EVALUATION OF THE DEVELOPMENTAL MORPHOLOGY OF THE SMALL INTESTINE OF LIGHT ECOTYPE NIGERIAN INDIGENOUS CHICKEN

Abstract

The aim of this study was to evaluate the developmental morphology of the small intestine  of Nigerian indigenous chicken using histological and transmission electron microscopic techniques. Thirty fertile eggs of light ecotype Nigerian indigenous chicken were used for this study. Samples of the duodenum, jejunum and ileum were obtained from 6 randomly selected birds on embryonic days 14 (ED 14), 19 (ED 19) and post-hatch day 1 (PD 1) after ketamine euthanasia. At ED 14, the lamina epithelialis mucosae of the small intestine of Nigerian indigenous chicken exhibited low columnar enterocytes with irregularly shaped surface microvilli, lamina propria-submucosa, and poorly defined basal lamina. In the ileum, areas of cuboidal-like enterocytes were also observed. At ED 19, the tunica mucosa comprised of low columnar-shaped enterocytes, few Goblet cells, microfold cells (M-cells), enteroendocrine cells and well formed basal lamina. Areas of lamina muscularis mucosae were occasionally seen in the tunica mucosa of the jejunum at ED 19. At post-hatch day 1, distinct lamina propria mucosae and submucosal areas were observed. In addition, areas of lymphocyte infiltration were present in the connective tissue of the lamina propria mucosae and submucosa. Acidic mucin which predominated and neutral mucin areas were demonstrated by Periodic Acid Schiff -  lcian blue histochemistry. It was concluded that the small intestine of light ecotype Nigerian indigenous chicken exhibit certain unique features which highlights that the functional and structural maturation of the small intestine may occur just before hatch.