4 X. H. Agr. Experiment Station [Bulletin 310 



Review of Early Literature* 



Experimental evidence available up to the time of the institution of 

 the rej^ortetl i)rojccts on the subject of vitamin A requirements of chicks 

 is at a minimum. Sc^■el•al workers have reported on phases rather closely 

 allied to certain portions of the enclosed studies. Hart, Steenbock, 

 Hali^in and Johnston'' have reported that a ration containing 72 per cent 

 yellow corn as the chief source of fat-soluble vitamin A produces satis- 

 factory growth. Hauge, Carrick and Prange" reported along similar 

 lines, stating that 50 per cent yellow corn meal in a ration otherwise de- 

 ficient in fat-soluble A meets the requirement for development of pullets 

 up to the laying age. 



In discussing the relation between the fat-soluble A vitamin and yellow 

 pigmentation, Steenbock and BoutwelP'' state that these two factors are 

 intimately associated in the maize kernel. 



Mitchell, Kendall and Card^^ state that the growing chick has quite an 

 intense ref|uirement for vitamin A and that cereal grains must be sup- 

 l)lemente(l by more concentrated vitamin sources. Their experiments 

 also showed that a dietary deficiency of vitamin A will almost invariably 

 lead to leg weakness in gro^^^ng chicks. 



Hauge, Carrick and Prange further state that chicks fed on rations 

 deficient in fat-soluble A usually reflect such a deficiency in their gi'owth 

 response at almost four weeks of age. 



Cruickshank, Hart and Halpin'' observed kidney lesions in practically 

 all of the birds that died during their experiment and tentatively con- 

 cluded that the accumulation of urates in the ureters occurs only shortly 

 before death. They further state that such kidney lesions; i. e. mottled 

 ai)i)earance and accumulation of urates in ureters, were not entirely con- 

 fined to a vitamin A deficiency. They report similar observed lesions in 

 chicks sufTering from coccidiosis. 



Experiment A, 1931-32 

 Procedure 



Nine groups of New Ham])shire chicks were fed varying levels of cod 

 liver oil standardized at a potency of at least 1,000 units per gram in ad- 

 dition to a basal ration deficient in vitamin A. Each group was sub- 

 jected to irradiation from a uviarc poultiy treater at thirty inches dis- 

 tance for a period of fifteen minutes daily to supply a sufficiency of 

 vitamin D. 



Levels of one jier cent to five jn'r cent inclusive were used in addition 

 t(j the control and reserve groups. The control group received the basal 

 ration only, which was deficient in vitamin A. but they were subjected to 

 ultra-violet treatment. Xo hard grains were fed to ;iny of the grou]is 

 throughout the 16 weeks of the exjieriment period. 



Each grouj) consisted originally of fifty day-old chicks except the re- 

 serve group which was started with one hundred chicks. This was made 

 large so that we could sejiarate at four weeks and at eight weeks two 

 sizeable groups (25 chicks each) to lie known as the 4-to-12 week control 

 and the 8-to-12 week control, respectively. These groups received for 



♦Numbers refer to biblioizraphy following text. 



