CHAPTER XIII 

 NUTRITION 



Tissue waste or wear and tear is constantly going on in the 

 body of the fowl. As fast as destruction takes place repair 

 must follow or death is the result. 



The body of a mature fowl consists of 55.8 per cent, water, 

 3.8 per cent, ash, 21.6 per cent, protein, and 17 per cent. fat. 



A larger portion of the body weight is always water. Salts 

 are always the smallest amount. The amount of fat depends 

 on the condition of the bird. In fat adult birds it may be 

 three times the estimate above. 



The bulk of the body is muscle, which holds half the water 

 and half the protein found. 



As shown before, the income of the body consists of four 

 essential elements — ^namely, carbon, hydrogen, oxygen, and 

 nitrogen, together with water, sulphur, phosphorus, and other 

 salts. All of these elements, except a part of the oxygen, are 

 taken in through the food. Much oxygen is taken in through 

 the lungs in respiration. 



The outgo or expenditures of the body consist of the same 

 elements, and are eliminated from the body by way of the 

 lungs, urine, and skin. 



It is probable that nitrogen is excreted almost wholly through 

 the kidneys by the urine. It is eliminated principally as 

 uric acid. The hydrogen is ehminated from the body in form 

 of water (H2O). Water is given off by the urine and lungs. 



Carbon is eliminated from the body principally as carbon di- 

 oxid (CO2) by way of the lungs. Some is also gotten rid of 

 through the kidneys. Salts (ash) are eliminated by the kidneys 

 through the cells of the tubules. Sulphur is utilized and lost 

 through the formation of epithelium, feathers and horn of the 

 spurs, toes, and beak, as well as through the kidneys. 



Since the feces or droppings consist of food nutrients which 



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