FEED NUTRIENTS IN THE ANIMAL BODY 83 



only a small amount of certain of the essential amino acids, 

 larger amounts of feed must be fed in order to supply these 

 acids, or they must be added to the ration by the use of a 

 supplementary feed which contains them. 



Zein, the protein which makes up more than half the crude 

 protein of corn, is entirely lacking in three amino acids, one 

 of which is essential to life, and another of which is essential 



1^ 



Fig. 16. — The ration of these pigs was deficient in the amount and 

 quality of protein. Another pig of this lot died before this photograph was 

 taken. The " runt " died the day after this photograph was taken. 

 (Illinois Experiment Station.) 



to growth. Thus corn, when fed alone, as is often done in 

 case of hogs, does not furnish enough of these two essential 

 amino acids to satisfactorily fulfill the requirements of the 

 animal. In experiments at the Ilhnois Experiment Station,^ 

 by Emmett, Grindley, Joseph, and Williams, pigs fed 

 corn, a small amount of blood-meal, and mineral matter 

 were stunted in their growth, had weak, hght bones, lost 



1 Bui. 168. 



