_ Li^ny 
CBBSAL CROPS A DISEASES^ 
JOURNAL OF mm TO iSEOT 
Vol. XXXI Washington, D. C., August 1 , 1925 No. 3 
VITAMIN A IN BEEF, PORK, AND LAMB 1 
By Ralph Hoagland, Senior Biochemist , and George G. Snider, Chemical 
Laboratorian, Biochemic Division , Bureau of Animal Industry , United States 
Department of Agriculture 
INTRODUCTION 
Until comparatively recently the term “vitamin A” has been 
used synonymously with “ fat-soluble A” to denote that vitamin 
which is found most abundantly in cod-liver oil, egg yolk, butter 
fat, liver, and certain other products. It is now believed, however 
(#, 5, 6 , 7), 2 that fat-soluble A really consists of two vitamins. One 
of these is necessary for growth in young animals, its absence being 
indicated by nutritive failure, by the development of ophthalmia, 
and by certain other symptoms. The other is essential for the 
normal development of bones, and its absence is denoted by a dis¬ 
turbed calcium and phosphorus metabolism resulting in the onset 
of rickets. The first of these fat-soluble vitamins is now designated 
as vitamin A, while the other is commonly known as the antirachitic 
vitamin. It is with the first of these vitamins, vitamin A, that this 
paper is concerned. 
Adequate information concerning the distribution of vitamin A 
among our foodstuffs is much to be desired in order that such foods 
as will provide an abundance of. this vitamin may be selected for 
the diet. Since meat is one of our most important food products, 
it is desirable to have more information regarding its value as a 
source of vitamin A than is now available. It is important, also, 
to know the extent to which vitamin A is stored in the muscles of 
the ox, the sheep, and the hog, because of the bearing that such 
reserves have upon the vitamin A requirements of those animals. 
Although meats are generally considered to be very deficient in 
vitamin A, it appears that relatively little systematic work has been 
done on the subject. McCollum, Simmonds, and Parsons 4) found 
that rats made very poor growth when fed rations containing even 
very large proportions of dried lean beef as the source of vitamin A. 
They conclude that “ muscle tissue is very deficient in these vitamins 
but does not entirely lack any one of them.” 
Wright ( 8 ) determined the vitamin A content of pork that had 
been held in cold storage for nine years, the feeding tests being carried 
on with young chickens. The amount of pork fed to each group of 
chickens is not stated, but the birds that were fed the rations con¬ 
taining pork as the source of vitamin A made practically as good 
growth as those fed a normal ration. 
The purpose of this investigation was to determine the vitamin A 
content of beef, pork, and lamb as measured by the growth induced 
in young albino rats when fed a ration adequate in other respects 
but containing dried lean meat as the sole source of vitamin A. 
1 Received for publication August 28, 1924; issued September, 1925. The authors extend their thanks 
to Oliver P. Clipper, assistant laboratorian, for assistance rendered in conducting the feeding tests. 
2 Reference is made by number (italic) to “Literature cited,” p. 221. 
Journal of Agricultural Research, 
Washington, D. C. 
60304—25t-1 ( 201 ) 
Vol. XXXI, No. 3 
Aug. 1,1925 
Key No. A-82 
C r HtAL INVESTIGATIONS. 
