Physiological and biochemical aspects of the avian uropygial gland

Salibián, Alfredo; Montalti, Diego

doi:10.1590/s1519-69842009000200029

Cited by 71 publications

(51 citation statements)

References 48 publications

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“…These oils are typically hydrophobic and consist of a mixture of waxes, esters and fatty acids that determine the local surface rsif.royalsocietypublishing.org J. R. Soc. Interface 11: 20140287 energy of the bird feathers [1,[28][29][30][31]. On a smooth, chemically homogeneous surface, a liquid droplet exhibits a contact angle at equilibrium (u E ) given by Young's relation cos u E ¼ (g sv 2 g sl )/g lv , where g is the pairwise interfacial tension between the solid (s), liquid (l) and vapour (v) phases, respectively [32].…”

Section: Resultsmentioning

confidence: 99%

Quantification of feather structure, wettability and resistance to liquid penetration

Srinivasan

Chhatre

Guardado

et al. 2014

J. R. Soc. Interface.

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Birds in the cormorant (Phalacrocoracidae) family dive tens of metres into water to prey on fish while entraining a thin layer of air (a plastron film) within the microstructures of their feathers. In addition, many species within the family spread their wings for long periods of time upon emerging from water. To investigate whether wetting and wing-spreading are related to feather structure, microscopy and photographic studies have previously been used to extract structural parameters for barbs and barbules. In this work, we describe a systematic methodology to characterize the quasihierarchical topography of bird feathers that is based on contact angle measurements using a set of polar and non-polar probing liquids. Contact angle measurements on dip-coated feathers of six aquatic bird species (including three from the Phalacrocoracidae family) are used to extract two distinguishing structural parameters, a dimensionless spacing ratio of the barbule (D*) and a characteristic length scale corresponding to the spacing of defect sites. The dimensionless spacing parameter can be used in conjunction with a model for the surface topography to enable us to predict a priori the apparent contact angles of water droplets on feathers as well as the water breakthrough pressure required for the disruption of the plastron on the feather barbules. The predicted values of breakthrough depths in water (1-4 m) are towards the lower end of typical diving depths for the aquatic bird species examined here, and therefore a representative feather is expected to be fully wetted in a typical deep dive. However, thermodynamic surface energy analysis based on a simple one-dimensional cylindrical model of the feathers using parameters extracted from the goniometric analysis reveals that for water droplets on feathers of all six species under consideration, the non-wetting 'Cassie-Baxter' composite state represents the global energy minimum of the system. By contrast, for other wetting liquids, such as alkanes and common oils, the global energy minimum corresponds to a fully wetted or Wenzel state. For diving birds, individual feathers therefore spontaneously dewet once the bird emerges out of water, and the 'wing-spreading' posture might assist in overcoming kinetic barriers associated with pinning of liquid droplets that retard the rate of drying of the wet plumage of diving birds.

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Section: Resultsmentioning

confidence: 99%

Quantification of feather structure, wettability and resistance to liquid penetration

Srinivasan

Chhatre

Guardado

et al. 2014

J. R. Soc. Interface.

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“…Its secretion confers water-repellent properties to the feather coat and also maintains the suppleness of the feathers. Other physiological roles of the secretion of the uropygial gland may be associated with pheromone production, control of plumage hygiene, thermal insulation and defence against bacteria and predators Bhattacharyya 1996, 1999;Montalti et al 2006;Salibián and Montalti 2009;Møller et al 2010;Soler et al 2012;Vincze et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Morphology and histology of the uropygial gland in Antarctic birds: relationship with their contact with the aquatic environment?

et al. 2014

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The uropygial gland is morphologically different in diverse bird species. This gland was macroscopically and microscopically examined in penguins, storm petrels and skuas. In all the studied species, the gland showed a connective tissue capsule and one papilla. A negative relationship was observed between the relative glandular mass and the body mass, being highest in petrels (small glands) and lowest in penguins (large glands). Birds that spend much time in water (penguins) have gland characteristics related to a continuous, but not stored, secretion, such as straight adenomers, the presence of abundant elastic fibres in the connective tissue and the absence of a primary storage chamber. Instead, birds that have less contact with water (storm petrels) have a gland with much more tortuous adenomers and a small primary storage chamber. The secretory cells showed a positive PAS reaction in all the glandular zones. Therefore, no differences could be seen between the sebaceous and glucogenic zones, as proposed in other birds. These results allow the conclusion that, in aquatic birds, there is no connection between the relative mass of the uropygial gland and the time in contact with water, though the differences found in the histological structure could be related to a different contact with the aquatic environment.

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“…Anatomically, the uropygial gland, which is situated dorsally on the last sacral or first coccygeal vertebra, is a sebaceous organ composed of two lobes, of which the shape and size vary among different avian species (Gezici;Nickel et al, 1977;Tas¸bas¸). Although this gland is always present in the embryonic stage, depending on the sex, species and family of the animal, the gland may either exist in a trace form or may completely disappear in some adult birds (Salibian & Montalti, 2009). …”

Section: Introductionmentioning

confidence: 99%

A Macroanatomical and Histological Study of the Uropygial Gland in the White Stork (Ciconia cicionia)

2011

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KOZLU, T.; AKAYDIN BOZKURT, Y. & ATES¸, S.A macroanatomical and histological study of the uropygial gland in the white stork (Ciconia cicionia). Int. J. Morphol., 29(3):723-726, 2011. SUMMARY:The present study was aimed at the macroanatomical and histological investigation and the demonstration of the structural characteristics of the uropygial gland in the white stork. The uropygial gland of two adult male white storks constituted the material of the study. It was determined that the gland was situated subcutaneously in between the caudal aspect of the lumbosacral bone and the first coccygeal vertebrae. The gland was composed of two lobes, which displayed an oval appearance when viewed from above and resembled a water drop when observed medially. Tuft of feathers were present on the caudal margin of each lobe. The present study revealed that the uropygial gland of the white stork is a simple tubular gland, which discharges its secretion into the lumen by a holocrine mode. Each lobe, possessed centrally located large cavities and a main excretory duct and displayed the presence of externally situated "peripheral tubules" and interiorly situated "central tubules". These secretory tubules, which composed the parenchyma, were separated by connective tissue septa referred to as "trabeculae", and released their secretion into a centrally located lumen. The wall of the secretory tubules was comprised of four layers, referred to as the germinative, intermediary, secretory and degenerative layers. The silver-staining procedure demonstrated that the stroma of the uropygial gland did not contain reticulum fibres. The anatomy and histology of the gland has been examined in few avian species. Up to date, this study is the first to describe the histological and anatomical peculiarities of the uropygial gland in white stork. The results acquired hereby will surely contribute to further studies to be conducted on the related area.

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Physiological and biochemical aspects of the avian uropygial gland

Cited by 71 publications

References 48 publications

Quantification of feather structure, wettability and resistance to liquid penetration

Quantification of feather structure, wettability and resistance to liquid penetration

Morphology and histology of the uropygial gland in Antarctic birds: relationship with their contact with the aquatic environment?

A Macroanatomical and Histological Study of the Uropygial Gland in the White Stork (Ciconia cicionia)

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