Effect of Vitamin A and Vitamin A Acid on Cerebrospinal Fluid Pressure and Blood and Liver Vitamin A Concentrations in the Pig

Abstract

Thirty-six pigs, weaned at 3 weeks of age, were depleted until their blood plasma vitamin A concentrations had decreased to less than 12 µg/100 ml. They were then supplemented for 75 ± 1 days with vitamin A or vitamin A acid, or both. Blood plasma vitamin A increased with vitamin A intake but decreased and was unrelated to any level of vitamin A acid fed. Liver vitamin A increased with vitamin A and vitamin A acid intake although values for the pigs fed vitamin A acid were low. In addition, those pigs fed a combination of vitamin A and vitamin A acid had considerably higher liver vitamin A concentrations than those pigs fed vitamin A alone, indicating that vitamin A acid had a sparing effect on liver vitamin A in the pig. No vitamin A acid could be detected in the plasma or liver. A similar decrease in cerebrospinal fluid pressure occurred with an increase in vitamin A or vitamin A acid intake, suggesting that vitamin A acid was effective in meeting this physiological requirement. Cerebrospinal fluid pressure proved to be an adequate criterion in measuring the vitamin A status of the pig when fed either vitamin A or vitamin A acid.