THE NUTRIENTS AND NUTRITION 305 



part of tlie skeleton or framework of plants. In connection 

 with ])()ultry I'eeiling it is usually referred to as crude fiber 

 which is largely cellulose, and will be throughout this work. 

 It constitutes from 2 to 5 per cent of seeds and grains. All 

 of the other carbohydrates of nutritive value are found in 

 the nitrogen-free extract. 



Carbohydrates, which are so plentiful in plants, are 

 scarcely found in the fowl's body or the egg. Glycogen, 

 an animal starch, is stored in the liver, which converts 

 it into a sugar called glucose, and gives it out to the 

 circulation, from whence it helps to supply energy to 

 the muscles. 



According to Atwater,' carbohydrates form 2.4 per cent 

 of the total weight of the liver of the young chicken. Lang- 

 worthy'-^ reports that 0.67 per cent of the egg is carbohydrate, 

 one-third of which occurs in the yolk and two-thirds in the 

 albumen. 



Fats. — Fat contains the same elements as do the carbohy- 

 drates, but in very different proportions. Perhaps the most 

 characteristic difference is in the propdrtion of oxygen, 

 which is very much lower in the case of fat. The carbo- 

 hydrates are oxidized fats. The comparison between the 

 percentage composition of starch and stearin, a fat found in 

 both the fowl's body and the egg, is as follows: 



Carbon, 

 per cent 



Starch 44.44 



Stearin 76.85 



Fats (lipins) are jjresent in nearly all grains, but in very 

 small proportions as compared with the body of the fowl or 

 even the egg. While they form .5 per cent of the air-dry 

 weight of corn and oats and 2.1 per cent of wheat, they 

 constitute 17 per cent of the live weight of a nervous, active 

 Leghorn hen and 38 per cent of the dry-matter weight. 

 Fat comprises 8.9 per cent of the weight of the new-laid egg, 

 all but a trace being located in the yolk, of which it forms 



1 U. S. Farmers' Bulletin No. 182. 

 » Ibid., No, 128. 



