Uptake and distribution of astaxanthin in several tissues and plasma lipoproteins in male broiler chickens fed a yeast (Phaffia rhodozyma) with a high concentration of astaxanthin.

1. The experiments were conducted to evaluate astaxanthin (Ax) uptake in several tissues and plasma lipoproteins of male broiler chickens fed on Phaffia rhodozyma containing a high concentration of Ax. 2. Male broiler chicks (5 weeks of age) fasted for 16h were given 0 or 45 mg Ax as Phaffia rhodozyma through the crop and blood was collected over the following 24 h. Ax appeared in the plasma at 2 h after administration into the crop. Most (more than 70%) of the Ax was contained in the high density lipoprotein (HDL) fraction in the plasma irrespective of blood sampling times and administration procedure of Ax. 3. Male broiler chicks (2 weeks of age) were fed on a diet containing 0, 50 or 100 mg/kg of yeast Ax for 2 weeks. Of the tissues examined, Ax concentration in the small intestine was highest, followed by subcutaneous fat, abdominal fat, spleen, liver, heart, kidney and skin. The lowest concentration was in the muscles. Ax concentration in the small intestine, subcutaneous fat, abdominal fat, liver and skin rose as dietary content increased, but this was not the case for the spleen, heart, kidney and muscles except for M. pecloralis superficialis. 4. Over 50% of Ax deposited in liver tissues was detected in the microsomal fraction and 15% was in the mitochondrial fraction. In muscles, both fractions of mitochondria and sarcoplasmic reticulum contained Ax.