Vitamin A Storage in the Livers of Turkeys and Chickens

Abstract
A study of the Carr-Price reaction as a means for estimating liver storage of vitamin A in turkeys and chickens is reported. A direct correlation was found between the liver storage (as expressed by the color test with antimony trichloride) and the level of vitamin A in the ration, the growth and mortality records, and the survival period of penmates when placed on the vitamin A deficient basal ration. White Leghorn chickens were found to have greater storage of vitamin A than Bronze turkeys comparable as regards maturity and feeding history. Large variations in liver storage were found among individuals from pens receiving the same feeds. It is suggested then, when selection is possible, individual variation in food habits may partly account for the variation in storage. Attention is called to similar variations in storage found in biological tests. Turkeys receiving 8 per cent dehydrated alfalfa leaf meal showed a much lower liver storage of vitamin A than did turkeys having access to green feed in addition to vitamin A carrying feeds in their mash. Though the 8 per cent level of leaf meal sufficed for normal growth, the reserves were inadequate for protection against long periods of low vitamin A intake such as may occur on certain turkey ranges. Data are presented on the correlation between vitamin A storage and age. Like other species, young growing turkeys had relatively little storage even on rations abundantly supplied with the vitamin. On such rations liver storage increased rapidly as percentage rate of growth decreased. The blue value of liver samples taken at the time of the first clinical evidence of deficiency varied from a trace to 2 units per gram of liver. Birds in this condition survived from 20 to 30 days. Numerous tests on liver extracts from birds that died of avitaminosis-A or were killed in cachexia gave no blue color with antimony trichloride. Though the intensity of the blue color reaction using the technic described by Guilbert and Hart ('34) has limitations from the standpoint of a precise quantitative method, the simplicity of the procedure and equipment renders it adaptable to general use. As shown by the data here presented, it may be a valuable aid to diagnosis and may also add materially to the information obtained by experiments on vitamin A requirements of fowls.