الفهرس Only 14 pages are availabe for public view
 |  | from | 254 |  |  |
| | | from | 254 | | |
Abstract
The comparative morphological and histological study of the gastrointestinal system of African collard dove, Streptopelia roseogrisea, a granivorous bird, and Japanese quail, Coturnix japonica, an omnivorous bird has revealed the following:
Gross anatomy:
1- The crop of the dove has two ovoid swellings on each side of the esophagus, while in the quail, the crop consists of only one lobe on the right side of the neck.
2- The gastric apparatus of both species is differentiated into a glandular proventriculus and gizzard. The gizzard of the dove is larger in size than that of the quail.
3- In both species, the intestine is divided into duodenum, jejunoileum and rectum. Meckel’s diverticulum is absent in both species. The rectum is shorter in the dove than it is in the quail in relation to the gut length.
4- The rectal ceca are paired in the two birds. The ceca are long in the quail, while they are extremely short in dove.
Microscopical anatomy:
1- In the dove, the tunica muscularis of the esophagus consists of two layers, an outer circular and an inner longitudinal. In the quail, the tunica muscularis of the esophagus consists of three layers, two rather thin longitudinal layers, and a thick circular layer between them.
2- In the dove, the mucous glands of the esophageal mucosa are composed of compound tubuo-alveolar glands and occur only in the posterior esophagus. In the quail, the mucous glands also consist of simple tubuo-alveolar glands, but it occur in the entire length of the esophagus. The density of the mucous glands increases towards the glandular stomach.
3- In the dove, the muscularis of the proventriculus is composed of two muscle layers, an outer circular and an inner longitudinal layer. But in the quail, the muscularis of the proventriculus consists of three layers, an outer and an inner thin longitudinal muscle layers and an intermediate circular layer.
4- Two types of glands are present in the proventriculus mucosa of both species, superficial simple tubular glands and deep compound tubular gastric glands.
5- The gizzard of dove and quail is composed of a very thick layer of circular muscle fibers. The mucosa of the gizzard is lined by a thick koilin layer.
6- The muscular layer of the intestine in the two birds is similar, it consists of an outer longitudinal and an inner circular muscle layers.
7- The muscularis mucosa of the intestine is absent in both species.
8- In both species, the intestinal mucosa forms simple villi, which are higher and more numerous in duodenum than they are in in jejunoileum.
9- The basic structure of the rectum of the two birds is similar to the rest of the intestine except its thicker muscular layer. Als, the quail rectum has branched villi.
10- Histological structure of the middle part quail rectal ceca is similar to that of the small intestine except that the muscular layer is thicker and villi are narrower and lower than that of the small intestine.
Morphometry:
1- Morphometrical changes were observed of a variety of measurements in the dove intestine in relation to seasonal changes of food composition. Also, there was observed changes in size of the alimentary tract of the quail when food compositions were altered experimentally.
2- In dove and quail, consumption of high fibre diet (i.e., low quality diet) results in increased gut length as compared to standard diet (high quality food).
3- Quail feeding on high fibre diet ate more than those feeding on standard food.
4- Quail feeding on high fibre diet weight less than those feeding on standard diet.
5- The epithelial surface magnification and the thickness of the muscle layer increased when quail were feeding on high fibre diet and when dove were feeding on their winter diet (i.e., high fiber diet).
6- Gizzard length and mass increased when quail and doves fed on high fibre diet. The relative amount of lipids in the gizzard muscle decreased at the same time.
7- Liver mass decreased in both species, when birds fed a high fiber diet. In parallel with liver mass, the relative amount of lipids decreased.
8- In quail feeding on high fiber diet, the capillarization of the intestinal villi was increased in comparison to quail feeding on standard food.
9- The cell proliferation in the intestinal crypts and, consequently, mucosal growth was elevated in quail feeding on high fibre diet as compared to those feeding on standard diet.
Food passage:
1- The quality of the diet had effects on the retention time of food consumed by the quail, especially the particulate food.
2- There was no significant difference in retention time of liquid phase marker (cobalt) between quail fed standard diet and those fed high fibre diet.
3- Retention time of solid phase marker (chromium) was shorter in quail fed high fibre diet than those fed standard diet.