Histometerical and morphological studies on digestive tract and associated glands in pigeon (Columba livia) with regards to age

The present study was planned to determine the age related macroscopic and microscopic alternations in digestive tract and associated glands in pigeon (Columba livia). For this purpose, a total of30 clinically healthy pigeons of both sexes and three different age groups namely, immature (group A), adult (group B) and old age (group C) were included in this study. Each age group consisted of ten birds with equal number of birds of both sexes. The organs of digestive system and associated glands of each group were studied grossly and histologically. Grossly, the colour, shape, consistency, weight, and various dimensions (length, width and circumference) of organs of digestive tract and associated glands were recorded. The mean (plus minus SEM) of all gross anatomical parameters in group A was significantly (p less than 0.01) different from that of both adult and old age groups while a non significant difference was observed between adult and old age groups. The samples of the organs of digestive system (oesophagus, crop, proventriculus, gizzard, small intestine, large intestine, liver and pancreas) were collected from each bird. For microscopic studies, 1-2 cm tissue samples of organs of digestive system were taken. The tissues were marked and fixed in the neutral buffered formaldehyde solution for histological studies. After fixation, sections of 5-6 mum thickness were cut. These sections were stained with haematoxyline and eosin for microscopic studies. All the layers (epithelium, lamina propria, muscularis mucosae, submucosa and tunica muscularis) were measured (mum) with the help of automated image analysis system Image J (registered) version 1.43n. The microscopic studies of different parts of the digestive system revealed highly significant differences (P less than 0.01) among all the three groups. The oesophagus was lined by non-keratinized stratified squamous epithelium. The duodenum, jejunum and ileum were found similar in histological structure. Statistical analysis revealed significant (P less than 0.05) rise in the thickness of different tunics of GI tract in adult birds (one year old) as compared with immature birds (one month old). A non-significant difference was recorded in old birds (five years old) as compared with adult group of birds.