Polysaccharides from Pinus massoniana pollen improve intestinal mucosal immunity in chickens

Intestinal mucosa is the largest immune organ in animals, and its immune function is directly related to the resistance against various diseases. Taishan Pinus massoniana pollen polysaccharides (TPPPS) have been recognized as an effective vaccine adjuvant and potential immune enhancer against viral infections. However, little is known about their direct immune-enhancing activity on intestinal mucosa. In this study, we extracted the polysaccharides from Taishan masson pine pollen to investigate its promotive effect on intestinal mucosal immunity. A total of 120 1-day-old chickens were divided into 4 groups and inoculated with PBS or 3 different doses of TPPPS (10 mg/mL, 20 mg/mL, and 40 mg/mL), respectively. Feces, intestinal specimens, and serum samples were collected from the chickens at 7, 14, and 21 d after inoculation. The antibodies in serum, mucosal secretion of IgA, structure of intestinal villi, and expressions of cytokine genes and mucosal immune-related genes in the chickens were all significantly improved by TPPPS treatments. At 21 d after inoculation following the challenge of Newcastle disease virus, the chickens inoculated with 20 and 40 mg/mL TPPPS exhibited decreased weight loss and reduced intestinal pathologic damage and viral loads in the intestine. In summary, our results demonstrate that TPPPS can enhance mucosal immunity and promote intestinal villi development. This study has established the foundation for the development of novel immune-enhancing agent with immune-regulatory effects on intestinal mucosa.