The Study On Morphological Structure And Endocrine Cells Of Digestive Tract In Gray Goose

In order to enrich the theoretical basis of morphology and endocrinology for digestive system in birds, the histological structure of digestive tracs from adult Gray goose were studied by HE taining, while using transmission electron microscopy observation the ultrastructure of the mucous layer of gastrointestinal tract.To investigate the morphology and the distribution density of 5–hydroxytryptamine (5-HT), somatostatin(SS), gastrin(Gas), glucagon(Glu), substance P and pancreatic polypeptide(PP) immunoreactive cells in the digestive tract of Gray goose by immunohistochemistry of Streptavidin - Peroxidase (SP) method.Found by light microscope: Epithelium mucosae of oesophagus was composed by stratified squamous epithelium with cornification of Gray Goose, there were well-developed muscularis mucosa and many esophageal gland. Compound tubnlar glands were abundance distributed in the glandular stomach, with larger diameter. The stomach wall of muscular stomach was composed by well-developed smooth muscle, gastric gland quantity, blood vessels and nerves were rich in the muscular layer. The villi showed finger-like in the duodenum, the number of goblet cells gradually increased from the duodenum to the rectum, no duodenal gland. The villi of jejunum and ileum became shorter and thicker, the thickness of muscular layer became accrescent, no central chyliferous vessel. The thickness of muscular layer in rectum significantly thicker than small intestine, the diameter of intestinal gland were larger, much showed rotundity -shaped. Throughout the lamina propria and mucosal layer of intestinal tract were rich in diffuse lymphoid tissue, and appeared assemble in the ileum and large intestine.Electron microscopy study found that: The surface of epithelial cell in glandular stomach had no microvilli, compound tubnlar glands with large diameter, the endocrine cells sparsely distributed between the epithelial cells of gland. The gap of epithelial cell in muscle stomach was wider, the cytoplasm contains a large number of organelles, but the distribution of endocrine cells was less. The microvilli of mucosal epithelial in the duodenum was longer, the goblet cells of glandular epithelial was relatively less, endocrine cells were distributed more widely. The microvilli of jejunum shorter, loosely arranged, the number of goblet cells increased significantly. The organelles of columnar cells in the ileum changed decline, the microvilli of epithelial continued to shorter, lymphocytes was increased in the lamina propria. Ultrastructure of the large intestine were similar as small intestine, but not observed microvilli, goblet cells and lymphoid tissue were more than small intestine, undifferentiated cells and endocrine cells with large number in the base of intestinal glands.6 kinds of immunoreactive cells were mainly distributed in the epithelium between mucosa and intestinal gland in the digestive tract of Gray goose. The density of 5-HT immunoreactive cells reached maximum in the rectum and duodenum, and followed by ileum, jejunum, glandular stomach and cecum, less dispersed in the muscular stomach and esophagus, but none observed in the pylorus. SS immunoreactive cells were appeared with greater numbers in the pylorus, duodenum and cecum, followed by rectum, ileum, glandular stomach, jejunum, and muscular stomach, were not found in esophagus. Gas immunoreactive cells were mainly distributed in the glandular stomach and jejunum, less dispersed in the duodenum and muscular stomach, but none in any other tissue. Glu immunoreactive cells were appeared with less number in the glandular stomach, duodenum and jejunum, but none in any other tissue; Substance P were only expressed in the jejunum, cecum and rectum. PP was no distribution in the entire digestive tract of Gray goose.These results indicated that the esophagus of Gray goose had a strong ability to soften and transport of food.The epithelial cells of gastric gland might have the function of chief cells and parietal cells. The developed compound tubular glands of glandular stomach, improve the speed of food digestion. The smooth muscle and development mucosal muscle of muscle stomach, might speed up the grinding, help the secretions of digestive gland into the digestive tract. The special histological structure of the small intestine indicated that the duodenum was the primary venue which nutrient absorption and assimilationthe, but the jejunum and ileum were in charge of lubrication and transport food. The mucosa of large intestine without striated border obviously,so the large intestine did not have digestive function.The folds of the cecum wall formed by the lymph tissue, indicating that the cecum had the function of immune protection, while the apparent sarcomere would increase the scalability of muscle layer. The thicker muscle layer of rectum showed strong regulation of defecation.The distribution and morphology features of endocrine cells in the digestive tract of Gray goose were related to feeding habit and metabolic type.