Mineral Content of Southern Poultry Feeds 5 
proteins. The eliminated phosphorus by way of the urine is in the form 
of di- and mono-hydrogen phosphates of sodium and potassium, and 
less abundantly in the form of phosphates of calcium and magnesium. 
The phosphorus of the feces is largely in the form of phosphates. 
Chlorine enters the body as chlorides and is eliminated by the kidneys 
almost wholly as chlorides. 
To summarize, the mineral bases are calcium, sodium, magnesium, 
and potassium, which enter the body as salts of various organic and 
inorganic acids. These alkali reacting elements are used in the body 
mostly in combination with phosphoric, sulphuric, hydrochloric, and 
carbonic acids, principally for structural, regulative and catalytic 
purposes, and are eliminated from the body as inorganic salts. 
Forbes 4 summarizes as follows: “The organic acids of feedstuffs, 
such as citric, malic, and tartanic acids of fruits, are mostly oxidized 
in the animal body to carbondioxide and water, in which compounds 
they are excreted from the body. There are formed within the body 
mineral acids which cannot be eliminated in this way. These acids 
must be neutralized in order to protect the animal from a disturbance 
of conditions essential to the continuance of vital reactions.” 
These acids are formed chiefly by the cleavage and oxidation of pro- 
teids, either of the body or of the feed, the sulphur and phosphorus 
contained therein, as constituent parts, being oxidized to the corres¬ 
ponding inorganic acids. 
These acids are neutralized: 
First—By carbonates of the feed, water, or tissues. 
Second—By alkalies liberated by the oxidation of organic-acid salts. 
Third—By ammonia withdrawn from constructive formation or urea. 
Fourth—By ammonia from the tissues. 
Fifth—By ammonia split off from proteids, especially, for acid 
neutralization. 
The practical bearing of the subject is on feeding of such animals 
as poultry which are largely raised on cereals or their by-products. 
There is especially considered in this connection the acid mineral 
elements, sulphur, phosphorus, and chlorine, and the basic mineral 
elements, sodium, potassium, magnesium, and calcium. 
The relative amounts of mineral acids formed in the body may be 
greatly modified by a choice of feedstuffs. Alkaline ash is contained 
in fruits, vegetables, milk, oyster shell and lime stone grit, while acid 
ash is contained in meat scrap, or meat meal, eggs, cereals, and their 
by-products. 
The bases are more deficient than the acids. The basic mineral 
elements in a ration must be in quantities corresponding to the protein, 
4 Forbes, E. B., Ohio Experiment Station. Bulletin 207, p. 49. 
