A comparative study of the macro and microscopic anatomy of the liver and biliary system in pigeon (Columba livia domestica) and gull (Larus canus)

The aim of the study was to compare the anatomy and histology of the liver and biliary system in pigeons (Columba livia domestica) and gulls (Larus canus). A total of twenty adult birds (10 pigeons and 10 gulls) obtained from Tikrit and Mosul in Iraq were examined. Following euthanasia, the liver tissues were investigated both macroscopically and microscopically by using staining techniques such as Hematoxylin and Eosin, Masson’s trichrome, and Best’s carmine stains. both bird species exhibited bilobed livers positioned within the thoracic-abdominal cavity; however, in contrast to pigeons, gulls were found to have a gallbladder. The analysis of liver size and weight showed variations between gulls and pigeons, indicating that gulls have larger and heavier livers than pigeons do. The thickness of the liver capsules was greater in female gulls. This implies that there are species variations in liver protection mechanisms. Under the microscope, hepatocytes were found to be arranged in cords radiating around central veins. However, pigeons exhibited wider sinusoids compared to gulls. The liver structures of gulls show differences in thickness and size, with their bile duct system and blood vessels being particularly well-developed in comparison. Female gulls have had larger microscopic measurements of portal structures than male gulls. These findings highlight variations in liver anatomy and composition among bird species as well as between male and female birds.