Studies on the utilization of vitamin E alcohol and esters by the chick

Experiments were conducted to evaluate the utilization of d1-alpha-tocopherol, d1-alpha-tocopheryl acetate and a water-soluble ester, d-alpha-tocopheryl polyethylene glycol 1000 (TPGS), as dietary sources of vitamin E for the chick. Results showed that tocopheryl acetate is utilized with efficiency equal to that of vitamin E alcohol at dietary concentrations less than or equal to approximately 40 ml d1-alpha-tocopherol equivalents per kg. At greater dietary concentrations of the vitamin, the alcohol form appeared to be better utilized than the acetate when it was adequately stabilized in the diet. However, TPGS was poorly utilized at all dietary levels examined. Saponification of both esters improved the utilization of vitamin E from these sources. The utilization of all forms of vitamin E was depressed in hypervitaminotic A chicks and, to a lesser extent, in chicks fed ethoxyquin.