Egg Color Research Articles

As rare as hen’s teeth: aberrantly coloured eggs of the northern lapwing (Vanellus vanellus) and the interface between oology and ornithology

The majority of birds lay eggs of a colour and maculation “typical” of their species, but very occasionally individual females produce eggs of unusual colours. In the past, such eggs were often the target of egg collectors. Four trays of unusually coloured northern lapwing Vanellus vanellus eggs originally accumulated by two notable collectors, F.C.R. Jourdain and J. M. Goodall in the late 1800s and early 1900s, were recovered from the home of David Wilson after his death in 2020. Wilson had acquired this lapwing material, comprising 91 clutches and 347 eggs in total, from the avid collector and millionaire, Captain Vivian Hewitt after Hewitt’s death in 1965. The lapwing clutches are unusual both in terms of their colours, ranging from pale blue with almost no maculation (“cyanic”), through to red (“erythristic”), but also in terms of the completeness of their accompanying data. During the 1800s and early 1900s, hundreds of thousands of lapwing eggs were collected annually in Britain and the Netherlands for human consumption, providing egg collectors, like Goodall and Jourdain, the opportunity to screen large numbers of clutches and acquire rare types. The occurrence of rare egg types in museum egg collections have the potential to provide opportunities to better understand the normal physiological and genetic bases of avian egg colour.

REPRODUCTIVE, SERUM BIOCHEMICAL AND HORMONAL TRAITS OF LOCAL QUAIL IN RESPONSE TO DIETARY SUPPLEMENTATION OF GREEN TEA POWDER

This study was conducted on 90 local quail females in six different treatments in order to know the effect of adding green tea powder to the quail diet on the productive, reproductive, biochemical and hormonal characteristics of quail females. The results showed a significant superiority of the birds of the group fed on 1% of green tea powder in hot and cold carcass weight, average egg weight, albumin weight, yolk height and color, and the lowest feed consumption, while the control-treated birds in the number of eggs produced, HDP, ALT, Alkaline and Bilirubin exceeded the other treatments birds. Concerning the lipid profile, blood urea ratio, and AST, the highest significant figures were recorded in the treatment of birds fed a ration to which 3% lipids were added. In contrast, the lowest values ​​for total cholesterol, Tri, VLDL, and blood nitrogen were recorded for birds of the treatment fed at 2% of green tea powder. The results showed that there were significant differences between the six treatment birds in the level of blood hormones, as the highest level of (estrogen), (Ghrelin, leptin, FSH), (T4) and (Growth and LH) were recorded for the control birds, 3% lipid and 1% dried green tea and 2% green tea with 3% lipid, respectively. We conclude from the above that birds fed a supplemented diet of 1% green tea powder were superior in most productive and reproductive traits, especially carcass weight, dressed %, egg weight and internal egg characteristics, compared to other treated birds.

Rejection of Conspecific Eggs Associated with the Appearance of Eggs, in the Azure-Winged Magpie Cyanopica cyanus in Korea

Avian brood parasitism is a reproductive strategy in which a parasitic species lays its eggs in the nests of a host. In response to parasitism, hosts have evolved various defence strategies. One of the host defences against intraspecific and interspecific brood parasitism is to distinguish parasitic eggs based on intraclutch variation in egg appearance. Hosts can improve their ability to discriminate parasitic eggs by lowering the degree of their intraclutch variation in egg appearance. Therefore, intraclutch variation may affect the egg rejection behaviour of hosts. In this study, we conducted experiments to study egg recognition and rejection behavior for mimetic eggs in Azure-winged Magpies Cyanopica cyanus in Korea. We also investigated the level of variation in egg appearance (egg color, spottiness and volume) in order to explore whether the degree of this variation is associated with the rejection decision. We found that there were no differences in egg coloration or spottiness between the rejecter and accepter. However, we found that intraclutch egg volume variation in rejecters was significantly lower than that in accepters, indicating that the Azure-winged Magpie is likely to recognize its own eggs by lowering its intraclutch variation in egg volume as a defensive strategy against brood parasitism. This study suggests that the Azure-winged Magpie use not the differences in egg coloration but egg volume to discriminate and reject closely mimetic conspecific eggs.

The red egg gene as a novel effective egg color marker for silkworm transgenesis

Ommochromes are major pigments involved in coloration of eggs, eyes, and epidermis of arthropods. The recessive homozygous of egg and eye color mutant of Bombyx mori, red egg (re), exhibits red eggs and dark red eyes instead of normal purplish-brown eggs and black eyes, due to a defect in ommochrome pigment synthesis. The gene responsible for the re mutant is a major facilitator superfamily transporter gene, Bm-re. Here, we demonstrate that the re phenotype can be effectively rescued by an intact Bm-re gene driven by the Bombyx Actin A3 promoter or the baculovirus Immediate Early 1 promoter, indicating that the Bm-re gene can be used as a marker gene for visual screening of transgenic silkworms. The coloration of eggs rescued by the Bm-re transgene could be distinguished from that of host mutant eggs from diapausing period through head pigmentation stage. This allows transgenic screening at earlier embryonic stages and over a longer time period compared to conventional 3xP3 fluorescent markers, without requiring the skill and equipment to detect stemmata fluorescence.

Experimentally impaired female condition does not affect biliverdin‐based egg colour

It has been proposed that blue‐green egg coloration is a condition‐dependent female sexual trait that may modify paternal care in a post‐mating sexual selection scenario. This pattern may arise because the pigment responsible for eggshell colouration (biliverdin) may be a costly and limited resource, whose availability is linked to female health state. Thus, it can be predicted that females whose condition is compromised should be constrained in their capacity to deposit biliverdin in the eggshell, thus producing paler clutches. To test this hypothesis, we performed a handicapping experiment by clipping some feathers of female spotless starlings before egg laying and measuring the colour of their clutches. We expected the handicapping treatment to increase flying costs, impairing female overall condition and resulting in paler clutches. Our experiment was successful in lowering the weight gain of handicapped with respect to control females. However, in contrast to our expectations, we found no effect of the treatment on eggshell colouration. Eggshell colour varied along the laying order, with initial eggs of the laying sequence being relatively paler than the rest of the clutch, but this pattern was not different between experimental groups. Despite a very similar methodology, our results differ from a previous study on the same species and offer no support to the post mating sexual selected hypothesis, questioning the general applicability of the sexual selection role of eggshell coloration.

Nesting Of Montezuma Quail In Mexico

Although Mexico has the greatest diversity of quail of any New World country, basic information on the ecology and life history of Mexican quails remains unknown. Our objective was to describe nest characteristics of the Montezuma quail (Cyrtonyx montezumae montezumae) in central Mexico. We searched for Montezuma quail nests within 8 counties in the state of México, Mexico during May–September 2003. We conducted nest searches along 66 transects (3–5 km × 40 m) distributed across 17 study sites. We recorded vegetation community, elevation, and nesting substrate for each nest. We measured nest characteristics: height, depth, nest entrance diameter, and orientation. If eggs were found, we recorded clutch size and egg mass, texture, color, and shape. We observed 324 quail and located 6 nests along a 254-km route. Nests were located at elevations ranging from 2,568–2,692 m above sea level. Mean (± standard deviation) nest height and depth were 122.2 ± 7.7 mm and 195 ± 61.8 mm, respectively. Nest entrance orientation for 5 of 6 nests was toward a southerly direction. Mean nest egg mass was 9.9 ± 0.1 g. Our study provides basic and descriptive information on a poorly known quail species in Mexico.

Influence of lycopene and astaxanthin in feed on metabolic parameters of laying hens, yolk color of eggs and their content of carotenoids and vitamin A when stored under refrigerated conditions.

Orientating investigations were carried out in order to test the influence of oil extracts of lycopene (20, 40 and 60 mg/kg feed) and astaxanthin (10, 20 and 30 mg/kg feed) as feed additives on the metabolic parameters (glucose, creatinine, cholesterol) and enzyme activities (alanine aminotransferase, ALT; aspartate transaminase, AST) of laying hens. Eggs from these hens were stored at refrigerator temperatures of 4°C and 12°C for up to 30 days and analyzed for vitamin A, carotenoid and yolk color. 45 laying hens (Hy-Line W36 cross, 23 weeks of age) were divided in three groups of 15 birds each (control, lycopene fed group, astaxanthin fed group). Blood samples were taken from the hens and laid eggs were collected on days 31, 61, and 91 of the study. The eggs were stored for 30 days in refrigerators. Both lycopene and astaxanthin increased the content of glucose in serum (Р⟨0.05). The content of creatinine and cholesterol, and the activity of ALT, AST and alkaline phosphatase varied dose-dependently. With the exception of cholesterol, metabolite concentrations in the serum of laying hens fed different lycopene and astaxanthin doses did not exceed clinically accepted physiological levels. The carotenoid content and color of the egg yolks from laying hens fed astaxanthin was significantly higher (Р⟨0.05) compared to lycopene fed birds. Refrigerator storage of the eggs did not affect carotenoid content and egg yolk color compared to freshly laid eggs. Both feed additives showed a favorable effect on the metabolism of laying hens and the enrichment of egg yolks with carotenoids, astaxanthin significantly more (Р⟨0.05) than lycopene.

Egg mimicry and host selection by common cuckoos among four sympatric host species breeding within a reed habitat

AbstractIn the case of cuckoo parasitism, the maintenance of host specificity may be closely related to active host selection. In the reed wetlands of the Yongnian National Wetland Park, China, four host species of common cuckoos (Cuculus canorus) with similar nest structures breed sympatrically, namely, the Oriental reed warbler (Acrocephalus orientalis) (ORW), vinous-throated parrotbill (Sinosuthora webbiana) (VP), reed parrotbill (Paradoxornis heudei) (RP) and blunt-winged warbler (Acrocephalus concinens) (BW). Cuckoo parasitism rates on ORW (14.5%) and BW (18.2%) were found to be significantly higher than those on two species of parrotbills (RP 1.4% and VP 0%), and cuckoo eggs mimicked the size and coloration of ORW eggs significantly more closely than those of the eggs of the other three hosts. Egg recognition experiments revealed that the ability of ORW and VP to recognize nonmimetic eggs was significantly greater than that of BW and RP. Different life history strategies of the four hosts, including antiparasitic strategy, breeding time period and population density may partly explain the difference of parasitism in this multiple cuckoo-host system. Our study suggests that determining host life history traits and antiparasitic strategies are important for a better understanding of the specificity of host selection in common cuckoos.

Effects of Different Levels of Dietary Energy and Nutrient Density during the Pre-Peak and Peak Periods on Egg Quality in Hy-Line Brown Laying Hens

In this study, we investigated the effects of feeding diets with different levels of energy and nutrient density on the egg quality of laying hens during the pre-peak and peak periods. A total of 192 (Hy-line brown) laying hens were used in a 15-week trial. The hens were randomly allotted to one of four treatments, each with four replicates (12 hens per replication). We assessed the effects of four level of dietary energy (2,710, 2,850, 2,870 and 2,890 kcal/kg) and three levels of nutrient density (Methionine + Cysteine: 0.56%, 0.85%, 0.80% and Crude Protein: 14.5%, 19%, 18%). Differences in the energy and nutrient density contents of diets showed no significant effect (<i>P</i>&gt;0.05) on the average daily gain, average daily feed intake, feed conversion ratio, egg weight, or egg production of hens during the pre-peak and peak periods. However, hens subjected to 2,890 kcal/kg during the pre-peak period were found to lay eggs with significantly thicker shells, and yolk color was found to be significant enhanced in hens fed this diet during the pre-and peak periods. In contrast, we detected no significant effects of dietary energy or nutrient density on the Haugh unit or eggshell strength. In summary, increasing the energy level of diets from 2,710 to 2,890 kcal/kg was found to have positive effects on the shell thickness and yolk color of eggs produced by laying hens.

CONTROVERSIES PAST AND PRESENT: PHENOTYPIC PLASTICITY AND PLASTICITY-LED EVOLUTION.

CONTROVERSIES PAST AND PRESENT: PHENOTYPIC PLASTICITY AND PLASTICITY-LED EVOLUTION.

Effect of Dietary Black Cumin Seeds (Nigella Stavia),Garlic(Allium Sativum)and Lettuce Leaves (Lactuca Sativa) on Performance and Egg Qualty Traits of Native Layer Hens

This work is done in rental house at Shaqlawa/Erbil city and It has been adapted to be a typical miniature field for experiment. (two month rearing ),for native layer at age (35week). Aimed of this experiment to investigate the effect of dietary 5% individual powder of black seeds, garlic and grinding of lettuce leaves on performance and egg quality traits of layer Hens. Atotal number of 64 layer distributed for four treatments, each of treatment included 16 hen and 4 cock, The treatments were as follows : T1 (control) without any addition, T2: 5% black cumin seeds powder, T3: 5% garlic powder, T4 : 5% lettuce leaves grinding. Result observed that T4 impact to improve the egg performance and color yolk egg, best value pointed in T1 for eggs phenotype characterized further for Albumin, yolk length/cm and significant (P≤0.05) with other treatments. Results also shown in T3 were the best value for egg shell strength (Kg/cm2). T2 observed better value for thickness, egg shell weight/g and percentage of egg shell. T3 obtained best value for yolk height and yolk Albumin index egg and H.U, followed by T2.

The effect of additional turmeric flour in rations on the performance and egg quality of laying chicken isa brown strain age 70th weeks

This research aims to study and analyze the effect of adding turmeric flour (Curcuma domestica Val) in the rations on the performance of 70 weeks old Isa Brown strain of laying hens. The research method used in this study was an experimental method with a completely randomized design (CRD) step with five treatments and four replications. The number of chickens used was as many as 40 laying hens. The treatments given to the sample were P0 = feed without giving turmeric flour (control), P1 = feed with 0.3% turmeric flour, P2 = feed with 0.5% turmeric flour, P3 = feed with 0.7% turmeric flour and treatment P4 = feed by giving turmeric flour 0,9%. The results showed that giving turmeric flour in the rations of the Isa Brown strain of laying hens affected chicken performance and egg quality. This research concludes that giving turmeric flour a percentage of 0.7% in Isa Brown’s 70-week old laying hens is the best for ration consumption, Hen Day Production, egg weight, feed conversion, and egg quality: Haught Unit, yolk egg color, yolk egg index, grading egg and egg mass. Based on the haugh unit value, all eggs produced are still in the AA grade category

The evolution of egg colour and patterning in Australian songbirds.

To understand why avian eggs are so variable in colour and patterning, we investigated the characteristics of extant bird species that provide insight into the evolutionary transitions that occurred during the early radiation of the songbirds. We quantified egg colour and patterning from museum collections of 269 species of Australian passerine and collated it to nest type data (cup- or dome-nesting species). Using phylogenetically reconstructed trait data, we showed that the ancestral passerine egg was likely to be white, and to have been laid inside a domed nest. Egg colouration and nest type were both phylogenetically clustered, and there was evidence of correlated evolution between the two traits. As nests transitioned from domes to cups, there was an increase in the range of egg colours observed, presumably as a response to additional stressors. Finally, we found that egg colour changes occurred more than twice as frequently in cup-nesting species than in dome-nesting species. This suggests that colour may be an adaptive trait that compensates for the loss of the protective nest roof in cup-nesting species.

Analysis of Egg Variation and Foreign Egg Rejection in Rüppell’s Weaver (Ploceus galbula)

Egg appearance is notable for its variation and as a source of recognition cues in bird species that are subject to egg-mimicking brood parasitism. Here I analyze the egg appearance of an East African weaverbird species that has variable eggs and is a host of brood parasitism by an egg-mimicking cuckoo, in order to (1) compare population variation to variation within a clutch as a measure of the distinctiveness of eggs; (2) assess modularity versus correlation among egg appearance traits as an indication of the complexity of egg signatures; and (3) address whether the eggs are discretely polymorphic or continuously variable in appearance. I also compare three methods of assessing egg coloration: reduction of spectral data to orthogonal components, targeted spectral shape variables, and avian visual modeling. Then I report the results of egg replacement experiments that assess the relationship between egg rejection behavior and the difference in appearance between own and foreign eggs. Rüppell’s weaver (Ploceus galbula) eggs are variable in appearance between individuals and consistent within a clutch, but vary widely in the distinctiveness of particular traits. Most aspects of color and spotting are decoupled from each other, including coloration likely to derive from different pigments. Egg ground color is bimodal, with a broad continuous class of off-white/UV eggs and another broad class of blue-green eggs. Variation in all other traits is unimodal and usually normal in distribution. Females reject foreign eggs on the basis of the difference in brightness of the ground color and spotting of foreign eggs relative to their own, and the difference in degree to which spots are aggregated at the broad end of the egg. This aggregation is among the most distinctive features of their eggs, but the brightness of the ground color and spotting brightness are not; the birds’ use of brightness rather than the more distinctive chromatic variation to recognize eggs might reflect the salience of achromatic contrast in a dim enclosed nest.

Genetic effect on free amino acid contents of egg yolk and albumen using five different chicken genotypes under floor rearing system.

Chicken eggs play an important role as food resources in the world. Although genetic effects on yolk and albumen contents have been reported, the number of chicken genotypes analyzed so far is still limited. To investigate the effect of genetic background on 10 egg traits, 19 yolk amino acid traits, and 19 albumen amino acid traits, we evaluated a total of 58 eggs from five genotypes: two Japanese indigenous breeds (Ukokkei and Nagoya) and three hybrids (Araucana cross, Kurohisui, and Boris Brown) under a floor rearing system. One-way ANOVA revealed significant effects of genotype on 10 egg traits, 8 yolk amino acids (Asp, Glu, Ser, Gly, Thr, Tyr, Cys, and Leu), and 11 albumen amino acids (Asp, Glu, Asn, Ser, Gln, His, Ala, Tyr, Trp, Phe, and Ile) contents. Moderate to strong positive phenotypic correlations among traits within each trait category (size and weight traits, yolk amino acid traits, and albumen amino acid traits), whereas there were basically no or weak correlations among the trait categories. However, a unique feature was found in the Araucana cross indicating moderate positive correlations of amino acids between yolk and albumen. These results suggest that genetic factors can modify not only the size and weight of the egg and eggshell color but also yolk and albumen free amino acids contents.

Estimation of Genetic Parameters for Body Weight and Some Colour Traits in the Seventh-generation Index Selected Nigeria Heavy Local Chicken Ecotype

Background: This study was conducted to estimate the genetic parameters of body weight and some colour traits in seventh generation (G7) index selected Nigerian Heavy Local Chicken Ecotype (NHLCE) progenies at point of lay to 12 weeks. Methods: 5 sires and 12 hens were used to generate the progenies used for the experiment. Traits measured included weekly body weight, egg colour, beak colour and feather colour. Data collected were subjected to one way analysis of variance in a Paternal half sib analysis using Animal model of SAS (2003). Four weeks body weight measurements, egg colour, beak colour and feather colour for 5 sires ranged from 1.29±0.05 1.54±0.07; 2.55±0.02 to 4.00±0.02; 2.45±0.02 to 4.83±0.02 and 1.73±0.02 to 4.58±0.04 respectively. Result: The new Duncan’s multiple range test shows that sire families are similar (p greater than 0.05) in the body weight and beak colour, but significantly differed (p greater than 0.05) in the egg colour and feather colour. The heritability estimates of mature body weight for week 3 was medium, while estimates of heritability for weekly mature body weight for weeks 1, 2 and 4, egg colour, beak colour and feather colour of NHLCE were low heritability. Low h2 of traits suggest that progeny and pedigree selection could be employed for improvement of the egg colour, beak colour and feather colour of NHLCE. The study showed positive genetic correlations between beak colour and egg colour, negative genetic correlations between beak and feather colour. This means that no decision can be taken in isolation as the selection of one trait will have consequences on other traits.

Estimation of genetic parameters for growth and egg related traits in Russian sturgeon (Acipenser gueldenstaedtii)

Russian sturgeon (Acipenser gueldenstaedtii) is one of the species of sturgeon, which has high economic value as its source of caviar. The aim of this study was to estimate genetic parameters of growth and egg related traits in Russian sturgeon. The heritability, genetic and phenotypic correlations and breeding values were estimated for body weight (BW), egg maturation (EM) and egg color (EC). In total, 3385 fish from 26 full-sib families (26 sires and 6 dams) were used for genetic analyses based on animal model (AM), sire model (SM) and sire-dam model (SDM). The results shown that the estimated heritability of BW ranged from 0.18 to 0.21 and the estimated heritability ranged from 0.32 to 0.54 and 0.33 to 0.59 for EM and EC based on three models, respectively. The Pearson and Spearman correlation coefficients among family estimated breeding value (EBV) were high (correlation coefficients ≥0.800), indicating that the predictive ability of different models for family EBVs was consistent. However, AM had a superior ability to predict EBV and SM was the best model for sire selection. The genetic and phenotypic correlations between growth and egg related traits were low, indicating that growth trait and egg related traits were relatively independent traits that could be improved respectively. Our results represent the first report of genetic parameters for growth and egg related traits in Russian sturgeon and indicate that these traits might be improved through selection breeding.

Mutations in a β-group of solute carrier gene are responsible for egg and eye coloration of the brown egg 4 (b-4) mutant in the silkworm, Bombyx mori

The brown egg 4 (b-4) is a recessive mutant in the silkworm (Bombyx mori), whose egg and adult compound eyes exhibit a reddish-brown color instead of normal purple and black, respectively. By double digest restriction-site associated DNA sequencing (ddRAD-seq) analysis, we narrowed down a region linked to the b-4 phenotype to approximately 1.1 Mb that contains 69 predicted gene models. RNA-seq analysis in a b-4 strain indicated that one of the candidate genes had a different transcription start site, which generates a short open reading frame. We also found that exon skipping was induced in the same gene due to an insertion of a transposable element in other two b-4 mutant strains. This gene encoded a putative amino acid transporter that belongs to the β-group of solute carrier (SLC) family and is orthologous to Drosophila eye color mutant gene, mahogany (mah). Accordingly, we named this gene Bmmah. We performed CRISPR/Cas9-mediated gene knockout targeting Bmmah. Several adult moths in generation 0 (G0) had totally or partially reddish-brown compound eyes. We also established three Bmmah knockout strains, all of which exhibit reddish-brown eggs and adult compound eyes. Furthermore, eggs from complementation crosses between the b-4 mutants and the Bmmah knockout mutants also exhibited reddish-brown color, which was similar to the b-4 mutant eggs, indicating that Bmmah is responsible for the b-4 phenotypes.

Quail eggs in artificial nests change their coloration when exposed to ambient conditions: implication for studies on nest predation.

Quail eggs have been widely used in field experiments, mainly to study factors associated with the risk of nest predation. Some shortcomings of using quail eggs in this type of study have been previously addressed (e.g., these eggs might be too big for some predators of eggs of small birds). Here, we show experimental evidence of another shortcoming of the use of these eggs in field experiments. Quail eggs exposed to sunlight rapidly faded in colour after three days, both in the visible and UV spectra, and this change was related to the amount of solar radiation received. This caused changes in the camouflage of the eggs, which may be perceived by predators with different visual systems (dichromatic, trichromatic, and tetrachromatic (for both violet- and UV-sensitive species)). Therefore, the results of field studies of nest predation using quail eggs might be questioned in those cases in which the camouflage has been altered due to the rapid changes in coloration, as this can affect the resulting predation rates. We recommend that researchers planning to use quail eggs should perform a prospective assessment of changes in coloration of eggs exposed to environmental conditions in the nest sites used by the target species.

Relationship among egg quality traits in Japanese quails and prediction of egg weight and color using data mining algorithms.

The present paper aims to predict egg weight from some egg quality characteristics (egg weight, yolk weight, albumen weight, shell thickness, shell weight, shape index, albumen index, yolk index, yolk scale, and Haugh unit) in Japanese quails and to classify 94 eggs collected in regards to their shell colors. In the present study, CART and MARS data mining algorithms were assessed in the prediction of egg weight of the quails with the content of detecting egg quality standards of the studied quail genotypes for breeding and marketing strategies. In the classification of the collected quail eggs on their shell colors, classification performances of CART, CHAID, exhaustive CHAID, and QUEST algorithms were measured. Among those, CART was selected as the best classification algorithm according to eggshell color. The highest significant correlations were obtained for egg weight-yolk weight (0.740) and egg weight-albumen weight (0.735), respectively, in considering egg internal and external quality traits in quails. CART algorithm more accurately classified all eggshell colors compared with other algorithms. MARS showed much better predictive performance than CART that produced 0.850 Rsq and 0.728 cross-validation Rsq for prediction of egg weight in quails. In conclusion, the obtained results revealed that data mining algorithms may be useful references in practice for quail breeders in the development of new selection strategies and characterization of the studied animal materials.