Summary
The different shapes and sizes of birds’ digestive systems reflect the wide range of feeding behaviors that birds exhibit. Hence, the present study was undertaken to clarify the differences in anatomical perspective variations, evaluate the histological components, and underline the histochemical differences among the pancreas and duodenum in three avian species (budgie, owl, and moorhen). The current study was conducted and performed at the College of Veterinary Medicine, University of Diyala, from August 2023 to August 2024. This study was carried out following the strictest standards for animal care and research. The current study used thirty mature birds collected from local markets in the capital of Baghdad and the Diyala Governorate. These birds were divided into three groups, each containing ten birds of each type. Each group was subdivided into two groups; five of them were used for anatomical study and the other five for histological and histochemical study.
The results indicated that the pancreas in all three birds was situated in the coelomic cavity, which is situated between and related to the duodenum. Three lobes, white to creamy in color and flat to wide in shape, make up the owl pancreas, which partially fills the space between the two limbs of the duodenum and connects to it through two major ducts. The pancreas of the moorhen bird was an elongated, strand-like structure with a light pink color, and its four lobes were connected to the duodenum by three main pancreatic ducts. It filled the space between the two arms of the duodenum.
The pancreas in budgie birds was a long, narrow, lobulated structure, pink in color, and consisted of four lobes, connected to the duodenum by two main pancreatic ducts. The morphometric data showed that the budgie bird has a higher relative weight of pancreas than that of the other two birds, as well as the owl bird has a higher relative length of the pancreas than the other two birds in the study.
The histological analysis revealed that the owl pancreas lacks separate lobules in its exocrine portion; which was different from the pancreas of the other two birds. The pancreas of the owl and the moorhen has a poorly developed oval islet of Langerhans in each micrometer, while the budgie bird has two or more large, well-developed islets of Langerhans in each micrometer. Owl pancreatic capsules are thicker than those of the other two birds. The budgie bird has an islet of Langerhans diameter larger than that of the other two birds; on the other hand, the moorhen bird has an exocrine portion diameter larger than others. The owl’s pancreas displayed collagen fibers in both the interlobular septa and the capsule, whereas the moorhen and budgie birds only exhibited a positive reaction within the capsule. Alcian blue staining showed a positive reaction in the owl and the budgie pancreas only. The Alcian-PAS mixture only exhibited a positive myosin reaction in the lobular and glandular portion of the owl pancreas.
The owl’s duodenum exhibited a relatively longer length compared to other birds. It consisted of four layers: the tunica mucosa, submucosa, the muscularis, and the serosa in the three studied birds. The serosa showed a positive Masson trichrome reaction in the budgie bird, as did the core of the villi and the submucosa. The duodenum of the moorhen bird only displayed this staining reaction in the subserosa, mucosa, and muscularis. Alcian blue staining showed a positive reaction of the muscularis and serosa in the budgie bird. All three birds showed a positive mucin acid reaction using Alcian-PAS staining due to the presence of a large number of goblet cells. Ultimately, further analysis showed that the owl bird exhibited a lower insulin hormone level compared to the other two birds.
