Nutrient Limitations

Limiting nutrients to the embryo is a possible intrinsic factor that may be limiting to growth capacity of avian embryos.[20] The supply of yolk or the mechanism providing yolk to the developing embryos may limit embryonic growth, particularly late in development. Early in development, embryos in both large and small eggs have ample yolk because of equal access to nutrients. Late in development, the acquisition of yolk is dependent upon the surface area covered by the yolk sac membrane. Large eggs have larger yolks than small eggs, thus providing more nutrients, but the surface covering the yolk increases according to the surface law. The absorptive surface of the yolk sac membrane covering the yolk, calculated as the yolk volume to the two-thirds power, declines in large eggs.[2] Thus, larger eggs have larger yolks, and the surface area and the vascularity of the yolk sac membrane available for nutrient assimilation decreases compared to smaller eggs.

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