Effects of graded dietary levels of Spirulina maxima on vitamins A and E in male rats.

The effects of ingesting the alga Spirulina maxima on the storage and utilization of vitamins A and E were investigated by feeding diets containing 0, 2.7, 10.7, 18.7 and 26.7% S. maxima to male rats for 6 wk. All diets contained 18% protein, which was contributed by S. maxima or by casein or by a mixture of them. Growth results indicated that rats did not utilize the diets containing S. maxima as well as the casein control diet (0% S. maxima) when levels were 10.7% or more of the diet. The ingestion of S. maxima caused a significant increase in dry matter and chloroform-extractable crude fat in the feces. A low level of 2.7% S. maxima caused a significant reduction in plasma, liver and heart alpha-tocopherol levels. The concentrations of alpha-tocopherol in these tissues showed a marked decline with 10.7% S. maxima in the diet, followed by a lesser decline at higher levels. Liver retinoid levels of rats increased when S. maxima was added to the diet, suggesting conversion of the naturally occurring carotenoids in S. maxima to vitamin A. However, the plasma levels of retinol decreased when S. maxima was fed at 10.7% or more. These data demonstrate that S. maxima can significantly alter the storage and utilization of vitamins A and E.