Comparative study on encapsulation and sustained release of anti-Campylobacter jejuni Immunoglobulin Y Using Various pH-Responsive Beads

To protect egg yolk immunoglobulin (IgY) from degradation by pepsin and acidic conditions during oral administration, Campylobacter jejuni (C. jejuni)-specific IgY was encapsulated in polypeptide beads using various methodologies. This study compared different pH-sensitive bead formulations to optimize IgY release at the target site, enhancing C. jejuni control and improving broiler chicken performance. Among the tested formulations, methacrylic acid copolymer (Mac) and β-cyclodextrin (β-CyD) beads demonstrated high encapsulation efficiency, with Mac beads achieving the highest (94.16 %). The inclusion of β-CyD further improved encapsulation efficiency by 3.5 % compared to alginate (Alg) alone. In vitro and in vivo gastrointestinal digestion models, and enzyme-linked immunosorbent assay (ELISA), were used to assess IgY stability and release. β-CyD beads exhibited the highest stability, followed by Alg and Mac, particularly in the gastric phase. Additionally, in vivo studies confirmed that encapsulated IgY, particularly Mac beads, maintained its biological activity and effectively neutralized C. jejuni post-encapsulation. This approach presents a promising strategy for protecting IgY during digestion and ensuring its targeted release in the intestine, thereby improving intestinal health and broiler performance. Consequently, IgY encapsulation may be an efficient feed additive for mitigating C. jejuni infections in poultry.