Immunoprotection effects of chicken egg yolk immunoglobulins (IgY) against Aeromonas veronii infection in Sinocyclocheilus grahami

Sinocyclocheilus grahami (S. grahami) has been artificially bred since it was domesticated in early 21st century. However, the large-scale breeding has exposed that S. grahami is susceptible to Aeromonas veronii (A. veronii). Herein, the specific immunoglobulin of yolk (IgY) against A. veronii was produced, which showed high specificity and sensitivity to bind with A. veronii. The stability scopes of temperature and pH were 20–60 °C and 4–7, respectively. The specific IgY significantly inhibited the growth of A. veronii by direct agglutination. Injection with the specific IgY protected S. grahami coping A. veronii infection by increasing ROS elimination speed and reducing the inflammatory damage, analyzed by activity of antioxidative enzymes (CAT, SOD and GSH-Px) and expression of TNF-α and IFN-γ genes, respectively. Our study will contribute to develop a type of antibiotic substitute IgY which could be applied to elevate the culture benefit in S. grahami.