The Effect of Incorporating Diphenyl-p-Phenylenediamine (DPPD) into a Ration Containing Various Levels of Vitamin A from Fish Oils

IT HAS been known for many years that vitamin A is unstable in the presence of oxidized fats (Fridericia, 1924). Experiments of Lease et al. (1938), in which vitamin A and oxidized oils were mixed after they were in the stomach of a rat, demonstrated that destruction of vitamin A could take place in the body as well as in the feed. Quackenbush et al. (1942), in reviewing the literature on the effect of tocopherol on carotene stability, concluded from this early work that tocopherol functioned in the gastro-intestinal tract by virtue of its antioxidant activities in its apparent protection of carotene. Hickman et al. (1944) extended the work on the sparing action of natural tocopherol concentrates on vitamin A and showed that natural mixed tocopherols enhanced the growth-promoting power of vitamin A alcohol, vitamin A acetate, and U.S.P. reference oil. Miles et al. (1949) found that, in the bio-assay …