80 COLOR FEEDING 



the fat is made from the protein in the albumen. Attention is also 

 called to the presence of the small amount of protein in the albumen fed 

 upon by the embryo. This leads us to question whether the bulk of 

 nourishment provided for the embryo is in the form of protein or fat. 



An opposite result pointing to the same conclusion occurs when incubat- 

 ing the Rhodamine Red colored eggs. In this instance the soft albumen no 

 longer retains the pink color of the fresh egg but becomes a light yellow, 

 resembling the yolk in appearance, but being fine grained. (Plate I, B). 

 As the colored protein is changed under the influence of incubation it 

 loses its color entirely. 



The infertile egg does not change in color or composition. The bands of 

 color in the yolk remain as in the fresh egg even after five days of incubation. 



THE CHICK 



The feeding of these dyes does not impair the hatching power of the 

 eggs. The chicks hatched from Sudan III colored eggs were colored 

 wherever their bodies contained fat, especially along the breast and 

 abdomen, just underneath the skin. (Plate I, E). The yolk in the day 

 old chick still contained color, indicating that some fat remained. In one 

 chick, twenty-four hours old, the coloring of the yolk was concentrated 

 around the outer portion of the yolk sac where it could be most easily 

 digested and assimilated. 5 Analysis showed that there was a large percent- 

 age of fat remaining. Except for a slight increase in the percentage of pro- 

 tein and a decrease in the percentage of fat, the proportion of each remains 

 about constant while the yolk is being absorbed. The moisture content, 

 also, remains practically constant. 



Upon withholding food from Sudan III colored chicks till four days of 

 age the fat tissues in the body were used up in developing energy and heat. 

 Consequently, the color passed away and was lost. 



Since the color leaves the albumen of the Rhodamine Red colored egg 

 when it is digested for the use of the embryo, one does not expect to 

 see color appear conspicuously in the chick. This is true except for a very 

 slight tint of pink, which shows in the down. 



THE FLESH 



Sudan III was also fed to fattening fowls. The exact extent and amount 

 of the fat deposits was shown by the pink color. The color did not show up 



6 Frank R. Lillie explains in "The Development of the Chick" page 225 the feasibility 

 of the contents of the unabsorbed yolk in the day old chick being digested and assimilated 

 by a special glandular and absorbing epithelium surrounding the yolk sac. 



