Efficacy of Feed-Based Genome-Free Bacterial Vaccine Against Aeromonas hydrophila Infection in Red Tilapia ( Oreochromis sp.)

• Published in: Vaccines (Basel) 2024-11, Vol.12 (11), p.1271
• Main Authors: Ali, Nur Shidaa Mohd, Ngalimat, Mohamad Syazwan, Lim, Boon Chuan, Hsu, Chia-Chen, Salleh, Annas, Nazarudin, Muhammad Farhan, Yasin, Ina Salwany Md, Azmai, Mohammad Noor Amal
• Format: Article
• Language: English
• Subjects: Aeromonas hydrophila; Aquaculture; Bacteria; Bacterial vaccines; Body weight; CD4 antigen; Cell culture; Disease control; Diseases; Dosage and administration; E coli; Effectiveness; feed-based vaccine; Feeds; Fish; Food and nutrition; Genes; genome-free bacteria; Genomes; Gram-negative bacterial infections; Hindgut; Immune system; immunity; Immunization; Immunoglobulin M; Immunology; Infections; Kidneys; Lysozyme; Major histocompatibility complex; Mortality; Mucus; Prevention; Risk factors; Septicemia; Testing; Thermal cycling; Tilapia; Vaccines; Vegetable oils
• ISSN: 2076-393X; 2076-393X
• DOI: 10.3390/vaccines12111271

causes motile septicemia (MAS), a disease with a high mortality rate in tilapia culture. Feed-based vaccines with the incorporation of inactivated whole-cell bacteria into the feed offer promising tools to control MAS. Currently, the incorporation of genome-free bacteria as bacterial vaccine through the implementation of SimCells technology into the feed has become a particular interest. : This study investigates the efficacy of a feed-based vaccine incorporating genome-free (FBV-GFAH) against MAS infection in red tilapia. : The vaccine was prepared and delivered at 5% fish body weight for three consecutive days in weeks 0 (prime vaccination) and 2 (first booster vaccination), orally. Throughout a five-week experimental period, the immune-related genes (IL-1 , MHC-II, CD4, IgT, and IgM) expression in the hindgut and head kidney of the fish was determined using RT-qPCR assay. Lysozyme (serum) and overall IgM (serum, gut lavage, and skin mucus) productions were also detected. : Fish vaccinated with FBV-GFAH showed a significant ( ≤ 0.05) improvement in relative percent survival compared with unvaccinated fish following bacterial challenge. FBV-GFAH induced the expression of immune-related genes in the hindgut and head kidney, especially after booster vaccination. Furthermore, serum lysozyme activity and overall IgM production in serum, skin mucus, and gut lavage were also significantly ( ≤ 0.05) improved in the FBV-GFAH vaccinated fish than the unvaccinated fish. : This study showed that FBV-GFAH is a promising feed-based vaccine technology to control MAS in cultured tilapia.