In-Feed Immunostimulant for Broiler Chickens: Upregulation of Antiviral Genes and Immunoglobulin Y (IgY)

As a vital global protein source, the commercial poultry industry relies on high-density breeding systems, which significantly heightens the risk of infectious disease. Broilers are particularly vulnerable at 2 to 3 weeks post-hatch due to a critical ‘immune vacuum’ caused by the waning of maternal antibodies before endogenous immunity fully matures. To address this gap, non-invasive and in-feed immunostimulants offer a cost-effective and stress-free strategy to rapidly enhance early innate defenses. This study evaluated the temporal immunological effects of a newly formulated immunostimulant administered ad libitum to 14-day-old broilers. By analyzing mRNA expression levels in the bursa of Fabricius at 3 and 7 days post-administration (dpa), we aimed to determine whether this formulation successfully bridges innate and adaptive immunity. Notably, our findings revealed a distinct sequential immune cascade: a significant early induction of antiviral genes such as interferon γ (IFNγ) and interferon regulatory factor 1 (IRF1) at 3 dpa, followed by the robust upregulation of specific antiviral 2′-5′-oligoadenylate synthetase-like (OASL) gene and adaptive immunoglobulin Y (IgY) gene effectors at 7 dpa. Ultimately, these results suggest that this in-feed immunostimulant could be a practical strategy for enhancing broad-spectrum disease resistance in poultry farms.