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ARS Home » Southeast Area » Auburn, Alabama » Aquatic Animal Health Research » Research » Publications at this Location » Publication #417925
Research Project: Integrated Research to Improve Aquatic Animal Health in Warmwater Aquaculture

Location: Aquatic Animal Health Research

Title: Evaluation of Recombinant Flavobacterium covae Protein Vaccines in Channel Catfish (Ictalurus punctatus)

Author
item CHURCHMAN, EMILY - Auburn University
item Lange, Miles
item SANKAPPA, NITHIN - Orise Fellow
item Justice, Megan
item QUIROZ, VICTORIA - Auburn University
item Abernathy, Jason
item LILES, MARK - Auburn University

Submitted to: American Fisheries Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/11/2024
Publication Date: 7/11/2024
Citation: Evaluation of Recombinant Flavobacterium covae Protein Vaccines in Channel Catfish (Ictalurus punctatus) [ABSTRACT]. American Fisheries Society Fish Health Section Seminars 2024, Webinar, July 11, 2024.

Interpretive Summary:

Technical Abstract: Columnaris disease is one of the leading causes of mortality in channel catfish production. Flavobacterium covae, an etiological agent of columnaris disease, has shown to be highly virulent in channel catfish and is a major problem for the US aquaculture industry. Here, we test the immunogenicity and efficacy of several biofilm-associated F. covae proteins to be used as recombinant subunit vaccines. The genes encoding these predicted proteins were cloned into expression vector pET-28a(+). After expression in Escherichia coli strain BL21 (DE3), the antigens were purified under native conditions. Channel catfish were injected intraperitoneally with purified protein (20 ug/mL), and peripheral blood was collected 30 days post-vaccination. Preliminary data shows vaccinated fish exhibited sera IgM antibody specificity to the respective antigens when blotted to the reduced proteins and had an increase of sera IgM antibodies. In our next trial, groups of fish (n=540) were immunized by bath immersion with the recombinant protein(s) (1 ug/ml) or sham immunized. There was no significant mucosal IgM antibody production among the vaccinated groups. However, each vaccinated group showed significant survival when challenged with F. covae (>30% compared to the control group) at nine weeks post-immunization. Significant upregulation of innate and adaptive and immune genes was seen in vaccine groups compared to baseline gene regulation in the sham immunized group. These results lay the groundwork for potential vaccine candidates to protect farmed fish against columnaris disease during the production cycle.