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Subject: Veterinary Anatomy × End date: 2009 × Start date: 2009 ×
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    ThesisItemOpen Access
    Gross morphometric, light-and electron microscopic studies on the small intestine of the Kadaknath fowl
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2009-04) Kalita, Pranab Chandra; Singh, G.K.
    The present study was aimed at promotion and advancement of the knowledge with respect to the gross morphometry, histology, histochemistry and electron microscopy of the small intestine in Kadaknath breed of poultry from the day of hatch to day 112. The changes in intestinal size and morphology with age were different in the three intestinal segments examined. The duodenum, jejunum and ileum increased in weight and length as age advanced. Histologically the mucosa of entire small intestine showed villi of variable shapes and sizes according to age. The cells which formed the surface of villi and glands were arranged in simple columnar epithelium comprised of the chief or main epithelial cells, the goblet cells and the enterochromaffin cells. The chief cells of the glands of Lieberkuhn differed from those of the villi. The goblet cells in the duodenal villi of the Kadaknath fowl were always in the form of a neatly shaped goblet. Argentaffin cells were present both in the villi and the glands and were most numerous in the glands. Frequency of argentaffin cells increased in 56 and 112 day old birds. Globular Leucocyts (GL) were also observed in the basal half of the intestinal epithelium, lying between the epithelial cells. The lamina propria was composed of loose connective tissue which had very few large collagen fibers but possessed a network of fine reticular fibrils, which were associated with the reticular networks of the blood vessels and muscle fibers. The muscularis mucosae consisted of a layer of longitudinally oriented smooth muscle fibers, which passed inwards into the corium of each villus. The submucosa was so poorly developed as to be almost non-existent. The tunica muscularis consisted of a well developed inner circular muscle layer and a weakly developed outer longitudinal muscle layer. There was greater density of collagen fibers in the tunica serosa layer of 112 day old birds. The depth of crypts of Lieberkuhn decreased considerably and there was decrease in the density of argentaffin cells in the middle segment of the small intestine. There was gradient increase in the goblet cell count upto 14 days of age in the ileum. Histochemically, the intestinal goblet cells showed very strong PAS reaction in 14 days old birds, the intensity of which increased towards ileum. Alcian-Blue stain revealed strong reaction of acid mucin in the villi as well as gland epithelium of the ileum of 14 day old birds. Modified Giemsa stain for argentaffin granules revealed varied occurrence of granules per cell. Pronounced activities of all the enzymes studied (viz. alkaline and acid phosphatase, ATPase, glucose-6-phosphatase and succinic dehydrogenase) were found in the villous epithelium of 14 to 112 day old birds. The SEM study revealed, finger-like villi in day old chicks in each intestinal segment. The villi developed to a plate-like pattern in duodenum and jejunum, whereas in ileum the villi were low and narrow tongue like by day 28 of age. By day 112 of age, the villi developed to a common wave like pattern in all the three segments. Structural variations among similar types of cells were not observed in the different parts of the small intestine under TEM study. Ultrastructurally, the duodenal villous epithelium at day 1 revealed chief cells having basally located oval nucleus and prominent nucleolus. Globule leucocytes and lymphocytes were sandwiched between the epithelial cells throughout the intestine in all the three groups under study. Mast cells were located in the lamina propria just beneath the epithelium, but never populated the intestinal epithelium. The argentaffin cells were almost always seen between the bases of the epithelial cells, on or near the basal lamina. These cells never reached the intestinal lumen. The results obtained indicate that the changes observed in different age groups may contribute significantly in satisfying the functional requirements of the indigenous poultry breed during development.