Interpretive Summary: Effect of Egg Yolk IgY on Salmonella Typhimurium Colonization, Gut Health, and Growth performance in Broiler Chickens
By Tanmaie Kalapala, University of Arkansas
Researchers from Tarbiat Modares University in Iran, in collaboration with a researcher at North Carolina State University, conducted a study to evaluate the effects of different administration methods of egg yolk-derived immunoglobulin Y (IgY) on reducing Salmonella Typhimurium colonization in broiler chickens.
320-day-old Ross 308 broiler chicks, that were randomly allocated to eight treatment groups and duration of the study was 42 days. All the treatment groups expect negative control group were orally challenged with Salmonella Typhimurium on days 7 and 8. The birds received either specific or non-specific IgY in powdered form, water-soluble IgY through drinking water, encapsulated IgY (using sodium alginate–calcium chloride microencapsulation), or an antibiotic (enrofloxacin). These treatment groups were designed to compare the efficacy of various IgY delivery routes and to compare their effectiveness to conventional antibiotic treatments in Salmonella colonization.
The research findings from this study demonstrated that encapsulated IgY (CIPY) was highly effective in reduction of Salmonella colonization in both the liver and ceca and demonstrating similar outcomes to the antibiotic treated group. By day 28, both chloride-encapsulated immunized yolk powder and antibiotic groups have reduced Salmonella counts to below detection limits in the collected liver tissues. The encapsulated form of IgY significantly improved intestinal health, which was based on increased villus height and villus height-to-crypt depth ratios, that are indicators of enhanced nutrient absorption and mucosal integrity.
Furthermore, birds treated with CIPY had significantly reduced the levels of pro-inflammatory cytokines (INF-γ and IL-10), has higher serum IgY levels, and increased weights of immune organs such as the spleen and bursa of Fabricius, suggesting enhanced immune system activity. Although body weight gain was not significantly different across treatment groups, feed conversion ratio (FCR) improved significantly in the CIPY group in comparison to the antibiotic group. These findings suggest that encapsulated IgY not only controlled the Salmonella Typhimurium infection but also enhanced the feed efficiency by preserving intestinal structure and reducing inflammation-induced metabolic stress. In contrast, the non-encapsulated and water-soluble IgY forms showed moderate immune and intestinal benefits but were less effective in controlling Salmonella colonization, that can be possibly due to the degradation in the digestive tract that was reported.
These research findings highlight the potential of encapsulated IgY as a safe, antibiotic-free strategy for poultry producers. The results are highly applicable to the industry, offering an alternative strategy that aligns with growing consumer demand for antibiotic-free meat, cleaner labels like No Antibiotics Ever (NAE), Raised Without Antibiotics (RWA), and improved food safety.
Encapsulation technology ensures the functional stability of IgY in extreme gastrointestinal environments allowing precise delivery to the infection sites, particularly in the ileum and ceca. This approach helps producers reduce reliance on antibiotics, minimize antimicrobial resistance risks, and maintain poultry health and productivity.
Although the results are promising, the study also identified important areas for future research, including optimizing encapsulation techniques for scaling up at industry level, assessing the stability of IgY during feed processing and long-term storage, and expanding research to other foodborne pathogens in poultry and other poultry species. Further studies could also investigate local immune responses and gene expression patterns to get better understanding of the immunomodulatory effect of IgY.
The full paper can be found in Volume 104, Issue 10 of Poultry Science and is available online
Doi: https://doi.org/10.1016/j.psj.2025.105487
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