Post-feeding changes in distribution of free amino acids and ammonia in plasma and erythrocytes of carp.

Abstract

Distributions of free amino acids and ammonia in plasma and erythrocytes of carp Cyprinus carpio after feeding of a casein-gelatin diet were examined to clarify physiological role of the erythrocytes in inter-organ transport of amino acids. Postprandial changes in contents of arginine, lysine, and methionine in the plasma were highly correlated to those in the whole blood, while those in the erythrocytes were not. Even when these contents in the erythrocytes reached to the maximum values, these were still less than 10% of the whole blood. Highly significant correlations were detected between levels in the whole blood and plasma or erythrocytes on the following amino acids: isoleucine, leucine, tyrosine, phenylalanine, tryptophan, and histidine. At the peak levels, contents of tyrosine, phenylalanine, and tryptophan in the erythrocytes represented approximately 40% of the respective values in the whole blood. Change of ammonia content in the whole blood was more highly correlated to that in the erythrocytes than that in the plasma. The erythrocyte ammonia content expressed as a percentage of the whole blood content rose from 45 to 85%. in accordance with the increment in the whole blood ammonia content. These results indicate presence of three types of inter-organ transport of free amino acids in carp.