The structural significance of the avian yolk in embryogenesis

Schlesinger, Allen B.

doi:10.1002/jez.1401380204

Cited by 19 publications

(1 citation statement)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is the period when the vitelline arteries that carry blood from the embryo heart to the periphery of the blastoderm become clearly visible (Baggott 2009). Another important physiological change occurring at this time was the appearance of sub-embryonic fluid (SEF) in the yolk sac beneath the embryo (New 1956), which increases rapidly to occupy the upper portion of the yolk sac, destroying the internal structure of the yolk (Schlesinger 1958). This was probably why no significant decreases in T575/T598 ratio (P > 0.01) were observed in fertile eggs until d 2 of incubation, as shown in Figure 5.…”

Section: Discussionmentioning

confidence: 99%

Nondestructive sex-specific monitoring of early embryonic development rate in white layer chicken eggs using visible light transmission

Rahman

Syduzzaman

Khaliduzzaman

et al. 2020

British Poultry Science

View full text Add to dashboard Cite

1. Sex-specific variations in early embryonic development rates may preempt later variations in embryonic development through to pipping and hatching. Given that erythropoiesis (blood production) can be equated with early embryonic growth rate, it was hypothesised that blood pigment haemoglobin can act as a specific spectral fingerprint for changes in growth rate. Moreover, by measuring longitudinal, rather than lateral, spectral transmission through the egg, a more consistent spectrum with a higher signal-to-noise ratio could be captured. 2. Longitudinal visible transmission (T575/T598 ratio), which is sensitive to haemoglobin, was used to monitor sex-specific early embryonic development rate in white layer chicken eggs from d 0 to 8 of incubation. The sex of these eggs was subsequently confirmed two days after hatching. 3. Embryonic development was detectable from d 3 (72 h) of incubation, 36 h earlier than previously reported lateral spectral measurements, supporting the greater sensitivity of longitudinal measurements. 4. At d 3, the mean T575/T598 ratio for male embryos was significantly lower (P < 0.001) (i.e. higher absorbance of haemoglobin) than for female embryos, which was thought to be due to sexdifferences in early embryogenesis. On the other hand, female embryos had a significantly lower (P < 0.05) mean T575/T598 ratio than male embryos at d 7 of incubation, presumably due to the combined effects of oestrogen synthesis receptors and enzymes on erythropoiesis in female embryos at this time. 5. In conclusion, the proposed methodology has the sensitivity to differentiate sex-specific embryonic development rates during early incubation and the potentiality to advance precision incubation management and poultry research.

show abstract

Section: Discussionmentioning

confidence: 99%

Nondestructive sex-specific monitoring of early embryonic development rate in white layer chicken eggs using visible light transmission

Rahman

Syduzzaman

Khaliduzzaman

et al. 2020

British Poultry Science

View full text Add to dashboard Cite

show abstract

Nutritional requirements for the realization of regulative (repair) capacities of young chick blastoderms

Spratt

Haas

1967

J. Exp. Zool.

View full text Add to dashboard Cite

Studies of the regulative (repair) capacities of young chick blastoderms in ovo and explanted i n vitro on culture media varying in their growth promoting properties clearly indicate that these capacities are realized fully only under the most optimal nutrient conditions. Thus the ability of an explanted part of a young blastoderm to form a bilaterally symmetrical embryo body depends not only on the region of the blastoderm isolated, on its intrinsic growth potentiality and on its size (cell number) but also on the growth promoting properties of the culture medium. Realization of regulative potentiality goes hand-in-hand with realization of growth (or other synthetic) potentiality.The growth and regulative capacities of separated parts (halves, quarters, etc.) of unincubated and early streak chick blastoderms explanted on an egg-extract culture medium are pronounced (Spratt and Haas, '60c; '61a, b). In general, any part of the unincubated blastoderm which includes the growth center or a segment of the marginal zone ( pellucid-opaque area junction) and is larger than one-sixteenth of the area of the blastoderm may form a bilateraIIy symmetrical and essentially complete embryo body axis. More recently, it was discovered that an isolated and explanted central part of a very young unincubated blastoderm (from a winter egg) which included neither the growth center nor part of the marginal zone could form an embryo axis (Eyal-Giladi and Spratt, '65). Chick and duck (Lutz et al., '63) blastoderms thus seem to have similar regulative capacities to the extent that both are almost equipotential (or totipotential).Older sudies of organ-forming capacities of parts of prestreak and early streak blastoderms (stages 1 +-2+, Hamburger and Hamilton, '51) explanted on a blood plasma and embryo extract medium suggested that the young blastoderm had mosaic properties (Spratt, '42 p. 83). Parts of the embryo body axis seemed to be localized in the blastoderm during and even before streak-formation. Separated anterior and posterior parts developed in accord with their prospective fates, i.e., there was little increase in size of the explants J. EXP. ZOOL., 164: 31-46 and regulative capacity was minimal. The primary difference between the older experiments and more recent ones seems to be the kind of culture medium used. This suggested the need for a study of the infiuence of the nutritional composition of a culture medium on growth and regulative ~apacities.~ METHODSExplantation procedures were the same as those reported earlier (Spratt, '47a, b; Spratt and Haas, '60a, b). In all in vitro experiments the blastoderms or fractions thereof were explanted upper layer (epiblast) down on the solid agar medium. This position is important in unincubated and prestreak blastoderms, less important in older blastoderms (Spratt and Haas, '60a, b; '65; Spratt, '66). The upside-down position of the explant simulates that of the in ovo blastoderm. The surface of the solid culture medium corresponds to the underside of the vitelline membr...

show abstract

Failure to turn eggs during incubation: Development of the area vasculosa and embryonic growth

Deeming¹

1989

Journal of Morphology

View full text Add to dashboard Cite

Effect of turning of the egg during incubation on development of the area vasculosa of the chick embryo was investigated. The size of the area vasculosa was determined by two methods: direct measurement with calipers and measurement of a template cut from the eggshell by use of an automatic surface area recorder. The effects of turning and additionally the effects of lowered temperature (36°C) on both growth of the area vasculosa by day 7 and embryo growth by day 14 of incubation were investigated. The effects of turning during a critical period for turning, from 3 to 7 days of incubation, were also recorded. Generally, failure to turn eggs retarded growth of the area vasculosa. Turning during the critical period stimulated the extent of growth of the area vasculosa by day 7 of incubation and of subsequent embryonic growth by day 14. Incubation at low temperature resulted both in reduced expansion of the area vasculosa and retarded embryonic growth in a pattern similar to that observed for unturned eggs. It is suggested that turning stimulates development of blood vessels in the area vasculosa via localized increases in blood pressure. The effect of a reduced area vasculosa is considered to retard embryonic development through restricted nutrient uptake from the yolk. The prevailing hypothesis that turning prevents deleterious membrane adhesions is questioned in light of these observations. It is suggested that the physiological basis for the need for turning lies in maximizing the growth rate of the area vasculosa to maximize yolk use and embryonic growth rate.

show abstract

The structural significance of the avian yolk in embryogenesis

Abstract: ISTRODUCTIONThe avian yolk is an exhaustively studied biological entity.

Cited by 19 publications

References 16 publications

Nondestructive sex-specific monitoring of early embryonic development rate in white layer chicken eggs using visible light transmission

Nondestructive sex-specific monitoring of early embryonic development rate in white layer chicken eggs using visible light transmission

Nutritional requirements for the realization of regulative (repair) capacities of young chick blastoderms

Failure to turn eggs during incubation: Development of the area vasculosa and embryonic growth

Contact Info

Product

Resources

About