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



averaged 2.264 pounds. Group 4 weighed 2.093 pounds, and Group 1 av- 

 eraged but 1.1912 jiounds. At the twelfth week weighing only five chicks 

 remained in Group 1. 



It is evident from these results that although the cod liver oil fed groups 

 were slightly heavier than the sardine oil fed groups, the latter made sub- 

 stantial gains over the experimental period. 



There was no significant dift'ercnce in mortality between comparative 

 groups. It is interesting to note that both oil groups at the 1/2% level 

 had a rather high mortality of 16.6 per cent. There were no deaths 

 caused by a vitamin A deficiency in any of the oil fed groups. Appar- 

 ently the sardine oil as used in this test when fed at either 1/2% or 1% 

 level supplied sufficient vitamin A to prevent death directly attributable 

 to such deficiency. 



The group receiving the deficient ration showed a mortality of 83.3 per 

 cent. There was considerable variation between individuals in their 

 ability to withstand a deficiency in vitamin A. 



Experiment E — 1935-36 

 Procedure 



Individually^ pedigreed sex-linked pullets from Barred Rock-New 

 Hampshire crosses were maintained in 20 individual cages starting as 

 day-olds April 16, 1936, and extending over a period of six weeks. 

 Twenty chicks were divided into five groups of four chicks each. The es- 

 timated daily vitamin A unit consumption by groups was as follows: 

 Grouj) 1 Basal ration 



Group 2 Basal ration plus 33 U.S.P. X (1934) A units 

 Group 3 Basal ration plus 99 " " " " " 

 Group 4 Basal ration plus 165 " " " " " 

 Group 5 New England College Conference formula 

 The basal ration fed to the first four groups consisted of 46 pounds 

 white corn, 20 pounds ground wheat, 5 pounds wheat bran, 15 pounds 

 dried skimmilk, 10 pounds meat scraps, 1 pound sodium chloride, 2 

 pounds calcium carbonate and 1 pound irradiated yeast 400,000 U.S.P. 

 vitamin D units per pound. The vitamin A supply to groups 2, 3 and 4 

 was administered daily by means of a graduated pipette, using a com- 

 mercial pro-vitamin A carotene solution, analyzing 1,500,000 U.S.P.X 

 (1934) units per pound. Daily feed consumption and body weight 

 records were obtained as indicated. 



Discussion 

 By a study of the comparative growth rates of the five lots of chicks 

 on test, (Table X) it is noticed that there is a relatively high demand for 

 vitamin A by growing chicks during the primary stages of growth. The 

 lead in growth or weight of chicks established by the group fed 165 U.S.P. 

 X (1934) vitamin A units per day was maintained up until the fifth week. 

 At this time the rate of growth slowed to some extent and the lower vita- 

 min A fed groups rapidly made up the relatively small difference in 

 weight. Groups 2 and 3 exceeded group 4 in average weight per chick 

 by a slight margin at the end of the experimental period with group 3 

 leading at 1.102 pounds per chick. The differences, however, are so small 

 as to be of no significance. 



