Endocrine Control of Avian Carbohydrate Metabolism ,

THE topic at hand is somewhat overwhelming in its naivety considering the fact that rarely does an organism restrict its nutritive intake and attendant metabolism to only one form of substrate, in this case carbohydrate. Of necessity, therefore, some interrelationships with lipid and protein metabolism will be considered in the following discussion of carbohydrate metabolism in pre- and post-hatch avian forms. Unfortunately, most of the significant data available on this topic are those drawn from one or two avian species and therein our general understanding of avian carbohydrate metabolism may well be a very restricted one indeed. A. EMBRYO METABOLISM The earliest detection of plasma glucose in chick embryos has been approximately day 4 of incubation and the values obtained at this stage of development (80 mg.%) progressively rise until by hatching time they are essentially “adult” levels of 190 mg.% or more. While a rather prolonged plateau in plasma…