 4 treatments: free cell vaccine (FCV) of P. putida, Biofilm-coated vaccine (BFV) of P. putida, chitin only and a control group. Blood samples were taken before the experiment and every two weeks starting from the initial dose for antibody titration using ELISA. Experimental challenge with hot strains of the 3 Pseudomonas strains (P. putida, P. Aeruginosa and P. Fluorescens) has been done to test the vaccines efficacy and level of protection. Daily mortality was recorded for 14 days to estimate the cumulative mortality and relative percent survival (RPS) of the fish in different treatments. Results revealed that antibody (Ab) titers were significantly higher in all groups of vaccinated fish than those of fish in the chitin (+ve control) and control groups (-ve control). Similarly, estimates of the RPS showed significant differences between vaccinated fish (with an average of 80%) and the fish of the control group that showed 0% RPS. However, the BF coated P. putida vaccine showed the highest Ab titers and RPS (90% protection). Thus, using Biofilm coated vaccine (BFV) was recommended compared to free cells vaccine (FCV).
Pseudomonas putida, chitin, Biofilm, vaccines, ELISA