Nov., 1938] Vitamin A Requirements of Growing Chicks 11 



Since the vitamin D content would be a variable also under these con- 

 ditions all groups were subjected to irradiation by an ultra-violet ray- 

 lamp for a period of fifteen minutes daily throughout the course of the 

 experiment. 



All chicks were wingbanded and individual weights were taken each 

 week for the 400 chicks. Feed consumption and mortality figures were 

 also recorded. All dead chicks were autopsied and reports held for 

 reference. 



During the course of the experiment representative specimens from 

 each group were removed for autopsy for determination of presence or 

 absence of vitamin A deficiency. 



Sex determination of chicks in each group was made at the age of eight 

 weeks in order that we could determine influence of sex on results such 

 as weight, growth and feed consumption. 



Discussion 



In the analysis of Table IV on average weight records per chick for 

 the various groups, we find at the end of the twelve-week experimental 

 period a difference between high and low groups of only .424 pounds, less 

 than one-half pound. With such a small difference in weight between 

 groups definite conclusions are difficult as to the better level of cod liver 

 oil to feed or the number of vitamin A units required. Of the groups re- 

 ceiving various levels of cod liver oil, the 2 per cent group led in weight 

 gains at the end of the experiment. 



The control 0-12 weeks group showed definite symptoms of vitamin A 

 deficiency at the age of three weeks. Autopsy findings noted diseased 

 kidneys, grayish in color; enlarged ureters; urinary crystals present in 

 fecal material of the large intestine; and watery and swollen eyes. In 

 some cases a complete closing of the eye occurred. 



In comparison of mortality as shown in the same table we note con- 

 siderable increase as the content of cod liver oil in ration was increased. 

 The 1% cod liver oil group suffered no mortality, the 2% cod liver oil 

 group showed 2 per cent mortality, while the 3% cod liver oil group 

 had 10 per cent mortality for the twelve-week period. 



The feed consumption for all groups varied considerably by weekly 

 periods but the total consumed per chick per group as computed at the 

 end of the experiment, differed by approximately one and one-half pounds 

 between high and low groups. The 3% cod liver oil group consumed the 

 least amount of feed, 9.834 pounds per chick, and were most eflBcient, in 

 regard to feed consumed per pound of gain, 3.62 pounds. The 2% cod 

 liver oil group consumed 11.5 pounds of feed per chick and used 3.93 

 pounds of feed per pound of gain. The reserve group consumed 10.458 

 pounds of feed per chick and needed 3.81 pounds to produce a pound of 

 gain up to 12 weeks. 



The groups known as control 4-12 weeks and control 8-12 weeks, which 

 had received a ration adequate in vitamin A for the first four and eight 

 weeks respectively and then were fed a ration deficient in vitamin A, were 

 slower showing the effects than in the previous year's work. Both groups 

 made greater gains after being placed on the vitamin A deficient ration 

 than did the reserve group from which they were taken. However, the 



