POULTRY FOODS 33 



POULTRY FOODS 



COMPOSITION OF FOOD 



Food is any substance that a plant or an animal may 

 take into its body and use for building up wasted 

 tissues and maintaining natural conditions. Besides 

 water, which is present in all foods, the different com- 

 pounds of which solid animal foods are composed have 

 been grouped into four classes: carbohydrates, fats, 

 protein, and ash. All the compounds belonging to these 

 classes of food elements, or principles, are not completely 

 digestible, and the value of poultry food is determined 

 largely by the amount of these food constituents that 

 can be digested by the fowls. 



When food is digested it forms blood, which circulates 

 throughout the body and sustains life. By means of 

 the blood the nutritious portions of the food are assimi- 

 lated, or incorporated into the body of the fowl for the 

 purpose of nourishing it and for renewing wasted tissues. 

 Eggs are composed largely of the same kind of materials 

 that are utilized in the formation of blood and flesh. 



All foods contain water; dry grains, meals, and hays 

 contain from 7 to 10%, and grasses, green plants, roots, 

 and unripened grains contain from 60 to 70%. The 

 flesh of fowls and their eggs are from 41 to 65% water, 

 1 doz. new-laid eggs containing almost 1 Ib. 



The greater portion of the solid part of poultry food 

 is composed of carbohydrates, or nitrogen-free extracts, as 

 they are sometimes called. Carbohydrates are made up 

 largely of starch, sugar, gums, vegetable acids, and crude 

 fiber. Carbohydrates are used by fowls to supply 

 energy, to produce animal fats and oils, and to maintain 

 the body heat. 



The food elements known as fats, or oils, differ from 

 carbohydrates in being able to produce more heat. For 



