Abstract
The present work is the first in a series of studies aiming at establishing a connection between the food habits of aves and the anatomical, histological and histochemical structures of their alimentary canal. In this study the gross anatomy, histology and histochemistry of the alimentary canal of common quail, Coturnix coturnix, a granivorous bird, have been investigated. This study revealed that, the oesophagus is not ably long with a well developed crop; thus stomach is differentiated into a glandular proventriculus and a muscular ventritculus or gizzard. The gizzard is much more developed having a thick hard cuticle, its wall consists of two strong smooth muscles, the small intestine is divided into duodenum, jejunum and ileum and the transition from the jejunum to ileum is indicated by the vitelline (Meckel's) diverticulum, and the ileum was the longest part of the small intestine. The large intestine consists of paired well developed caeca and a short rectum. The present histological studies revealed that the alimentary tract showed the usual four laminae: serosa, musculosa, submucosa and mucosa. The oesophageal mucosa of the quail was thrown into numerous longitudinal folds. The mucosa of oesophagus is lined with stratified squamous epithelium. The proventricular glands are simple tubular to simple branched tubular glands. The mucosal surface of the ventriculus is indented by deep, broad crypts into which simple to branched tubular gastric glands open. A thick gastric keratinoid material covers the mucosa of the ventriculus. The intestinal mucosa is thrown into intestinal villi which show a marked variation in density, shape and size in the different regions of the intestine. The goblet cells gradually increase in frequency from the duodenum to the rectum. Also, the histochemical study revealed the existence of a high amount of mucopolysaccharides in the oesophageal glands, PAS and Alcian blue positive mucin granules as well (neutral and acid mucin, respectively). The ventriculus mucosa is covered by a thick keratinized laminated layer of koilin membrane which is formed of proteinous material similar to keratin and stained positive for PAS and Alcian blue indicating the presence of neutral and acid mucin within its contents. The proventriculus mucosa shows folds lined by simple columnar cells containing PAS and Alcian blue positive mucin granules. The goblet cells and crypts of Lieberkuhn have acid and neutral mucopolysaccharide secretions and the luminal surface of the columnar cells and the lamina propria of the intestine contains proteins. [Mostafa Zaher, Abdel-Wahab El-Ghareeb, Hamida Hamdi and Fathia Abu Amod. Anatomical, histological and histochemical adaptations of the avian alimentary canal to their food habits: I-Coturnix coturnix. Life Sci J 2012;9(3):253-275]. (ISSN: 1097-8135). http://www.lifesciencesite.com. 37