Morphohistogenesis of gizzard in fowl (Gallus domesticus)

Gizzard was globular in group 2, flattened in group 3 and appeared tendinou s in group 4. It extended from rostral third of the abdominal cavity to the rostral limit of the cloaca in group 10. The length and width of the gizza rd ranged from 7.00-82.00 mm and 6.40-76.00 mm(2) from groups 2 to 10 respe ctively. The growth spurts of both the parameters revealed maximum increase in group s 2 to 3. The cross sectional: CCS) area increased from 54.00-1 150.00 mm i n groups 4 to 10 and revealed maximum (206.45% and minimum (25.81%) increas e in groups 6 to 7 and 8 to 9 respectively. The wail of the gizzard was thi ckest in comparison to other regions of the digestive canal. It increased f rom 901.00 mu m in group 2 to 4 964.00 mu m in group 10. Tunics muscularis was 4-6 times thicker than the mucosal layer and contributed 59.72-73.28% t o the total wall thickness against tunica mucosa (15.84-27.37%), The submuc osa was very thin. Papillary character was not conspicuous in gizzard. The tubuloalveolar mucous glands appeared in group 3 and were subepithelially p laced. in groups 4 onward on the surface of the epithelium a well developed keratinoid or kiolin layer was present. Folding character of mucosa and de nsity of the connective tissue increased with the advancement of age. In la ter groups 3-external, middle and internal muscle layers were evident. The numerous fibrocartilaginous plates of variable thickness were embedded in b etween the muscle bundles of middle layer of the tunica muscularis in posth atch chick. Tunica mucosa (30.925%) revealed maximum mean percentage increa se.