Immunopromoter improves liver apoptosis and immune response in Shaoxing ducklings

Antibiotics as feed additives, play a vital role in animal husbandry. However, overused antibiotics could cause endogenous infections in animals, and even endanger human health through the food chain. And immunopotentiators can make the low immune function improve and accelerate the induction of immune response. The aim of this study was to investigate the effects of five different immunopotentiators on the expression of liver apoptosis and immune factor related genes in Shaoxing ducklings (Anas Platyrhynchos). A total of 150 one-day-old Shaoxing ducklings were randomly divided into six groups including saline, chlorogenic acid, β-D-glucan, astragalus flavone, CpG DNA and chicken IgG, which were injected subcutaneously into the neck, respectively. At 18 days old, the liver tissues were collected to detecte the mRNA and protein expression levels of inflammatory and apoptosis-related genes. The results showed that compared with the control group, the mRNA and protein levels of liver Bcl2 with chlorogenic acid, β-D-glucan, astragalus flavone, CpG-DNA and chicken IgG were significantly decreased (p < 0.05), while the expression level of Caspase3 was up-regulated in some different degrees. In addition,The expression levels of liver iNOS and COX2 were significantly increased after the injection of five immunopotentiators (p < 0.05), and the mRNA levels of IFN-α, IFN-β, IL-1β, RIG-I, TLR3 and TLR7 genes were also significantly up-regulated compared with the control group (p < 0.05). In conclusion, chlorogenic acid, β-D-glucan, astragalus flavone, CpG-DNA and chicken IgG can be used as immunopotentiators to regulate duck innate immunity. This study provides a new way to prevent important infectious diseases of ducks, and also provides a certain reference for the application of antibiotic substitutes in animal production.