Correlation between shell colour and ultrastructure in pheasant eggs

Richards, P.D.G.; Deeming, D. C.

doi:10.1080/00071660120055304

Cited by 21 publications

(11 citation statements)

References 14 publications

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“…Support for this hypothesis stems from the biochemical properties of protoporphyrin (Gosler et al ) as well as a negative correlation between protoporphyrin and eggshell thickness, with multiple lines of evidence suggesting that birds that are calcium‐limited may use protoporphyrin to compensate for necessarily thinner eggshells (Cherry and Gosler , Gosler et al ). While previous studies have shown no significant link between blue‐green eggshell coloration and eggshell thickness (Jagannath et al ), other studies have documented such relationships, with bluer eggshells sometimes having thinner (Richards and Deeming ) or thicker (Morales et al ) eggshells (but see Cassey et al ). However, these studies all examined relationships between eggshell thickness and blue‐green coloration, but not with biliverdin concentration per se.…”

Section: Discussionmentioning

confidence: 96%

Eggshell biliverdin concentration does not sufficiently predict eggshell coloration

Butler

Waite

2016

Journal of Avian Biology

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Avian eggshell coloration may have arisen due to selection on the biological, chemical, or physical properties of the pigments embedded within the eggshell, or due to selection on the coloration that emerges due to pigment deposition. Within both hypothetical frameworks, pigment‐based eggshell coloration would be related to metrics of egg quality; however, no one has evaluated the relative strength of coloration and pigment concentration in predicting egg quality. Here, we examined 66 European starling Sturnus vulgaris eggs and quantified eggshell biliverdin concentration (an antioxidant that produces the eggshell's blue coloration) and used 28 different coloration metrics derived from both photographic and spectrophotometric data. We also measured egg size, eggshell thickness, concentration of carotenoids in the yolk, and concentration of lysozyme in the albumen to capture variation in egg quality. We found that throughout the laying sequence, biliverdin concentration increased while eggshell thickness, yolk carotenoid concentration, and lysozyme concentration in the albumen all decreased, but this variation was not captured by any eggshell coloration metric. Both eggshell coloration and biliverdin concentration were negatively associated with yolk carotenoid concentration, but only eggshell biliverdin concentration was negatively associated with yolk mass. Lastly, biliverdin concentration explained, at most, only 46% of the variation for all eggshell coloration metrics. Our results suggest biliverdin concentration is a better predictor of egg quality than egg coloration in European starlings, supporting the hypothesis that eggshell pigment concentration per se may be the target of selection.

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Section: Discussionmentioning

confidence: 96%

Eggshell biliverdin concentration does not sufficiently predict eggshell coloration

Butler

Waite

2016

Journal of Avian Biology

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“…On the other hand, the results obtained for hatchability and the hatchability of fertile eggs in the present study diverged from those reported by Farghly et al (2015) and Hassan et al (2013) suggesting eggshell colour to have an effect on both hatchability and hatchability of fertile eggs. In research conducted by Hulet et al (1985) and Richards and Deeming (2001) on pheasant eggs, it was ascertained that blue and tan coloured eggs had a thinner eggshell and presented a lower hatchability, in comparison with green, dark brown, and grey/white eggs. Furthermore, Kożuszek et al (2009a) reported that the hatchability of fertile eggs was lower in blue eggs compared with dark brown eggs.…”

Section: Discussionmentioning

confidence: 99%

“…Hulet et al (1978) demonstrated that, in pheasant eggs, eggshell colour and hatchability were correlated with each other. Richards and Deeming (2001) suggested that eggs with blue eggshell colour are structurally defective eggs with a thin eggshell. These researchers explained the low hatchability of blue coloured eggs as being due to the high weight loss resulting from their structural defection.…”

Section: Introductionmentioning

confidence: 99%

The impact of eggshell colour and spot area in Japanese quails: I. eggshell temperature during incubation and hatching results

et al. 2016

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-This study was carried out to investigate the effects of eggshell colour and spot properties (colour and size of the spot area) on eggshell incubation temperature and hatching outcomes of Japanese quail eggs (Coturnix coturnix japonica). Study material was allocated to five groups according to their eggshell and spot colours: black spots on greyish white coloured eggshell (I), blue spots on greyish white coloured eggshell (II), diffuse brown spots on greyish brown coloured eggshell (III), brown spots on light green coloured eggshell (IV), and small brown spots on greyish brown coloured eggshell (V). The size of the spotted area was determined in each egg group using digital image analysis. Mean relative weight losses of hatched and unhatched eggs between days 0-10 and 0-14 of embryonic development were 4.76% and 10.48% and 9.17% and 15.46%, respectively. The mean eggshell temperatures of hatched and unhatched eggs measured at the equatorial region on days 10 and 14 during embryonic development were 36.92 and 37.79 ºC and 36.84 and 37.18 ºC, respectively. Eggshell temperatures at the equatorial region on days 10 (36.89 ºC) and 14 (37.57 ºC) of embryonic development were lower than the fixed temperature of the incubator (37.6 ºC). Fertility, hatchability of fertile eggs, and hatchability and embryonic mortality rates do not vary in relation to eggshell colour or the size of the spotted area.

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“…Brown eggshell color has been positively correlated with some shell characteristics such as shell strength and hatchability (Sekeroglu and Duman, 2011), while egg internal quality has no correlation with shell color (Yang et al, 2009). Further, it has been suggested that some shell quality parameters such as shell strength, shell weight, shell thickness, and shell ultrastructure can be assessed via shell color because of significant correlations between the shell quality indicator and shell color (Schreiweis et al, 2006;Yang et al, 2009); however, others have provided conflicting evidence (Joseph et al, 1999;Richards and Deeming, 2001), and thus shell color cannot be applied reliably as a quality assessment tool.…”

Section: Shell Color and Egg Qualitymentioning

confidence: 99%

Eggshell color in brown-egg laying hens — a review

2015

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The major pigment in eggshells of brown-egg laying hens is protoporphyrin IX, but traces of biliverdin and its zinc chelates are also present. The pigment appears to be synthesized in the shell gland. The protoporphyrin IX synthetic pathway is well defined, but precisely where and how it is synthesized in the shell gland of the brown-egg laying hen is still ambiguous. The pigment is deposited onto all shell layers including the shell membranes, but most of it is concentrated in the outermost layer of the calcareous shell and in the cuticle. Recently, the genes that are involved in pigment synthesis have been identified, but the genetic control of synthesis and deposition of brown pigment in the commercial laying hen is not fully understood. The brown coloration of the shell is an important shell quality parameter and has a positive influence on consumer preference. The extent of pigment deposition is influenced by the housing system, hen age, hen strain, diet, stressors, and certain diseases such as infectious bronchitis. In this article, the physiological and biochemical characteristics of the brown pigment in commercial brown-egg layers are reviewed in relation to its various functions in the poultry industry.

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Correlation between shell colour and ultrastructure in pheasant eggs

Cited by 21 publications

References 14 publications

Eggshell biliverdin concentration does not sufficiently predict eggshell coloration

Eggshell biliverdin concentration does not sufficiently predict eggshell coloration

The impact of eggshell colour and spot area in Japanese quails: I. eggshell temperature during incubation and hatching results

Eggshell color in brown-egg laying hens — a review

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