Sex differences in blood amino acid concentration and cell/plasma distribution in the domestic fowl.

The amino acid concentration of and distribution between the cell and plasma of the blood of male and non-laying female domestic fowl have been determined. No significant differences in plasma amino acid content were observed between the sexes, except for higher serine and lower asparagine concentrations in the female. Hens had higher intracellular concentrations of aspartate, hydroxyproline, arginine, lysine and cystine and lower concentrations of cysteic acid and taurine. The proportion of amino acids carried in the blood cells of fowls was about 80%, a value that is much higher than that found in mammals. The mean ratio of combined total amino acid concentrations between plasma and cells was about 8-fold, again much higher than the corresponding figures in mammals.