Effect of the oral administration of astragalus polysaccharides on jejunum mucosal immunity in chickens vaccinated against Newcastle disease

• Published in: Microbial pathogenesis Vol. 135; p. 103621
• Main Authors: Shan, Chunlan, Sun, Bodong, Dalloul, Rami A., Zhai, Zhichao, Sun, Peng, Li, Maohui, Yang, Shubao, Luan, Weimin
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2019
• Subjects: Administration, Oral; Animals; Astragalus Plant - chemistry; Astragalus polysaccharides; Chicken; Chickens - immunology; Disease Models, Animal; Immunity, Mucosal - drug effects; Immunoglobulin A, Secretory; Intestinal immunity; Jejunum; Jejunum - drug effects; Jejunum - pathology; Male; Medicine, Chinese Traditional; Newcastle Disease - immunology; Newcastle disease virus; Newcastle disease virus - immunology; Plant Extracts - administration & dosage; Polysaccharides - administration & dosage; Vaccination - veterinary; Intestinal immunity; PBS; NDV; CD; APS; DAB; sIgA; H&E; VC; VH; Astragalus polysaccharides; Jejunum; NC; ND; PBST; Chicken; Newcastle disease virus
• ISSN: 0882-4010; 1096-1208
• DOI: 10.1016/j.micpath.2019.103621

Astragalus polysaccharides (APS) are a traditional Chinese medicine with a therapeutic effect by enhancing immune function; however, the underlying functional mechanism is still unclear. The aim of the present study was to determine the effect of oral administration of APS on jejunum mucosal immunity in chickens vaccinated against Newcastle disease (ND). One-day-old Hy-Line male chickens were divided into five groups of 20 chicks each: three APS groups, one vaccinated control (VC) group and one non-vaccinated negative control (NC) group. On d 10, the APS groups were orally administered 0.5 mL of APS at doses of 1 mg/mL (APSL), 2 mg/mL (APSM) and 4 mg/mL (APSH) daily for 4 consecutive days. The chicks in the control groups were administered 0.5 mL saline for those 4 days. All groups except NC were administered a ND virus (NDV) vaccine on day 14. The jejunum was removed from 4 randomly selected chickens of each group at 1, 7, 14 and 28 days after vaccination. The jejunal villus height (VH) and crypt depth (CD) were measured and the VH:CD ratio calculated. Immunohistochemistry was used to analyze the differences of IgA+ cells in the jejunum. NDV specific secretory IgA (sIgA) levels in jejunal contents were detected using an indirect ELISA. At most time points, VH:CD ratios, number of IgA+ cells, and sIgA levels were significantly higher in the APS groups than those in VC and NC groups, but there were little differences among the three doses of APS groups. These results indicate that oral administration of APS could enhance the intestinal mucosal immune function of chickens, and APS could be used as a vaccine enhancer. •The oral administration of APS can modulate morphological development of the jejunum.•APS increases IgA+ cell expression in the jejunal lamina propria.•APS enhances the level of NDV specific sIgA antibodies.•APS can be used as a vaccine enhancer.