No single hypothesis is likely to explain the diversity in eggshell coloration and patterning across birds, suggesting that eggshell appearance is most likely to have evolved to fulfill many nonexclusive functions. By controlling for nonindependent phylogenetic associations between related species, we describe this diversity using museum eggshells of 71 British breeding passerine species to examine how eggshell pigment composition and concentrations vary with phylogeny and with life-history and nesting ecology traits. Across species, concentrations of biliverdin and protoporphyrin, the two main pigments found in eggshells, were strongly and positively correlated, and both pigments strongly covaried with phylogenetic relatedness. Controlling for phylogeny, cavity-nesting species laid eggs with lower protoporphyrin concentrations in the shell, while higher biliverdin concentrations were associated with thicker eggshells for species of all nest types. Overall, these relationships between eggshell pigment concentrations and the biology of passerines are similar to those previously found in nonpasserine eggs, and imply that phylogenetic dependence must be considered across the class in further explanations of the functional significance of avian eggshell coloration.

• Klíčová slova
• Biliverdin, eggshell coloration, eggshell pigment, phylogeny, protoporphyrin,
• Publikační typ
• časopisecké články MeSH

Birds' eggshells are renowned for their striking colours and varied patterns. Although often considered exceptionally diverse, we report that avian eggshell coloration, sampled here across the full phylogenetic diversity of birds, occupies only 0.08-0.10% of the avian perceivable colour space. The concentrations of the two known tetrapyrrole eggshell pigments (protoporphyrin and biliverdin) are generally poor predictors of colour, both intra- and interspecifically. Here, we show that the constrained diversity of eggshell coloration can be accurately predicted by colour mixing models based on the relative contribution of both pigments and we demonstrate that the models' predictions can be improved by accounting for the reflectance of the eggshell's calcium carbonate matrix. The establishment of these proximate links between pigmentation and colour will enable future tests of hypotheses on the functions of perceived avian eggshell colours that depend on eggshell chemistry. More generally, colour mixing models are not limited to avian eggshell colours but apply to any natural colour. Our approach illustrates how modelling can aid the understanding of constraints on phenotypic diversity.

• Klíčová slova
• biliverdin, eggshell colour, protoporphyrin, subtractive colour mixing,
• MeSH
• pigmentace * MeSH
• ptáci fyziologie   MeSH
• vaječná skořápka fyziologie   MeSH
• zraková percepce * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The proteins and pigment of the eggshell of the Siamese crocodile (Crocodylus siamensis) were analysed. For proteomic analysis, various decalcification methods were used when the two main surface layers were analyzed. These layers are important for antimicrobial defense of egg (particularly the cuticle). We found 58 proteins in both layers, of which 4 were specific for the cuticle and 26 for the palisade (honeycomb) layer. Substantial differences between proteins in the eggshell of crocodile and previously described birds' eggshells exist (both in terms of quality and quantity), however, the entire proteome of Crocodilians has not been described yet. The most abundant protein was thyroglobulin. The role of determined proteins in the eggshell of the Siamese crocodile is discussed. For the first time, the presence of porphyrin pigment is reported in a crocodilian eggshell, albeit in a small amount (about 2 to 3 orders of magnitude lower than white avian eggs).

• Klíčová slova
• Crocodile, Eggshell pigment, Proteins of eggshell,
• MeSH
• aligátoři a krokodýli metabolismus   MeSH
• proteiny plazů metabolismus   MeSH
• proteom metabolismus   MeSH
• vaječná skořápka metabolismus   MeSH
• vaječné proteiny metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chorion proteins MeSH Prohlížeč
• proteiny plazů MeSH
• proteom MeSH
• vaječné proteiny MeSH

Avian eggshells are variable in appearance, including coloration. Here, we demonstrate that Raman spectroscopy can provide accurate diagnostic information about major eggshell constituents, including the pigments biliverdin and protoporphyrin IX. Eggshells pigmented with biliverdin showed a series of pigment-diagnostic Raman peaks under 785 nm excitation. Eggshells pigmented with protoporphyrin IX showed strong emission under 1064 nm and 785 nm excitation, whereas resonance Raman spectra (351 nm excitation) showed a set of protoporphyrin IX informative peaks characteristic of protoporphyrin IX. As representative examples, we identified biliverdin in the olive green eggshells of elegant crested tinamous (Eudromia elegans) and in the blue eggshells of extinct upland moa (Megalapteryx didinus). This study encourages the wider use of Raman spectroscopy in pigment and coloration research and highlights the value of this technique for non-destructive analyses of museum eggshell specimens.

• Klíčová slova
• Biliverdin, Chemical analysis, Moa, Non-destructive, Protoporphyrin IX, Tinamou,
• MeSH
• barva MeSH
• biliverdin analýza   MeSH
• biologické pigmenty analýza   MeSH
• protoporfyriny analýza   MeSH
• ptáci * MeSH
• Ramanova spektroskopie MeSH
• vaječná skořápka chemie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biliverdin MeSH
• biologické pigmenty MeSH
• protoporfyriny MeSH
• protoporphyrin IX MeSH Prohlížeč

Physiological constraints on colouration have been widely reported; especially in birds, which trade-off antioxidant responses against colourful costly signals. One female extended phenotypic trait, which might also highlight important physiological trade-offs, is the pigmentation of their eggshells. In ground-nesting species, producing eggs that are visually undetectable by predators is the best camouflage strategy. However, the condition-dependence of eggshell pigmentation, and the pigments role in oxidative stress, may constrain females to trade-off between their antioxidant capacity and maximising the camouflage of their eggs when they deposit eggshell pigments. Developmental stress is one factor that influences female antioxidant capacity, and could lead to variations in eggshell pigmentation that might have crucial consequences on individual fitness if egg crypsis is compromised especially under stressful conditions. We investigated the interaction between developmental and breeding conditions with respect to eggshell pigmentation in Japanese quail. We studied 30 females that bred under both control and stressful conditions, and were exposed to pre- and/or post-natal stress, or neither. Pre- and post-natal stress independently influenced eggshell pigmentation strategies under stressful breeding conditions. Under stressful reproduction, eggshell protoporphyrin concentration and maculation were affected by pre-natal stress, whereas eggshell reflectance and biliverdin concentration were influenced by post-natal stress. These changes may reflect potential adaptive strategies shaped by developmental stress, but additional data on the benefit of egg crypsis in quail, combined with studies on the role of both pigments on chick survival, will help to clarify whether early life stress can enhance fitness through eggshell pigmentation when developmental and reproductive environments match.

• Klíčová slova
• Breeding conditions, Developmental history, Early-life stress, Eggshell pigmentation, Japanese quail1,
• MeSH
• chov MeSH
• Coturnix fyziologie   MeSH
• fyziologický stres * MeSH
• novorozená zvířata MeSH
• pigmentace fyziologie   MeSH
• rozmnožování fyziologie   MeSH
• tělesná hmotnost MeSH
• vaječná skořápka fyziologie   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Eggshell colour, quality, and biosafety of table eggs are of significant commercial interest. To date, there have been few studies investigating the relationship between eggshell pigmentation and internal egg quality in commercially bred birds. Moreover, the genetic basis and mechanisms behind the effects of extrinsic factors on deposition of antimicrobial compounds in egg white and eggshell pigments are not fully understood. In the present study, we evaluate the effect of chicken breed identity, eggshell pigmentation and the role of extrinsic factors (year and breeder identity) on variability in the concentrations of 2 major egg white antimicrobial proteins (AMPs), lysozyme (LSM), and ovotransferrin (OVOTR), across 23 traditional chicken breeds. We found that chicken breed identity and eggshell pigmentation explained most variability in the concentration of egg white LSM and OVOTR. Year and breeder identity were also significant predictors of egg white LSM and OVOTR variability, and showed selective effects on the deposition of both AMPs in egg white. We also documented a positive correlation between concentration of egg white LSM and eggshell cuticle protoporphyrin in tinted and dark brown eggs, but not in brown, white, and blue eggs. We assume that a combination of both intrinsic genetic and hormonally regulated extrinsic factors is responsible for this relationship and for the variability in egg white AMPs. In this study, we demonstrate the existence of a relationship between eggshell pigmentation and egg white AMPs content in the eggs of traditional chicken breeds that may advertise the egg's antimicrobial potential and biosafety. These findings provide novel insights into the relationship between eggshell pigmentation and egg internal quality and may stimulate the recovery and exploitation of traditional chicken breeds for egg production, where the demands for egg quality and biosafety, in conjunction with animal welfare, are a priority.

• Klíčová slova
• albumen, eggshell colour, lysozyme, ovotransferrin, protoporphyrin IX,
• MeSH
• imunomodulace genetika   MeSH
• kationické antimikrobiální peptidy genetika   metabolismus   MeSH
• kur domácí genetika   imunologie   metabolismus   MeSH
• pigmentace MeSH
• ptačí proteiny genetika   metabolismus   MeSH
• vaječná skořápka chemie   MeSH
• vaječné proteiny genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kationické antimikrobiální peptidy MeSH
• ptačí proteiny MeSH
• vaječné proteiny MeSH

Recent studies have shown that the egg yolk maternal components, which are a mixture of substances that can affect the developing embryo, do not act separately but are interconnected and co-adapted. Surprisingly, no study to date has focused on the associations between maternally derived albumen steroids and albumen and eggshell compounds with pleiotropic effects. Eggshell pigment protoporphyrin (PROTO IX) should provide primary antimicrobial protection for eggs, but as a proven pro-oxidant, it may compromise female fitness. Abundant albumen proteins ovotransferrin (OVOTR) and lysozyme (LSM) have been shown to have antimicrobial, antioxidant, immunoregulatory and growth-regulatory roles. To investigate associations between albumen steroids and OVOTR, LSM and eggshell cuticle PROTO IX, we used chicken eggs with differently pigmented eggshells. We found that albumen steroid hormones were strongly intercorrelated. In addition, we revealed that albumen LSM and testosterone (T) were positively associated, while a negative association was found between albumen LSM and pregnenolone (P5). Eggshell cuticle PROTO IX was negatively associated with the concentration of albumen 17α-hydroxypregnenolone (17-OHP5). Finally, of all the hormones tested, only the concentration of albumen 17-OHP5 correlated negatively with egg volume and varied with eggshell colour and chicken breed. Although experimental evidence for the effect of maternal albumen steroids on avian developing embryo is still scarce, our study is the first to highlight co-variation and potential co-adjustment of maternally derived albumen steroids, proteins and eggshell cuticle pigment suggesting similar allocation mechanisms known for yolk maternal compounds with the potential to influence the avian embryo and offspring phenotype.

• Klíčová slova
• Antimicrobials, Eggshell pigmentation, Hormones, Maternally derived egg components, Precocial birds,
• MeSH
• antiinfekční látky * metabolismus   MeSH
• hormony metabolismus   MeSH
• kur domácí genetika   MeSH
• proteiny metabolismus   MeSH
• protoporfyriny metabolismus   MeSH
• steroidy metabolismus   MeSH
• vaječná skořápka * fyziologie   MeSH
• vaječný žloutek MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antiinfekční látky * MeSH
• hormony MeSH
• proteiny MeSH
• protoporfyriny MeSH
• steroidy MeSH

Avian eggshell color seems to fulfill multiple functions, some of them being structural and others signaling. In this study, we tested whether or not eggshell coloration may play a role in sexual selection of Tree Sparrows (Passer montanus). According to the "Sexually selected eggshell coloration" hypothesis, eggshell coloration signals female, egg or chick quality and males adjust parental investment according to this signal. Eggs of this species are covered with brown spots and patches, and variation between clutches is high. We found that eggshell coloration correlates with both protoporphyrin and biliverdin, but protoporphyrin concentrations are ten times higher. Eggshell coloration reflects egg and offspring quality, but not female quality. Thus, eggshell coloration may signal female postmating investment in offspring rather than female quality. Furthermore, differential allocation in terms of maternal investment is supported by the fact that females lay more pigmented clutches when mated to males with bigger melanin-based ornaments relative to their own. Moreover, males invested proportionally more to chicks that hatched from more pigmented clutches. Our correlative results thus seem to support a role of sexual selection in the evolution of eggshell coloration in birds laying brown eggs, pigmented mainly by protoporphyrin.

• Klíčová slova
• Tree Sparrow, differential allocation, eggshell coloration, female quality, paternal investment, sexual selection,
• Publikační typ
• časopisecké články MeSH

The protein composition of the insoluble avian eggshell matrix was studied. The determination of these proteins insoluble in water (EDTA-insoluble) was carried out using enzymatic cleavage followed by a high-performance liquid chromatography-mass spectrometry method. The influence of various enzymes on the protein splitting also was studied. The distribution of proteins depends on the type of layer (localization within the eggshell): ovocalyxin-32 was found mainly in the outer layer (the cuticle); ovocleidin-116 and 17 and ovocalyxin-36 were found throughout the whole eggshell, whereas ovalbumin was only found in the inner layer, the mammillary. The pigment (protoporphyrin IX) was mainly found in the cuticle and is incorporated into the protein network.

• MeSH
• aminokyseliny analýza   MeSH
• EDTA MeSH
• elektroforéza kapilární MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
• kur domácí MeSH
• protoporfyriny analýza   MeSH
• rozpustnost MeSH
• tandemová hmotnostní spektrometrie MeSH
• vaječná skořápka chemie   MeSH
• vaječné proteiny analýza   izolace a purifikace   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aminokyseliny MeSH
• EDTA MeSH
• ovocalyxin 32 MeSH Prohlížeč
• ovocleidin-116 MeSH Prohlížeč
• protoporfyriny MeSH
• protoporphyrin IX MeSH Prohlížeč
• vaječné proteiny MeSH

In recent decades, interest in non-traditionally colored eggs has increased. For breeders, this market interest means breeding lines of laying hens that lay eggs of varied colors, such as the blue-green eggshells (Dominant Greenshell) in this study. This study presents the results of genotyping the polymorphism of the O locus responsible for shell coloration and photometric measurement of eggshell color based on the CIELAb system, which was carried out on the unique Czech breeding population Dominant Greenshell. The aim was to use a combination of phenotyping using the CIELab System method and genotyping of the O locus using the end-point PCR approach with the main focus on the accuracy of distinguishing shell color genotypes, streamlining the selection of dominant homozygotes in the O locus, optimizing this technology for the most efficient and cost-effective selection procedure in practical hen breeding. The optometric method was able to reliably distinguish only dominant and recessive phenotypes and eliminate from the population only undesirable recessive homozygotes with a white colored shell. The parameter a* (redness/greenness) from the CIELab color space turned out to be absolutely key for distinguishing dominant and recessive phenotypes. Using the CART methodology, a classification tree built on discriminating optometric characteristics a-blunt was obtained, however, for the group of desirable O/O homozygotes, the selection approach would result in incorrect genotyping of 31% of individuals. Therefore, a combined approach based on rapid and simple elimination of recessive homozygotes using phenotyping (CIELab photometric measurement) and molecular identification of the EAV-HP insertion in the SLCO1B3 gene in dominant phenotypes, regardless of color intensity affected by laying time/order, and allowing reliable elimination, has proven to be the most effective method to distinguish heterozygotes from the breeding population. The combination of optometric and molecular selection methods then leads to more efficient selection, reduction of overall selection costs. This process led to the stabilization of the breeding population within one generation and the achievement of a pure homozygous line with regard to eggshell color.

• Klíčová slova
• CART methodology, Czech blue-shelled breed, L*a*b* color space, PCR marker, SLCO1B3,
• MeSH
• barva * MeSH
• chov * MeSH
• fenotyp * MeSH
• genotyp MeSH
• kur domácí * genetika   fyziologie   MeSH
• pigmentace * genetika   MeSH
• selekce (genetika) MeSH
• vaječná skořápka * fyziologie   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH