172 PRINCIPLES OF POULTRY FEEDING 



energy. In vegetable feeding stuffs they constitute a distinct group. 

 In animal feeding stuffs they are represented chiefly by the small 

 proportion of glycogen present. Their principal elements are 

 carbon, hydrogen, and oxygen. Like fat, they contain neither 

 nitrogen nor sulphur, but they differ from fat in that they contain 

 less carbon and more oxygen. Carbohydrates can usually be pro- 

 duced at home ; very little should be purchased on a well-managed 

 poultry plant, provided there is land enough for the growing of 

 the proper crops. As found in feeding stuffs, carbohydrates may 

 be divided into two general classes: 



(1) Substances which go to make up the cells or framework of 

 the plant, such as cellulose and fibrous materials difficult to sepa- 

 rate, represented in the analysis by the term " crude fibre." 



(2) Substances illustrated by starches and sugars found stored 

 up in cells as reserve material, dissolving readily in water and 

 sometimes represented in analysis tables by the term " nitrogen- 

 free extract." 



Ash. The mineral matter in feeding stuffs which supplies the 

 incombustible material to the bird's body is called ash. This 

 ingredient is very necessary, especially in the growing of young 

 animals, and can be supplied to poultry in the form of grit, shell, 

 bone, and feeds such as bran and alfalfa, which are rich in ash. 



Uses of Nutrients in the Body. All the nutrients in the ration, 

 minus the water present, constitute what is commonly termed the 

 total dry matter. Each nutrient has a definite work to do in 

 nourishing the body. In an efficient method of feeding they must 

 all be supplied in abundance and in the right proportion. 



The most obvious use of protein is the production of tissue, as de- 

 sired in growing chicks or young animals, the repairing and building 

 up of the waste tissue in the adult, and the supplying of material 

 which goes into the formation of feathers, claws, and similar parts. 

 The second use is exemplified by the part which protein takes in the 

 production of the egg. In compounding the ration it must be 

 remembered that protein is indispensable and that its place cannot 

 be satisfactorily filled by carbohydrates or fat. If, however, the 

 protein content of the feed consumed is in excess of that required 

 for tissue building and egg production, it is burned in the body 

 like carbohydrates and furnishes material for the formation of fat. 



The uses of the carbohydrates and the fats of feeding stuffs are 

 so similar that they may be considered together. Three uses are 

 given: (1) They are burned and produce heat, which keeps the 



