IgY antibodies as a non-antibiotic approach to combat Vibrio vulnificus infection and gut microbiota dysbiosis in zebrafish.

This study investigates the protective effects of immunoglobulin Y (IgY) antibodies as a targeted treatment against Vibrio vulnificus infection in zebrafish (Danio rerio), focusing on survival - outcomes and microbiota modulation. IgY antibodies were generated by immunizing hens with inactivated V. vulnificus, purified from egg yolks, and administered to zebrafish via intraperitoneal injection, oral feeding, and immersion. Following IgY treatment, zebrafish were exposed to V. vulnificus, and survival rates were recorded. Gut microbiota composition was assessed using 16S rRNA gene sequencing. Results showed that IgY treatment significantly enhanced survival rates, with injected groups achieving up to 90 % survival compared to 40 % in untreated controls. Additionally, IgY-treated fish displayed favorable shifts in gut microbiota, including increased Lactobacillus and Faecalibacterium prausnitzii and reduced pathogenic genera such as Vibrio and Aeromonas. These findings highlight the dual benefits of IgY: pathogen-specific inhibition and microbiota-friendly modulation, supporting its potential as an antibiotic alternative in aquaculture. Future studies should optimize IgY dosing and evaluate its efficacy across diverse fish species.