Vitamin A Requirements of Growing Chicks 



A Review of Experimental Work 



A. E. Tepper and R. C. Durgin 



•yHIS report covers investigations from 1931 to 1937 inclusive. The 

 *■ work of each of these six years is discussed as an individual experi- 

 ment. The first four experiments — A, B, C and D — were conducted on a 

 group basis but in Experiments E and F, recordings were made on the 

 basis of individual chick action on birds maintained in individual cages. 



Introduction 



This report covers investigations from 1931 to 1937 inclusive. The 

 work of each of these six years is discussed as an individual experiment. 

 The first four experiments — A, B, C and D — were conducted on a group 

 basis but in Experiments E and F, recordings were made on the basis of 

 individual chick action on birds maintained in individual cages. 



The objectives, in general, of the several tests were as follows: 



1931-32 (1) To deteiTuine the eflSciency of various levels of cod liver 

 oil in the supply of an adequate amount of vitamin A to 

 growing chicks; (2) to study the effect on growth of pre- 

 viously stored up vitamin A, if any, when the ration was 

 later changed to a deficiency basis. 



1932-33 (1) and (2) as in previous year; (3) the effect of increasing 



(levels of cod liver oil for the supply of vitamin A as the 

 age of chicks increases, and (4) the relative value of the 

 New England College Conference ration from a vitamin A 

 standpoint when fortified and when lacking in cod liver oil. 



1933-34 (1) and (2) as in previous years; (3) the relative amount of 



» vitamin A in sardine oil and its ability to prevent the 



occurrence of opthalmia. 



1934-35 To determine the relative efficiency of California sardine oil 

 as compared to cod liver oil from the standpoint of vitamin A 

 supply when fed to growing chicks. 



1935-36 To determine the optimum number of vitamin A units required 

 by growing chicks up to six weeks of age. 



1936-37 Same as in 1935-36. 



Acknowledgment is here made of the work of H. 0. Stuart and F. D. 

 Reed, formerly of this station, and intimately associated with the early 

 phases of vitamin A research at this institution. 



