20 



N. H. Agr. Experiment Station 



[Bulletin 310 



the highest daily vitamin A intake consumed the greatest amount of feed 

 with an average consumption per bird of 3.079 pounds. 



Experiment E, com- 

 parative growth chart, 

 1935-36. 



In a conversion of feed intake per bird to a gram basis and comparing 

 this to vitamin A intake, we find Group 2 consumed 108.7 U.S.P. X units 

 of vitamin A per 100 grams of feed. Group 3 consumed 375.2 units, and 

 Group 4 consumed 508 units per 100 grams of feed. 



Mortality during the experimental period was experienced only in 

 Group 1, the vitamin A deficient group. All other groups completed the 

 six-week period with 100 per cent livability. The chart illustrating 

 growth curves of the various groups shows the periods at which deaths 

 occurred in Group 1. One death occurred on the 26th day, one on the 

 31st day and two on the 35th day. 



Experiment F.— 1936-37 

 Procedure 



Twenty pullet chicks derived from the cross of Barred Rock females 

 with a New Hampshire male were used on test. Pedigree hatching of 

 eggs from parent stock was resorted to in order that we might secure four 

 female breeders having, after hatch, a group of at least five daughters. 

 These chicks were then placed in four groups so that each group contained 

 five chicks, one from each pedigreed female. By sorting chicks within 

 groups on this basis more equality was obtained and variations between 

 groups on vitamin A storage content of chicks from different parents was 

 balanced among groups. 



The source of vitamin A was a concentrate of carotene or pro-vitamin A 

 possessing 3307 U.S.P.X. units of vitamin A per gram. The vitamin A 

 content was secured substantially by a method advanced by H. R. Guil- 

 bert^, whereby the carotene content is determined by methyl alcohol ex- 

 traction and then transferred on the basis of .6 gamma carotene equal to 

 one international unit of vitamin A. An 89 per cent methyl alcohol solu- 

 tion was used in place of the 85 and 92 per cent solutions recommended 



