Histogenesis of intestinal villi in fowl (Gallus domesticus)

The study on development, age-changes and regional differences of intestina l villi was conducted in 18 prehatch and 42 posthatch chicks of White Legho rn (WLH) birds divided into 10 groups with 6 birds in each group. The entir e intestinal mucosa of fowl showed villi of variable shape and size. Howeve r, these were longer and numerous in small intestine than in large intestin e. Among the parts of intestine the villi were longest (1260.00 mu m) in du odenum. The villi were short and cylindrical in early groups and appeared t hin, long and cylindrical in the chicks of zero day, changing to foliate an d slender shape in the chicks of 1 week onward. In jejunum the villi were c ylindrical and maximum (48/field) in number in the embryos of 19 days of in cubation while in later groups these appeared short, club-shaped and less n umerous. In ileum villi were either club shaped or cylindrical in embryos o f 19 days and long cylindrical without secondary villi in later groups. In caecum and colon characteristic folds with secondary villi were present. Th e lining epithelium covering the villi was low, columnar in the embryos of 12 days of incubation and increased in height from day 12 of incubation to 1 week of age. The goblet cells increased caudad and were maximum Its colon .