Late-stage Chicken (Gallus domesticus) Embryo Growth Patterns and Albumen Consumption
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Authors
Groth, Kevin D.
Issue Date
2009
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
Maternal investment of energy and nutrients, in the form of yolk and albumen
contained in each bird egg, has a profound effect on hatchling phenotype. Composition
of the egg and mechanisms by which nutrients are utilized match th e needs of the
organism developing inside an eggshell. We used the natural variation in the mass and
composition of chicken (Gallus domesticus) eggs to examine consequences of variation in yolk and albumen mass on hatchling mass in a precocial bird. The eggs we examined contained 68% albumen and 32% yolk and ranged in mass from 45 to 75 g. Variation in egg mass arose from changes in both albumen and yolk mass, but changes in albumen mass explained most of the variation in egg mass. We found a positive correlation between initial egg mass and wet body mass as embryos approached hatching, suggesting that embryos in larger eggs utilized additional albumen and yolk to increase embryonic growth. SDS-P AGE revealed that albumen was ingested by embryos and transported via the gut into the yolk sac during incubation. Variation in quantity of albumen added to the yolk sac during the latter half of incubation probably contributes to variation in structural growth (tibiotarsus and culmen length) and body mass of embryos. Although the exact means by which egg albumen is translocated into the amnion of bird embryos has yet to be identified, our findings suggest that albumen is a major contributor to variation in hatchling phenotype.
Description
vi, 31 p.
Citation
Publisher
Kalamazoo College
License
U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder.