Dietary Artemisia Ordosica Polysaccharide Enhances Spleen and Intestinal Immune Response of Broiler Chickens

SIMPLE SUMMARY: With the increasing demand for safe livestock and poultry products, antibiotic growth promoters have been banned in several countries, and new alternatives are sought to improve the health of poultry and animals. Plant polysaccharides have been used in functional feed additives as an alternative to antibiotic growth promoters. As a natural bioactive component, Artemisia ordosica polysaccharide (AOP) has good activity in immune regulation, as well as antioxidant and anti-inflammatory properties. However, no previous studies have evaluated the response of the immune organs to a diet supplemented with AOP in broiler birds. We hypothesized that AOP supplementation would improve the immune function of broiler chickens. Hence, this study investigated the effects of AOP on the spleen and small intestine immune molecule contents and gene expression in broiler chickens. The present study has revealed that the inclusion of 750 mg/kg AOP led to a significant improvement in immune function and growth performance. This finding suggests that AOP can be used to improve the growth and health of broiler chickens. ABSTRACT: The spleen and small intestines are the primary immune organs that provide important immunity against various diseases. Artemisia ordosica polysaccharide (AOP) could be used as an immunologic enhancer to boost immunity in response to infection. This study was performed to explore the effects of the dietary supplementation of AOP on the growth performance and spleen and small intestine immune function in broilers. A total of 288 AA broilers (1 day old) were randomly assigned into six dietary groups. Each group included six replicates of eight broilers per cage. The broilers were fed with a basal diet supplemented with 0 mg/kg (CON), 50 mg/kg chlortetracycline (CTC), 250, 500, 750, and 1000 mg/kg AOP for 42 d. The results showed that dietary AOP supplementation affected broiler growth performance, with 750 and 1000 mg/kg of AOP being able to significantly improve broiler BWG, and 750 mg/kg of AOP was able to significantly reduce the FCR. The dietary AOP supplementation increased the levels of IgA, IgG, IgM, IL-1β, IL-2, and IL-4 in the spleen and small intestine in a dose-dependent manner (p < 0.05). Meanwhile, we found that AOP can promote the mRNA expression of TLR4/MAPK/NF-κB signaling-pathway-related factors (TLR4, MyD88, P38 MAPK, JNK, NF-κB p50, and IL-1β). In addition, the dietary supplementation of 750 mg/kg AOP provides better immunity in the tissue than the CON group but showed no significant difference from the CTC group. Therefore, AOP has an immunoregulatory action and can modulate the immune function of broilers via the TLR4/ NF-ΚB/MAPK signal pathway. In conclusion, dietary supplementation with 750 mg/kg AOP may be alternatives to antibiotics for enhancing broilers’ health, immunity, and growth performance.