FAT METABOLISM OF THE CHICK EMBRYO UNDER STANDARD CONDITIONS OF ARTIFICIAL INCUBATION

¹ CORNELL UNIVERSITY

1. Fat content of fresh eggs is a subject of great variation, due primarily to disparity in size of individual eggs.

2. Iodine value, saponification number and refractive index of the fat from fresh eggs are rather constant, but only under a given experimental condition.

3. The main source of fat in an egg is the egg yolk, which furnishes the fat for nutrition and energy-supply of the developing embryo.

4. The amounts of fat in the growing embryo and egg yolk give a comprehensive idea about the changes in fat which go on within an egg during incubation.

5. The relative increase of fat in the embryo and the decrease of it in the yolk can be well demonstrated by the curves plotted from the data on the percentages of fat in dry weight.

6. The curve of combusted fat is quite similar to the curve of the growth of embryo.

7. Iodine value, saponification number and refractive index of the fat from the yolk sac of the developing egg are almost constant through the incubation period.

8. Iodine value and refractive index of the fat from the developing embryo are increasing and decreasing respectively during the latter part of incubation.