Histological and histochemical study of the uropygial gland of chimango caracara (Milvago chimango vieillot, 1816)

Abstract

The uropygial glands of birds are sebaceous organs that contribute to the water-repellent properties of the feather coat. We studied the histological and histochemical characteristics of the uropygial gland of chimango caracara using hematoxylin and eosin (H & E), Gomori´s trichrome, orcein, Gomori´s reticulin, periodic acid-Schiff (PAS), Alcian blue (AB) and a variety of lectins. The gland is composed of two lobes and a papilla with 20 downy feathers. It is surrounded by a capsule of dense connective tissue that contains elastic, reticular and smooth muscle fibers. The papilla is delicate and has two excretory ducts. The gland mass relative to body mass was 0.143%. Both adenomer cells and their secretions were stained with Sudan IV, PAS and AB, and were positive for numerous lectins that indicated the presence of lipids and carbohydrates. Immunohistochemical techniques to detect PCNA confirmed cell proliferation in the basal stratum of the adenomer cells. The lipids and glycoconjugates secreted by the uropygial gland serve numerous functions including protection against microorganisms.

Key words::

• caracaras
• Falconiformes
• glycoconjugates
• histology
• preen gland

Acknowledgments

The authors thank Mr. Luis Pagano, División Zoología Vertebrados, Facultad de Ciencias Naturales y Museo, for sample collection and Mr. Jerónimo Pan who revised the grammar and style of the manuscript. This work was partially supported by grants 11/V191 and 11/N583 from Universidad Nacional de La Plata, Argentina.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this paper.