Morphometric, macroscopic and microscopic investigation of glandulae uropygiale in turkeys (Meleagris gallopavo)

Abstract

This study was carried out to investigate the macroanatomical, morphometric, histological, and electron microscopic characteristics of the uropygial gland in adult male and female turkeys (Meleagris gallopavo). The glandula uropygialis of 13 adult turkeys (6 males and 7 females) were used for this study. It was determined that this glandular structure located dorsal to the last caudal vertebrae was heart‐shaped and consisted of two lobes and a papilla system. As a result of statistical evaluation, significant differences were found between the sexes in the parameters of lobe length, papilla width and papilla height (p < .05). Also, papilla uropygialis index (PUI) value had a statistically significant difference (p < .05). Tissue samples taken to determine the histological structure of the gland were stained with Hematoxylin & Eosin, Crossman's triple, periodic acid Schiff (PAS), diastase, and orcein. Histological examination revealed that the gland had a two‐lobed structure surrounded by a capsule composed of connective tissue. It was determined that the gland had a tubular structure and the epithelial layer consisted of cellular layers as a germinative layer, intermediate layer, secretory layer, and degenerative layer from the periphery to center. In the scanning electron microscope examination, the lobe structure of the gland consisted of different shaped follicles protruding from the surface. It was observed that these glandular follicle structures were gathered together in different ways or mostly disorganized. As a result of the study, it was determined that the morphological and histological structure of the uropygial gland in turkeys was similar to that of other bird species, but showed some species‐specific and habitat‐dependent differences in general. ArıcanResearch Highlights The uropygial gland consisted of a system of two lobes and one papilla in each of male and female turkeys. The glandular lobes consisted of follicles surrounded by connective tissue, while the follicles were connected to each other by interfollicular septae. The results obtained in morphometric measurements revealed statistical differences between male and female birds. Histological examination showed periodic acid Schiff (PAS) (+) reaction in the basal membranes of tubule epithelial cells and secretion. Lymphoid cell communities were found in both connective tissue and intertubular regions. The fact that the reaction was not glycogen‐induced was determined by the observation of PAS positivity as a result of staining with the PAS‐diastase technique.