Multivalent Immune-Protective Effects of Egg Yolk Immunoglobulin Y (IgY) Derived from Live or InactivatedAgainst Major Aquaculture Pathogens.

Abstract

Egg yolk immunoglobulin Y (IgY) possesses advantages such as low cost, easy availability, simple preparation, high antigen specificity, absence of drug residues, and compliance with animal welfare standards, making it an environmentally friendly and safe alternative to antibiotics. This research utilizes IgY antibody technology to develop a multivalent passive immune vaccine for major pathogenic bacteria in aquaculture. In this study, IgY antibodies against live(LSX-IgY) and inactivated(ISX-IgY) were prepared by immunizing laying hens, and passive immunization protection experiments were conducted ininfected withand. The passive immunization protection rates of LSX-IgY and ISX-IgY againstwere 63.64% and 72.73%, respectively, and the passive cross-protection rates againstwere 50% and 71.43%, respectively. Further,sera could specifically bind toorin vitro, and the phagocytic activity of leukocytes was increased. LSX-IgY and ISX-IgY could reduce the bacterial load in thekidneys. Meanwhile, they could significantly reduce the levels of antioxidant factors in serum and inhibit the mRNA expression of inflammation-related factors in the kidneys and spleens. Additionally, histopathology and immunofluorescence analysis showed that both IgY preparations preserved tissue integrity and reduced the expression of apoptosis factor (p53) and DNA damage factor (γH2A.X) of visceral organs, respectively. In summary, LSX-IgY and ISX-IgY can combat various bacterial infections, with no significant difference between the two. Additionally, inactivated bacterial immunization is more aligned with animal welfare standards for laying hens. Therefore, ISX-IgY is expected to serve as a multivalent vaccine against major aquaculture pathogens.