In-vitro evaluation of IgY antibodies against Aeromonas caviae and cross-reactivity with Aeromonas hydrophila

Aeromonas caviae , one of the most prevalent Aeromonas species, remains understudied compared to Aeromonas hydrophila. A. caviae is known to infect a wide range of aquatic organisms including fish, prawns, and crabs, leading to opportunistic diseases. The frequent use of antibiotics to combat these infections has resulted in the emergence of multidrug-resistant bacteria, causing significant residue-related issues in both biotic and abiotic environments. In this study, we propose the use of IgY antibodies as an innovative solution to prevent and treat bacterial infections. Formaldehyde-inactivated A. caviae and A. hydrophila strains were administered into the breast muscles of two different groups of 22 to 24 week old white leghorn hens on a weekly basis. A. caviae and A. hydrophila IgY antibodies was subsequently extracted and purified from the egg yolks, yielding an average protein concentration of 5.2 mg/mL and 11.88 mg/mL respectively. Our findings demonstrate that, IgY antibodies generated against A. caviae inhibit the growth of A. hydrophila at a dilution of 1:10,000. Furthermore, IgY antibodies specific to A. hydrophila exhibit cross-reactivity with A. caviae at the same dilution. In conclusion, IgY antibodies demonstrated significant in vitro inhibition and cross-reactivity offering a sustainable alternative to conventional antibiotic treatments. • A. caviae is a most understudied bacteria • Developed IgY antibodies against A.hydrophila and A. caviae antigens • Protein concentration estimated • Cross reactivity studies by agglutination, growth inhibition assay and ELISA methods • A. caviae can be controlled by A. hydrophila antigens and vice versa • Can reduce the use of antibiotics in aquaculture farms.