Capsulation as a strategy for oral delivery of immunoglobulin Y in broilers challenged with Escherichia coli O78:K80

Egg yolk immunoglobulin Y ( IgY ) can be used as an alternative to antibiotics for preventing and treating intestinal pathogenic infections. In the present study, sixty Lohmann-LSL-Lite laying hens were immunized intramuscularly with formaldehyde-killed whole-cell E. coli antigens. Lyophilized antibodies were obtained from eggs and encapsulated with sodium alginate, beta-cyclodextrin/alginate, and methacrylic acid co-polymer (L100–55). A total of 450 day-old ROSS 308 broiler chicks were randomly allocated into six groups (five replicates of 15 birds each) to evaluate the protective effects of IgY. The groups were as follows: Negative control (NC) — unchallenged and unsupplemented; Positive control (PC) — challenged with E. coli O78, unsupplemented; Non-encapsulated IgY (Non-ECIgY) — challenged and given 5 g/kg IgY powder; IgY-eudragit pellet (IgY-EP) — challenged and given 10 g/kg IgY-EP; IgY-beta-cyclodextrin-alginate microcapsules (IgY-βCyD-Alg) — challenged and given 11 g/kg IgY-βCyD-Alg; and IgY-alginate microcapsules (IgY-Alg) — challenged and given 12.5 g/kg IgY-Alg. Dietary supplementation with both encapsulated and non-encapsulated IgY significantly enhanced (P < 0.05) performance and intestinal histology compared to the PC group. However, the improvements (P < 0.05) were more pronounced in the encapsulated IgY group. The total number of E. coli in ceca and liver of birds fed with encapsulated IgY was lower (P < 0.05) than non-encapsulated IgY. Therefore, encapsulated IgY improved the efficacy of IgY against E. coli in broiler chickens because the encapsulation of IgY could protect it from gastrointestinal inactivation and enhance its delivery to the intestines.