Development of the Goose Tongue Filiform Papillae: Could it be Tooth-Like Sense Organs? / Desarrollo de las Papilas Filiformes de la Lengua de Ganso: ¿Podrían ser Órganos Sensoriales Parecidos a los Dientes?

SUMMARY: The geese's tongue filiform papillae are particularly long, and exhibit the same morphology of a tooth, evoking the lingual teeth of several fishes. In adult animals, they contain numerous mechanical Herbst's corpuscles but no taste buds. In the embryo, they appear since stage 38 and acquire their definitive shape between stages 38 and 42. They express several proteins associated with mammalian tooth development (BMP4, β-catenin, SHH, PITX2, PAX9), also known to be linked to parrot's pseudoteeth and goose's denticulations development. Neurofilaments are early present in the papillae primordia, and appear particularly numerous in adult papillae. Our results suggest that these papillae constitute a mechanical organ with a « tooth shape » derived from ancestral odontodes, whose development is controlled by numerous genes involved in classical odontogenesis.

Las papilas filiformes de la lengua de los gansos son particularmente largas y exhiben la morfología de un diente, evocando los dientes linguales presentes en varios peces. En los animales adultos, contienen numerosos corpúsculos de Herbst mecánicos, aunque una ausencia de papilas gustativas. En el embrión, aparecen a partir del estadio 38 y adquieren su forma definitiva entre los estadios 38 y 42. Expresan varias proteínas asociadas al desarrollo dentario de los mamíferos (BMP4, β-catenina, SHH, PITX2, PAX9), también conocidas por estar asociadas al desarrollo de pseudodientes en el loro y denticulaciones en el ganso. Los neurofilamentos están presentes tempranamente en los primordios de las papilas y aparecen particularmente numerosos en las papilas adultas. Nuestros resultados sugieren que estas papilas constituyen un órgano mecánico con «forma de diente» derivado de odontoides ancestrales, cuyo desarrollo está controlado por numerosos genes implicados en la odontogénesis clásica.

Effects of angel wings on morphological and histological characteristics of White Roman geese.

This study aims to determine the effects of normal and angel wing on morphological and histological characteristics of white Roman geese. Angel wing is a torsion of a wing at the carpometacarpus all the way down to the end, stretching outward away from the body lateral. In this study, 30 geese were raised for observing the whole appearance, including stretched wings and morphologies of defeathered wings at 14 wk old. A group of 30 goslings was raised to observe the feature of conformation development of wing bones from 4 to 8 wk old by X-ray photography. The results show that normal wing on angles of the metacarpals and radioulnar bones has a trend greater than the angel wing group (P = 0.927) at the age of 10 wk. According to 64-slice images of computerized tomography scanner on a group of 10-wk-old geese, the interstice at the carpus joint of the angel wing was larger than that of the normal wing. The slight to moderate dilated space of the carpometacarpal joint was found in the angel wing group. In conclusion, the angel wing is torqued outward away from the body laterals at the carpometacarpus and has a slight to moderate dilated space in the carpometacarpal joint. The normal wing geese exhibited an angel that is 9.24% greater than those of angel wing geese at the age of 14 wk (130 vs. 118.5°).

Geometrical characteristics of eggs from 3 poultry species.

We studied the correlations between egg geometrical parameters (i.e., egg shape index, sphericity, geometric mean diameter, surface area, and volume) and eggshell qualities, or the organic matrix in eggshell. Eggs were collected from 5 poultry breeds belonging to 3 species (commercial Hy-line Brown Chicken, Shaoxing Duck, Jinding Duck, Taihu Goose, and Zhedong White Goose). The geometrical parameters showed high variation among 3 species of poultry, and even between breeds in the same species. The five geometrical parameters were grouped into 2 sets, one contained shape index and sphericity, the other comprised geometric mean diameter, surface area, and volume. The parameters in the same set can be perfectly fitted to one another. Egg weight, shell membrane weight, and calcified shell weight were significantly correlated with geometric mean diameter, surface area, and volume. In accordance with false discovery rate-adjusted P value, both shell membrane relative weight and calcified shell thickness showed no significant correlations with any of the geometrical parameters. However, the correlations between geometrical parameters and other shell variables (calcified shell weight, shell relative weight, calcified shell thickness uniformity, and eggshell breaking strength) depend on breed. Both constitutive proportions and percentage contents of 3 eggshell matrix components (acid-insoluble, water-insoluble, and both acid and water facultative-soluble matrix) had no effects on egg shape and size. The correlations between the amounts of various shell matrix, egg shape and size depend on breed or species. This study provides a methodology and the correlation between geometrical parameters and eggshell qualities, and between geometrical parameters and organic matrix components in calcified shells.

Histomorphology and gene expression profiles during early ovarian folliculogenesis in duck and goose.

In contrast to the later stages of follicle development, little is known about the characteristics and mechanisms associated with early folliculogenesis in avian species. The objectives of the present study were to examine and compare the histomorphological and molecular changes of primordial, primary, and secondary follicles from duck and goose ovaries during the first 6 post-hatching week. Morphological analysis showed that the length and width of both duck and goose ovaries increased steadily during weeks 1 to 5 but increased acutely at week 6, whereas a greater increment was observed in the ovarian length of ducks than that of geese during weeks 4 to 5. Furthermore, smaller diameters of the 3 categories of follicles were observed in ducks than those in geese at the first appearance, but they reached a similar size at week 6. More importantly, secondary follicles were found in the ovaries of ducks 1 wk earlier than in those of geese. These results indicated a more rapid growth rate for ovarian follicles in ducks than in geese during early post-hatching development. At the molecular level, it was found that the mRNAs encoding follicle stimulating hormone receptor (FSHR), anti-Müllerian hormone (AMH), B-cell leukemia/lymphoma 2, and cysteine-dependent aspartate specific protease 3 (CASPASE3) were ubiquitously expressed in all ovarian follicles of ducks and geese with different expression profiles in each follicular category during the first 6 post-hatching week. Notably, transcript levels of FSHR, AMH, and CASPASE3 changed differently between ducks and geese during weeks 5 to 6, which was postulated to be one of the mechanisms inducing more rapid growth of ovarian follicles in ducks rather than in geese. In conclusion, our results revealed, for the first time, differences in early folliculogenesis, including the rate of growth of each follicular category and the timing of transition of primary to secondary follicles, between ducks and geese, and these differences could result from different expression profiles of FSHR, AMH, and CASPASE3 during early post-hatching development.

A morphometric analysis of the lungs of high-altitude ducks and geese.

We examined the morphology of the lungs of five species of high-altitude resident ducks from Lake Titicaca in the Peruvian Andes (yellow-billed pintail [Anas georgica], cinnamon teal [Anas cyanoptera orinomus], puna teal [Anas puna], speckled teal [Anas flavirostris oxyptera], and ruddy duck [Oxyura jamaicensis ferruginea]) and compared them with those of the high-altitude migratory bar-headed goose (Anser indicus) and the low-altitude migratory barnacle goose (Branta leucopsis). We then determined the relationship between mass-specific lung volume, the volume densities of the component parts of the lung, and previously reported hypoxia-induced increases in pulmonary O2 extraction. We found that the mass-specific lung volumes and the mass-specific volume of the exchange tissue were larger in the lungs of high-altitude resident birds. The bar-headed goose had a mass-specific lung volume that fell between those of the low-altitude species and the high-altitude residents, but a mass-specific volume of exchange tissue that was not significantly different than that of the high-altitude residents. The data suggest that the mass-specific volume of the lung may increase with evolutionary time spent at altitude. We found an inverse relationship between the percentage increase in pulmonary O2 extraction and the percentage increase in ventilation across species that was independent of the volume density of the exchange tissue, at least for the resident Andean birds.

Microstructure and compression resistance of bean goose (Anser fabalis) feather shaft.

The bean goose Anser fabalis, noted for its excellent flying ability, has feathers composed of keratinized products derived from epidermal cells, which play a crucial role in flight. The feather shaft is an important connective unit, made of a lightweight material, which also contributes to aiding flight. The shaft can withstand loads from different directions and has outstanding compression resistance. In this study, the microstructure and composition of the A. fabalis feather shaft were observed by scanning electron microscopy and Fourier transform infrared spectrometry, and its compression resistance was studied by compression testing. The results indicated that the mechanical property of the shaft is related to its microstructure. Compression testing verified that the primary feathers had the strongest mechanical properties, followed by the secondaries, and finally the alulae. Under the same conditions, the specific energy absorption of the three feather types was 5.96, 5.02, and 3.17 J/g, respectively. With increasing moisture content, the rachis was softened and the energy absorption was reduced. At low moisture content, the specific energy absorption of the primaries was reduced to 1.03 J/g, that of the secondaries was reduced to 1.72 J/g, and that of the alulae to 0.39 J/g. The feather shafts have the advantage of light weight while maintaining the required mechanical properties. These results provide a theoretical and experimental basis for crashworthiness in bionic designs based on the requirements of light weight.

Osteogenic Evaluation of Goose-beak Bones According to Processing Temperature.

BACKGROUND/AIM: As an alternative material to autogenous bone, goose-beak bone particles (GBP) have been attracting great attention as a bone substitute due to their biological properties. This study was performed to assess bone generation using GBP in calvarial defects in a rat model. The study focus was the osteogenic potential of goose-beak bone at different processing temperatures. MATERIALS AND METHODS: There were three experimental groups: Control group (critical defect only), low-temperature (LT) group (filled with GBP heat-treated for 20 h at 400°C), and high-temperature (HT) group (filled with GBP heat-treated for 3 h at 1,200°C). RESULTS: The Ca/P atomic ratio of the goose-beak bone was 1.63, and the bones had a bony structure with open pores and interconnected rod-like struts. Micro-computed tomographic analysis revealed the quantity of new bone formation of the HT group was higher than that of the LT group. At 12 weeks after GBP insertion, new bone formation was significantly higher (p<0.05) in the HT group, and there were more new osteocytes in the lacuna in the HT group than in the LT group. Thus, GBP treated at a high temperature formed more new bone than that treated at a low temperature. CONCLUSION: It can be concluded that HT-treated GBP is a graft material that can be effective in promoting bone formation.

Effects of cottonseed meal on growth performance, small intestinal morphology, digestive enzyme activities, and serum biochemical parameters of geese.

Cottonseed meal (CSM), an oil industry by-product, is an attractive alternative protein source in poultry diets. To investigate the effects of CSM on growth performance, small intestinal morphology, digestive enzyme activities, and serum biochemical parameters of geese, a total of 300 healthy, 28-day-old, male Jiangnan geese were randomly divided into 5 treatments, with 6 pens of 10 geese each. Five isonitrogenous and isocaloric experimental diets were formulated to produce diets in which 0% (control), 25% (CSM25), 50% (CSM50), 75% (CSM75), and 100% (CSM100) of protein from soybean meal was replaced by CSM (corresponding to 0, 6.73, 13.46, 20.18, and 26.91% CSM in the feed, respectively). At 28, 42, and 70 d, BW and feed intake for each pen were measured. Blood, small intestine, and chyme samples were collected at 70 d. The results showed that dietary 13.46% CSM or more decreased BW at 42 d and ADG from 28 to 42 d but increased the feed/gain ratio (F/G) from 28 to 42 d (P < 0.05). From 42 to 70 d, geese in the CSM groups had higher ADFI and ADG than those of the control group (P < 0.05). Geese in the CSM75 and CSM100 groups had a higher ADG from 28 to 70 d and BW at 70 d and a lower F/G from 42 to 70 d than those of the control group (P < 0.05). Dietary 6.73% CSM also improved ADFI from 28 to 70 d (P < 0.05). Compared to the control, geese in the CSM groups had decreased pepsin and lipase activities, and those in the CSM25, CSM50, and CSM75 groups had increased villus height in the jejunum at 70 d (P < 0.05). All groups had similar concentrations of total protein, blood urea nitrogen, uric acid, cholesterol, triglyceride, calcium, and phosphorus in serum (P > 0.05). In conclusion, excessive use of CSM (>6.73%) decreased growth performance at an early age (28 to 42 d) in geese, whereas 6.73 to 26.91% CSM in feed improved growth performance from 28 to 70 d.

A morphological and stereological study on calculating volume values of thoracic segments of geese.

BACKGROUND: In this study, the total volume of the thoracic segments of the spinal cord and volume densities of grey matter and white matter were examined by using stereological methods in adult geese having a weight of 3-4 kg. MATERIALS AND METHODS: Ten geese were used as material without sex discrimi- nation. All animals were perfused with 10% formaldehyde. In addition, after perfusion, the geese were kept in 10% formaldehyde for 1 week. Afterwards, thoracic spine was removed and thoracic part of spinal cord was excised. 5 µm thick sections were taken from these tissue samples by microtome. The cross- sectional series were obtained by sampling from each segment at 250th section. Twelve sections were taken from tissue specimens of every segment. The sections were stained by using haematoxylin-eosin and photographed on a microscope. RESULTS: By using the Cavalieri's Principle, the volume densities (volume fractions) of thoracic segments of spinal cord, volume of white matter, and volume of grey matter in segments were calculated. CONCLUSIONS: In the study, total volume of the thoracic segment, volume of white matter, and the volume of grey matter, and the ratio of these volume values to each other were calculated. The SHTEREOM 1.0 software was used for calculating the volume of section specimens.

A morphometric and stereological study on cervical spinal cord segment of goose.

In this study, volume density of white matter and grey matter areas of cervical segment of spinal cord in adult geese weighing 3-4 kg was examined using stereological methods. 10 geese were used as material without sex discrimination. All animals underwent perfusion with 10% buffered formaldehyde. Following the perfusion, animals were kept in 10% formaldehyde for 1 week. Geese were then dissected. Cervical area of spinal cord was revealed removing cervical spine. Tissue samples were obtained from each segment of cervical area. 5 µm thick cross-sections were taken from these tissue samples via microtome. Series of cross-sections were obtained by sampling in the ratio of 1/250 including 12 cross-sections from each cervical segment of every animal. Cross-sections were stained by haematoxylin eosin. They were photographed under microscope. Volume density (volume fractions) of both whole tissue and white matter and grey matter parts in each cervical segment of spinal cord were calculated using Cavalieri's Principle. In the study, total volume of cervical segment, volume of white matter and grey matter, and ratios of these volumes one another were assessed in goose.

The distribution and heterogeneity of mast cells in tongue from five different avian species.

This study was conducted with the aim of determining the morphology, distribution and heterogeneity of mast cells in the tongues of seagull (Larus fuscus), common buzzard (Buteo buteo), goose (Anser anser), white stork (Ciconia ciconia) and Gerze rooster. The study used five samples of tongue material from each of the healthy adult avian species. The samples were fixed in 10% neutral-buffered formalin (NBF) solution, then, after routine tissue follow-up, the samples blocked with paraplast. Cross-sections with 5-6 µm of thickness were stained with the 0.5% toluidine blue and alcian blue/safranin O (AB/SO). In all five avian species, it was found that the mast cells were in different sizes and round, oval or spindle-shaped based on their place of distribution. Mast cell numbers were determined in stained with toluidine blue, examined ×40 objectives in a 1 mm2 area. It was observed that mast cell density in subepithelial lamina propria and microscopic papilla was higher in the tongues of all species. Mast cell distribution and heterogeneity varied through the tongue, and there were more mast cells in the dorsal side of the tongue than the ventral side. The highest amount of mast cells was found in the tongue of the Gerze rooster among all five species. In the tongue cross-sections stained with the combined method of alcian blue/safranin O (AB/SO), the mast cells were stained as AB (+), SO (+) and AB/SO (+) (mixed).

Respiratory mechanics and morphology of Tibetan and Andean high-altitude geese with divergent life histories.

High-altitude bar-headed geese (Anser indicus) and Andean geese (Chloephaga melanoptera) have been shown to preferentially increase tidal volume over breathing frequency when increasing ventilation during exposure to hypoxia. Increasing tidal volume is a more effective breathing strategy but is also thought to be more mechanically and metabolically expensive. We asked whether there might be differences in the mechanics or morphology of the respiratory systems of high-altitude transient bar-headed geese and high-altitude resident Andean geese that could minimize the cost of breathing more deeply. We compared these two species with a low-altitude migratory species, the barnacle goose (Branta leucopsis). We ventilated anesthetized birds to measure mechanical properties of the respiratory system and used CT scans to quantify respiratory morphology. We found that the respiratory system of Andean geese was disproportionately larger than that of the other two species, allowing use of a deeper breathing strategy for the same energetic cost. The relative size of the respiratory system, especially the caudal air sacs, of bar-headed geese was also larger than that of barnacle geese. However, when normalized to respiratory system size, the mechanical cost of breathing did not differ significantly among these three species, indicating that deeper breathing is enabled by morphological but not mechanical differences between species. The metabolic cost of breathing was estimated to be <1% of basal metabolic rate at rest in normoxia. Because of differences in the magnitude of the ventilatory response, the cost of breathing was estimated to increase 7- to 10-fold in bar-headed and barnacle geese in severe hypoxia, but less than 1-fold in Andean geese exposed to the same low atmospheric PO2.

Localization of Alpha-Keratin and Beta-Keratin (Corneous Beta Protein) in the Epithelium on the Ventral Surface of the Lingual Apex and Its Lingual Nail in the Domestic Goose (Anser Anser f. domestica) by Using Immunohistochemistry and Raman Microspectroscopy Analysis.

The epithelium of the ventral surface of the apex of the tongue in most birds is specified by the presence of the special superficial layer called lingual nail. The aim of the present study is to determine the localization of the alpha-keratin and beta-keratin (corneous beta protein) in this special epithelium in the domestic goose by using immunohistochemistry staining and the Raman spectroscopy analysis. Due to lack of commercially available antibodies to detect beta-keratin (corneous beta protein), the Raman spectroscopy was used as a specific tool to detect and describe the secondary structure of proteins. The immunohistochemical (IHC) detections reveal the presence of alpha-keratin in all layers of the epithelium, but significant differences in the distribution of the alpha-keratin in the epithelial layers appear. The staining reaction is stronger from the basal layer to the upper zone of the intermediate layer. The unique result is weak staining for the alpha-keratin in the lingual nail. Applications of the Raman spectroscopy as a complementary method not only confirmed results of IHC staining for alpha-keratin, but showed that this technique could be used to demonstrate the presence of beta-keratin (corneous beta protein). Functionally, the localization of alpha-keratin in the epithelium of the ventral surface of the lingual apex provides a proper scaffold for epithelial cells and promotes structural integrity, whereas the presence of beta-keratin (corneous beta protein) in the lingual nail, described also as exoskeleton of the ventral surface of the apex, endures mechanical stress. Anat Rec, 300:1361-1368, 2017. © 2017 Wiley Periodicals, Inc.

Morphological and morphometric specializations of the lung of the Andean goose, Chloephaga melanoptera: A lifelong high-altitude resident.

High altitude flight in rarefied, extremely cold and hypoxic air is a very challenging activity. Only a few species of birds can achieve it. Hitherto, the structure of the lungs of such birds has not been studied. This is because of the rarity of such species and the challenges of preparing well-fixed lung tissue. Here, it was posited that in addition to the now proven physiological adaptations, high altitude flying birds will also have acquired pulmonary structural adaptations that enable them to obtain the large amounts of oxygen (O2) needed for flight at high elevation, an environment where O2 levels are very low. The Andean goose (Chloephaga melanoptera) normally resides at altitudes above 3000 meters and flies to elevations as high as 6000 meters where O2 becomes limiting. In this study, its lung was morphologically- and morphometrically investigated. It was found that structurally the lungs are exceptionally specialized for gas exchange. Atypically, the infundibulae are well-vascularized. The mass-specific volume of the lung (42.8 cm3.kg-1), the mass-specific respiratory surface area of the blood-gas (tissue) barrier (96.5 cm2.g-1) and the mass-specific volume of the pulmonary capillary blood (7.44 cm3.kg-1) were some of the highest values so far reported in birds. The pulmonary structural specializations have generated a mass-specific total (overall) pulmonary morphometric diffusing capacity of the lung for oxygen (DLo2) of 0.119 mlO2.sec-1.mbar-1.kg-1, a value that is among some of the highest ones in birds that have been studied. The adaptations of the lung of the Andean goose possibly produce the high O2 conductance needed to live and fly at high altitude.

Distinctive gut microbial community structure in both the wild and farmed Swan goose (Anser cygnoides).

Swan goose (Anser cygnoides) is currently one of the most popular economic wildfowl for rare birds breeding industries in several provinces of China. However, the farmed Swan geese, reared in artificial environment and fed on both natural and artificial diets, display a reduced reproductive rate compared to wild species. Little is known about the gut microbiota of this species, which could play a role in nutrient and energy metabolism, immune homeostasis and reproduction. The present comparative study was designed to provide a first characterization of gut microbial communities related to both wild and farmed Swan geese by 16 S rRNA sequences using the Illumina HiSeq platform. The results showed that dominant microbial components in both groups consisted of Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria. The abundances of these four phyla were not statistically different between the groups. At the genus level, significantly decreased abundance of Clostridium and increased abundance of SMB53, Enterococcus and Paenibacillus were observed in farmed group compared to wild group. The marked differences of genus level group-specific microbes create a baseline for future Swan goose microbiology research and make a valuable contribution to forming relationships between gut microbiota and domestic bird reproduction.

A tree of geese: A phylogenomic perspective on the evolutionary history of True Geese.

Phylogenetic incongruence can be caused by analytical shortcomings or can be the result of biological processes, such as hybridization, incomplete lineage sorting and gene duplication. Differentiation between these causes of incongruence is essential to unravel complex speciation and diversification events. The phylogeny of the True Geese (tribe Anserini, Anatidae, Anseriformes) was, until now, contentious, i.e., the phylogenetic relationships and the timing of divergence between the different goose species could not be fully resolved. We sequenced nineteen goose genomes (representing seventeen species of which three subspecies of the Brent Goose, Branta bernicla) and used an exon-based phylogenomic approach (41,736 exons, representing 5887 genes) to unravel the evolutionary history of this bird group. We thereby provide general guidance on the combination of whole genome evolutionary analyses and analytical tools for such cases where previous attempts to resolve the phylogenetic history of several taxa could not be unravelled. Identical topologies were obtained using either a concatenation (based upon an alignment of 6,630,626 base pairs) or a coalescent-based consensus method. Two major lineages, corresponding to the genera Anser and Branta, were strongly supported. Within the Branta lineage, the White-cheeked Geese form a well-supported sub-lineage that is sister to the Red-breasted Goose (Branta ruficollis). In addition, two main clades of Anser species could be identified, the White Geese and the Grey Geese. The results from the consensus method suggest that the diversification of the genus Anser is heavily influenced by rapid speciation and by hybridization, which may explain the failure of previous studies to resolve the phylogenetic relationships within this genus. The majority of speciation events took place in the late Pliocene and early Pleistocene (between 4 and 2millionyears ago), conceivably driven by a global cooling trend that led to the establishment of a circumpolar tundra belt and the emergence of temperate grasslands. Our approach will be a fruitful strategy for resolving many other complex evolutionary histories at the level of genera, species, and subspecies.

Light and electron microscopic study of the eyelids, conjunctiva-associated lymphoid tissue and lacrimal gland in Bilgorajska Goose (Anser anser).

Normal structure of the accessory organs of the eye is essential for normal eye physiology. Among the most important accessory organs of the eye are the eyelids, the conjunctiva-associated lymphoid tissue (CALT) and the lacrimal gland (LG). The aim of this study was to demonstrate the histological structure of the eyelids and LG by histochemical and ultrastructural analysis. The study was performed on 13 adult female Bilgorajska geese. Eyelid samples were stained with the Alcian blue (AB pH 2.5) and periodic acid-Schiff (PAS) methods. Staining methods used for LG were AB pH 2.5, aldehyde fuchsin (AF), PAS and Hale's dialysed iron (HDI). Within the connective tissue of the eyelids, well-developed, diffuse, CALT follicles were observed, mostly under the conjunctival epithelium. Numerous lymphocytes were present within loose connective tissue. Staining of the eyelids with the PAS method demonstrated the presence of goblet cells of a mucous nature, and AB pH 2.5 staining indicated the presence of sulfated acid mucopolysaccharides. PAS staining of LG revealed the presence of secretory cells containing weakly PAS-positive granules. All epithelial cells of the corpus glandulae and the duct systems reacted positively to AB pH 2.5. HDI staining detected the presence of carboxylated acid mucopolysaccharides. Transmission electron microscopy investigations revealed two types of secretory epithelial cells in LG. Both types of LG cells contained drop-like secretory vesicles of different sizes with low or high electron density in cytoplasm, as well as small and large lipid vacuoles, and numerous small primary lysosomes.

Comparison of the structure, crystallography and composition of eggshells of the guinea fowl and graylag goose.

The structure and composition of the eggshells of two commercial species (guinea fowl and greylag goose) have been studied. Thin sections and scanning electron microcopy show the similarity of the overall structure, but the relative thickness of the layers differs in these two taxa. Atomic force microscopy shows that the different layers are composed of rounded, heterogeneous granules, the diameter of which is between 50 and 100 nm, with a thin cortex. Infrared data and thermogravimetric analyses show that both eggshells are made of calcite, but differing on the quality and quantity when the organic component is considered. Chemical maps show that chemical element distribution is not uniform within a sample, and differs between the species, but with low magnesium content. Electron back scattered diffraction confirms the eggshells are calcite, but the microtexture strongly differs between the two species. Based on the chemical-structural differences, a species-specific biological control on the biomineralization is found, despite the rapid formation of an eggshell. Overall results indicate that to estimate the quality of eggshells, such as resistance to breakage, is not a straightforward process because of the high complexity of avian eggshell biomineralization.

Light and electron microscopic studies of the Harderian gland in Bilgorajska goose (Anser anser).

The Harderian gland (HG) in birds is the dominant orbital gland, which plays an important role in immunological response. Tissue sections taken from adult females of Bilgorajska goose were stained with hematoxylin-eosin, Azan, PAS, AB pH 2.5, AF and HDI. Based on the histological structure the HG in Bilgorajska geese had compound tubular structure with multiple lobules and two types of epithelial cells lining the tubules. Epithelial cells in the central part of the lobes were dark in color and contained serous fluid, while in the deeper layers, epithelial cells were lightly coloured and contained mucous fluid. Histochemical studies showed the presence of neutral mucopolysaccharides and carboxylated acid mucopolysaccharides in the secretory cells. The small number of single plasma cells were present in HDI staining below the basement membrane of the secondary and primary ducts, near the crypts of the main duct. TEM study demonstrated that plasma cells had a large nucleus with condensed heterochromatin and were rich in rough endoplasmic reticulum. The knowledge of gland's structure, and above all an analysis of the immune system components may affect clinical practice and properly conducted immunization of birds.

Carry-Over or Compensation? The Impact of Winter Harshness and Post-Winter Body Condition on Spring-Fattening in a Migratory Goose Species.

Environmental conditions at one point of the annual cycle of migratory species may lead to cross-seasonal effects affecting fitness in subsequent seasons. Based on a long-term mark-resighting dataset and scoring of body condition in an arctic breeding goose species, we demonstrate a substantial effect of winter harshness on post-winter body condition. However, this effect was compensated along the spring migration corridor, and did not persist long enough to influence future reproduction. This highlights the importance of temporal scale when assessing impacts of environmental effects, and suggests a state-dependent physiological mechanism adjusting energy accumulation according to internal energy stores carried into spring. In support of these findings, the development of body condition was unaffected by whether geese used supplementary feeding sites or not. While there was no effect of winter harshness on the average population pre-breeding body condition, individual variations in early spring body condition (probably related to different life-histories) were partly traceable throughout spring. This strongly indicates a carry-over effect on the individual level, possibly related to differences in dominance, site use, disturbance or migration strategy, which may potentially affect future reproduction.