Mineral Composition of Yolk Fractions and Whole Yolk from Eggs of Restricted Ovulator Hens

Grau, C. R.; Roudybush, T. E.; McGibbon, W. H.

doi:10.3382/ps.0581143

Cited by 12 publications

(11 citation statements)

References 6 publications

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“…Based on the dye deposition pattern, Birrenkott and McGibbon (1975) reported that yolks from WT and R/O hens took approximately 8 d and 7 d, respectively, to develop, but they did not mention whether there was any disruption of the normal yolk banding pattern in eggs from R/O hens compared with those from WT hens. In contrast, Grau et al (1979) observed rings in the yolk of hierarchal follicles of R/O hens but, in laid R/O eggs, the yolk ring structure was completely disrupted. This suggested that the yolk structure of R/O eggs was not as stable as that of eggs from WT hens.…”

Section: Reproductive Characteristics—hemizygous R/o Femalesmentioning

confidence: 83%

“…Yolks from R/O eggs stained less intensely with acidic ferrocyanide than WT yolks, suggesting that they contained relatively less iron. Mineral analyses performed by atomic absorption spectrophotometry revealed that R/O egg yolks contained less iron and copper, similar levels of phosphorus, and more sodium and potassium than egg yolks from WT hens (Grau et al, 1979). In addition, the yolk granule fraction of R/O eggs contained less iron and manganese than those from WT layers.…”

Section: Other Metabolic or Physiological Characteristics Of Mutant Rmentioning

confidence: 95%

“…This can be easily visualized either by feeding fat-soluble dyes to hens or by injecting the dye as a colloidal dispersion into their blood stream, hard-cooking (or freezing) the eggs, and then preparing a cross-section of the yolk. Using this method, Birrenkott and McGibbon (1975) and Grau et al (1979) investigated the yolk ring structure of laid eggs from WT and R/O hens. Based on the dye deposition pattern, Birrenkott and McGibbon (1975) reported that yolks from WT and R/O hens took approximately 8 d and 7 d, respectively, to develop, but they did not mention whether there was any disruption of the normal yolk banding pattern in eggs from R/O hens compared with those from WT hens.…”

Section: Reproductive Characteristics—hemizygous R/o Femalesmentioning

confidence: 99%

“…This suggested that the yolk structure of R/O eggs was not as stable as that of eggs from WT hens. Although the underlying cause of this phenomenon is unknown, Grau et al (1979) found that yolks of R/O eggs contained 16% more water than WT egg yolks, while Schjeide et al (1975) observed a paucity of maturing yolk granules in the ooplasm of small hierarchal follicles (5 mm in diameter) of R/O hens.…”

Section: Reproductive Characteristics—hemizygous R/o Femalesmentioning

confidence: 99%

“…Grau et al (1979) examined the ring structure and relative iron content of yolks by freezing intact eggs from R/O and W/T hens, fixing them with formalin, cutting them in half and then staining one half with potassium dichromate and the other half with acidic potassium ferrocyanide. Yolks from R/O eggs stained less intensely with acidic ferrocyanide than WT yolks, suggesting that they contained relatively less iron.…”

Section: Other Metabolic or Physiological Characteristics Of Mutant Rmentioning

confidence: 99%

See 4 more Smart Citations

The restricted ovulator chicken strain: An oviparous vertebrate model of reproductive dysfunction caused by a gene defect affecting an oocyte-specific receptor

Elkin

Bauer

Schneider

2012

Animal Reproduction Science

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A unique non-laying strain of chickens with heritable hyperlipidemia and aortic atherosclerosis was first described in 1974. Subsequent work established that the phenotype results from a naturally occurring point mutation in the gene specifying the very low density lipoprotein (VLDL) receptor, a 95-kDa membrane protein which normally mediates the massive uptake of the main circulating hepatically-synthesized yolk precursors, VLDL and vitellogenin. As a result, hens of the mutant strain termed “restricted ovulator” (R/O) have approximately 5-fold elevations in circulating cholesterol and triglyceride concentrations compared with normal layers, and hepatic lipogenesis and cholesterogenesis are markedly attenuated due to feedback inhibition. R/O hens also exhibit hyperestrogenemia, hypoprogesteronemia, elevated circulating gonadotropins, and up-regulated pituitary progesterone receptor mRNA and isoforms. The ovaries of R/O hens are abnormal in that they lack a follicular hierarchy and contain many small preovulatory follicles of various colors, shapes, and sizes. However, since R/O hens occasionally lay eggs, it is possible that endocytic receptors other than the VLDL receptor may be able to facilitate oocyte growth and/or that yolk precursor uptake can occur via a nonspecific bulk process. A mammalian model of impaired fecundity with abnormal lipoprotein metabolism also has been described, but different mechanisms are likely responsible for its reproductive dysfunction. Nevertheless, as our understanding of the molecular physiology and biochemistry of avian oocyte growth continues to expand, in part due to studies of the R/O model, new analogies may emerge between avian and mammalian systems, which ultimately could help to answer important questions in reproductive biology.

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Section: Reproductive Characteristics—hemizygous R/o Femalesmentioning

confidence: 83%

Section: Other Metabolic or Physiological Characteristics Of Mutant Rmentioning

confidence: 95%

Section: Reproductive Characteristics—hemizygous R/o Femalesmentioning

confidence: 99%

Section: Reproductive Characteristics—hemizygous R/o Femalesmentioning

confidence: 99%

Section: Other Metabolic or Physiological Characteristics Of Mutant Rmentioning

confidence: 99%

See 3 more Smart Citations

The restricted ovulator chicken strain: An oviparous vertebrate model of reproductive dysfunction caused by a gene defect affecting an oocyte-specific receptor

Elkin

Bauer

Schneider

2012

Animal Reproduction Science

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Hepatic zinc, copper, and iron in the developing turkey embryo and newly hatched poult

Richards

Weinland

1985

Biol Trace Elem Res

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The ontogeny of hepatic tissue growth and trace metal deposition was examined in the developing turkey embryo and newly hatched poult. Hepatic concentrations of zinc and iron in the embryo declined by about twofold between day 16 of incubation and hatching. Hepatic copper concentration increased approximately fourfold by day 23 of incubation and then declined rapidly through hatching. During the post-hatching period, hepatic zinc concentration increased twofold by day 10, whereas a small increase in hepatic iron concentration occurred just prior to hatching and continued through the third day post-hatching. A significant positive correlation existed between hepatic zinc and iron concentrations in the developing embryo. The concentrations of both these metals were inversely correlated with hepatic copper concentration during the same time. Total hepatic zinc and iron content increased throughout the entire time studied, whereas total copper content increased up to hatching and then declined during the first week post-hatching. The most rapid phase of hepatic metal accretion differed for each metal, with zinc being rapidly accumulated during the post-hatching period, copper during the last half of incubation and iron at about the time of hatching and the first few days post-hatching. Each of these metals demonstrated a specific relationship to hepatic tissue growth that changed between the embryonic and neonatal periods of development.

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Mineral metabolism in the developing turkey embryo—II. The role of the yolk sac

Richards

1991

Comparative Biochemistry and Physiology Part A: Physiology

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Mineral Composition of Yolk Fractions and Whole Yolk from Eggs of Restricted Ovulator Hens

Cited by 12 publications

References 6 publications

The restricted ovulator chicken strain: An oviparous vertebrate model of reproductive dysfunction caused by a gene defect affecting an oocyte-specific receptor

The restricted ovulator chicken strain: An oviparous vertebrate model of reproductive dysfunction caused by a gene defect affecting an oocyte-specific receptor

Hepatic zinc, copper, and iron in the developing turkey embryo and newly hatched poult

Mineral metabolism in the developing turkey embryo—II. The role of the yolk sac

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